Loans and Asset Quality Information (Details 6) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Impaired loans at period end	$ 106,838	$ 140,976	$ 168,828
Average amount of impaired loans for period	139,971	152,312	185,124
Impaired loans with related allowance - Related Allowance	8,560	10,910	18,768
Impaired loans with no related allowance - Recorded Investment	47,245	79,423	92,865
Non-covered
Impaired loans at period end	57,882	85,286	96,003
Average amount of impaired loans for period	85,198	89,023	89,751
Impaired loans with related allowance - Related Allowance	5,051	5,804	7,613
Impaired loans with no related allowance - Recorded Investment	12,049	35,721	42,874
Covered
Impaired loans at period end	48,956	55,690	72,825
Average amount of impaired loans for period	54,773	63,289	95,373
Impaired loans with related allowance - Related Allowance	3,509	5,106	11,155
Impaired loans with no related allowance - Recorded Investment	$ 35,196	$ 43,702	$ 49,991