Loans and the Allowance for Loan Losses (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Summary of loans
Gross loans	$ 3,867,439		$ 3,881,019
Unearned income	(11)		(1)
Loans, net of unearned income	3,867,428		3,881,018
Allowance for loan losses	(48,048)		(47,665)
Loans, net	3,819,380		3,833,353
Commercial, financial, agricultural
Summary of loans
Gross loans	440,116		468,963
Loans, net of unearned income	440,116		468,963
Lease financing
Summary of loans
Gross loans	623		53
Real estate – construction
Summary of loans
Gross loans	155,900		161,436
Loans, net of unearned income	155,900		161,436
Real estate – 1-4 family mortgage
Summary of loans
Gross loans	1,211,260		1,208,233
Loans, net of unearned income	1,211,260		1,208,233
Real estate – commercial mortgage
Summary of loans
Gross loans	1,968,158		1,950,572
Loans, net of unearned income	1,968,158		1,950,572
Installment loans to individuals
Summary of loans
Gross loans	91,382		91,762
Loans, net of unearned income	$ 91,994	[1]	$ 91,814	[1]

[1] Includes lease financing receivables.