Related Party Transactions (Narrative) (Details) $ / shares in Units, ft² in Millions			1 Months Ended									6 Months Ended	12 Months Ended
		Dec. 01, 2021 shares	Nov. 30, 2021 USD ($)	Sep. 30, 2021 USD ($)	Aug. 31, 2021 director	Jun. 30, 2021 USD ($) ft² agreement	Mar. 31, 2021 USD ($)	Feb. 28, 2021 USD ($)	Oct. 31, 2020 USD ($)	Jun. 30, 2020	Oct. 31, 2017 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($) lease $ / shares	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Related Party Transaction [Line Items]
Management fee paid with common stock, period of restriction from selling stock													2 years
Management fee, transaction share price (in dollars per share) | $ / shares													$ 20.00
Management fee, percent, threshold one													1.00%
Management fee, percent, threshold two													1.25%
Management fee, percent, threshold three													1.375%
Management fee, percent, threshold four													1.50%
Management fee expense													$ 14,865,000	$ 12,684,000	$ 7,461,000
Termination fee, percent of prior years management fee													300.00%
Long-term debt, gross													$ 2,738,113,000	1,713,113,000
Future funding obligation, amount													363,900,000
Leasehold improvement allowance, unfunded, pending milestone achievement													165,500,000
Assets	[1]												$ 4,515,726,000	3,208,970,000
Number of ground leases | lease													23
Number of directors with affiliated trusts which hold CARET Units | director					2
Number of common shares issued in exchange for Caret Units | shares		2,546
iStar Inc.
Related Party Transaction [Line Items]
Number of years as active real estate investor													20 years
Real estate investments, aggregate transactions, value													$ 40,000,000,000.0
iStar Inc. | General and Administrative Expense
Related Party Transaction [Line Items]
Expenses from transactions with related party													7,500,000	5,000,000.0	2,100,000
Manager | General and Administrative Expense | Management Fees
Related Party Transaction [Line Items]
Expenses from transactions with related party													14,900,000	12,700,000	$ 7,500,000
Manager | General and Administrative Expense | Incentive Fee
Related Party Transaction [Line Items]
Expenses from transactions with related party													0
Office space development property
Related Party Transaction [Line Items]
Number of square feet | ft²						1.1
Purchase price of property under purchase option agreement						$ 215,000,000.0
Minimum
Related Party Transaction [Line Items]
Management fee, shareholders' equity, incremental threshold amount two													$ 1,500,000,000
Ground leases term													30 years
Maximum
Related Party Transaction [Line Items]
Management fee, shareholders' equity, incremental threshold amount two													$ 3,000,000,000.0
Management fee, shareholders' equity, incremental threshold amount three													$ 5,000,000,000.0
Ground leases term													99 years
Ground Lease Tenant for Recapitalization of an Existing Hotel Property | Hotel | iStar Inc.
Related Party Transaction [Line Items]
Ground lease, additional construction, funding commitment								$ 50,000,000.0
Multi-Family Project Under Construction | iStar Inc.
Related Party Transaction [Line Items]
Ground lease, additional construction, funding commitment							$ 75,000,000.0
Multi-Family Project Under Construction | iStar Inc. | Land
Related Party Transaction [Line Items]
Payments to acquire productive assets							16,100,000
Future funding obligation, amount							11,900,000
Leasehold improvement allowance, unfunded, pending milestone achievement							$ 52,000,000.0
Payment of deferred purchase price obligation												$ 6,000,000.0
iStar Inc. | Land and Related Ground Lease
Related Party Transaction [Line Items]
Number of agreements entered into to acquire land and related ground lease | agreement						2
Purchase price per agreement for acquisition of land and related Ground Lease, subject to certain conditions being met			$ 33,300,000			$ 42,000,000.0
Multiple required by seller that may trigger payment of additional consideration			1.25			1.25
Percentage of required seller return on investment that may trigger payment of additional consideration			12.00%			9.00%
Acquisition of Property and Ground Lease, Seller Required Percentage Return on Investment			12.00%			9.00%
Future funding obligation, amount			$ 51,800,000
iStar Inc. | Office space development property
Related Party Transaction [Line Items]
Payment to acquire purchase option agreement						$ 1,200,000
iStar Inc. | Maximum | Land and Related Ground Lease
Related Party Transaction [Line Items]
Real estate, leasehold improvement allowance						$ 83,000,000.0
iStar Inc. | Ground Lease Tenant for Recapitalization of an Existing Hotel Property | Hotel
Related Party Transaction [Line Items]
Expenses from transactions with related party								$ 1,900,000
iStar Inc. | Multi-Family Project Under Construction | Land
Related Party Transaction [Line Items]
Payments to acquire productive assets				$ 24,800,000
Pending ownership interests acquired, subject to conditions being met							100.00%
Secured Debt
Related Party Transaction [Line Items]
Long-term debt, gross													$ 1,498,113,000	$ 1,713,113,000
San Jose, CA | iStar Inc.
Related Party Transaction [Line Items]
Ground lease, additional construction, funding commitment											$ 80,500,000
Payments to acquire productive assets											$ 34,000,000.0
Honolulu, HI
Related Party Transaction [Line Items]
Term of contract, initial lease term										99 years
Honolulu, HI | Office Condominium Tenant Venture | iStar Inc.
Related Party Transaction [Line Items]
Ownership percentage													51.90%
Ownership percentage acquired during the period													47.50%
Seattle, WA | iStar Inc.
Related Party Transaction [Line Items]
Ground lease, additional construction, funding commitment									$ 22,500,000
iStar Inc. | Seattle, WA | Commitment II
Related Party Transaction [Line Items]
Expenses from transactions with related party									$ 2,300,000
Performance Shares
Related Party Transaction [Line Items]
Number of CARET Units exchanged for common shares | shares		3,750

[1] Refer to Note 2 for details on the Company’s consolidated variable interest entities ("VIEs").