Loans and Allowance for Loan Losses - Summary of Troubled Debt Restructurings by Loan Class, Excluding Purchased Non-Covered and Covered Loans (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Financing Receivable, Modifications [Line Items]
Troubled debt restructuring loans	$ 20,900	$ 23,900
Excluding Purchased Non-Covered and Covered Loans [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructuring loans	17,214	18,744	17,951
Excluding Purchased Non-Covered and Covered Loans [Member] | Accruing Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	72	55
Troubled debt restructuring loans	17,214	18,744
Excluding Purchased Non-Covered and Covered Loans [Member] | Accruing Loans [Member] | Commercial, Financial and Agricultural [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	4	5
Troubled debt restructuring loans	515	802
Excluding Purchased Non-Covered and Covered Loans [Member] | Accruing Loans [Member] | Real Estate - Construction and Development [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	8	5
Troubled debt restructuring loans	1,896	1,735
Excluding Purchased Non-Covered and Covered Loans [Member] | Accruing Loans [Member] | Real Estate - Commercial and Farmland [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	17	16
Troubled debt restructuring loans	6,913	8,947
Excluding Purchased Non-Covered and Covered Loans [Member] | Accruing Loans [Member] | Real Estate - Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	37	28
Troubled debt restructuring loans	7,818	7,254
Excluding Purchased Non-Covered and Covered Loans [Member] | Accruing Loans [Member] | Consumer Installment Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	6	1
Troubled debt restructuring loans	72	6
Excluding Purchased Non-Covered and Covered Loans [Member] | Non-Accruing Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	20	5
Troubled debt restructuring loans	3,683	5,171
Excluding Purchased Non-Covered and Covered Loans [Member] | Non-Accruing Loans [Member] | Commercial, Financial and Agricultural [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	3
Troubled debt restructuring loans	525
Excluding Purchased Non-Covered and Covered Loans [Member] | Non-Accruing Loans [Member] | Real Estate - Construction and Development [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	2
Troubled debt restructuring loans	32
Excluding Purchased Non-Covered and Covered Loans [Member] | Non-Accruing Loans [Member] | Real Estate - Commercial and Farmland [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	4	3
Troubled debt restructuring loans	2,273	4,149
Excluding Purchased Non-Covered and Covered Loans [Member] | Non-Accruing Loans [Member] | Real Estate - Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	8	2
Troubled debt restructuring loans	834	1,022
Excluding Purchased Non-Covered and Covered Loans [Member] | Non-Accruing Loans [Member] | Consumer Installment Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of contracts	3
Troubled debt restructuring loans	$ 19