Fair Value Measurements - Activity for Level 3 Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Level 3 CMO [Roll Forward]
Unrealized net holding gains (losses) on securities available-for-sale arising during the period	$ (288,174,000)	$ (63,956,000)	$ (970,572,000)	$ (101,403,000)
Fair Value, Assets, Level 3 to Level 2 Transfers, Amount			(4,600,000)
Net increase (decrease) in borrowings			1,864,815,000	$ (55,210,000)
Credit-Link Notes
Level 3 CMO [Roll Forward]
Net increase (decrease) in borrowings			128,700,000
Other Borrowings, Fair Value Disclosure	132,815,000		$ 132,815,000		$ 0
Discounted Cash Flow
Level 3 CMO [Roll Forward]
Financing Receivable, before Allowance for Credit Loss, Average Yield			7.05%
Level 3
Level 3 CMO [Roll Forward]
Equity warrants, Balance, beginning of period			$ 3,555,000
Total included in earnings, Equity Warrants			2,536,000
Total included in other comprehensive income			0
Stock and Warrants Issued During Period, Value, Preferred Stock and Warrants			604,000
Sales, Equity Warrants			(2,470,000)
Net settlements, Equity Warrants			0
Proceeds from Issuance of Debt			0
Fair Value, Equity, Transfers to Level 1, Amount			10,000
Fair Value, Assets, Level 3 to Level 2 Transfers, Amount			0
Net increase (decrease) in borrowings			132,815,000
Level 3 | Credit-Link Notes
Level 3 CMO [Roll Forward]
Total included in earnings, Equity Warrants			0
Total included in other comprehensive income			0
Net settlements, Equity Warrants			0
Fair Value, Equity, Transfers to Level 1, Amount			0
Fair Value, Assets, Level 3 to Level 2 Transfers, Amount			0
Fair Value, Measurements, Recurring
Level 3 CMO [Roll Forward]
Equity warrants, Balance, beginning of period			3,555,000
Equity warrants, Balance, end of period	4,215,000		4,215,000
Fair Value, Measurements, Recurring | Level 3
Level 3 CMO [Roll Forward]
Equity warrants, Balance, beginning of period			3,555,000
Equity warrants, Balance, end of period	4,215,000		4,215,000
Asset-backed | Fair Value, Measurements, Recurring | Level 3
Level 3 CMO [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value			15,001,000
Total included in earnings			(8,000)
Total included in other comprehensive income			(156,000)
Stock and Warrants Issued During Period, Value, Preferred Stock and Warrants			0
Net settlements			(10,285,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$ 0		0
Unrealized net holding gains (losses) on securities available-for-sale arising during the period			0
Fair Value, Equity, Transfers to Level 1, Amount			0
Fair Value, Assets, Level 3 to Level 2 Transfers, Amount			(4,552,000)
Warrant
Level 3 CMO [Roll Forward]
Fair value transfers of assets measured on a recurring basis			$ 10,000