Loans - 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	6 Months Ended		12 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	$ 50,900	$ 66,987	$ 61,024
Recorded Investment With No Allowance
Recorded Investment With Allowance	39,448	49,826	46,417
Total impaired loans	39,448	49,826	46,417
Related Allowance	3,619	5,072	3,871
Average Recorded Investment	43,814	54,481	51,721
Commercial, Financial and Agricultural [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	3,398	7,723	6,240
Recorded Investment With No Allowance
Recorded Investment With Allowance	1,852	5,384	4,618
Total impaired loans	1,852	5,384	4,618
Related Allowance	298	1,018	435
Average Recorded Investment	3,397	4,960	4,844
Real Estate - Construction and Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	9,336	15,324	11,363
Recorded Investment With No Allowance
Recorded Investment With Allowance	5,532	7,394	5,867
Total impaired loans	5,532	7,394	5,867
Related Allowance	798	687	512
Average Recorded Investment	5,811	9,894	8,341
Real Estate - Commercial and Farmland [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	19,215	19,759	18,456
Recorded Investment With No Allowance
Recorded Investment With Allowance	16,421	16,491	15,479
Total impaired loans	16,421	16,491	15,479
Related Allowance	1,629	1,657	1,443
Average Recorded Investment	16,394	18,692	17,559
Real Estate - Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	18,313	23,373	24,342
Recorded Investment With No Allowance
Recorded Investment With Allowance	15,131	19,893	19,970
Total impaired loans	15,131	19,893	19,970
Related Allowance	884	1,692	1,472
Average Recorded Investment	17,698	20,178	20,335
Consumer Installment Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Contractual Principal Balance	638	808	623
Recorded Investment With No Allowance
Recorded Investment With Allowance	512	664	483
Total impaired loans	512	664	483
Related Allowance	10	18	9
Average Recorded Investment	$ 514	$ 757	$ 642