Loans and the Allowance for Loan Losses (Details 8) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality	$ 271,663	$ 348,626
Impaired Covered Loans [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality	42,633	61,315
Other Covered Loans [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality	217,912	278,147
Not Covered Loans [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality	11,118	9,164
Commercial, financial, agricultural [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality	11,474	18,258
Commercial, financial, agricultural [Member] | Impaired Covered Loans [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality	10	38
Commercial, financial, agricultural [Member] | Other Covered Loans [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality	11,272	17,765
Commercial, financial, agricultural [Member] | Not Covered Loans [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality	192	455
Lease financing [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality
Lease financing [Member] | Impaired Covered Loans [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality
Lease financing [Member] | Other Covered Loans [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality
Lease financing [Member] | Not Covered Loans [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality
Real estate - construction [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality	1,932	7,076
Real estate - construction [Member] | Impaired Covered Loans [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality		4,031
Real estate - construction [Member] | Other Covered Loans [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality	1,932	3,045
Real estate - construction [Member] | Not Covered Loans [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality
Real estate - 1-4 family mortgage [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality	83,519	109,456
Real estate - 1-4 family mortgage [Member] | Impaired Covered Loans [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality	7,047	12,252
Real estate - 1-4 family mortgage [Member] | Other Covered Loans [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality	74,737	95,671
Real estate - 1-4 family mortgage [Member] | Not Covered Loans [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality	1,735	1,533
Real estate - commercial mortgage [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality	171,963	209,392
Real estate - commercial mortgage [Member] | Impaired Covered Loans [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality	35,576	44,994
Real estate - commercial mortgage [Member] | Other Covered Loans [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality	129,918	161,498
Real estate - commercial mortgage [Member] | Not Covered Loans [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality	6,469	2,900
Installment loans to individuals [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality	2,775	4,444
Installment loans to individuals [Member] | Impaired Covered Loans [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality
Installment loans to individuals [Member] | Other Covered Loans [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality	53	168
Installment loans to individuals [Member] | Not Covered Loans [Member]
Loans acquired with deteriorated credit quality
Acquired with deteriorated credit quality	$ 2,722	$ 4,276