Loans and Leases and the Allowance for Loan and Lease Losses (Allowance for Loan and Lease Losses) (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for Loan and Lease Losses:
Balance at the Beginning of Period	$ 102,880	$ 108,688	$ 115,454
Loans and Leases Charged-Off	(18,509)	(16,439)	(15,439)
Recoveries on Loans and Leases Previously Charged-Off	15,152	9,631	13,537
Net Loans and Leases Recovered (Charged-Off)	(3,357)	(6,808)	(1,902)
Provision for Credit Losses	4,750	1,000	(4,864)
Balance at End of Period	104,273	102,880	108,688
Allowance for Loan and Lease Losses:
Individually Evaluated for Impairment				$ 3,555	$ 3,578	$ 5,948
Collectively Evaluated for Impairment				100,718	99,302	102,740
Total	102,880	108,688	115,454	104,273	102,880	108,688
Recorded Investment in Loans and Leases:
Individually Evaluated for Impairment				60,698	66,697	64,747
Collectively Evaluated for Impairment				8,889,087	7,812,288	6,832,842
Total Loans and Leases				8,949,785	7,878,985	6,897,589
Commercial
Allowance for Loan and Lease Losses:
Balance at the Beginning of Period	60,714	64,551	71,446
Loans and Leases Charged-Off	(865)	(954)	(2,068)
Recoveries on Loans and Leases Previously Charged-Off	8,137	2,173	4,721
Net Loans and Leases Recovered (Charged-Off)	7,272	1,219	2,653
Provision for Credit Losses	(2,306)	(5,056)	(9,548)
Balance at End of Period	65,680	60,714	64,551
Allowance for Loan and Lease Losses:
Individually Evaluated for Impairment				45	205	2,387
Collectively Evaluated for Impairment				65,635	60,509	62,164
Total	60,714	64,551	71,446	65,680	60,714	64,551
Recorded Investment in Loans and Leases:
Individually Evaluated for Impairment				21,572	27,950	25,116
Collectively Evaluated for Impairment				3,596,120	3,125,902	2,803,012
Total Loans and Leases				3,617,692	3,153,852	2,828,128
Consumer
Allowance for Loan and Lease Losses:
Balance at the Beginning of Period	42,166	44,137	44,008
Loans and Leases Charged-Off	(17,644)	(15,485)	(13,371)
Recoveries on Loans and Leases Previously Charged-Off	7,015	7,458	8,816
Net Loans and Leases Recovered (Charged-Off)	(10,629)	(8,027)	(4,555)
Provision for Credit Losses	7,056	6,056	4,684
Balance at End of Period	38,593	42,166	44,137
Allowance for Loan and Lease Losses:
Individually Evaluated for Impairment				3,510	3,373	3,561
Collectively Evaluated for Impairment				35,083	38,793	40,576
Total	$ 42,166	$ 44,137	$ 44,008	38,593	42,166	44,137
Recorded Investment in Loans and Leases:
Individually Evaluated for Impairment				39,126	38,747	39,631
Collectively Evaluated for Impairment				5,292,967	4,686,386	4,029,830
Total Loans and Leases				$ 5,332,093	$ 4,725,133	$ 4,069,461