Goodwill and Intangible Assets - Additional Information (Detail) (USD $)				12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 TCB and FCB acquisitions	Dec. 31, 2012 First Commercial Bank("FCB")	Dec. 31, 2012 Tennessee Commerce Bank ("TCB")
Finite-Lived Intangible Assets [Line Items]
Core deposits associated with intangible assets	$ 1,160,000	$ 601,000	$ 623,000		$ 64,000
Core deposits associated with intangible assets beginning balance				559,000
Core deposits amortization period				24 month runoff period
Core deposits associated with intangible assets, ending balance				$ 489,000