Long-Term Borrowings and Subordinated Debt - Schedule of Long-Term Borrowings, Interest Expense and Weighted Average Interest Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Debt Disclosure [Abstract]
Long-term borrowings	$ 117,043	$ 19,442	$ 21,810
Weighted average interest rate	0.81%	3.00%	3.01%
Interest expense	$ 790	$ 617	$ 746