Loans and Allowance for Loan Losses - Summarizes the Changes in the Allowance for Loan Losses (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at the beginning of period	$ 113,031	$ 82,297
Loans charged off	(1,982)	(2,343)
Recoveries	611	584
(Release of) provision for loan losses	(580)	28,600
Balance at end of period	$ 111,080	$ 109,138

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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Period Type:	instant

- Definition

Amount of increase in allowance for credit loss on financing receivable from recovery.

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of writeoff of financing receivable, charged against allowance for credit loss.

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- Definition

Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

+ References

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