Loans - Summary of Covered Past Due Financial Receivables (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans 30-59 Days Past Due	$ 20,700	$ 40,300
Total Loans	1,555,827	1,450,635	1,365,489
Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans 30-59 Days Past Due	13,572	21,536	21,427
Loans 60-89 Days Past Due	5,891	14,479	14,637
Loans 90 or More Days Past Due	76,904	108,072	130,640
Total Loans Past Due	96,367	144,087	166,704
Current Loans	347,150	363,625	435,033
Total Loans	443,517	507,712	601,737
Loans 90 Days or More Past Due and Still Accruing	1,107	3,301	1,267
Commercial, Financial and Agricultural [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	208,424	174,217	174,903
Commercial, Financial and Agricultural [Member] | Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans 30-59 Days Past Due	529	2,390	851
Loans 60-89 Days Past Due	441	1,105	754
Loans 90 or More Days Past Due	7,333	10,612	12,703
Total Loans Past Due	8,303	14,107	14,308
Current Loans	19,068	18,499	27,064
Total Loans	27,371	32,606	41,372
Loans 90 Days or More Past Due and Still Accruing	63	98	298
Real Estate - Construction and Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	134,607	114,199	124,556
Real Estate - Construction and Development [Member] | Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans 30-59 Days Past Due	2,672	1,584	2,688
Loans 60-89 Days Past Due	743	2,592	3,007
Loans 90 or More Days Past Due	15,911	19,656	25,021
Total Loans Past Due	19,326	23,832	30,716
Current Loans	33,646	46,352	53,275
Total Loans	52,972	70,184	83,991
Loans 90 Days or More Past Due and Still Accruing	348	1,077
Real Estate - Commercial and Farmland [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	788,654	732,322	675,404
Real Estate - Commercial and Farmland [Member] | Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans 30-59 Days Past Due	4,020	11,451	12,452
Loans 60-89 Days Past Due	3,929	7,373	7,656
Loans 90 or More Days Past Due	41,250	52,570	60,879
Total Loans Past Due	49,199	71,394	80,987
Current Loans	205,903	207,112	241,406
Total Loans	255,102	278,506	322,393
Loans 90 Days or More Past Due and Still Accruing	636	1,347	891
Real Estate - Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	357,685	346,480	332,124
Real Estate - Residential [Member] | Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans 30-59 Days Past Due	6,283	6,066	5,366
Loans 60-89 Days Past Due	772	3,396	3,180
Loans 90 or More Days Past Due	12,155	24,976	31,607
Total Loans Past Due	19,210	34,438	40,153
Current Loans	87,897	90,618	110,530
Total Loans	107,107	125,056	150,683
Loans 90 Days or More Past Due and Still Accruing	60	779	78
Consumer Installment Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	36,923	40,178	41,431
Consumer Installment Loans [Member] | Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans 30-59 Days Past Due	68	45	70
Loans 60-89 Days Past Due	6	13	40
Loans 90 or More Days Past Due	255	258	430
Total Loans Past Due	329	316	540
Current Loans	636	1,044	2,758
Total Loans	$ 965	$ 1,360	$ 3,298