Loans and the Allowance for Loan Losses (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012
Summary of loans
Gross loans	$ 2,884,513		$ 2,810,258
Unearned income	(2)		(5)
Loans, net of unearned income	2,884,511		2,810,253
Allowance for loan losses	(47,034)		(44,347)
Loans, net	2,837,477		2,765,906
Commercial, financial, agricultural [Member]
Summary of loans
Gross loans	318,001		317,050
Loans, net of unearned income	318,001		317,050
Lease financing [Member]
Summary of loans
Gross loans	105		195
Real estate - construction [Member]
Summary of loans
Gross loans	118,987		105,706
Loans, net of unearned income	118,987		105,706
Real estate - 1-4 family mortgage [Member]
Summary of loans
Gross loans	920,293		903,423
Loans, net of unearned income	920,293		903,423
Real estate - commercial mortgage [Member]
Summary of loans
Gross loans	1,464,522		1,426,643
Loans, net of unearned income	1,464,522		1,426,643
Installment loans to individuals [Member]
Summary of loans
Gross loans	62,605		57,241
Loans, net of unearned income	$ 62,708	[1]	$ 57,431	[1]

[1] Includes lease financing receivables.