Loans and the Allowance for Loan Losses (Details 6) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Loan portfolio by risk-rating grades
Total	$ 1,578,119	$ 1,530,101
Pass [Member]
Loan portfolio by risk-rating grades
Total	1,457,818	1,383,422
Watch [Member]
Loan portfolio by risk-rating grades
Total	50,510	72,876
Substandard [Member]
Loan portfolio by risk-rating grades
Total	69,791	73,803
Commercial, financial, agricultural [Member]
Loan portfolio by risk-rating grades
Total	233,701	231,697
Commercial, financial, agricultural [Member] | Pass [Member]
Loan portfolio by risk-rating grades
Total	228,692	226,540
Commercial, financial, agricultural [Member] | Watch [Member]
Loan portfolio by risk-rating grades
Total	3,086	1,939
Commercial, financial, agricultural [Member] | Substandard [Member]
Loan portfolio by risk-rating grades
Total	1,923	3,218
Real estate - construction [Member]
Loan portfolio by risk-rating grades
Total	84,791	72,284
Real estate - construction [Member] | Pass [Member]
Loan portfolio by risk-rating grades
Total	84,121	71,633
Real estate - construction [Member] | Watch [Member]
Loan portfolio by risk-rating grades
Total	659	651
Real estate - construction [Member] | Substandard [Member]
Loan portfolio by risk-rating grades
Total	11	0
Real estate - 1-4 family mortgage [Member]
Loan portfolio by risk-rating grades
Total	147,352	152,874
Real estate - 1-4 family mortgage [Member] | Pass [Member]
Loan portfolio by risk-rating grades
Total	102,217	96,147
Real estate - 1-4 family mortgage [Member] | Watch [Member]
Loan portfolio by risk-rating grades
Total	13,716	24,138
Real estate - 1-4 family mortgage [Member] | Substandard [Member]
Loan portfolio by risk-rating grades
Total	31,419	32,589
Real estate - commercial mortgage [Member]
Loan portfolio by risk-rating grades
Total	1,112,275	1,073,239
Real estate - commercial mortgage [Member] | Pass [Member]
Loan portfolio by risk-rating grades
Total	1,042,788	989,095
Real estate - commercial mortgage [Member] | Watch [Member]
Loan portfolio by risk-rating grades
Total	33,049	46,148
Real estate - commercial mortgage [Member] | Substandard [Member]
Loan portfolio by risk-rating grades
Total	36,438	37,996
Installment loans to individuals [Member]
Loan portfolio by risk-rating grades
Total	0	7
Installment loans to individuals [Member] | Pass [Member]
Loan portfolio by risk-rating grades
Total	0	7
Installment loans to individuals [Member] | Watch [Member]
Loan portfolio by risk-rating grades
Total	0	0
Installment loans to individuals [Member] | Substandard [Member]
Loan portfolio by risk-rating grades
Total	$ 0	$ 0