Loans and the Allowance for Loan Losses (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014		Dec. 31, 2013
Summary of loans
Gross loans	$ 3,957,577		$ 3,881,019
Unearned income	(47)		(1)
Loans, net of unearned income	3,957,530		3,881,018
Allowance for loan losses	(47,304)		(47,665)
Loans, net	3,910,226		3,833,353
Commercial, financial, agricultural
Summary of loans
Gross loans	447,826		468,963
Loans, net of unearned income	447,826		468,963
Lease financing
Summary of loans
Gross loans	1,814		53
Real estate – construction
Summary of loans
Gross loans	176,577		161,436
Loans, net of unearned income	176,577		161,436
Real estate – 1-4 family mortgage
Summary of loans
Gross loans	1,221,288		1,208,233
Loans, net of unearned income	1,221,288		1,208,233
Real estate – commercial mortgage
Summary of loans
Gross loans	2,015,319		1,950,572
Loans, net of unearned income	2,015,319		1,950,572
Installment loans to individuals
Summary of loans
Gross loans	94,753		91,762
Loans, net of unearned income	$ 96,520	[1]	$ 91,814	[1]

[1] Includes lease financing receivables.