Loans and Allowance for Loan Losses - Schedule of Accounts Notes Loans and Financial Receivables (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and deferred loan fees receivables	$ 1,695,382	$ 1,618,454	$ 1,492,753
Commercial, Financial and Agricultural [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and deferred loan fees receivables	270,571	244,373	180,888
Real Estate - Construction and Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and deferred loan fees receivables	149,543	146,371	130,161
Real Estate - Commercial and Farmland [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and deferred loan fees receivables	836,230	808,323	766,227
Real Estate - Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and deferred loan fees receivables	393,001	366,882	367,056
Consumer Installment Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and deferred loan fees receivables	32,345	34,249	37,335
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and deferred loan fees receivables	$ 13,692	$ 18,256	$ 11,086