Covered Loans Held for Investment, Net of Unearned Income (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans held for investment, net of unearned income	$ 195,060	$ 207,106
Commercial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans held for investment, net of unearned income	87,128	97,382
Commercial Loans | Construction Development And Other Land
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans held for investment, net of unearned income	24,495	26,595
Commercial Loans | Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans held for investment, net of unearned income	5,205	6,948
Commercial Loans | Multi-family Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans held for investment, net of unearned income	2,549	2,611
Commercial Loans | Single-family Non-owner Occupied
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans held for investment, net of unearned income	10,672	11,428
Commercial Loans | Non-farm Non-residential Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans held for investment, net of unearned income	42,857	48,565
Commercial Loans | Agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans held for investment, net of unearned income	128	144
Commercial Loans | Farmland Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans held for investment, net of unearned income	1,222	1,091
Consumer Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans held for investment, net of unearned income	105,133	106,050
Consumer Real Estate | Home Equity Lines
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans held for investment, net of unearned income	80,463	81,445
Consumer Real Estate | Single Family Owner Occupied
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans held for investment, net of unearned income	23,042	22,961
Consumer Real Estate | Owner Occupied Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans held for investment, net of unearned income	1,628	1,644
Consumer and Other Loans | Consumer Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans held for investment, net of unearned income	$ 2,799	$ 3,674