Loans and Leases and the Allowance for Loan and Lease Losses (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Allowance for Loan and Lease Losses:
Balance at the beginning of the period	$ 128,857	$ 138,606
Loans and Leases Charged-Off	(5,299)	(7,759)
Recoveries on Loans and Leases Previously Charged-Off	3,320	4,408
Net Loans and Leases Charged-Off	(1,979)	(3,351)
Provision for Credit Losses	0	351
Balance at end of the period	126,878	135,606
Allowance for Loan and Lease Losses:
Individually Evaluated for Impairment	3,703	4,183
Collectively Evaluated for Impairment	123,175	131,423
Total	126,878	135,606
Recorded Investment in Loans and Leases:
Individually Evaluated for Impairment	49,585	43,976
Collectively Evaluated for Impairment	5,733,384	5,554,956
Total Loans and Leases	5,782,969	5,598,932	5,854,521
Commercial
Allowance for Loan and Lease Losses:
Balance at the beginning of the period	72,704	80,562
Loans and Leases Charged-Off	(382)	(1,761)
Recoveries on Loans and Leases Previously Charged-Off	797	2,029
Net Loans and Leases Charged-Off	415	268
Provision for Credit Losses	297	(2,656)
Balance at end of the period	73,416	78,174
Allowance for Loan and Lease Losses:
Individually Evaluated for Impairment	177	83
Collectively Evaluated for Impairment	73,239	78,091
Total	73,416	78,174
Recorded Investment in Loans and Leases:
Individually Evaluated for Impairment	13,115	13,989
Collectively Evaluated for Impairment	2,313,308	2,118,969
Total Loans and Leases	2,326,423	2,132,958	2,315,893
Consumer
Allowance for Loan and Lease Losses:
Balance at the beginning of the period	56,153	58,044
Loans and Leases Charged-Off	(4,917)	(5,998)
Recoveries on Loans and Leases Previously Charged-Off	2,523	2,379
Net Loans and Leases Charged-Off	(2,394)	(3,619)
Provision for Credit Losses	(297)	3,007
Balance at end of the period	53,462	57,432
Allowance for Loan and Lease Losses:
Individually Evaluated for Impairment	3,526	4,100
Collectively Evaluated for Impairment	49,936	53,332
Total	53,462	57,432
Recorded Investment in Loans and Leases:
Individually Evaluated for Impairment	36,470	29,987
Collectively Evaluated for Impairment	3,420,076	3,435,987
Total Loans and Leases	$ 3,456,546	$ 3,465,974	$ 3,538,628