Composition of Deposits (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Deposit Liabilities [Line Items]
Brokered deposits	Less than, equal to and greater than $100,000	Less than, equal to and greater than $100,000
Tennessee Commerce Bank ("TCB")
Deposit Liabilities [Line Items]
Brokered deposits	Less than, equal to and greater than $100,000
First Commercial Bank("FCB")
Deposit Liabilities [Line Items]
Brokered deposits	Less than, equal to and greater than $100,000