Loans and the Allowance for Loan Losses (Details 6) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Loan portfolio by risk-rating grades
Total	$ 2,095,961	$ 2,029,351
Commercial, financial, agricultural
Loan portfolio by risk-rating grades
Total	325,895	343,813
Real estate – construction
Loan portfolio by risk-rating grades
Total	124,644	115,016
Real estate – 1-4 family mortgage
Loan portfolio by risk-rating grades
Total	151,233	164,150
Real estate – commercial mortgage
Loan portfolio by risk-rating grades
Total	1,492,512	1,406,353
Installment loans to individuals
Loan portfolio by risk-rating grades
Total	1,677	19
Pass
Loan portfolio by risk-rating grades
Total	1,990,550	1,908,662
Pass | Commercial, financial, agricultural
Loan portfolio by risk-rating grades
Total	319,948	328,959
Pass | Real estate – construction
Loan portfolio by risk-rating grades
Total	123,503	114,428
Pass | Real estate – 1-4 family mortgage
Loan portfolio by risk-rating grades
Total	130,837	126,916
Pass | Real estate – commercial mortgage
Loan portfolio by risk-rating grades
Total	1,414,585	1,338,340
Pass | Installment loans to individuals
Loan portfolio by risk-rating grades
Total	1,677	19
Watch
Loan portfolio by risk-rating grades
Total	45,719	57,932
Watch | Commercial, financial, agricultural
Loan portfolio by risk-rating grades
Total	4,500	10,588
Watch | Real estate – construction
Loan portfolio by risk-rating grades
Total	1,141	588
Watch | Real estate – 1-4 family mortgage
Loan portfolio by risk-rating grades
Total	10,329	13,864
Watch | Real estate – commercial mortgage
Loan portfolio by risk-rating grades
Total	29,749	32,892
Watch | Installment loans to individuals
Loan portfolio by risk-rating grades
Total	0	0
Substandard
Loan portfolio by risk-rating grades
Total	59,692	62,757
Substandard | Commercial, financial, agricultural
Loan portfolio by risk-rating grades
Total	1,447	4,266
Substandard | Real estate – construction
Loan portfolio by risk-rating grades
Total	0	0
Substandard | Real estate – 1-4 family mortgage
Loan portfolio by risk-rating grades
Total	10,067	23,370
Substandard | Real estate – commercial mortgage
Loan portfolio by risk-rating grades
Total	48,178	35,121
Substandard | Installment loans to individuals
Loan portfolio by risk-rating grades
Total	$ 0	$ 0