Loans and Preferred Equity Held for Investment, net - Nonaccrual and Past Due Loans (Details) $ in Thousands	3 Months Ended
	Jun. 30, 2025 loan	Sep. 30, 2025 USD ($) loan	Dec. 31, 2024 USD ($) loan
Financing Receivable, Past Due [Line Items]
Carrying Value		$ 2,363,215	$ 2,518,925
Multifamily
Financing Receivable, Past Due [Line Items]
Number of loans on nonaccrual collateral dependent | loan	1
Senior loans
Financing Receivable, Past Due [Line Items]
Carrying Value		$ 2,305,887	$ 2,473,793
Denver, Colorado
Financing Receivable, Past Due [Line Items]
Number of loans on nonaccrual status | loan	1	1	1
Loan carrying value, nonaccrual		$ 24,600	$ 136,000
Denver, Colorado | Senior loans
Financing Receivable, Past Due [Line Items]
Number of loans on nonaccrual status | loan		1
Baltimore, Maryland
Financing Receivable, Past Due [Line Items]
Number of loans on nonaccrual status | loan		1
Loan carrying value, nonaccrual		$ 14,700	14,400
Commercial mortgage
Financing Receivable, Past Due [Line Items]
Carrying Value		2,363,215	2,518,925
Commercial mortgage | Current or Less Than 30 Days Past Due
Financing Receivable, Past Due [Line Items]
Carrying Value		2,348,523	2,368,591
Commercial mortgage | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Carrying Value		0	0
Commercial mortgage | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Carrying Value		0	0
Commercial mortgage | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Carrying Value		$ 14,692	$ 150,334