Loans - Summary of Excluding Purchased Non-Covered and Covered Past Due Financial Receivables (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-59 Days Past Due	$ 8,400		$ 20,700
Total Loans	1,770,059	1,618,454	1,555,827
Excluding Purchased Non-Covered and Covered Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-59 Days Past Due	15,895	21,890	13,646
Loans 60-89 Days Past Due	7,127	3,661	7,617
Loans 90 or More Days Past Due	19,437	27,659	27,057
Total Loans Past Due	42,459	53,210	48,320
Current Loans	1,727,600	1,565,244	1,507,507
Total Loans	1,770,059	1,618,454	1,555,827
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	304,588	244,373	208,424
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	1,180	10,893	1,449
Loans 60-89 Days Past Due	966	272	502
Loans 90 or More Days Past Due	1,077	4,081	4,013
Total Loans Past Due	3,223	15,246	5,964
Current Loans	301,365	229,127	202,460
Total Loans	304,588	244,373	208,424
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	149,346	146,371	134,607
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	3,942	1,026	1,638
Loans 60-89 Days Past Due	296	69	104
Loans 90 or More Days Past Due	3,449	3,935	5,418
Total Loans Past Due	7,687	5,030	7,160
Current Loans	141,659	141,341	127,447
Total Loans	149,346	146,371	134,607
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	850,000	808,323	788,654
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	4,622	3,981	5,392
Loans 60-89 Days Past Due	1,860	1,388	1,580
Loans 90 or More Days Past Due	7,404	7,751	5,333
Total Loans Past Due	13,886	13,120	12,305
Current Loans	836,114	795,203	776,349
Total Loans	850,000	808,323	788,654
Loans 90 Days or More Past Due and Still Accruing
Real Estate - Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	422,731	366,882	357,685
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	5,806	5,422	4,735
Loans 60-89 Days Past Due	3,829	1,735	5,256
Loans 90 or More Days Past Due	7,197	11,587	11,745
Total Loans Past Due	16,832	18,744	21,736
Current Loans	405,899	348,138	335,949
Total Loans	422,731	366,882	357,685
Loans 90 Days or More Past Due and Still Accruing
Consumer Installment Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	31,902	34,249	36,923
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	345	568	432
Loans 60-89 Days Past Due	176	197	175
Loans 90 or More Days Past Due	310	305	548
Total Loans Past Due	831	1,070	1,155
Current Loans	31,071	33,179	35,768
Total Loans	31,902	34,249	36,923
Loans 90 Days or More Past Due and Still Accruing
Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	11,492	18,256	29,534
Other [Member] | Excluding Purchased Non-Covered and Covered Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	11,492	18,256	29,534
Total Loans	11,492	18,256	29,534
Loans 90 Days or More Past Due and Still Accruing