Derivative Financial Instruments - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of collateral posted for the net liability positions	$ 1,400,000		$ 1,400,000
Not Designated as Hedging Instrument [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivatives recorded gains (losses) during the period	(403,000)	$ (659,000)	(313,000)	$ (1,600,000)
Interest Rate Swaps/Derivatives [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Reclassification from accumulated other comprehensive income as increase to interest income			$ 188,000
Reclassification from accumulated other comprehensive income, time period			12 months
Cash flow hedge ineffectiveness	$ 0	$ 0	$ 0	$ 0