Loans and Allowance for Loan Losses - Summary of Non-Covered Past Due Financial Receivables (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-59 Days Past Due	$ 40,300	$ 37,200
Total Loans	1,450,635	1,332,086
Non-Covered Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-59 Days Past Due	11,825	16,376
Loans 60-89 Days Past Due	6,097	14,583
Loans 90 or More Days Past Due	34,287	64,135
Total Loans Past Due	52,209	95,094
Current Loans	1,398,426	1,236,992
Total Loans	1,450,635	1,332,086
Loans 90 Days or More Past Due and Still Accruing
Commercial, financial & agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	174,217	142,960
Commercial, financial & agricultural [Member] | Non-Covered Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-59 Days Past Due	258	1,103
Loans 60-89 Days Past Due	312	705
Loans 90 or More Days Past Due	3,969	3,975
Total Loans Past Due	4,539	5,783
Current Loans	169,678	137,177
Total Loans	174,217	142,960
Loans 90 Days or More Past Due and Still Accruing
Real estate - construction & development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	114,199	130,270
Real estate - construction & development [Member] | Non-Covered Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-59 Days Past Due	347	2,395
Loans 60-89 Days Past Due	332	1,507
Loans 90 or More Days Past Due	8,969	13,608
Total Loans Past Due	9,648	17,510
Current Loans	104,551	112,760
Total Loans	114,199	130,270
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	732,322	672,765
Real estate - commercial and farmland [Member] | Non-Covered Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-59 Days Past Due	2,867	6,686
Loans 60-89 Days Past Due	2,296	7,071
Loans 90 or More Days Past Due	9,544	32,953
Total Loans Past Due	14,707	46,710
Current Loans	717,615	626,055
Total Loans	732,322	672,765
Loans 90 Days or More Past Due and Still Accruing
Real estate - residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	346,480	330,727
Real estate - residential [Member] | Non-Covered Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-59 Days Past Due	7,651	5,229
Loans 60-89 Days Past Due	2,766	4,995
Loans 90 or More Days Past Due	10,990	12,874
Total Loans Past Due	21,407	23,098
Current Loans	325,073	307,629
Total Loans	346,480	330,727
Loans 90 Days or More Past Due and Still Accruing
Consumer installment loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	40,178	37,296
Consumer installment loans [Member] | Non-Covered Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-59 Days Past Due	702	963
Loans 60-89 Days Past Due	391	305
Loans 90 or More Days Past Due	815	725
Total Loans Past Due	1,908	1,993
Current Loans	38,270	35,303
Total Loans	40,178	37,296
Loans 90 Days or More Past Due and Still Accruing
Other Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	43,239	18,068
Other Loans [Member] | Non-Covered Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans 30-59 Days Past Due
Loans 60-89 Days Past Due
Loans 90 or More Days Past Due
Total Loans Past Due
Current Loans	43,239	18,068
Total Loans	43,239	18,068
Loans 90 Days or More Past Due and Still Accruing