Loans and Allowance for Loan Losses - Summary of Covered Past Due Financial Receivables (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Finance Receivable Transferred To Held For Sale [Line Items]
Loans 30-59 Days Past Due	$ 40,300	$ 37,200
Total Loans	1,450,635	1,332,086
Covered Loan [Member]
Finance Receivable Transferred To Held For Sale [Line Items]
Loans 30-59 Days Past Due	21,536	25,306
Loans 60-89 Days Past Due	14,479	15,922
Loans 90 or More Days Past Due	108,072	139,601
Total Loans Past Due	144,087	180,829
Current Loans	363,625	390,660
Total Loans	507,712	571,489
Loans 90 Days or More Past Due and Still Accruing	3,301	455
Commercial, financial & agricultural [Member]
Finance Receivable Transferred To Held For Sale [Line Items]
Total Loans	174,217	142,960
Commercial, financial & agricultural [Member] | Covered Loan [Member]
Finance Receivable Transferred To Held For Sale [Line Items]
Loans 30-59 Days Past Due	2,390	968
Loans 60-89 Days Past Due	1,105	4,297
Loans 90 or More Days Past Due	10,612	11,253
Total Loans Past Due	14,107	16,518
Current Loans	18,499	25,349
Total Loans	32,606	41,867
Loans 90 Days or More Past Due and Still Accruing	98
Real estate - construction & development [Member]
Finance Receivable Transferred To Held For Sale [Line Items]
Total Loans	114,199	130,270
Real estate - construction & development [Member] | Covered Loan [Member]
Finance Receivable Transferred To Held For Sale [Line Items]
Loans 30-59 Days Past Due	1,584	2,444
Loans 60-89 Days Past Due	2,592	1,318
Loans 90 or More Days Past Due	19,656	27,867
Total Loans Past Due	23,832	31,629
Current Loans	46,352	45,448
Total Loans	70,184	77,077
Loans 90 Days or More Past Due and Still Accruing	1,077
Real estate - commercial and farmland [Member]
Finance Receivable Transferred To Held For Sale [Line Items]
Total Loans	732,322	672,765
Real estate - commercial and farmland [Member] | Covered Loan [Member]
Finance Receivable Transferred To Held For Sale [Line Items]
Loans 30-59 Days Past Due	11,451	18,282
Loans 60-89 Days Past Due	7,373	8,544
Loans 90 or More Days Past Due	52,570	64,091
Total Loans Past Due	71,394	90,917
Current Loans	207,112	230,340
Total Loans	278,506	321,257
Loans 90 Days or More Past Due and Still Accruing	1,347	165
Real estate - residential [Member]
Finance Receivable Transferred To Held For Sale [Line Items]
Total Loans	346,480	330,727
Real estate - residential [Member] | Covered Loan [Member]
Finance Receivable Transferred To Held For Sale [Line Items]
Loans 30-59 Days Past Due	6,066	3,485
Loans 60-89 Days Past Due	3,396	1,493
Loans 90 or More Days Past Due	24,976	35,950
Total Loans Past Due	34,438	40,928
Current Loans	90,618	86,716
Total Loans	125,056	127,644
Loans 90 Days or More Past Due and Still Accruing	779	290
Consumer installment loans [Member]
Finance Receivable Transferred To Held For Sale [Line Items]
Total Loans	40,178	37,296
Consumer installment loans [Member] | Covered Loan [Member]
Finance Receivable Transferred To Held For Sale [Line Items]
Loans 30-59 Days Past Due	45	127
Loans 60-89 Days Past Due	13	270
Loans 90 or More Days Past Due	258	440
Total Loans Past Due	316	837
Current Loans	1,044	2,807
Total Loans	$ 1,360	$ 3,644