Commitments and Letters of Credit - Additional Information (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Loss Contingencies [Line Items]
Notional amount of financial standby letters of credit	$ 5,900,000
Notional amount of performance standby letters of credit	2,600,000
Notional amount of commercial letters of credit	0
Financial instrument of credit risk	200,000	$ 200,000
Unused commitments and letters of credit [Member]
Loss Contingencies [Line Items]
Commitment liability	$ 4,400,000	$ 3,100,000