Condensed Financial Information (Parent Company Only) - Condensed Balance Sheets (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Assets
Total cash and cash equivalents	$ 48,650	$ 43,476	$ 31,721	$ 30,735
Other assets	31,995	32,141
Total assets	2,652,401	2,076,922
Liabilities
Subordinated debentures	32,797	32,642
Other liabilities	22,765	15,852
Stockholders' Equity	266,832	194,414	164,520	158,968
Total liabilities and stockholders' equity	2,652,401	2,076,922
Parent Company [Member]
Assets
Total cash and cash equivalents	26,507	19,195	$ 16,807	$ 13,639
Investment in Bank	276,718	211,928
Other assets	3,392	2,758
Total assets	306,617	233,881
Liabilities
Subordinated debentures	32,797	32,642
Other liabilities	6,988	6,825
Stockholders' Equity	266,832	194,414
Total liabilities and stockholders' equity	$ 306,617	$ 233,881