Loans - Summary of Covered Loans According to Loan Type (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Covered Loans	$ 313,589,000	$ 390,237,000	$ 417,649,000
Commercial, Financial and Agricultural [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Covered Loans	22,545,000	26,550,000	27,768,000
Real Estate - Construction and Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Covered Loans	27,756,000	43,179,000	50,702,000
Real Estate - Commercial and Farmland [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Covered Loans	180,566,000	224,451,000	237,086,000
Real Estate - Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Covered Loans	82,445,000	95,173,000	101,146,000
Consumer Installment Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Covered Loans	$ 277,000	$ 884,000	$ 947,000