Loans - Summary of Covered Past Due Financial Receivables (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans 30-59 Days Past Due	$ 17,000		$ 23,500
Total Loans	1,589,267	1,450,635	1,439,862
Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans 30-59 Days Past Due	13,544	21,536	16,825
Loans 60-89 Days Past Due	7,785	14,479	12,451
Loans 90 or More Days Past Due	64,368	108,072	113,705
Total Loans Past Due	85,697	144,087	142,981
Current Loans	331,952	363,625	403,253
Total Loans	417,649	507,712	546,234
Loans 90 Days or More Past Due and Still Accruing	1,657	3,301	4,138
Commercial, Financial and Agricultural [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	244,991	174,217	189,374
Commercial, Financial and Agricultural [Member] | Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans 30-59 Days Past Due	319	2,390	1,384
Loans 60-89 Days Past Due	50	1,105	788
Loans 90 or More Days Past Due	6,695	10,612	11,315
Total Loans Past Due	7,064	14,107	13,487
Current Loans	20,704	18,499	23,680
Total Loans	27,768	32,606	37,167
Loans 90 Days or More Past Due and Still Accruing		98
Real Estate - Construction and Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	132,277	114,199	125,315
Real Estate - Construction and Development [Member] | Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans 30-59 Days Past Due	2,831	1,584	3,611
Loans 60-89 Days Past Due	658	2,592	1,663
Loans 90 or More Days Past Due	15,781	19,656	22,194
Total Loans Past Due	19,270	23,832	27,468
Current Loans	31,432	46,352	45,888
Total Loans	50,702	70,184	73,356
Loans 90 Days or More Past Due and Still Accruing	266	1,077	2,312
Real Estate - Commercial and Farmland [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	799,149	732,322	713,240
Real Estate - Commercial and Farmland [Member] | Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans 30-59 Days Past Due	7,365	11,451	7,072
Loans 60-89 Days Past Due	5,350	7,373	6,559
Loans 90 or More Days Past Due	30,503	52,570	51,382
Total Loans Past Due	43,218	71,394	65,013
Current Loans	193,868	207,112	233,890
Total Loans	237,086	278,506	298,903
Loans 90 Days or More Past Due and Still Accruing	568	1,347	808
Real Estate - Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	355,920	346,480	343,332
Real Estate - Residential [Member] | Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans 30-59 Days Past Due	2,980	6,066	4,702
Loans 60-89 Days Past Due	1,727	3,396	3,349
Loans 90 or More Days Past Due	11,078	24,976	28,559
Total Loans Past Due	15,785	34,438	36,610
Current Loans	85,361	90,618	98,544
Total Loans	101,146	125,056	135,154
Loans 90 Days or More Past Due and Still Accruing	823	779	1,018
Consumer Installment Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	36,303	40,178	43,441
Consumer Installment Loans [Member] | Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans 30-59 Days Past Due	49	45	56
Loans 60-89 Days Past Due		13	92
Loans 90 or More Days Past Due	311	258	255
Total Loans Past Due	360	316	403
Current Loans	587	1,044	1,251
Total Loans	$ 947	$ 1,360	$ 1,654