Goodwill and Other Intangible Assets - Schedule of Other Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Other intangible assets	$ 5,759	$ 8,147
Core deposits [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets	3,537	5,296
Customer relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets	1,796	2,262
Non-compete agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets	$ 426	$ 589