Debt and Preferred Equity Investments - Narrative (Details)	3 Months Ended		9 Months Ended		12 Months Ended	38 Months Ended
	Sep. 30, 2023 USD ($) investment	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($) investment segment	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($) segment investment	Sep. 30, 2023 USD ($) investment
Preferred equity investment
Number of investments, nonperforming | investment	3		3		1	3
Debt and preferred equity investments	$ 334,327,000		$ 334,327,000		$ 623,280,000	$ 334,327,000
Recorded investment, past due	334,327,000		$ 334,327,000		$ 623,280,000	334,327,000
Number of portfolio segments of financial receivables (segment) | segment			1		1
Current period provision for loan loss	0	$ 0	$ 6,890,000	$ 0	$ 0
Recorded investment, nonaccrual status	5,600,000		5,600,000			5,600,000
Loan interest income						0
Other Assets
Preferred equity investment
Additional amount of financing receivables included in other assets	9,100,000		9,100,000		9,000,000	9,100,000
Current period provision for loan loss	0	$ 0	0	$ 0
Financing Receivables, Equal to Greater than 90 Days Past Due
Preferred equity investment
Recorded investment, past due	0		0		0	0
Preferred equity investments
Preferred equity investment
Additional amount of financing receivables included in other assets	125,897,000		125,897,000		119,858,000	125,897,000
Total floating rate
Preferred equity investment
Debt and preferred equity investments	158,584,000		158,584,000		144,210,000	158,584,000
Total floating rate | Three Mortgage Investments
Preferred equity investment
Debt and preferred equity investments	$ 88,800,000		$ 88,800,000			$ 88,800,000
Total floating rate | Mortgage Investment One
Preferred equity investment
Debt and preferred equity investments					$ 6,900,000