Borrowings and Financing Activities - Schedule of Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Total secured borrowings	$ 178,762	$ 155,822
Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
FHLB, floating SOFR advances	$ 13,400
FHLB, weighted average interest rate	5.26%	3.62%
Senior notes
Debt Instrument [Line Items]
Total senior notes	$ 1,415,610	$ 1,413,504
Senior notes \| Senior Notes due 2024
Debt Instrument [Line Items]
Interest rate on senior notes	4.50%
Total senior notes	$ 448,414	447,805
Senior notes \| Senior Notes due 2025
Debt Instrument [Line Items]
Interest rate on senior notes	6.625%
Total senior notes	$ 521,306	520,305
Senior notes \| Senior Notes due 2027
Debt Instrument [Line Items]
Interest rate on senior notes	4.875%
Total senior notes	$ 445,890	445,394
FHLB advances
Debt Instrument [Line Items]
FHLB advances due 2023, average interest rate	4.596%
FHLB advances due 2024, average interest rate	3.222%
FHLB advances due 2025, average interest rate	2.34%
FHLB advances due 2026, average interest rate	4.469%
FHLB advances due 2027, average interest rate	2.562%
2023	$ 75,036	104,895
2024	32,371	32,371
2025	12,684	9,984
2026	1,835	0
2027	7,887	6,436
Total FHLB advances	129,813	153,686
Mortgage financing facilities
Debt Instrument [Line Items]
Total senior notes	$ 48,949	$ 2,136
Mortgage financing facilities, average interest rate	6.88%

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