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	12 Months Ended
Dec. 31, 2023 USD ($) loan	Dec. 31, 2022 USD ($) loan
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans \| loan	50	61
Total	$ 8,384,575	$ 8,708,214
Mortgage loans on real estate, commercial and consumer, percentage of portfolio	100.00%	100.00%
Year 1	$ 440,720	$ 2,575,455
Year 2	2,707,083	2,462,499
Year 3	2,285,902	687,329
Year 4	557,204	1,637,050
Year 5	1,597,927	499,720
Prior	795,739	846,161
General CECL Allowance	(26,482)	(26,224)
Total carrying value, net	$ 8,358,093	$ 8,681,990
Weighted Average Risk Rating	3.0	3.0
Gross write-offs	$ 81,890	$ 7,000
Off-balance-sheet, credit loss, liability, amount excluded	$ 4,000	$ 4,300
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	4	2
Total	$ 478,440	$ 65,943
Mortgage loans on real estate, commercial and consumer, percentage of portfolio	5.70%	0.80%
Year 1	$ 0	$ 0
Year 2	280,572	0
Year 3	0	0
Year 4	0	0
Year 5	132,309	0
Prior	$ 65,560	$ 65,943
3
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans \| loan	42	54
Total	$ 7,548,252	$ 8,401,925
Mortgage loans on real estate, commercial and consumer, percentage of portfolio	90.00%	96.50%
Year 1	$ 440,720	$ 2,575,455
Year 2	2,426,511	2,462,499
Year 3	2,285,902	687,329
Year 4	387,323	1,637,050
Year 5	1,465,618	479,769
Prior	$ 542,177	$ 559,823
4
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans \| loan	2	2
Total	$ 88,112	$ 27,451
Mortgage loans on real estate, commercial and consumer, percentage of portfolio	1.10%	0.30%
Year 1	$ 0	$ 0
Year 2	0	0
Year 3	0	0
Year 4	0	0
Year 5	0	19,951
Prior	$ 88,112	$ 7,500
5
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans \| loan	2	3
Total	$ 269,771	$ 212,895
Mortgage loans on real estate, commercial and consumer, percentage of portfolio	3.20%	2.40%
Year 1	$ 0	$ 0
Year 2	0	0
Year 3	0	0
Year 4	169,881	0
Year 5	0	0
Prior	$ 99,890	$ 212,895

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The reserve to cover probable credit losses related to specifically identified fixed maturity real estate loans as well as probable credit losses inherent in the remainder of that loan portfolio.

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Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable from writeoff. Excludes net investment in lease.

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Amortized cost excluding accrued interest, of financing receivable originated four years prior to current fiscal year. Excludes net investment in lease.

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The balance represents the amount of loans that are secured by real estate mortgages, offset by the reserve to cover probable credit losses on the loan portfolio.

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