Loans (Impaired Loans) (Details) (USD $) In Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Unpaid Contractual Principal Balance	$ 144,667	$ 147,923	$ 155,968
Recorded Investment With No Allowance	93,735	63,301	100,522
Recorded Investment With Allowance	26,291	61,452	26,542
Total Recorded Investment	120,026	124,753	127,064
Related Allowance	18,399	20,361	13,513
Commercial And Industrial, Energy [Member]
Unpaid Contractual Principal Balance		1,500
Recorded Investment With Allowance		1,430
Total Recorded Investment		1,430
Related Allowance		750
Commercial And Industrial, Energy [Member] | Quarter To Date [Member]
Average Recorded Investment		1,997
Commercial And Industrial, Energy [Member] | Year To Date [Member]
Average Recorded Investment		1,686	1,012
Commercial And Industrial, Other Commercial [Member]
Unpaid Contractual Principal Balance	82,311	65,060	73,518
Recorded Investment With No Allowance	48,401	18,148	40,901
Recorded Investment With Allowance	20,021	34,314	14,541
Total Recorded Investment	68,422	52,462	55,442
Related Allowance	16,983	15,336	9,137
Commercial And Industrial, Other Commercial [Member] | Quarter To Date [Member]
Average Recorded Investment	60,705	58,238	57,563
Commercial And Industrial, Other Commercial [Member] | Year To Date [Member]
Average Recorded Investment	58,950	63,418	61,076
Commercial Real Estate, Buildings, Land And Other [Member]
Unpaid Contractual Principal Balance	57,117	72,100	72,099
Recorded Investment With No Allowance	40,937	37,902	50,551
Recorded Investment With Allowance	5,854	24,033	11,254
Total Recorded Investment	46,791	61,935	61,805
Related Allowance	1,316	3,644	4,076
Commercial Real Estate, Buildings, Land And Other [Member] | Quarter To Date [Member]
Average Recorded Investment	49,164	59,467	62,231
Commercial Real Estate, Buildings, Land And Other [Member] | Year To Date [Member]
Average Recorded Investment	53,377	57,145	59,179
Commercial Real Estate, Construction [Member]
Unpaid Contractual Principal Balance	3,181	8,017	9,834
Recorded Investment With No Allowance	2,756	6,005	8,553
Recorded Investment With Allowance		1,675	747
Total Recorded Investment	2,756	7,680	9,300
Related Allowance		631	300
Commercial Real Estate, Construction [Member] | Quarter To Date [Member]
Average Recorded Investment	4,672	7,307	9,715
Commercial Real Estate, Construction [Member] | Year To Date [Member]
Average Recorded Investment	6,214	7,076	8,132
Consumer Real Estate [Member]
Unpaid Contractual Principal Balance	1,956	976	517
Recorded Investment With No Allowance	1,540	976	517
Recorded Investment With Allowance	416
Total Recorded Investment	1,956	976	517
Related Allowance	100
Consumer Real Estate [Member] | Quarter To Date [Member]
Average Recorded Investment	1,871	1,118	655
Consumer Real Estate [Member] | Year To Date [Member]
Average Recorded Investment	1,420	1,164	960
Consumer And Other [Member]
Unpaid Contractual Principal Balance	102	270
Recorded Investment With No Allowance	101	270
Total Recorded Investment	101	270
Consumer And Other [Member] | Quarter To Date [Member]
Average Recorded Investment	101	763	79
Consumer And Other [Member] | Year To Date [Member]
Average Recorded Investment	67	603	393
Quarter To Date [Member]
Average Recorded Investment	116,513	128,890	130,242
Year To Date [Member]
Average Recorded Investment	$ 120,028	$ 131,092	$ 130,752