Goodwill and Intangibles - Summary of Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	$ 14,583	$ 14,560
Accumulated Amortization	(6,038)	(5,618)
Net Intangible Assets	8,545	8,942
Core Deposits [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	7,610	7,610
Accumulated Amortization	(3,578)	(3,321)
Net Intangible Assets	4,032	4,289
CB&T Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	3,142	3,142
Accumulated Amortization	(1,035)	(985)
Net Intangible Assets	2,107	2,157
Array and Arrow Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	2,353	2,353
Accumulated Amortization	(584)	(497)
Net Intangible Assets	1,769	1,856
Mortgage Servicing Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	1,478	1,455
Accumulated Amortization	(841)	(815)
Net Intangible Assets	$ 637	$ 640