Loans and Leases and the Allowance for Loan and Lease Losses (Details 4) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012
Aging Analysis of Accruing and Non-Accruing Loans and Leases
30 - 59 Days Past Due	$ 18,584	$ 20,555
60 - 89 Days Past Due	20,024	21,303
Past Due 90 Days or More	11,398	10,409
Non-Accrual	30,796	33,196
Total Past Due and Non-Accrual	80,802	85,463
Current	5,925,840	5,769,058
Total Loans and Leases	6,006,642	5,854,521	5,782,304
Non-Accrual Loans and Leases that are Current	10,747	12,738
Number of days non-accrual loans and leases are not past due	30 days
Commercial
Aging Analysis of Accruing and Non-Accruing Loans and Leases
30 - 59 Days Past Due	1,352	994
60 - 89 Days Past Due	11,111	10,924
Past Due 90 Days or More	8	27
Non-Accrual	7,650	9,397
Total Past Due and Non-Accrual	20,121	21,342
Current	2,458,369	2,294,551
Total Loans and Leases	2,478,490	2,315,893	2,227,323
Non-Accrual Loans and Leases that are Current	4,479	7,606
Commercial and Industrial
Aging Analysis of Accruing and Non-Accruing Loans and Leases
30 - 59 Days Past Due	779	806
60 - 89 Days Past Due	11,111	10,382
Past Due 90 Days or More	8	27
Non-Accrual	5,295	5,534
Total Past Due and Non-Accrual	17,193	16,749
Current	877,847	812,763
Total Loans and Leases	895,040	829,512
Non-Accrual Loans and Leases that are Current	3,696	4,963
Commercial Mortgage
Aging Analysis of Accruing and Non-Accruing Loans and Leases
30 - 59 Days Past Due	573	188
60 - 89 Days Past Due	0	542
Non-Accrual	2,355	3,030
Total Past Due and Non-Accrual	2,928	3,760
Current	1,200,742	1,093,665
Total Loans and Leases	1,203,670	1,097,425
Non-Accrual Loans and Leases that are Current	783	1,810
Construction
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Non-Accrual		833
Total Past Due and Non-Accrual		833
Current	124,230	113,154
Total Loans and Leases	124,230	113,987
Non-Accrual Loans and Leases that are Current		833
Lease Financing
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Non-Accrual	0
Total Past Due and Non-Accrual	0
Current	255,550	274,969
Total Loans and Leases	255,550	274,969
Consumer
Aging Analysis of Accruing and Non-Accruing Loans and Leases
30 - 59 Days Past Due	17,232	19,561
60 - 89 Days Past Due	8,913	10,379
Past Due 90 Days or More	11,390	10,382
Non-Accrual	23,146	23,799
Total Past Due and Non-Accrual	60,681	64,121
Current	3,467,471	3,474,507
Total Loans and Leases	3,528,152	3,538,628	3,554,981
Non-Accrual Loans and Leases that are Current	6,268	5,132
Residential Mortgage
Aging Analysis of Accruing and Non-Accruing Loans and Leases
30 - 59 Days Past Due	7,014	6,891
60 - 89 Days Past Due	2,508	5,433
Past Due 90 Days or More	7,460	6,908
Non-Accrual	20,637	21,725
Total Past Due and Non-Accrual	37,619	40,957
Current	2,244,686	2,308,959
Total Loans and Leases	2,282,305	2,349,916
Non-Accrual Loans and Leases that are Current	5,611	4,941
Home Equity
Aging Analysis of Accruing and Non-Accruing Loans and Leases
30 - 59 Days Past Due	3,546	6,768
60 - 89 Days Past Due	4,518	3,267
Past Due 90 Days or More	2,896	2,701
Non-Accrual	2,509	2,074
Total Past Due and Non-Accrual	13,469	14,810
Current	752,372	755,566
Total Loans and Leases	765,841	770,376
Non-Accrual Loans and Leases that are Current	657	191
Automobile
Aging Analysis of Accruing and Non-Accruing Loans and Leases
30 - 59 Days Past Due	3,811	3,758
60 - 89 Days Past Due	614	586
Past Due 90 Days or More	193	186
Total Past Due and Non-Accrual	4,618	4,530
Current	242,086	205,302
Total Loans and Leases	246,704	209,832
Other
Aging Analysis of Accruing and Non-Accruing Loans and Leases
30 - 59 Days Past Due	2,861	2,144
60 - 89 Days Past Due	1,273	1,093
Past Due 90 Days or More	841	587
Total Past Due and Non-Accrual	4,975	3,824
Current	228,327	204,680
Total Loans and Leases	$ 233,302	$ 208,504