Income Taxes - Summary of Net Deferred Tax Asset Reported in Other Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Provision for loan losses	$ 16,110	$ 15,814
Write-downs of other real estate owned	1,252	1,297
Deferred compensation	3,108	2,652
Stock-based compensation	3,201	3,190
Investments in partnership interests	3,651	1,966
Other	917	306
Gross deferred tax assets	28,239	25,225
Unrealized net gains on securities	(962)	(2,644)
Premium on securities of banks acquired	(563)	(715)
Intangibles	(5,575)	(2,917)
Basis difference related to tax credits	(2,689)	(1,977)
Depreciation	(6,449)	(5,504)
Leveraged lease	(1,671)	(1,964)
Other	(606)	(89)
Gross deferred tax liabilities	(18,515)	(15,810)
Net deferred tax asset	$ 9,724	$ 9,415