Derivative Instruments and Hedging Activities - Effect of Derivative Instruments on Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income	$ (1,407)	$ 2,917	$ (2,634)
Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivatives	(15,656)	1,477	406
Interest Rate Contract
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income	(1,407)	2,917	(2,634)
Interest expense | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income	(1,407)	95	(2,634)
Other non-interest income | Interest Rate Contract
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income	0	2,822	0
Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, gain on derivative, net	3,172	3,545	790
Not Designated as Hedging Instrument | Other non-interest income | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, gain on derivative, net	2,549	3,409	604
Not Designated as Hedging Instrument | Other non-interest income | Interest rate caps
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, gain on derivative, net	24	0	0
Not Designated as Hedging Instrument | Other non-interest income | Credit contracts
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, gain on derivative, net	589	127	171
Not Designated as Hedging Instrument | Mortgage banking income | Residential mortgage loan commitments
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, gain on derivative, net	$ 10	$ 9	$ 15