Organization, Consolidation and Presentation of Financial Statements [Abstract] Deferred Expenses and Other Assets, Net and Accounts Payable, Accrued Expenses and Other Liabilities Supplemental Balance Sheet Disclosures [Text Block] Business and Organization Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Debt Disclosure [Abstract] Debt Obligations, net Debt Disclosure [Text Block] Statement of Cash Flows [Abstract] Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Adjustments to reconcile net income to cash flows from operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction Stock-based compensation expense Share-based Payment Arrangement, Noncash Expense Deferred operating lease income Straight Line Rent Non-cash interest income from sales-type leases Non-cash Interest Income on Leases and Leases Receivable During Period Non-cash Interest Income on Leases and Leases Receivable During Period Amortization of real estate-related intangibles, net Amortization of above and below Market Leases Loss on early extinguishment of debt Gain (Loss) on Extinguishment of Debt Losses (earnings) from equity method investments Income (Loss) from Equity Method Investments Amortization of premium, discount and deferred financing costs on debt obligations, net Amortization of Debt Issuance Costs and Discounts Non-cash management fees Management Fee Expense Other operating activities Other Operating Activities, Cash Flow Statement Changes in assets and liabilities: Increase (Decrease) in Other Operating Assets and Liabilities, Net [Abstract] Changes in deferred expenses and other assets, net Increase (Decrease) in Prepaid Expense and Other Assets Changes in accounts payable, accrued expenses and other liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Cash flows (used in) provided by operating activities Net Cash Provided by (Used in) Operating Activities Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Acquisitions of real estate Payments to Acquire Real Estate Origination/acquisition of net investment in sales-type leases and ground lease receivables Payments to Originate/Acquire Sales-Type Lease Payments to Originate/Acquire Sales-Type Leases Fundings on ground lease receivables Proceeds (Fundings) on Ground Lease receivables Proceeds (Fundings) on Ground Lease receivables Contributions to equity investments in ground leases Payments to Acquire Equity Method Investments Other investing activities Payments for (Proceeds from) Other Investing Activities Cash flows used in investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Proceeds from issuance of common stock Proceeds from Issuance of Common Stock Proceeds from debt obligations Proceeds from Issuance of Long-term Debt Repayments of debt obligations Repayments of Secured Debt Payments for debt prepayment or extinguishment costs Payment for Debt Extinguishment or Debt Prepayment Cost Payments for deferred financing costs Payments of Financing Costs Payment of offering costs Payments of Offering Costs Payments of Offering Costs Dividends paid to common shareholders Payments of Dividends Distributions to noncontrolling interests Payments to Noncontrolling Interests Contributions from noncontrolling interests Proceeds from Noncontrolling Interests Other financing activities Proceeds from (Payments for) Other Financing Activities Cash flows provided by financing activities Net Cash Provided by (Used in) Financing Activities Changes in cash, cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect Cash, cash equivalents and restricted cash at beginning of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash, cash equivalents and restricted cash at end of period Supplemental disclosure of cash flow information: Supplemental Cash Flow Information [Abstract] Cash paid for interest Interest Paid, Excluding Capitalized Interest, Operating Activities Supplemental disclosure of non-cash investing and financing activity: Noncash Investing and Financing Items [Abstract] Origination of sales-type lease Sales-type Lease, Origination And Acquisition Of Leases During Period, Non Cash Activity Sales-type Lease, Origination And Acquisition Of Leases During Period, Non Cash Activity Origination of sales-type lease Noncash or Part Noncash Acquisition, Debt Assumed Investor Unit conversion (refer to Note 11) Stock Issued During Period, Value, Conversion of Convertible Securities Contribution from iStar Inc. Non-cash Contributed Capital From Related Party Non-cash Contributed Capital From Related Party Dividends declared to common shareholders Dividends, Cash Accrued offering costs Non-Cash Accrued Offering Costs Non-Cash Accrued Offering Costs Accrued finance costs Non-Cash Accrued Financing Costs Non-Cash Accrued Financing Costs Leases [Abstract] Lessee, Lease, Description [Table] Lessee, Lease, Description [Table] Lease Maturity, by Arrangement Type [Axis] Lease Maturity, by Arrangement Type [Axis] Lease Maturity, by Arrangement Type [Axis] Lease Maturity, by Arrangement Type [Domain] Lease Maturity, by Arrangement Type [Domain] [Domain] for Lease Maturity, by Arrangement Type [Axis] Fixed Bumps with Inflation Adjustments Fixed Bumps with Inflation Adjustments [Member] Fixed Bumps with Inflation Adjustments [Member] Fixed Bumps with Percentage Rent Fixed Bumps with Percentage Rent [Member] Fixed Bumps with Percentage Rent [Member] Lessee, Lease, Description [Line Items] Lessee, Lease, Description [Line Items] 2020 Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received, Next Twelve Months 2021 Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received, Two Years 2022 Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received, Three Years 2023 Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received, Four Years 2024 Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received, Five Years Thereafter Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received, Thereafter Total undiscounted cash flows Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received Unguaranteed estimated residual value Sales-type Lease, Unguaranteed Residual Asset Present value discount Present value discount on sales-type leases Present value discount on sales-type leases Net investment in sales-type leases as of December 31, 2019 Sales-type Lease, Net Investment in Lease Operating lease, right-of-use asset Operating Lease, Right-of-Use Asset Gross Asset Derivative Asset, Fair Value, Gross Asset Other assets Other Deferred Costs, Net Deferred finance costs, net Debt Issuance Costs, Line of Credit Arrangements, Net Purchase deposits Deposit Assets Leasing costs, net Deferred Costs, Leasing, Net Deferred expenses and other assets, net Deferred Costs and Other Assets Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Accounting Standards Update 2016-02 Accounting Standards Update 2016-02 [Member] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Real estate expense Real Estate Expense [Member] Real Estate Expense [Member] Other Income Other Income [Member] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Below-market lease Below Market Leases [Member] Below Market Leases [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Annual lease fee Annual Lease Fee Annual Lease Fee Operating lease expense Operating Lease, Expense Discount rate Lessee, Operating Lease, Discount Rate Below market lease acquired Below Market Lease, Acquired Debt issuance costs, current Accumulated Amortization, Debt Issuance Costs, Current Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Secured Debt Secured Debt [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] 2020 Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months 2021 Long-term Debt, Maturities, Repayments of Principal in Year Two 2022 Long-term Debt, Maturities, Repayments of Principal in Year Three 2023 Long-term Debt, Maturities, Repayments of Principal in Year Four 2024 Long-term Debt, Maturities, Repayments of Principal in Year Five Thereafter Long-term Debt, Maturities, Repayments of Principal after Year Five Total principal maturities Long-term Debt, Gross Debt premium, discount and deferred financing costs, net Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net Total debt obligations, net Long-term Debt Long-term debt, weighted average maturity Long-term Debt, Weighted Average Maturity Long-term Debt, Weighted Average Maturity Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock Common Stock [Member] Additional Paid-In Capital Additional Paid-in Capital [Member] Retained Earnings / Accumulated (Deficit) Retained Earnings [Member] Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Noncontrolling Interests Noncontrolling Interest [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Balance at the beginning of the period Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Contributions from iStar Inc. Contributions (Distributions) from Parent Contributions (Distributions) from Parent Offering costs Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs Issuance of common stock, net / amortization Issuance of Stock and Restricted Stock Unit Amortization Net Value of stock related to restricted stocks awards issued during the period and the amortization of restricted stock units and other restricted stock activity. Issuance of common stock to iStar Inc. (refer to Note 11) Stock Issued During Period, Value, New Issues Issuance of common stock to directors/amortization APIC, Share-based Payment Arrangement, Increase for Cost Recognition Dividends declared Dividends Dividends declared, per share (usd per share) Common Stock, Dividends, Per Share, Declared Cumulative-effect adjustment for cash flow hedges Cumulative Effect of New Accounting Principle in Period of Adoption Change in accumulated other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest Contributions from noncontrolling interests Noncontrolling Interest, Increase from Subsidiary Equity Issuance Distributions to noncontrolling interests Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Balance at the end of the period Earnings Per Share [Abstract] Net income attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest Net income attributable to Safehold Inc. common shareholders for basic earnings per share Net Income (Loss) Available to Common Stockholders, Basic Real Estate [Abstract] Schedule of Real Estate Assets Schedule of Real Estate Properties [Table Text Block] Schedule of Real Estate-Related Intangible Assets, Net Schedule of Finite-Lived Intangible Assets [Table Text Block] Schedule or Amortization of Real Estate Properties Schedule of Amorization of Real Estate-Related Intangible Assets Table Text Block] [Text Block] Schedule of Amortization of Real Estate-Related Intangible Assets [Text Block] Schedule of Future Amortization Expense Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Real Estate - Related Intangibles, Liabilities Schedule of Intangible Assets and Goodwill [Table Text Block] Purchase Price Allocations Schedule of Amortiztion of Real Estate-Related Intangible Liabilities [Text Block] Schedule of Amortiztion of Real Estate-Related Intangible Liabilities [Text Block] Future Minimum Ground Net Lease Payments Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Basis of Presentation and Principles of Consolidation and Combination Related Party Transactions [Abstract] Schedule of Related Party Transactions Schedule of Related Party Transactions [Table Text Block] Risks and Uncertainties [Abstract] Derivative Instruments and Hedging Activities Disclosures [Table] Derivative Instruments and Hedging Activities Disclosures [Table] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Designated as Hedging Instrument Designated as Hedging Instrument [Member] Not Designated as Hedging Instrument Not Designated as Hedging Instrument [Member] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Interest rate swap Interest Rate Swap [Member] Interest rate cap Interest Rate Cap [Member] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income Reclassification out of Accumulated Other Comprehensive Income [Member] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Deferred expenses and other assets, net Deferred Expenses and Other Assets, Net [Member] Deferred Expenses and Other Assets, Net [Member] Accounts payable, accrued expenses and other liabilities Accounts Payable, Accrued Expenses, and Other Liabilities [Member] Accounts Payable, Accrued Expenses, and Other Liabilities [Member] Derivative Instruments and Hedging Activities Disclosures [Line Items] Derivative Instruments and Hedging Activities Disclosures [Line Items] Gross Liability Derivative Liability, Fair Value, Gross Liability Unrealized losses on derivatives Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax Cash flow hedge gain (loss) to be reclassified within twelve months Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation Disclosure [Abstract] SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation [Roll Forward] SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation [Roll Forward] Beginning balance SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation Additions SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation, Depreciation Expense Ending balance Accounting Policies [Abstract] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Principles of Combination and Consolidation Consolidation, Policy [Policy Text Block] Real estate Property, Plant and Equipment, Policy [Policy Text Block] Purchase price allocation Business Combinations Policy [Policy Text Block] Impairments Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block] Net Investment in Sales-type Leases and Ground Lease Receivables Policy for Sales-type Leases and Ground Leases [Policy Text Block] Policy for Sales-type Leases and Ground Leases [Policy Text Block] Reserve for losses in net investment in sales-type leases and Ground Lease receivables Reserve For Losses in Net Investment In Sales-type Leases and Ground Leases Receivables [Policy Text Block] Reserve For Losses in Net Investment In Sales-type Leases and Ground Leases Receivables [Policy Text Block] Interest Income from Sales-type Leases Interest Income from Sales-type Leases Policy [Policy Text Block] Interest Income from Sales-type Leases Policy [Policy Text Block] Equity Investments In Ground Leases Equity Investments In Ground Leases [Policy Text Block] Equity Investments In Ground Leases [Policy Text Block] Cash and cash equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Restricted cash Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Operating lease income Revenue [Policy Text Block] Other Income Other Income Policy [Policy Text Block] Other Income Policy [Policy Text Block] Earnings per share Earnings Per Share, Policy [Policy Text Block] Deferred expense and other assets Deferred Charges, Policy [Policy Text Block] Deferred financing fees Deferred Financing Fees Policy [Policy Text Block] Deferred Financing Fees Policy [Policy Text Block] Stock-based compensation Share-based Payment Arrangement [Policy Text Block] Income taxes Income Tax, Policy [Policy Text Block] Derivative instruments and hedging activity Derivatives, Policy [Policy Text Block] Variable interest entities Consolidation, Variable Interest Entity, Policy [Policy Text Block] Fair values Fair Value Measurement, Policy [Policy Text Block] New accounting pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Lessor, Lease, Description [Table] Lessor, Lease, Description [Table] Net Investment in Sales-type Leases Net Investment in Sales-type Leases [Member] Net Investment in Sales-type Leases [Member] Ground Lease Receivables Ground Lease Receivables, Net [Member] Ground Lease Receivables, Net [Member] Investment Type [Axis] Investment Type [Axis] Investments [Domain] Investments [Domain] Cash Cash [Member] Non-cash Non-cash [Member] Non-cash [Member] Lessor, Lease, Description [Line Items] Lessor, Lease, Description [Line Items] Interest income from sales-type leases Sales-type Lease, Interest Income Schedule of Cash and Cash Equivalents Schedule of Cash and Cash Equivalents [Table Text Block] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Restricted cash Restricted Cash Total cash, cash equivalents and restricted cash reported in the consolidated statement of cash flows Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Ownership [Axis] Ownership [Axis] Ownership [Domain] Ownership [Domain] Safehold Operating Partnership LP Safehold Operating Partnership LP [Member] Safehold Operating Partnership LP [Member] Statistical Measurement [Axis] Statistical Measurement [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Sale of Stock [Axis] Sale of Stock [Axis] Sale of Stock [Domain] Sale of Stock [Domain] IPO and Private Placement IPO and Private Placement [Member] IPO and Private Placement [Member] Partner Type [Axis] Partner Type [Axis] Partner Type of Partners' Capital Account, Name [Domain] Partner Type of Partners' Capital Account, Name [Domain] Limited Partner Limited Partner [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Number of Reportable Segments Number of Reportable Segments Ground leases term Ground Leases, Term Ground Leases, Term Ground lease investment initial targeted value of ground lease of combined value Ground Lease Investments, Initial Target Value of Ground Leases Regardless of Improvements, Percent Ground Lease Investments, Initial Target Value of Ground Leases Regardless of Improvements, Percent Ground lease, ratio of property net operating income to ground lease payments due Ground Lease, Ratio of Property Net Operating Income to Ground Lease Payment Due Ground Lease, Ratio of Property Net Operating Income to Ground Lease Payment Due Number of institutional investors Number Of Institutional Investors Number of Institutional Investors Proceeds from initial public offering Proceeds from Issuance Initial Public Offering Proceeds from private placement offering Proceeds from Issuance of Private Placement Investor units, price per unit (in dollars per share) Shares Issued, Price Per Share Ownership interest by shareholders' (percent) Limited Liability Company or Limited Partnership, Members or Limited Partners, Ownership Interest General partner interests ownership interest Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest Statement of Financial Position [Abstract] Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized (in shares) Common Stock, Shares Authorized Common stock, shares issued (in shares) Common Stock, Shares, Issued Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding Net Investment in Sales-type Leases Sales-type Lease, Net Investment in Lease, Allowance for Credit Loss [Roll Forward] Net Investment in Sales-type Leases, Beginning Balance Net Investment in Sales-type Leases, Origination/acquisition Sales-type Lease, Net Investment in Lease, Purchase Net Investment in Sales-type Leases, Accretion (amortization) Sales-type Lease, Net Investment in Lease, Non-Cash Interest Income Sales-type Lease, Net Investment in Lease, Non-Cash Interest Income Net Investment in Sales-type Leases, Ending Balance Ground Lease Receivables Ground Lease Receivables [Roll Forward] Ground Lease Receivables [Roll Forward] Ground Lease Receivables, Beginning balance Ground Lease Receivable Ground Lease Receivable Ground Lease Receivables, Origination/acquisition Ground Lease, Acquisition Ground Lease, Acquisition Ground Lease Receivables, Accretion (amortization) Ground Lease, Non-Cash Interest Income Ground Lease, Non-Cash Interest Income Ground Lease Receivables, Ending balance Total Net Investment in Leases [Roll Forward] Net Investment in Leases [Roll Forward] Beginning balance Sales-type and Direct Financing Leases, Lease Receivable Origination/acquisition Origination And Acquisition Of Lease and Lease Receivables During Period Origination And Acquisition Of Lease and Lease Receivables During Period Non-cash Accretion (Amortization) of Interest Income on Leases and Leases Receivable During Period Non-cash Accretion (Amortization) of Interest Income on Leases and Leases Receivable During Period Non-cash Accretion (Amortization) of Interest Income on Leases and Leases Receivable During Period Ending balance Weighted average accrual rate for net investment in sales-type leases Lease Receivable, Weighted Average Accrual Rate, Net Investment in Sales-type Lease Lease Receivable, Weighted Average Accrual Rate, Net Investment in Sales-type Lease Weighted average accrual rate for net investment in ground lease receivables Lease Receivable, Weighted Average Accrual Rate, Net Investment in Ground Lease Lease Receivable, Weighted Average Accrual Rate, Net Investment in Ground Lease Ground lease receivables Number of Ground Lease receivables Number of Ground Lease receivables Ground leases term Ground Lease receivables, Term Ground Lease receivables, Term Derivative Financial Instruments Designated in Hedging Relationships Schedule of Interest Rate Derivatives [Table Text Block] Derivative Instruments, Gain (Loss) Derivative Instruments, Gain (Loss) [Table Text Block] Equity [Abstract] Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] iStar Inc. iStar Inc. [Member] iStar Inc. [Member] General and Administrative Expense General and Administrative Expense [Member] Title of Individual [Axis] Title of Individual [Axis] Title of Individual [Domain] Title of Individual [Domain] Manager Manager [Member] Manager [Member] Stock Conversion Description [Axis] Stock Conversion Description [Axis] Conversion of Stock, Name [Domain] Conversion of Stock, Name [Domain] Stock Price Hurdle One Stock Price Hurdle One [Member] Stock Price Hurdle One [Member] Stock Price Hurdle Two Stock Price Hurdle Two [Member] Stock Price Hurdle Two [Member] Stock Price Hurdle Three Stock Price Hurdle Three [Member] Stock Price Hurdle Three [Member] Stock Price Hurdle Four Stock Price Hurdle Four [Member] Stock Price Hurdle Four [Member] Stock Price Hurdle Five Stock Price Hurdle Five [Member] Stock Price Hurdle Five [Member] Award Type [Axis] Award Type [Axis] Award Type [Domain] Award Type [Domain] Performance Shares Performance Shares [Member] Restricted Stock Units (RSUs) Restricted Stock Units (RSUs) [Member] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] Equity Plan Equity Plan [Member] Equity Plan [Member] 2017 Equity Incentive Plan 2017 Equity Incentive Plan [Member] 2017 Equity Incentive Plan [Member] SAFE SAFE [Member] SAFE [Member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Counterparty Name [Axis] Counterparty Name [Axis] Counterparty Name [Domain] Counterparty Name [Domain] Initial Capitalization Initial Capitalization [Member] Initial Capitalization [Member] IPO Director Compensation Director Compensation [Member] Director Compensation [Member] Public Offering Public Offering [Member] Public Offering [Member] Private Placement Private Placement [Member] Class of Stock [Line Items] Class of Stock [Line Items] Stock issued (in shares) Stock Issued During Period, Shares, New Issues Investor Unit conversion Proceeds from stock transaction Proceeds from Issuance or Sale of Equity Investor unit conversion Proceeds from Issuance of Common Limited Partners Units Number of shares issued in transaction Sale of Stock, Number of Shares Issued in Transaction Payment of financing and stock issuance costs Payment of Financing and Stock Issuance Costs Common stock purchase plan, shares, purchased in period Common Stock Purchase Plan, Shares, Purchased in Period Common Stock Purchase Plan, Shares, Purchased in Period Common stock purchase plan, amount purchased in period Common Stock Purchase Plan, Amount Purchased in Period Common Stock Purchase Plan, Amount Purchased in Period Common Stock purchase plan, average share price (in dollars per share) Common Stock Purchase Plan, Average Share Price Common Stock Purchase Plan, Average Share Price Common stock voting rights, investor units voting power threshold Common Stock, Voting Rights, Investor Units Voting Power Threshold Common Stock, Voting Rights, Investor Units Voting Power Threshold Number of shares purchased (in shares) Purchase of Common Stock, Number of Shares Purchase of Common Stock, Number of Shares Common stock, amount purchased Common Stock, Amount Purchased Common Stock, Amount Purchased Purchase of stock, average price per share (in dollars per share) Purchase of Stock, Average Price Per Share Purchase of Stock, Average Price Per Share Percentage of ownership before transaction Ownership Percentage by Shareholders Ownership Percentage by Shareholders Share price (in dollars per share) Share Price Ownership percentage after transaction Sale of Stock, Percentage of Ownership after Transaction Capital appreciation aggregate distribution, percent Share-based Compensation Arrangement by Share-based Payment Award, Capital Appreciation Aggregate Distribution, Percent Share-based Compensation Arrangement by Share-based Payment Award, Capital Appreciation Aggregate Distribution, Percent Awards subject to forfeiture based on continuing service conditions, percent Share-based Compensation Arrangement by Share-based Payment Award, Awards Subject to Forfeiture Based on Continuing Service Conditions, Percent Share-based Compensation Arrangement by Share-based Payment Award, Awards Subject to Forfeiture Based on Continuing Service Conditions, Percent Aggregate compensation cost Share-based Payment Arrangement, Expensed and Capitalized, Amount Awards with aggregate intrinsic value Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value Amortization period Share-based Compensation Arrangement by Share-based Payment Award, Amortization Period Share-based Compensation Arrangement by Share-based Payment Award, Amortization Period Cost not yet recognized, amount Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount Capital shares reserved for future issuance (in shares) Common Stock, Capital Shares Reserved for Future Issuance Share-based payment arrangement, expense Share-based Payment Arrangement, Expense Percentage of taxable income including capital gains to be distributed to qualify as REIT Percentage of Taxable Income Including Capital Gains to be Distributed to Qualify as REIT Represents the percentage of taxable income (including capital gains) to be distributed in order to qualify as REIT. Minimum percentage of taxable income excluding capital gains to be distributed to qualify as REIT Minimum Percentage of Taxable Income Excluding Capital Gains to be Distributed to Qualify as REIT Represents the minimum percentage of taxable income (excluding capital gains) to be distributed in order to qualify as REIT. Cash dividends declared Distribution payable to noncontrolling interest Distribution Payable to Noncontrolling Interest Distribution Payable to Noncontrolling Interest Distribution payable to noncontrolling interest, per investor unit Distribution Payable to Noncontrolling Interest, Per Investor Unit Distribution Payable to Noncontrolling Interest, Per Investor Unit Dividends, ordinary income amount (in dollars per share) Common Stock, Dividends, Per Share, Ordinary Income Amount Common Stock, Dividends, Per Share, Ordinary Income Amount Dividends, return of capital for tax reporting (in dollars per share) Common Stock, Dividends, Per Share, Return of Capital for Tax Reporting Common Stock, Dividends, Per Share, Return of Capital for Tax Reporting Stock issued during period, shares, issued for services Stock Issued During Period, Shares, Issued for Services Stock issued during period, value, issued for services Stock Issued During Period, Value, Issued for Services Related Party Transactions Related Party Transactions Disclosure [Text Block] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Investments, All Other Investments [Abstract] Equity Investments in Ground Leases Equity Method Investments and Joint Ventures Disclosure [Text Block] 2020 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months 2021 Finite-Lived Intangible Assets, Amortization Expense, Rolling Year Two 2022 Finite-Lived Intangible Assets, Amortization Expense, Rolling Year Three 2023 Finite-Lived Intangible Assets, Amortization Expense, Rolling Year Four 2024 Finite-Lived Intangible Assets, Amortization Expense, Rolling Year Five Useful life Finite-Lived Intangible Asset, Useful Life Net Investment In Sales-type Leases and Ground Lease Receivables Lessor, Sales-type Leases [Text Block] SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, by Property [Table] SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, by Property [Table] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] Detroit, MI Detroit, MI [Member] Detroit, MI [Member] Dallas, TX Dallas, Texas LTX001 [Member] Dallas, Texas LTX001 [Member] Dallas, Texas Dallas, Texas LTX002 [Member] Dallas, Texas LTX002 [Member] Atlanta, GA Atlanta, GA [Member] Atlanta, GA [Member] DISTRICT OF COLUMBIA 2 DISTRICT OF COLUMBIA 2 [Member] DISTRICT OF COLUMBIA 2 [Member] Milwaukee, WI Milwaukee, WI [Member] Milwaukee, WI [Member] Washington, DC DISTRICT OF COLUMBIA Minneapolis, MN Minneapolis, MN [Member] Minneapolis, MN [Member] Durango, CO Durango, CO [Member] Durango, CO [Member] Rohnert Park, CA Rohnert Park, CA [Member] Rohnert Park, CA [Member] Salt Lake City, UT Salt Lake City, UT [Member] Salt Lake City, UT [Member] San Diego, CA San Diego, CA [Member] San Diego, CA [Member] DISTRICT OF COLUMBIA 3 DISTRICT OF COLUMBIA 3 [Member] DISTRICT OF COLUMBIA 3 [Member] Seattle, WA Seattle, WA [Member] Seattle, WA [Member] Los Angeles, CA Los Angeles, CA 1 [Member] Los Angeles, CA 1 [Member] Los Angeles, CA 2 Los Angeles, CA 2 [Member] Los Angeles, CA 2 [Member] Atlanta, GA 2 Atlanta, GA 2 [Member] Atlanta, GA 2 [Member] Orlando, FL Orlando, FL [Member] Orlando, FL [Member] Atlanta, GA 3 Atlanta, GA 3 [Member] Atlanta, GA 3 [Member] Raleigh-Durham, NC Raleigh-Durham, NC [Member] Raleigh-Durham, NC [Member] Atlanta, GA 4 Atlanta, GA 4 [Member] Atlanta, GA 4 [Member] San Diego, CA 2 San Diego, CA 2 [Member] San Diego, CA 2 [Member] Phoenix, AZ Phoenix, AZ [Member] Phoenix, AZ [Member] DISTRICT OF COLUMBIA 4 DISTRICT OF COLUMBIA 4 [Member] DISTRICT OF COLUMBIA 4 [Member] Miami, FL Miami, FL [Member] Miami, FL [Member] Miami, FL 2 Miami, FL 2 [Member] Miami, FL 2 [Member] DISTRICT OF COLUMBIA 5 DISTRICT OF COLUMBIA 5 [Member] DISTRICT OF COLUMBIA 5 [Member] Nashville, TN Nashville, TN [Member] Nashville, TN [Member] Portland, OR Portland, OR [Member] Portland, OR [Member] San Antonio, TX San Antonio, TX [Member] San Antonio, TX [Member] Riverside, CA Riverside, CA [Member] Riverside, CA [Member] Minimum Maximum SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items] SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items] Encumbrances SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Amount of Encumbrances Initial Cost to Company, Land SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost of Land Initial Cost to Company, Building and Improvements SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Initial Cost of Building and Improvements Cost Capitalized Subsequent to Acquisition SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Cost Capitalized Subsequent to Acquisition, Improvements Gross Amount Carried at Close of Period, Land SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Land, Amount Gross Amount Carried at Close of Period, Building and Improvements SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Building and Improvements, Amount Gross Amount Carried at Close of Period, Total SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Gross Accumulated Depreciation Aggregate cost for federal income tax purposes Aggregate Cost for Federal Income Tax Purposes Aggregate Cost for Federal Income Tax Purposes Depreciable Life (Years) SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Life Used for Depreciation Income Statement [Abstract] Revenues: Revenues [Abstract] Operating lease income Operating Lease, Lease Income Other income Other Income Total revenues Revenues Costs and expenses: Costs and Expenses [Abstract] Interest expense Interest Expense Real estate expense Cost of Goods and Services Sold Depreciation and amortization General and administrative General and Administrative Expense Other expense Other Expenses Total costs and expenses Costs and Expenses Income from operations before other items Income (Loss) before Gain (Loss) on Sale of Properties Loss on early extinguishment of debt Earnings (losses) from equity method investments Net income Net income attributable to Safehold Inc. common shareholders Net Income (Loss) Attributable to Parent Net income (loss) Basic and diluted (in dollars per share) Earnings Per Share, Basic and Diluted Weighted average number of common shares: Basic and diluted (in shares) Weighted Average Number of Shares Outstanding, Basic and Diluted Risk Management and Derivatives Concentration Risk and Derivative Instruments Disclosure [Text Block] Concentration Risk and Derivative Instruments Disclosure [Text Block] Investment [Table] Investment [Table] Joint Venture Corporate Joint Venture [Member] Investment [Line Items] Investment [Line Items] Ownership percentage Equity Method Investment, Ownership Percentage (Earnings) losses from equity method investments Equity investments in Ground Leases Equity Method Investments Interest rate hedge liabilities Derivative Liability Accrued expenses Accrued Liabilities Dividends declared and payable Dividends Payable Operating lease liability Operating Lease, Liability Other liabilities Other Liabilities Interest payable Interest Payable Management fee payable Management Fee Payable Accounts payable, accrued expenses and other liabilities Accounts Payable and Accrued Liabilities Payable to the Manager for costs it paid on the Company's behalf Due to Other Related Parties SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate [Roll Forward] SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate [Roll Forward] Beginning balance Acquisitions SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Other Acquisition Ending balance Quarterly Financial Information Disclosure [Abstract] Schedule of quarterly financial information Quarterly Financial Information [Table Text Block] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Facilities Building [Member] Facilities useful life Property, Plant and Equipment, Useful Life Percentage rent from operating leases, amount Operating Leases, Income Statement, Percentage Revenue Income taxes paid Income Taxes Paid Fair value of debt Debt Instrument, Fair Value Disclosure Lender Name [Axis] Lender Name [Axis] Line of Credit Facility, Lender [Domain] Line of Credit Facility, Lender [Domain] Sarasota Florida Sarasota Florida [Member] Sarasota Florida [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] 3333 LifeHope Ground Lease Construction Loan 3333 LifeHope Ground Lease Construction Loan [Member] 3333 LifeHope Ground Lease Construction Loan [Member] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Class-A Office Building, Austin, Texas Class-A Office Building, Austin, Texas [Member] Class-A Office Building, Austin, Texas [Member] 3333 LifeHope in Alpharetta, Georgia 3333 LifeHope in Alpharetta, Georgia [Member] 3333 LifeHope in Alpharetta, Georgia [Member] 570 Washington Boulevard, Jersey City, NJ 570 Washington Boulevard, Jersey City, NJ [Member] 570 Washington Boulevard, Jersey City, NJ [Member] Commitment II Commitment II [Member] Commitment II [Member] Number of years as active real estate investor (over) Number of Years as Active Real Estate Investor Number of Years as Active Real Estate Investor Real estate investments, aggregate transactions, value Real Estate Investments, Aggregate Transactions, Value Real Estate Investments, Aggregate Transactions, Value Assets Assets Entity number of employees Entity Number of Employees Management fee paid with common stock, period of restriction from selling stock Related Party Transaction, Management Fee, Stock Compensation Maturity Related Party Transaction, Management Fee, Stock Compensation Maturity Management fee expense Related Party Transaction, Fee Wavier Related Party Transaction, Fee Wavier Management fee, transaction share price (in dollars per share) Related Party Transaction, Transaction Price, Share Price Related Party Transaction, Transaction Price, Share Price Expenses from transactions with related party Related Party Transaction, Expenses from Transactions with Related Party Management fee, percent, threshold Related Party Transaction, Management Fee, Percent, Threshold 1 Related Party Transaction, Management Fee, Percent, Threshold 1 Management fee, Shareholders' equity threshold amount Related Party Transaction, Management Fee, Shareholders' Equity Threshold Amount1 Related Party Transaction, Management Fee, Shareholders' Equity Threshold Amount1 Management fee, percent, threshold two Related Party Transaction, Management Fee, Percent, Threshold 2 Related Party Transaction, Management Fee, Percent, Threshold 2 Management fee, shareholders' equity, incremental threshold amount two Related Party Transaction, Management Fee, Shareholders' Equity, Incremental Threshold Amount2 Related Party Transaction, Management Fee, Shareholders' Equity, Incremental Threshold Amount2 Management fee, percent, threshold three Related Party Transaction, Management Fee, Percent, Threshold 3 Related Party Transaction, Management Fee, Percent, Threshold 3 Management fee, shareholders' equity, incremental threshold amount three Related Party Transaction, Management Fee, Shareholders' Equity, Incremental Threshold Amount3 Related Party Transaction, Management Fee, Shareholders' Equity, Incremental Threshold Amount3 Management fee, percent, threshold four Related Party Transaction, Management Fee, Percent, Threshold 4 Related Party Transaction, Management Fee, Percent, Threshold 4 Management fee, shareholders' equity, incremental threshold amount four Related Party Transaction, Management Fee, Shareholders' Equity, Incremental Threshold Amount4 Related Party Transaction, Management Fee, Shareholders' Equity, Incremental Threshold Amount4 Extension Term Master Lease Agreement Extension Term Master Lease Agreement Extension Term Master Lease Agreement Termination fee, percent of prior years management fee Related Party Transaction, Termination Fee, Percent of Prior Years Management Fee Related Party Transaction, Termination Fee, Percent of Prior Years Management Fee Termination fee, minimum equity raised threshold Related Party Transaction, Termination Fee, Shareholders' Equity Threshold Amount Related Party Transaction, Termination Fee, Shareholders' Equity Threshold Amount Ground Leases, Building, Number of Square Feet Ground Leases, Building, Number of Square Feet Ground Leases, Building, Number of Square Feet Term of contract, initial lease term Lessor, Sales-type Lease, Term of Contract, Initial Lease Term Lessor, Sales-type Lease, Term of Contract, Initial Lease Term Real estate, leasehold improvement allowance Real Estate, Leasehold Improvement Allowance Real Estate, Leasehold Improvement Allowance Ground lease, additional construction, funding commitment Ground Lease, Additional Construction, Funding Commitment Ground Lease, Additional Construction, Funding Commitment Ground lease, additional construction, funding commitment, term Ground Leases, Additional Construction, Funding Commitment, Term Ground Leases, Additional Construction, Funding Commitment, Term Ground leases, number of parking spaces to be constructed Ground Leases, Number of Parking Spaces to be Constructed Ground Leases, Number of Parking Spaces to be Constructed Ground lease, future construction funding, percent authorized Ground Leases, Future Construction Funding, Percent Authorized Ground Leases, Future Construction Funding, Percent Authorized Ground leases, additional construction, number of square feet Ground Leases, Additional Construction, Number of Square Feet Ground Leases, Additional Construction, Number of Square Feet Long-term debt, gross Noncontrolling Interest, Ownership Percentage by Parent Noncontrolling Interest, Ownership Percentage by Parent Sales-type Lease, Lease Income Sales-type Lease, Lease Income [Table Text Block] Future Minimum Lease Payments Under Sales-type Leases Sales-type and Direct Financing Leases, Lease Receivable, Maturity [Table Text Block] Schedule of earnings per share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Above-market lease assets, net Above Market Leases [Member] In-place lease assets, net Leases, Acquired-in-Place [Member] Other intangible assets, net Other Intangible Assets [Member] Operating Lease Income Operating Lease Income [Member] Ground Lease Income [Member] Depreciation and amortization Depreciation and Amortization [Member] Depreciation and Amortization [Member] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Gross Intangible Finite-Lived Intangible Assets, Gross Accumulated Depreciation Finite-Lived Intangible Assets, Accumulated Amortization Carrying Value Finite-Lived Intangible Assets, Net Annual payments to third-party owner of the property Below-market lease liabilities - Gross Intangible Below Market Lease, Gross Below-market lease liabilities - Accumulated Amortization Below Market Lease, Accumulated Amortization Below-market lease liabilities - Carrying Value Below Market Lease, Net Amortization of intangible assets Amortization of Intangible Assets ASSETS Assets [Abstract] Real estate, at cost Real Estate Investment Property, at Cost Less: accumulated depreciation Real Estate Investment Property, Accumulated Depreciation Real estate, net Real Estate Investment Property, Net Real estate-related intangible assets, net (refer to Note 4) Total real estate, net and real estate-related intangible assets, net Real Estate Investment Property Including Finite-Lived Intangible Assets, Net Real Estate Investment Property Including Finite-Lived Intangible Assets, Net Net investment in sales-type leases Ground Lease receivables Deferred operating lease income receivable Deferred Rent Receivables, Net Deferred expenses and other assets, net Total assets LIABILITIES AND EQUITY Liabilities and Equity [Abstract] Liabilities: Liabilities [Abstract] Accounts payable, accrued expenses and other liabilities Real estate-related intangible liabilities, net (refer to Note 4) Debt obligations, net Total liabilities Liabilities Commitments and contingencies (refer to Note 9) Commitments and Contingencies Safety, Income & Growth Inc. Predecessor Equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Safehold Inc. shareholders' equity: Stockholders' Equity Attributable to Parent [Abstract] Common stock, $0.01 par value, 400,000 shares authorized, 47,782 and 18,276 shares issued and outstanding as of December 31, 2019 and 2018, respectively Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital Accumulated deficit Retained Earnings (Accumulated Deficit) Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Total Safehold Inc. shareholders' equity Stockholders' Equity Attributable to Parent Noncontrolling interests Stockholders' Equity Attributable to Noncontrolling Interest Total equity Total liabilities and equity Liabilities and Equity Statement of Comprehensive Income [Abstract] Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax [Abstract] Cumulative-effect adjustment for cash flow hedges Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax Reclassification of (gains) losses on derivatives into earnings Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax Reclassification of (gains) losses on derivatives into earnings Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax Unrealized losses on derivatives Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax Other comprehensive loss Other Comprehensive Income (Loss), Net of Tax Comprehensive income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive (income) attributable to noncontrolling interests Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Comprehensive income (loss) attributable to Safehold Inc. Comprehensive Income (Loss), Net of Tax, Attributable to Parent Schedule of Operating Leased Assets [Table] Schedule of Operating Leased Assets [Table] Lease Arrangement, Type [Axis] Lease Arrangement, Type [Axis] Lease Arrangement, Type [Domain] Lease Arrangement, Type [Domain] Inflation- Linked Inflation-Linked Escalations [Member] Inflation-Linked [Member] Fixed Bumps Fixed Bumps [Member] Fixed Bumps [Member] Percentage Rent Percentage Rent [Member] Percentage Rent [Member] Operating Leased Assets [Line Items] Operating Leased Assets [Line Items] Future Minimum Ground Net Lease Payments to be Collected Operating Leases, Future Minimum Payments Receivable [Abstract] 2020 Lessor, Operating Lease, Payments to be Received, Next Twelve Months 2021 Lessor, Operating Lease, Payments to be Received, Two Years 2022 Lessor, Operating Lease, Payments to be Received, Three Years 2023 Lessor, Operating Lease, Payments to be Received, Four Years 2024 Lessor, Operating Lease, Payments to be Received, Five Years Thereafter Lessor, Operating Lease, Payments to be Received, Thereafter Earnings Per Share Earnings Per Share [Text Block] Net income Net Income (Loss) Attributable to Parent, Diluted Net Income (Loss) Attributable to Parent, Diluted Earnings Per Share, Basic Earnings Per Share, Basic Earnings Per Share, Diluted Earnings Per Share, Diluted Weighted Average Number of Shares Outstanding, Basic Weighted Average Number of Shares Outstanding, Basic Weighted Average Number of Shares Outstanding, Diluted Weighted Average Number of Shares Outstanding, Diluted Earnings per common share data: Earnings Per Common Share [Abstract] Earnings Per Common Share [Abstract] Derivative Instruments, Gain (Loss) [Table] Derivative Instruments, Gain (Loss) [Table] Interest Expense Interest Expense [Member] Derivative Instruments, Gain (Loss) [Line Items] Derivative Instruments, Gain (Loss) [Line Items] Amount of Gain (Loss) Recognized in Accumulated Other Comprehensive Income Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Earnings Real Estate and Real Estate-Related Intangibles Real Estate Disclosure [Text Block] Schedule of debt obligations Schedule of Long-term Debt Instruments [Table Text Block] Schedule of Maturities of Long-term Debt Schedule of Maturities of Long-term Debt [Table Text Block] SEC Schedule III, Real Estate and Accumulated Depreciation SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation Disclosure [Text Block] Equity Stockholders' Equity Note Disclosure [Text Block] Land and land improvements, at cost Land and Land Improvements Buildings and improvements, at cost Investment Building and Building Improvements Less: accumulated depreciation Collateral [Axis] Collateral [Axis] Collateral [Domain] Collateral [Domain] Real Estate Real Estate [Member] Mortgages Mortgages [Member] 2017 Revolver 2017 Senior Secured Revolving Credit Facility [Member] 2017 Senior Secured Revolving Credit Facility [Member] Consolidated Mortgage Debt Portfolio Mortgage Debt [Member] [Member] Portfolio Mortgage Debt [Member] [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] LIBOR London Interbank Offered Rate (LIBOR) [Member] Debt premium, net Total debt obligations, net Weighted average interest rate Debt, Weighted Average Interest Rate Real estate collateral amount Debt Instrument, Collateral Amount Stated interest rates debt instrument, cash interest rate debt instrument, cash interest rate Basis point spread on variable interest rate (as a percent) Debt Instrument, Basis Spread on Variable Rate Quarterly Financial Information (Unaudited) Quarterly Financial Information [Text Block] Concentration Risk [Table] Concentration Risk [Table] Restricted Cash Restricted Cash [Member] Restricted Cash [Member] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Revenue Revenue Benchmark [Member] Assets Assets, Total [Member] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Customer Concentration Risk Customer Concentration Risk [Member] Product Concentration Risk Product Concentration Risk [Member] Customer [Axis] Customer [Axis] Customer [Domain] Customer [Domain] Tenant 1 Largest Tenant One [Member] Largest Tenant One [Member] Tenant 2 Largest Tenant Two [Member] Largest Tenant Two [Member] Concentration Risk [Line Items] Concentration Risk [Line Items] Concentration risk percentage Concentration Risk, Percentage Number of hotels leased Number Of Hotels Leased Number Of Hotels Leased Maximum period of derivative Derivative, Term of Contract Restricted cash Derivative Liability, Fair Value of Collateral Cover page. Document Type Document Type Document Annual Report Document Annual Report Document Period End Date Document Period End Date Document Transition Report Document Transition Report Entity File Number Entity File Number Entity Registrant Name Entity Registrant Name Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity Tax Identification Number Entity Tax Identification Number Entity Address, Address Line One Entity Address, Address Line One Entity Address, Address Line Two Entity Address, Address Line Two Entity Address, City or Town Entity Address, City or Town Entity Address, State or Province Entity Address, State or Province Entity Address, Postal Zip Code Entity Address, Postal Zip Code City Area Code City Area Code Local Phone Number Local Phone Number Entity Filer Category Entity Filer Category Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Ex Transition Period Entity Ex Transition Period Entity Shell Company Entity Shell Company Title of 12(b) Security Title of 12(b) Security Trading Symbol Trading Symbol Security Exchange Name Security Exchange Name Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status Entity Public Float Entity Public Float Entity Interactive Data Current Entity Interactive Data Current Common Stock, Shares, Outstanding Entity Common Stock, Shares Outstanding Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Real Estate, Net and Real Estate Related Intangible Assets, Net Real Estate, Net, Real Estate Related Intangible Assets, Net and Deferred Operating Lease Income Receivable, Net [Member] Real Estate, Net, Real Estate Related Intangible Assets, Net and Deferred Operating Lease Income Receivable, Net [Member] Accounts payable, accrued expenses and other liabilities Debt Obligations, Net, Accounts Payable, Accrued Expenses, and Other Liabilities [Member] Debt Obligations, Net, Accounts Payable, Accrued Expenses, and Other Liabilities [Member] Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Consolidated VIE assets Variable Interest Entity, Consolidated, Carrying Amount, Assets Consolidated VIE liabilities Variable Interest Entity, Consolidated, Liabilities, No Recourse Schedule of deferred expenses and other assets, net Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Table Text Block] Schedule of accounts payable, accrued expenses and other liabilities Schedule of Accounts Payable and Accrued Liabilities [Table Text Block] Earnings allocable to common shares: Share-based Payment Arrangement, Expensed and Capitalized, Amount [Abstract] Numerator for basic and diluted earnings per share: Net Income (Loss) Available to Common Stockholders, Basic [Abstract] Denominator for basic and diluted earnings per share:(1) Weighted Average Number of Shares Outstanding, Basic and Diluted [Abstract] Weighted Average Number of Shares Outstanding, Basic and Diluted [Abstract] Weighted average common shares outstanding for basic and diluted earnings per common share Basic and diluted earnings per common share: Earnings Per Share, Basic and Diluted [Abstract] Net income attributable to Safehold Inc. common shareholders Investor Units that are anti-dilutive Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Long-term Purchase Commitment [Table] Long-term Purchase Commitment [Table] Name of Property [Axis] Name of Property [Axis] Name of Property [Domain] Name of Property [Domain] Commitment I Commitment I [Member] Commitment I [Member] Multi-Family Property, Washington DC Multi-Family Property, Washington DC [Member] Multi-Family Property, Washington DC [Member] Commitment III [Member] Commitment III [Member] Commitment III [Member] Land Land [Member] Leasehold Improvements Leasehold Improvements [Member] Long-term Purchase Commitment [Line Items] Long-term Purchase Commitment [Line Items] Unfunded commitment Payments to Acquire Productive Assets Notes payable, related parties Notes Payable, Related Parties Payments to acquire productive assets Long-term Purchase Commitment, Amount Real estate, leasehold improvement allowance, funded amount Real Estate, Leasehold Improvement Allowance, Funded Amount Real Estate, Leasehold Improvement Allowance, Funded Amount Line of Credit Facility [Table] Line of Credit Facility [Table] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] 2017 Revolver Revolving Credit Facility [Member] Line of Credit Line of Credit [Member] Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Number of Mortgages Refinanced Number of Mortgages Refinanced Number of Mortgages Refinanced Maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Accordion feature, increase limit Line Of Credit Facility, Accordion Feature, Increase Limit Line Of Credit Facility, Accordion Feature, Increase Limit Number of extension options available Debt Instrument, Number Of Extension Options Available Debt Instrument, Number Of Extension Options Available Debt extension term Debt Instrument, Extension Term Debt Instrument, Extension Term Unused capacity, commitment fee percentage Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Maximum leverage rate Line Of Credit Facility, Maximum Leverage Rate Line Of Credit Facility, Maximum Leverage Rate Remaining borrowing capacity Line of Credit Facility, Remaining Borrowing Capacity Additional unsecured borrowing capacity Line of Credit Facility, Additional Unsecured Borrowing Capacity Line of Credit Facility, Additional Unsecured Borrowing Capacity Maximum leverage ratio Debt Instrument, Covenant, Leverage Ratio, Maximum Debt Instrument, Covenant, Leverage Ratio, Maximum Maximum leverage ratio for 180 day period Debt Instrument, Covenant, Leverage Ratio, Maximum For 180 Day Period Debt Instrument, Covenant, Leverage Ratio, Maximum For 180 Day Period Debt instrument covenant multiple of minimum fixed charges on outstanding borrowings Debt Instrument, Covenant, Multiple of Minimum Fixed Charges on Outstanding Borrowings Debt Instrument, Covenant, Multiple of Minimum Fixed Charges on Outstanding Borrowings Consolidated tangible net worth Debt Instrument, Covenant, Consolidated Tangible Net Worth Debt Instrument, Covenant, Consolidated Tangible Net Worth Tangible net worth, percent of future issuances of net equity Debt Instrument, Covenant, Tangible Net Worth, Percent of Future Issuances of Net Equity Debt Instrument, Covenant, Tangible Net Worth, Percent of Future Issuances of Net Equity Maximum secured leverage ratio Debt Instrument, Covenant, Secured Leverage Ratio, Maximum Debt Instrument, Covenant, Secured Leverage Ratio, Maximum Maximum secured leverage ratio for 180 day period Debt Instrument, Covenant, Secured Leverage Ratio, Maximum For 180 Day Period Debt Instrument, Covenant, Secured Leverage Ratio, Maximum For 180 Day Period Covenant description secured recourse debt ratio maximum Debt Instrument, Covenant, Secured Leverage Ratio, Recourse Debt Ratio, Maximum Debt Instrument, Covenant, Secured Leverage Ratio, Recourse Debt Ratio, Maximum Future annualized distribution rate of adjusted funds from operations Debt Instrument, Covenant Compliance, Expected Annualized Distribution Rate of Adjusted Funds from Operations Debt Instrument, Covenant Compliance, Expected Annualized Distribution Rate of Adjusted Funds from Operations