Loans and the Allowance for Loan Losses (Details 6) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Loan portfolio by risk-rating grades
Total	$ 1,537,404	$ 1,377,988
Pass [Member]
Loan portfolio by risk-rating grades
Total	1,378,316	1,200,814
Watch [Member]
Loan portfolio by risk-rating grades
Total	74,957	92,091
Substandard [Member]
Loan portfolio by risk-rating grades
Total	84,131	85,083
Commercial, financial, agricultural [Member]
Loan portfolio by risk-rating grades
Total	227,867	197,771
Commercial, financial, agricultural [Member] | Pass [Member]
Loan portfolio by risk-rating grades
Total	221,676	187,550
Commercial, financial, agricultural [Member] | Watch [Member]
Loan portfolio by risk-rating grades
Total	2,653	2,929
Commercial, financial, agricultural [Member] | Substandard [Member]
Loan portfolio by risk-rating grades
Total	3,538	7,292
Real estate - construction [Member]
Loan portfolio by risk-rating grades
Total	77,194	55,063
Real estate - construction [Member] | Pass [Member]
Loan portfolio by risk-rating grades
Total	74,502	52,593
Real estate - construction [Member] | Watch [Member]
Loan portfolio by risk-rating grades
Total	902	2,362
Real estate - construction [Member] | Substandard [Member]
Loan portfolio by risk-rating grades
Total	1,790	108
Real estate - 1-4 family mortgage [Member]
Loan portfolio by risk-rating grades
Total	151,135	154,518
Real estate - 1-4 family mortgage [Member] | Pass [Member]
Loan portfolio by risk-rating grades
Total	89,333	86,858
Real estate - 1-4 family mortgage [Member] | Watch [Member]
Loan portfolio by risk-rating grades
Total	22,450	31,851
Real estate - 1-4 family mortgage [Member] | Substandard [Member]
Loan portfolio by risk-rating grades
Total	39,352	35,809
Real estate - commercial mortgage [Member]
Loan portfolio by risk-rating grades
Total	1,081,208	970,437
Real estate - commercial mortgage [Member] | Pass [Member]
Loan portfolio by risk-rating grades
Total	992,805	873,614
Real estate - commercial mortgage [Member] | Watch [Member]
Loan portfolio by risk-rating grades
Total	48,952	54,949
Real estate - commercial mortgage [Member] | Substandard [Member]
Loan portfolio by risk-rating grades
Total	39,451	41,874
Installment loans to individuals [Member]
Loan portfolio by risk-rating grades
Total		199
Installment loans to individuals [Member] | Pass [Member]
Loan portfolio by risk-rating grades
Total		199
Installment loans to individuals [Member] | Watch [Member]
Loan portfolio by risk-rating grades
Total
Installment loans to individuals [Member] | Substandard [Member]
Loan portfolio by risk-rating grades
Total