Derivatives and Hedging Activities - Summary of Effect of Derivative Instruments on Income Statement (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Derivatives, Fair Value [Line Items]
Total gain (loss) on derivative financial instruments	$ (2,088)	$ (402)	$ 4,175	$ (5,955)
Interest Rate Swaps [Member] | Other Income [Member]
Derivatives, Fair Value [Line Items]
Total gain (loss) on derivative financial instruments	(1,033)	(501)	1,728	(3,252)
Interest Rate Loan Commitments [Member] | Mortgage Banking Income [Member]
Derivatives, Fair Value [Line Items]
Total gain (loss) on derivative financial instruments	564	1,290	(452)	1,145
Forward TBA Contracts [Member] | Mortgage Banking Income [Member]
Derivatives, Fair Value [Line Items]
Total gain (loss) on derivative financial instruments	$ (1,619)	$ (1,191)	$ 2,899	$ (3,848)