Off Balance Sheet Activities - Schedule of Off-Balance Sheet Risks (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Commitments to Make Loans [Member] | Fixed Rate [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Line Items]
Off-balance sheet risks, amount, liability	$ 42,803	$ 28,831
Commitments to Make Loans [Member] | Variable Rate [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Line Items]
Off-balance sheet risks, amount, liability	259,032	254,269
Unused Lines of Credit [Member] | Fixed Rate [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Line Items]
Off-balance sheet risks, amount, liability	0	0
Unused Lines of Credit [Member] | Variable Rate [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Line Items]
Off-balance sheet risks, amount, liability	87,493	80,428
Standby Letters of Credit [Member] | Fixed Rate [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Line Items]
Off-balance sheet risks, amount, liability	0	0
Standby Letters of Credit [Member] | Variable Rate [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input [Line Items]
Off-balance sheet risks, amount, liability	$ 15,704	$ 15,132