Allowance for Credit Losses - Components of Allowance for Credit Losses (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit loss	$ 85,376	$ 91,847	$ 30,616	$ 32,582
Financial asset acquired with credit deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit loss	0	0
Total allowance for credit losses
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit loss	84,394	90,397
Qualitative and forecast factor allowance
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit loss	59,855	61,935
Quantitative (Cohort) model allowance reserves
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit loss	24,539	28,462
Allowance for individually evaluated loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit loss	$ 982	$ 1,450