Disclosures About Fair Value of Financial Instruments - Statement of Changes in Level 3 Assets Measured at Fair Value on a Recurring Basis (Detail) - Significant Unobservable Inputs (Level 3) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Residential Mortgage Loan Commitments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 179	$ 200
Issuances	149	196
Settlements	(179)	(200)
Balance at end of period	149	$ 196
Asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	142,885
Principal payments	(16,349)
Credit losses	(728)
Change in fair value recognized in OCI	(3,955)
Balance at end of period	$ 121,853