Derivative Financial Instruments - Summary of Instruments (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Loss) or Gain Recognized in OCI on Derivative (Effective Portion)	$ 1,560	$ 1,877	$ (56)
Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Loss) or Gain Recognized in Income	(5,736)	40	(364)
Interest income | Interest rate products
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Loss) or Gain Recognized in OCI on Derivative (Effective Portion)	1,560	1,877	(56)
Mortgage banking activities, net | Interest rate lock commitments with customers | Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Loss) or Gain Recognized in Income	6,490	1,399	(28)
Mortgage banking activities, net | Forward sale commitments | Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Loss) or Gain Recognized in Income	$ (12,226)	$ (1,359)	$ (336)