Significant Accounting Policies - Additional Cash Flow Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Accounting Policies [Abstract]
Cash paid for interest	$ 3,257	$ 2,794
Cash paid for income taxes	0	0
Unsettled purchases of securities	33,466	94,905
Loans foreclosed and transferred to other real estate owned and foreclosed assets	$ 0	$ 376