Derivative Financial Instruments - Summary of Recorded Net Gains (Losses) on Derivatives and Related Hedged Items in Fair Value Hedging Relationships (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Net Fair Value Hedge Gain/(Loss)	$ 0	$ 0
Fair Value Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(Loss) on Derivatives	(301)	429
Gain/(Loss) on Hedged Items	301	(429)
Net Fair Value Hedge Gain/(Loss)	0	0
Effect of Derivatives on Net Interest Income	9	(24)
Fair Value Hedging [Member] | Commercial Real Estate [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(Loss) on Derivatives	(301)	429
Gain/(Loss) on Hedged Items	301	(429)
Net Fair Value Hedge Gain/(Loss)	0	0
Effect of Derivatives on Net Interest Income	$ 9	$ (24)