Commercial Real Estate Loans - Amortized Cost of Loan Portfolio (Details) $ in Thousands	12 Months Ended
Dec. 31, 2021 USD ($) loan	Dec. 31, 2020 USD ($) loan
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Total	$ 6,316,733	$ 4,844,534
Carrying Amount	$ 6,294,489	$ 4,784,733
Commercial Real Estate Loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Loans (in loans) \| loan	63	42
Outstanding Principal	$ 6,364,105	$ 4,869,696
Current year	3,523,611	562,992
Year one	334,361	2,311,156
Year two	1,093,301	1,500,563
Year three	1,064,131	359,384
Year four	301,329	0
Prior	0	110,439
Total	6,316,733	4,844,534
Carrying Amount	$ 6,294,489	$ 4,784,733
Very Low Risk \| Commercial Real Estate Loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Loans (in loans) \| loan	1	0
Outstanding Principal	$ 243,552	$ 0
Current year	0	0
Year one	0	0
Year two	0	0
Year three	243,549	0
Year four	0	0
Prior	0	0
Total	243,549	0
Carrying Amount	$ 243,544	$ 0
Low Risk \| Commercial Real Estate Loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Loans (in loans) \| loan	3	2
Outstanding Principal	$ 411,424	$ 323,026
Current year	0	0
Year one	130,400	128,514
Year two	0	0
Year three	85,943	193,633
Year four	193,950	0
Prior	0	0
Total	410,293	322,147
Carrying Amount	$ 409,812	$ 321,686
Average Risk \| Commercial Real Estate Loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Loans (in loans) \| loan	54	32
Outstanding Principal	$ 5,309,293	$ 3,744,559
Current year	3,523,611	461,406
Year one	203,961	2,105,972
Year two	1,017,080	1,159,818
Year three	523,938	0
Year four	0	0
Prior	0	0
Total	5,268,590	3,727,196
Carrying Amount	$ 5,256,052	$ 3,715,132
High Risk/Potential for Loss \| Commercial Real Estate Loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Loans (in loans) \| loan	4	6
Outstanding Principal	$ 394,336	$ 687,040
Current year	0	101,586
Year one	0	76,670
Year two	76,221	340,745
Year three	210,701	165,751
Year four	107,379	0
Prior	0	0
Total	394,301	684,752
Carrying Amount	$ 385,081	$ 675,727
Impaired/Loss Likely \| Commercial Real Estate Loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Number of Loans (in loans) \| loan	1	2
Outstanding Principal	$ 5,500	$ 115,071
Current year	0	0
Year one	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Prior	0	110,439
Total	0	110,439
Carrying Amount	$ 0	$ 72,188

Amount of contractual principal due at origination of mortgage loan within investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate.

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