Loans and Leases and the Allowance for Loan and Lease Losses (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Allowance for Loan and Lease Losses:
Balance at the beginning of the period	$ 132,443	$ 144,976	$ 138,606	$ 147,358
Loans and Leases Charged-Off	(5,034)	(10,771)	(18,729)	(27,152)
Recoveries on Loans and Leases Previously Charged-Off	3,562	7,025	10,115	12,733
Net Loans and Leases Charged-Off	(1,472)	(3,746)	(8,614)	(14,419)
Provision for Credit Losses		2,180	979	10,471
Balance at end of the period	130,971	143,410	130,971	143,410
Allowance for Loan and Lease Losses:
Individually Evaluated for Impairment	3,283	4,179	3,283	4,179
Collectively Evaluated for Impairment	127,688	139,231	127,688	139,231
Total	130,971	143,410	130,971	143,410
Recorded Investment in Loans and Leases:
Individually Evaluated for Impairment	48,008	35,002	48,008	35,002
Collectively Evaluated for Impairment	5,734,296	5,313,470	5,734,296	5,313,470
Total Loans and Leases	5,782,304	5,348,472	5,782,304	5,348,472	5,538,304
Commercial
Allowance for Loan and Lease Losses:
Balance at the beginning of the period	78,012	88,985	80,562	80,977
Loans and Leases Charged-Off	(519)	(4,215)	(3,358)	(7,379)
Recoveries on Loans and Leases Previously Charged-Off	678	4,929	3,252	5,994
Net Loans and Leases Charged-Off	159	714	(106)	(1,385)
Provision for Credit Losses	1,647	(7,024)	(638)	3,083
Balance at end of the period	79,818	82,675	79,818	82,675
Allowance for Loan and Lease Losses:
Individually Evaluated for Impairment	39		39
Collectively Evaluated for Impairment	79,779	82,675	79,779	82,675
Total	79,818	82,675	79,818	82,675
Recorded Investment in Loans and Leases:
Individually Evaluated for Impairment	13,119	8,602	13,119	8,602
Collectively Evaluated for Impairment	2,214,204	2,085,561	2,214,204	2,085,561
Total Loans and Leases	2,227,323	2,094,163	2,227,323	2,094,163	2,166,017
Consumer
Allowance for Loan and Lease Losses:
Balance at the beginning of the period	54,431	55,991	58,044	66,381
Loans and Leases Charged-Off	(4,515)	(6,556)	(15,371)	(19,773)
Recoveries on Loans and Leases Previously Charged-Off	2,884	2,096	6,863	6,739
Net Loans and Leases Charged-Off	(1,631)	(4,460)	(8,508)	(13,034)
Provision for Credit Losses	(1,647)	9,204	1,617	7,388
Balance at end of the period	51,153	60,735	51,153	60,735
Allowance for Loan and Lease Losses:
Individually Evaluated for Impairment	3,244	4,179	3,244	4,179
Collectively Evaluated for Impairment	47,909	56,556	47,909	56,556
Total	51,153	60,735	51,153	60,735
Recorded Investment in Loans and Leases:
Individually Evaluated for Impairment	34,889	26,400	34,889	26,400
Collectively Evaluated for Impairment	3,520,092	3,227,909	3,520,092	3,227,909
Total Loans and Leases	$ 3,554,981	$ 3,254,309	$ 3,554,981	$ 3,254,309	$ 3,372,287