Commercial Mortgage Loans, Subordinate Loans and Other Lending Assets, Net - Allocation of Carrying Value of Loan Portfolio Based on Internal Risk Ratings (Details) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2025 USD ($) Loan	Dec. 31, 2024 USD ($) Loan
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans \| Loan	48	45
Total	$ 7,721,798	$ 7,134,992
Mortgage loans on real estate, commercial and consumer, percentage of portfolio	100.00%	100.00%
Year 1	$ 447,501	$ 1,218,189
Year 2	1,251,720	649,599
Year 3	667,922	2,097,601
Year 4	2,149,525	1,186,311
Year 5	1,220,525	425,853
Prior	1,984,605	1,557,439
General CECL Allowance	(34,712)	(30,836)
Mortgage loans on real estate, commercial and consumer, net	7,687,086	7,104,156
Carrying value, net	$ 7,728,286	$ 7,145,356
Weighted-Average Risk Rating	3	3
Gross write-offs	$ 0	$ 127,512
1
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans \| Loan	0	0
Total	$ 0	$ 0
Mortgage loans on real estate, commercial and consumer, percentage of portfolio	0.00%	0.00%
Year 1	$ 0	$ 0
Year 2	0	0
Year 3	0	0
Year 4	0	0
Year 5	0	0
Prior	$ 0	$ 0
2
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans \| Loan	2	3
Total	$ 578,527	$ 560,180
Mortgage loans on real estate, commercial and consumer, percentage of portfolio	7.50%	7.90%
Year 1	$ 0	$ 0
Year 2	0	0
Year 3	0	547,851
Year 4	578,527	12,329
Year 5	0	0
Prior	$ 0	$ 0
3
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans \| Loan	41	37
Total	$ 6,729,675	$ 6,169,860
Mortgage loans on real estate, commercial and consumer, percentage of portfolio	87.20%	86.40%
Year 1	$ 447,501	$ 1,218,189
Year 2	1,251,720	649,599
Year 3	667,922	1,549,750
Year 4	1,570,998	1,173,982
Year 5	1,220,525	397,972
Prior	$ 1,571,009	$ 1,180,368
4
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans \| Loan	2	2
Total	$ 288,961	$ 279,732
Mortgage loans on real estate, commercial and consumer, percentage of portfolio	3.70%	3.90%
Year 1	$ 0	$ 0
Year 2	0	0
Year 3	0	0
Year 4	0	0
Year 5	0	0
Prior	$ 288,961	$ 279,732
5
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans \| Loan	3	3
Total	$ 124,635	$ 125,220
Mortgage loans on real estate, commercial and consumer, percentage of portfolio	1.60%	1.80%
Year 1	$ 0	$ 0
Year 2	0	0
Year 3	0	0
Year 4	0	0
Year 5	0	27,881
Prior	$ 124,635	$ 97,339

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