Fair Value - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Accretion of discounts on securities included in interest income	$ 18	$ 18
Net carrying amount other real estate owned and other repossessed property		2,700
Other real estate owned property write-downs	$ 3,000	2,200
Past due period of mortgage loans held for sale, days	90 days
Interest income for residential loans held for sale	$ 100	100
Valuation Allowance, Real Estate Owned [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Net carrying amount other real estate owned and other repossessed property	1,700
Impaired Commercial and Commercial Real Estate Loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Principal amount of impaired commercial and commercial real estate loans	26,400	36,800
Valuation allowance	8,000	11,500
Recapture of provision loan	$ 1,100
Provision for loan losses expensed		$ 4,700