Loans (Impaired Loans) (Details) (USD $) In Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Unpaid Contractual Principal Balance	$ 136,760	$ 158,012	$ 155,968
Total Recorded Investment	99,924	133,419	127,064
Related Allowance	8,166	20,532	13,513
Commercial And Industrial, Energy [Member]
Unpaid Contractual Principal Balance
Total Recorded Investment
Related Allowance
Commercial And Industrial, Energy [Member] | Recorded Investment With Allowance [Member]
Recorded Investment
Commercial And Industrial, Energy [Member] | Recorded Investment With No Allowance [Member]
Recorded Investment
Commercial And Industrial, Energy [Member] | Quarter To Date [Member]
Average Recorded Investment		715
Commercial And Industrial, Energy [Member] | Year To Date [Member]
Average Recorded Investment		1,265	1,012
Commercial And Industrial, Other Commercial [Member]
Unpaid Contractual Principal Balance	79,327	71,485	73,518
Total Recorded Investment	52,970	59,684	55,442
Related Allowance	6,883	16,555	9,137
Commercial And Industrial, Other Commercial [Member] | Recorded Investment With Allowance [Member]
Recorded Investment	10,387	33,396	14,541
Commercial And Industrial, Other Commercial [Member] | Recorded Investment With No Allowance [Member]
Recorded Investment	42,583	26,288	40,901
Commercial And Industrial, Other Commercial [Member] | Quarter To Date [Member]
Average Recorded Investment	60,696	56,073	57,563
Commercial And Industrial, Other Commercial [Member] | Year To Date [Member]
Average Recorded Investment	57,455	62,485	61,076
Commercial Real Estate, Buildings, Land And Other [Member]
Unpaid Contractual Principal Balance	52,193	75,002	72,099
Total Recorded Investment	42,115	62,656	61,805
Related Allowance	1,283	3,827	4,076
Commercial Real Estate, Buildings, Land And Other [Member] | Recorded Investment With Allowance [Member]
Recorded Investment	7,848	12,246	11,254
Commercial Real Estate, Buildings, Land And Other [Member] | Recorded Investment With No Allowance [Member]
Recorded Investment	34,267	50,410	50,551
Commercial Real Estate, Buildings, Land And Other [Member] | Quarter To Date [Member]
Average Recorded Investment	44,453	62,296	62,231
Commercial Real Estate, Buildings, Land And Other [Member] | Year To Date [Member]
Average Recorded Investment	50,562	58,523	59,179
Commercial Real Estate, Construction [Member]
Unpaid Contractual Principal Balance	2,162	10,576	9,834
Total Recorded Investment	1,773	10,130	9,300
Related Allowance		150	300
Commercial Real Estate, Construction [Member] | Recorded Investment With Allowance [Member]
Recorded Investment		747	747
Commercial Real Estate, Construction [Member] | Recorded Investment With No Allowance [Member]
Recorded Investment	1,773	9,383	8,553
Commercial Real Estate, Construction [Member] | Quarter To Date [Member]
Average Recorded Investment	2,265	8,905	9,715
Commercial Real Estate, Construction [Member] | Year To Date [Member]
Average Recorded Investment	5,104	7,840	8,132
Consumer Real Estate [Member]
Unpaid Contractual Principal Balance	2,510	792	517
Total Recorded Investment	2,498	792	517
Consumer Real Estate [Member] | Recorded Investment With No Allowance [Member]
Recorded Investment	2,498	792	517
Consumer Real Estate [Member] | Quarter To Date [Member]
Average Recorded Investment	2,227	885	654
Consumer Real Estate [Member] | Year To Date [Member]
Average Recorded Investment	1,689	1,071	960
Consumer And Other [Member]
Unpaid Contractual Principal Balance	568	157
Total Recorded Investment	568	157
Consumer And Other [Member] | Recorded Investment With No Allowance [Member]
Recorded Investment	568	157
Consumer And Other [Member] | Quarter To Date [Member]
Average Recorded Investment	335	214	79
Consumer And Other [Member] | Year To Date [Member]
Average Recorded Investment	193	492	393
Recorded Investment With Allowance [Member]
Recorded Investment	18,235	46,389	26,542
Recorded Investment With No Allowance [Member]
Recorded Investment	81,689	87,030	100,522
Quarter To Date [Member]
Average Recorded Investment	109,976	129,088	130,242
Year To Date [Member]
Average Recorded Investment	$ 115,003	$ 131,676	$ 130,752