Securities - Information Pertaining to Security Sales (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]
Proceeds	$ 105,066	$ 61,236	$ 35,633
Gross Gains	1,032	606	849
Gross Losses	$ 366	$ 177	$ 494