Other Assets and Liabilities - Summary of Components of Other Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020
Schedule Of Other Assets [Line Items]
Loan portfolio payments held by servicer	$ 252,401		$ 77,624
Accrued interest receivable	123,517		86,101
Derivative assets	83,982		30,531
Accounts receivable and other assets	503		572
Prepaid expenses	742		956
Debt securities held-to-maturity	0		78,083
CECL reserve	0	$ 0	(70)	$ (122)	$ (889)	$ (1,723)
Debt securities held-to-maturity, net	0		78,013
Total	$ 461,145		273,797
2018 Single Asset Securitization
Schedule Of Other Assets [Line Items]
Total loan amount, securitized			$ 379,300