Investment Securities (Summary of Investment Securities with Gross Unrealized Losses) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Summary of continuous unrealized loss position of securities
Less Than 12 Months, Fair Value	$ 141,129	$ 288,058
Less Than 12 Months, Gross Unrealized Losses	2,734	1,306
12 Months or More, Fair Value	86,618	97,896
12 Months or More, Gross Unrealized Losses	6,351	7,107
Total, Fair Value	227,747	385,954
Total, Gross Unrealized Losses	9,085	8,413
Government sponsored agencies [Member]
Summary of continuous unrealized loss position of securities
Less Than 12 Months, Fair Value	46,103	9,883
Less Than 12 Months, Gross Unrealized Losses	213	36
12 Months or More, Fair Value	0	9,632
12 Months or More, Gross Unrealized Losses	0	11
Total, Fair Value	46,103	19,515
Total, Gross Unrealized Losses	213	47
State and political subdivisions [Member]
Summary of continuous unrealized loss position of securities
Less Than 12 Months, Fair Value	70,675	0
Less Than 12 Months, Gross Unrealized Losses	2,257	0
12 Months or More, Fair Value	8,046	31,706
12 Months or More, Gross Unrealized Losses	1,110	342
Total, Fair Value	78,721	31,706
Total, Gross Unrealized Losses	3,367	342
Residential mortgage-backed securities [Member]
Summary of continuous unrealized loss position of securities
Less Than 12 Months, Fair Value	273	27,367
Less Than 12 Months, Gross Unrealized Losses	1	152
12 Months or More, Fair Value	1,305	19,018
12 Months or More, Gross Unrealized Losses	8	149
Total, Fair Value	1,578	46,385
Total, Gross Unrealized Losses	9	301
Collateralized mortgage obligations [Member]
Summary of continuous unrealized loss position of securities
Less Than 12 Months, Fair Value	19,331	200,218
Less Than 12 Months, Gross Unrealized Losses	10	703
12 Months or More, Fair Value	36,835	18,176
12 Months or More, Gross Unrealized Losses	172	129
Total, Fair Value	56,166	218,394
Total, Gross Unrealized Losses	182	832
Corporate bonds [Member]
Summary of continuous unrealized loss position of securities
Less Than 12 Months, Fair Value	4,747	50,590
Less Than 12 Months, Gross Unrealized Losses	253	415
12 Months or More, Fair Value	34,707	14,580
12 Months or More, Gross Unrealized Losses	286	420
Total, Fair Value	39,454	65,170
Total, Gross Unrealized Losses	539	835
Trust preferred securities [Member]
Summary of continuous unrealized loss position of securities
Less Than 12 Months, Fair Value	0	0
Less Than 12 Months, Gross Unrealized Losses	0	0
12 Months or More, Fair Value	5,725	4,465
12 Months or More, Gross Unrealized Losses	4,775	6,035
Total, Fair Value	5,725	4,465
Total, Gross Unrealized Losses	4,775	6,035
Preferred stock [Member]
Summary of continuous unrealized loss position of securities
Less Than 12 Months, Fair Value		0
Less Than 12 Months, Gross Unrealized Losses		0
12 Months or More, Fair Value		319
12 Months or More, Gross Unrealized Losses		21
Total, Fair Value		319
Total, Gross Unrealized Losses		$ 21