Goodwill and Other Intangible Assets - Schedule of Other Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Other intangible assets	$ 7,327	$ 8,147
Core Deposits [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets	4,693	5,296
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets	2,099	2,262
Non-Compete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets	$ 535	$ 589