Subsequent Event - Additional Information (Detail) $ in Thousands		12 Months Ended
	Feb. 23, 2016 USD ($) Loan	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Subsequent Event [Line Items]
Total Loans amount, placed on nonaccrual status		$ 6,433	$ 1,954
Provision for impairment reserves		$ 1,597	$ 611
Subsequent Event | Bank's commercial borrowers pleaded guilty in a federal court
Subsequent Event [Line Items]
Number of loans | Loan	5
Total Loans amount, placed on nonaccrual status	$ 2,200
Provision for impairment reserves	$ 691