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		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period, allowance	$ 136,292	$ 130,243	$ 133,984	$ 130,322
Charge-offs	(13,944)	(12,682)	(26,946)	(20,532)
Recoveries	3,862	2,892	7,500	5,840
(Recapture) provision	10,657	10,589	22,329	15,412
Balance, end of period, allowance	136,867	131,042	136,867	131,042
Allowance for loans and leases:
Collectively evaluated for impairment					$ 132,416		$ 126,129
Individually evaluated for impairment					755		819
Total	136,292	130,243	133,984	130,322	136,867	$ 133,984	131,042
Financing Receivable, Allowance for Credit Loss, Loans And Leases [Abstract]
Collectively evaluated for impairment					18,022,573		16,969,555
Individually evaluated for impairment					62,859		54,835
Total					18,321,142	17,508,663	17,355,240
Receivables Acquired with Deteriorated Credit Quality
Allowance for loans and leases:
Loans acquired with deteriorated credit quality					3,696		4,094
Financing Receivable, Allowance for Credit Loss, Loans And Leases [Abstract]
Loans acquired with deteriorated credit quality					235,710	280,400	330,850
Commercial real estate
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period, allowance	49,006	51,450	47,795	54,293
Charge-offs	(809)	(564)	(1,148)	(1,066)
Recoveries	1,457	220	1,857	720
(Recapture) provision	(2,240)	(522)	(1,090)	(3,363)
Balance, end of period, allowance	47,414	50,584	47,414	50,584
Allowance for loans and leases:
Collectively evaluated for impairment					43,968		47,427
Individually evaluated for impairment					712		363
Total	49,006	51,450	47,795	54,293	47,414	47,795	50,584
Financing Receivable, Allowance for Credit Loss, Loans And Leases [Abstract]
Collectively evaluated for impairment					9,359,064		9,139,255
Individually evaluated for impairment					41,053		34,906
Total					9,590,571		9,443,960
Commercial real estate | Receivables Acquired with Deteriorated Credit Quality
Allowance for loans and leases:
Loans acquired with deteriorated credit quality					2,734		2,794
Financing Receivable, Allowance for Credit Loss, Loans And Leases [Abstract]
Loans acquired with deteriorated credit quality					190,454		269,799
Commercial
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period, allowance	59,117	50,781	58,840	47,487
Charge-offs	(10,696)	(9,594)	(20,800)	(14,249)
Recoveries	1,511	1,274	3,541	2,447
(Recapture) provision	10,125	9,894	18,476	16,670
Balance, end of period, allowance	60,057	52,355	60,057	52,355
Allowance for loans and leases:
Collectively evaluated for impairment					59,694		51,466
Individually evaluated for impairment					43		456
Total	59,117	50,781	58,840	47,487	60,057	58,840	52,355
Financing Receivable, Allowance for Credit Loss, Loans And Leases [Abstract]
Collectively evaluated for impairment					3,895,638		3,412,760
Individually evaluated for impairment					21,806		19,929
Total					3,922,657		3,442,086
Commercial | Receivables Acquired with Deteriorated Credit Quality
Allowance for loans and leases:
Loans acquired with deteriorated credit quality					320		433
Financing Receivable, Allowance for Credit Loss, Loans And Leases [Abstract]
Loans acquired with deteriorated credit quality					5,213		9,397
Residential
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period, allowance	17,966	20,897	17,946	22,017
Charge-offs	(407)	(294)	(617)	(631)
Recoveries	113	293	310	524
(Recapture) provision	379	(750)	412	(1,764)
Balance, end of period, allowance	18,051	20,146	18,051	20,146
Allowance for loans and leases:
Collectively evaluated for impairment					17,442		19,351
Individually evaluated for impairment					0		0
Total	17,966	20,897	17,946	22,017	18,051	17,946	20,146
Financing Receivable, Allowance for Credit Loss, Loans And Leases [Abstract]
Collectively evaluated for impairment					4,038,611		3,821,080
Individually evaluated for impairment					0		0
Total					4,078,179		3,871,890
Residential | Receivables Acquired with Deteriorated Credit Quality
Allowance for loans and leases:
Loans acquired with deteriorated credit quality					609		795
Financing Receivable, Allowance for Credit Loss, Loans And Leases [Abstract]
Loans acquired with deteriorated credit quality					39,568		50,810
Consumer & other, net
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period, allowance	10,203	7,115	9,403	6,525
Charge-offs	(2,032)	(2,230)	(4,381)	(4,586)
Recoveries	781	1,105	1,792	2,149
(Recapture) provision	2,393	1,967	4,531	3,869
Balance, end of period, allowance	11,345	7,957	11,345	7,957
Allowance for loans and leases:
Collectively evaluated for impairment					11,312		7,885
Individually evaluated for impairment					0		0
Total	$ 10,203	$ 7,115	$ 9,403	$ 6,525	11,345	$ 9,403	7,957
Financing Receivable, Allowance for Credit Loss, Loans And Leases [Abstract]
Collectively evaluated for impairment					729,260		596,460
Individually evaluated for impairment					0		0
Total					729,735		597,304
Consumer & other, net | Receivables Acquired with Deteriorated Credit Quality
Allowance for loans and leases:
Loans acquired with deteriorated credit quality					33		72
Financing Receivable, Allowance for Credit Loss, Loans And Leases [Abstract]
Loans acquired with deteriorated credit quality					$ 475		$ 844