Allowance for Loan and Lease Loss and Credit Quality (Activity In The Allowance For Loan And Lease Losses) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period, allowance	$ 133,984	$ 130,322
Charge-offs	(13,002)	(7,850)
Recoveries	3,638	2,948
Provision	11,672	4,823
Balance, end of period, allowance	136,292	130,243
Allowance for loans and leases:
Collectively evaluated for impairment			$ 132,005		$ 126,600
Individually evaluated for impairment			742		799
Total	133,984	130,322	136,292	$ 133,984	130,243
Financing Receivable, Allowance for Credit Loss, Loans And Leases [Abstract]
Collectively evaluated for impairment			17,513,669		16,542,041
Individually evaluated for impairment			55,710		51,248
Total			17,829,638	17,508,663	16,955,583
Receivables Acquired with Deteriorated Credit Quality
Allowance for loans and leases:
Loans acquired with deteriorated credit quality			3,545		2,844
Financing Receivable, Allowance for Credit Loss, Loans And Leases [Abstract]
Loans acquired with deteriorated credit quality			260,259	280,400	362,294
Commercial real estate
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period, allowance	47,795	54,293
Charge-offs	(339)	(502)
Recoveries	400	500
Provision	1,150	(2,841)
Balance, end of period, allowance	49,006	51,450
Allowance for loans and leases:
Collectively evaluated for impairment			45,722		49,069
Individually evaluated for impairment			735		317
Total	47,795	54,293	49,006	47,795	51,450
Financing Receivable, Allowance for Credit Loss, Loans And Leases [Abstract]
Collectively evaluated for impairment			9,243,447		9,013,669
Individually evaluated for impairment			40,353		30,819
Total			9,496,747		9,337,055
Commercial real estate | Receivables Acquired with Deteriorated Credit Quality
Allowance for loans and leases:
Loans acquired with deteriorated credit quality			2,549		2,064
Financing Receivable, Allowance for Credit Loss, Loans And Leases [Abstract]
Loans acquired with deteriorated credit quality			212,947		292,567
Commercial
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period, allowance	58,840	47,487
Charge-offs	(10,104)	(4,655)
Recoveries	2,030	1,173
Provision	8,351	6,776
Balance, end of period, allowance	59,117	50,781
Allowance for loans and leases:
Collectively evaluated for impairment			58,763		50,250
Individually evaluated for impairment			7		482
Total	58,840	47,487	59,117	58,840	50,781
Financing Receivable, Allowance for Credit Loss, Loans And Leases [Abstract]
Collectively evaluated for impairment			3,714,197		3,207,045
Individually evaluated for impairment			15,357		20,429
Total			3,734,847		3,241,003
Commercial | Receivables Acquired with Deteriorated Credit Quality
Allowance for loans and leases:
Loans acquired with deteriorated credit quality			347		49
Financing Receivable, Allowance for Credit Loss, Loans And Leases [Abstract]
Loans acquired with deteriorated credit quality			5,293		13,529
Residential
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period, allowance	17,946	22,017
Charge-offs	(210)	(337)
Recoveries	197	231
Provision	33	(1,014)
Balance, end of period, allowance	17,966	20,897
Allowance for loans and leases:
Collectively evaluated for impairment			17,374		20,223
Individually evaluated for impairment			0		0
Total	17,946	22,017	17,966	17,946	20,897
Financing Receivable, Allowance for Credit Loss, Loans And Leases [Abstract]
Collectively evaluated for impairment			3,890,613		3,767,604
Individually evaluated for impairment			0		0
Total			3,932,062		3,822,854
Residential | Receivables Acquired with Deteriorated Credit Quality
Allowance for loans and leases:
Loans acquired with deteriorated credit quality			592		674
Financing Receivable, Allowance for Credit Loss, Loans And Leases [Abstract]
Loans acquired with deteriorated credit quality			41,449		55,250
Consumer & other, net
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period, allowance	9,403	6,525
Charge-offs	(2,349)	(2,356)
Recoveries	1,011	1,044
Provision	2,138	1,902
Balance, end of period, allowance	10,203	7,115
Allowance for loans and leases:
Collectively evaluated for impairment			10,146		7,058
Individually evaluated for impairment			0		0
Total	$ 9,403	$ 6,525	10,203	$ 9,403	7,115
Financing Receivable, Allowance for Credit Loss, Loans And Leases [Abstract]
Collectively evaluated for impairment			665,412		553,723
Individually evaluated for impairment			0		0
Total			665,982		554,671
Consumer & other, net | Receivables Acquired with Deteriorated Credit Quality
Allowance for loans and leases:
Loans acquired with deteriorated credit quality			57		57
Financing Receivable, Allowance for Credit Loss, Loans And Leases [Abstract]
Loans acquired with deteriorated credit quality			$ 570		$ 948