Loans - Risk Ratings by Class of Loan (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Investments in loans
Total Amortized Cost Basis	$ 19,627,876	$ 20,528,925
Credit Loss Allowance	331,646	309,039
Loans under fair value option
Investments in loans
Total Amortized Cost Basis	2,689,368	$ 2,645,637
Credit Loss Allowance	0
Commercial Portfolio Segment
Investments in loans
2024	0
2023	913,198
2022	4,126,995
2021	6,552,514
2020	508,452
Prior	2,451,599
Revolving Loans Amortized Cost Total	0
Total Amortized Cost Basis	14,552,758
Credit Loss Allowance	322,087
Commercial Portfolio Segment \| LTV less than 60%
Investments in loans
2024	0
2023	39,940
2022	2,030,997
2021	2,722,811
2020	188,168
Prior	1,082,498
Revolving Loans Amortized Cost Total	0
Total Amortized Cost Basis	6,064,414
Credit Loss Allowance	18,658
Commercial Portfolio Segment \| LTV 60% - 70%
Investments in loans
2024	0
2023	797,229
2022	1,951,080
2021	3,429,617
2020	96,804
Prior	317,598
Revolving Loans Amortized Cost Total	0
Total Amortized Cost Basis	6,592,328
Credit Loss Allowance	127,080
Commercial Portfolio Segment \| LTV > 70%
Investments in loans
2024	0
2023	61,805
2022	103,050
2021	400,086
2020	223,480
Prior	1,032,003
Revolving Loans Amortized Cost Total	0
Total Amortized Cost Basis	1,820,424
Credit Loss Allowance	171,424
Commercial Portfolio Segment \| Credit deteriorated
Investments in loans
2024	0
2023	0
2022	0
2021	0
2020	0
Prior	4,925
Revolving Loans Amortized Cost Total	0
Total Amortized Cost Basis	4,925
Credit Loss Allowance	4,925
Commercial Portfolio Segment \| Defeased and other
Investments in loans
2024	0
2023	14,224
2022	41,868
2021	0
2020	0
Prior	14,575
Revolving Loans Amortized Cost Total	0
Total Amortized Cost Basis	70,667
Credit Loss Allowance	0
Infrastructure Portfolio Segment
Investments in loans
2024	0
2023	800,630
2022	141,259
2021	288,473
2020	104,546
Prior	1,037,336
Revolving Loans Amortized Cost Total	13,506
Total Amortized Cost Basis	2,385,750
Credit Loss Allowance	9,559
Infrastructure Portfolio Segment \| Loans under fair value option
Investments in loans
Total Amortized Cost Basis	47,149
Infrastructure Portfolio Segment \| Power
Investments in loans
2024	0
2023	390,601
2022	0
2021	104,679
2020	68,445
Prior	734,584
Revolving Loans Amortized Cost Total	13,506
Total Amortized Cost Basis	1,311,815
Credit Loss Allowance	3,674
Infrastructure Portfolio Segment \| Oil and gas
Investments in loans
2024	0
2023	410,029
2022	141,259
2021	183,794
2020	36,101
Prior	302,752
Revolving Loans Amortized Cost Total	0
Total Amortized Cost Basis	1,073,935
Credit Loss Allowance	$ 5,885

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