Commitments and Contingent Liabilities - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]
Allowance for credit losses associated with loan commitments	$ 571	$ 613	$ 455	$ 602
Liability associated with letters of credit	$ 200	$ 200