Derivatives - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) Derivative	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Derivative [Line Items]
Number of participation agreements for interest rate swaps, participant | Derivative	26
Number of participation agreements for interest rate swaps, lead bank | Derivative	8
Derivative, Gain (Loss) on Derivative, Net	$ 219	$ (274)	$ (345)
Interest Income [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 1,627	2,049	$ 330
Interest rate swap [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Number of interest rate swap contracts | Derivative	4
Derivative, notional amount	$ 200,000
Collateral Already Posted, Aggregate Fair Value	200,000
Interest rate swap [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, notional amount	200,000	$ 200,000
Three Year [Member] | Interest rate swap [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Derivative, notional amount	$ 85,000
Derivative, Term of Contract	3 years
Four Year [Member] | Interest rate swap [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Derivative, notional amount	$ 115,000
Derivative, Term of Contract	4 years