Supplemental Cash Flow Disclosures - Non-cash Investing and Financing Activities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash paid during the year for:
Interest	$ 19,208	$ 15,818	$ 18,943
Income taxes	19,950	8,331	10,700
Non-cash investing and financing activities:
Loans transferred to other real estate owned and repossessed assets	4,824	8,257	5,061
Fair value of loans transferred from held to maturity to available for sale	18,758	3,196	3,035
Gross (decrease) increase in market value adjustment to securities available for sale	(6,919)	2,949	24,601
Gross (decrease) increase in market value adjustment to securities derivatives	(549)	401	472
Investments committed to purchase, not settled	0	694	0
Net (liabilities) assets acquired through acquisition	$ (501,516)	$ 463	$ 0
Other Significant Noncash Transaction, Consideration Received	437	0	0
Other Significant Noncash Transaction, Value of Consideration Received	$ 3,769	$ 0	$ 0
Contribution of premises	$ 0	$ 0	$ 682