Loans - Summary of Covered Past Due Financial Receivables (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans 30-59 Days Past Due	$ 8,000		$ 17,000
Total Loans	1,848,759	1,618,454	1,589,267
Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans 30-59 Days Past Due	10,996	20,990	13,544
Loans 60-89 Days Past Due	2,062	6,434	7,785
Loans 90 or More Days Past Due	25,231	57,197	64,368
Total Loans Past Due	38,289	84,621	85,697
Current Loans	275,300	305,616	331,952
Total Loans	313,589	390,237	417,649
Loans 90 Days or More Past Due and Still Accruing	370	346	1,657
Commercial, Financial and Agricultural [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	334,783	244,373	244,991
Commercial, Financial and Agricultural [Member] | Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans 30-59 Days Past Due	568	3,966	319
Loans 60-89 Days Past Due	188	12	50
Loans 90 or More Days Past Due	1,978	6,165	6,695
Total Loans Past Due	2,734	10,143	7,064
Current Loans	19,811	16,407	20,704
Total Loans	22,545	26,550	27,768
Loans 90 Days or More Past Due and Still Accruing	0	0	0
Real Estate - Construction and Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	154,315	146,371	132,277
Real Estate - Construction and Development [Member] | Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans 30-59 Days Past Due	632	843	2,831
Loans 60-89 Days Past Due	72	144	658
Loans 90 or More Days Past Due	8,659	14,055	15,781
Total Loans Past Due	9,363	15,042	19,270
Current Loans	18,393	28,137	31,432
Total Loans	27,756	43,179	50,702
Loans 90 Days or More Past Due and Still Accruing	0	0	266
Real Estate - Commercial and Farmland [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	882,160	808,323	799,149
Real Estate - Commercial and Farmland [Member] | Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans 30-59 Days Past Due	7,100	8,482	7,365
Loans 60-89 Days Past Due	322	4,350	5,350
Loans 90 or More Days Past Due	8,930	26,428	30,503
Total Loans Past Due	16,352	39,260	43,218
Current Loans	164,214	185,191	193,868
Total Loans	180,566	224,451	237,086
Loans 90 Days or More Past Due and Still Accruing	305	346	568
Real Estate - Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	436,515	366,882	355,920
Real Estate - Residential [Member] | Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans 30-59 Days Past Due	2,694	7,648	2,980
Loans 60-89 Days Past Due	1,473	1,914	1,727
Loans 90 or More Days Past Due	5,563	10,244	11,078
Total Loans Past Due	9,730	19,806	15,785
Current Loans	72,715	75,367	85,361
Total Loans	82,445	95,173	101,146
Loans 90 Days or More Past Due and Still Accruing	65	0	823
Consumer Installment Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	31,403	34,249	36,303
Consumer Installment Loans [Member] | Covered Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans 30-59 Days Past Due	2	51	49
Loans 60-89 Days Past Due	7	14	0
Loans 90 or More Days Past Due	101	305	311
Total Loans Past Due	110	370	360
Current Loans	167	514	587
Total Loans	277	884	947
Loans 90 Days or More Past Due and Still Accruing	$ 0	$ 0	$ 0