Income Taxes - Summary of Net Deferred Tax Asset Reported in Other Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Provision for loan losses	$ 18,748	$ 16,110
Write-downs of other real estate owned	769	1,252
Deferred compensation	3,197	3,108
Stock-based compensation	2,441	3,201
Investments in partnership interests	4,603	3,651
Other	666	917
Gross deferred tax assets	30,424	28,239
Unrealized net gains on securities	(59)	(962)
Premium on securities of banks acquired	(453)	(563)
Intangibles	(5,365)	(5,575)
Basis difference related to tax credits	(3,435)	(2,689)
Depreciation	(6,758)	(6,449)
Leveraged lease	(1,408)	(1,671)
Other	(271)	(606)
Gross deferred tax liabilities	(17,749)	(18,515)
Net deferred tax asset	$ 12,675	$ 9,724