Other Assets and Liabilities - Summary of Components of Other Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Schedule Of Other Assets [Line Items]
Accrued interest receivable	$ 189,569	$ 86,101
Collateral deposited under derivative agreements	103,110	0
Loan portfolio payments held by servicer	68,489	77,624
Derivative assets	7,349	30,531
Accounts receivable and other assets	1,318	572
Prepaid expenses	1,067	956
Debt securities held-to-maturity	0	78,083
CECL reserve	0	(70)	$ (1,723)
Debt securities held-to-maturity, net	0	78,013
Total	$ 370,902	273,797
2018 Single Asset Securitization
Schedule Of Other Assets [Line Items]
Total loan amount, securitized		$ 379,300