Goodwill and Intangibles - Summary of Intangible Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	$ 14,527	$ 14,560
Accumulated Amortization	(6,975)	(5,618)
Net Intangible Assets	7,552	8,942
Core Deposits [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	7,610	7,610
Accumulated Amortization	(4,170)	(3,321)
Net Intangible Assets	3,440	4,289
CB&T Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	3,142	3,142
Accumulated Amortization	(1,133)	(985)
Net Intangible Assets	2,009	2,157
Array and Arrow Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	2,353	2,353
Accumulated Amortization	(759)	(497)
Net Intangible Assets	1,594	1,856
Mortgage Servicing Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	1,422	1,455
Accumulated Amortization	(913)	(815)
Net Intangible Assets	$ 509	$ 640