Loans and Allowance for Loan Losses - Additional Information (Detail) (USD $)	12 Months Ended			12 Months Ended							12 Months Ended								12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Refund Anticipation Loans	Dec. 31, 2011 Refund Anticipation Loans	Dec. 31, 2012 Troubled Debt Restructuring	Dec. 31, 2011 Troubled Debt Restructuring	Dec. 31, 2012 Subprime Lending	Dec. 31, 2011 Subprime Lending	Dec. 31, 2011 Unallocated Financing Receivables	Dec. 31, 2012 Commercial and Commercial Real Estate Loans	Dec. 31, 2012 Commercial and Commercial Real Estate Loans Minimum Business Line 1	Dec. 31, 2012 "Special Mention/Watch", "Substandard", "Doubtful" or "Loss" Minimum	Dec. 31, 2012 Pass Minimum	Dec. 31, 2012 Tennessee Commerce Bank ("TCB")	Jan. 27, 2012 Tennessee Commerce Bank ("TCB")	Dec. 31, 2012 First Commercial Bank("FCB")	Sep. 07, 2012 First Commercial Bank("FCB")	Dec. 31, 2012 TCB and FCB acquisitions
Financing Receivable, Allowance for Credit Losses [Line Items]
Contractual amount of loan	$ 180,833,000														$ 41,677,000	$ 79,000,000	$ 139,156,000	$ 172,000,000
Carrying value of the loans purchased															31,000,000	57,000,000	108,000,000	128,000,000
Loan acquired	13,000,000
Aggregate credit exposure validated by senior loan committee												2,000,000
Credit quality description	The SAC reviews all commercial and commercial real estate past due, classified, and impaired loans in excess of $100,000 and discusses the relative trends and current status of these assets. In addition,the SAC reviews all retail residential real estate loans exceeding $750,000 and all home equity loans exceeding $100,000 that are 80-days or more past due or that are on non-accrual status. SAC also reviews the actions taken by management regarding foreclosure mitigation, loan extensions, troubled debt restructures and collateral repossessions. Based on the information reviewed in this meeting, the SAC approves all specific loan loss allocations to be recognized by the Bank within its Allowance for Loan Loss analysis.										For new and renewed commercial, commercial real estate and real estate construction, the Bank's Credit Administration Department ("CAD") assigns the credit quality grade to the loan. Loan grades for new commercial, commercial real estate and real estate construction loans with an aggregate credit exposure of $2.0 million or greater are validated by the Senior Loan Committee ("SLC").
Impaired loans	100,000					15,000,000	6,000,000
Residential real estate loans	750,000
Home equity loans	100,000
Number of days for home equity loans due	80 days
Aggregate lending relationship outstanding amount													1,000,000	4,000,000
Allowance for loan losses	23,729,000	24,063,000								2,000,000
Loan totaled								66,000,000	93,000,000
Loan outstanding								19,000,000	22,000,000
Impaired loans	105,707,000	77,193,000	51,292,000																18,000,000
Allocated specific reserve to customers whose loan terms modified in TDRs	7,000,000	5,000,000																	18,000,000
Percentage of trouble debt restructuring occurred during period and performing according to modified terms	91.00%	89.00%
Amount of specific reserves to customers whose loan terms were modified in trouble debt restructurings	5,000,000
RAL's total uncollected	$ 20,844,000	$ 24,433,000		$ 10,500,000	$ 14,300,000														$ 5,967,000
RAL's gross total				1.31%	1.38%