Loans and Allowance for Loan Losses - Analysis of Information Pertaining to Impaired Loans, Excluding Purchased Non-Covered and Covered Loans (Detail) (Excluding Purchased Non-Covered and Covered Loans [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	$ 61,024	$ 78,758
Recorded Investment With No Allowance
Recorded Investment With Allowance	46,417	57,629	88,774
Total impaired loans	46,417	57,629	88,774
Related Allowance	3,871	5,115	18,478
Average Recorded Investment	51,721	70,209	88,320
Commercial, Financial and Agricultural [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	6,240	8,024
Recorded Investment With No Allowance
Recorded Investment With Allowance	4,618	4,940
Total impaired loans	4,618	4,940
Related Allowance	435	743
Average Recorded Investment	4,844	4,968
Real Estate - Construction and Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	11,363	20,316
Recorded Investment With No Allowance
Recorded Investment With Allowance	5,867	11,016
Total impaired loans	5,867	11,016
Related Allowance	512	910
Average Recorded Investment	8,341	11,706
Real Estate - Commercial and Farmland [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	18,456	25,076
Recorded Investment With No Allowance
Recorded Investment With Allowance	15,479	20,910
Total impaired loans	15,479	20,910
Related Allowance	1,443	2,191
Average Recorded Investment	17,559	30,638
Real Estate - Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	24,342	24,155
Recorded Investment With No Allowance
Recorded Investment With Allowance	19,970	19,848
Total impaired loans	19,970	19,848
Related Allowance	1,472	1,246
Average Recorded Investment	20,335	21,813
Consumer Installment Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	623	1,187
Recorded Investment With No Allowance
Recorded Investment With Allowance	483	915
Total impaired loans	483	915
Related Allowance	9	25
Average Recorded Investment	$ 642	$ 1,084