Loans - Summary of Excluding Purchased Non-Covered and Covered Past Due Financial Receivables (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-59 Days Past Due	$ 6,300		$ 27,400
Total Loans	1,695,382	1,618,454	1,492,753
Excluding Purchased Non-Covered and Covered Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-59 Days Past Due	8,773	21,890	22,881
Loans 60-89 Days Past Due	3,894	3,661	6,795
Loans 90 or More Days Past Due	25,140	27,659	33,655
Total Loans Past Due	37,807	53,210	63,331
Current Loans	1,657,575	1,565,244	1,429,422
Total Loans	1,695,382	1,618,454	1,492,753
Loans 90 Days or More Past Due and Still Accruing
Commercial, Financial and Agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	270,571	244,373	180,888
Commercial, Financial and Agricultural [Member] | Excluding Purchased Non-Covered and Covered Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-59 Days Past Due	1,083	10,893	1,797
Loans 60-89 Days Past Due	386	272	149
Loans 90 or More Days Past Due	2,956	4,081	3,729
Total Loans Past Due	4,425	15,246	5,675
Current Loans	266,146	229,127	175,213
Total Loans	270,571	244,373	180,888
Loans 90 Days or More Past Due and Still Accruing
Real Estate - Construction and Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	149,543	146,371	130,161
Real Estate - Construction and Development [Member] | Excluding Purchased Non-Covered and Covered Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-59 Days Past Due	1,304	1,026	1,538
Loans 60-89 Days Past Due	249	69	1,538
Loans 90 or More Days Past Due	3,919	3,935	8,312
Total Loans Past Due	5,472	5,030	11,388
Current Loans	144,071	141,341	118,773
Total Loans	149,543	146,371	130,161
Loans 90 Days or More Past Due and Still Accruing
Real Estate - Commercial and Farmland [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	836,230	808,323	766,227
Real Estate - Commercial and Farmland [Member] | Excluding Purchased Non-Covered and Covered Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-59 Days Past Due	2,255	3,981	11,115
Loans 60-89 Days Past Due	1,650	1,388	3,220
Loans 90 or More Days Past Due	7,622	7,751	9,352
Total Loans Past Due	11,527	13,120	23,687
Current Loans	824,703	795,203	742,540
Total Loans	836,230	808,323	766,227
Loans 90 Days or More Past Due and Still Accruing
Real Estate - Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	393,001	366,882	367,056
Real Estate - Residential [Member] | Excluding Purchased Non-Covered and Covered Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-59 Days Past Due	3,657	5,422	7,686
Loans 60-89 Days Past Due	1,541	1,735	1,719
Loans 90 or More Days Past Due	10,298	11,587	11,699
Total Loans Past Due	15,496	18,744	21,104
Current Loans	377,505	348,138	345,952
Total Loans	393,001	366,882	367,056
Loans 90 Days or More Past Due and Still Accruing
Consumer Installment Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	32,345	34,249	37,335
Consumer Installment Loans [Member] | Excluding Purchased Non-Covered and Covered Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-59 Days Past Due	474	568	745
Loans 60-89 Days Past Due	68	197	169
Loans 90 or More Days Past Due	345	305	563
Total Loans Past Due	887	1,070	1,477
Current Loans	31,458	33,179	35,858
Total Loans	32,345	34,249	37,335
Loans 90 Days or More Past Due and Still Accruing
Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	13,692	18,256	11,086
Other [Member] | Excluding Purchased Non-Covered and Covered Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	13,692	18,256	11,086
Total Loans	13,692	18,256	11,086
Loans 90 Days or More Past Due and Still Accruing