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		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 151,069	$ 144,556	$ 144,871	$ 140,608
Charge-offs	(23,112)	(15,896)	(56,971)	(46,523)
Recoveries	5,104	3,655	12,125	11,255
Provision	23,227	11,711	56,263	38,686
Ending balance	156,288	144,026	156,288	144,026
Allowance for loans and leases:
Collectively evaluated for impairment					$ 154,281		$ 141,332
Individually evaluated for impairment					198		220
Total	151,069	144,556	144,871	140,608	156,288	$ 144,871	144,026
Loans and leases:
Collectively evaluated for impairment					21,390,289		19,665,506
Individually evaluated for impairment					25,669		43,543
Total					21,520,794	20,422,666	19,854,033
Receivables Acquired with Deteriorated Credit Quality
Allowance for loans and leases:
Loans acquired with deteriorated credit quality					1,809		2,474
Loans and leases:
Loans acquired with deteriorated credit quality					104,836	134,500	144,984
Commercial real estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	48,997	47,285	47,904	45,765
Charge-offs	(497)	(415)	(3,035)	(1,088)
Recoveries	177	413	733	919
Provision	2,524	(942)	5,599	745
Ending balance	51,201	46,341	51,201	46,341
Allowance for loans and leases:
Collectively evaluated for impairment					49,676		44,353
Individually evaluated for impairment					188		215
Total	48,997	47,285	47,904	46,341	51,201	47,904	46,341
Loans and leases:
Collectively evaluated for impairment					10,402,556		9,934,169
Individually evaluated for impairment					17,973		25,410
Total					10,504,554		10,072,942
Commercial real estate | Receivables Acquired with Deteriorated Credit Quality
Allowance for loans and leases:
Loans acquired with deteriorated credit quality					1,337		1,773
Loans and leases:
Loans acquired with deteriorated credit quality					84,025		113,363
Commercial
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	68,353	65,765	63,957	63,305
Charge-offs	(20,457)	(13,926)	(48,364)	(40,270)
Recoveries	4,263	2,473	9,228	8,097
Provision	18,797	11,133	46,135	34,313
Ending balance	70,956	65,445	70,956	65,445
Allowance for loans and leases:
Collectively evaluated for impairment					70,783		65,135
Individually evaluated for impairment					10		5
Total	68,353	65,765	63,957	65,445	70,956	63,957	65,445
Loans and leases:
Collectively evaluated for impairment					5,043,000		4,543,599
Individually evaluated for impairment					7,696		18,133
Total					5,051,267		4,565,012
Commercial | Receivables Acquired with Deteriorated Credit Quality
Allowance for loans and leases:
Loans acquired with deteriorated credit quality					163		305
Loans and leases:
Loans acquired with deteriorated credit quality					571		3,280
Residential
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	23,654	20,275	22,034	19,360
Charge-offs	(305)	(95)	(507)	(801)
Recoveries	94	237	399	538
Provision	1,113	609	2,630	1,929
Ending balance	24,556	21,026	24,556	21,026
Allowance for loans and leases:
Collectively evaluated for impairment					24,255		20,671
Individually evaluated for impairment					0		0
Total	23,654	20,275	22,034	21,026	24,556	22,034	21,026
Loans and leases:
Collectively evaluated for impairment					5,450,319		4,583,986
Individually evaluated for impairment					0		0
Total					5,470,252		4,611,920
Residential | Receivables Acquired with Deteriorated Credit Quality
Allowance for loans and leases:
Loans acquired with deteriorated credit quality					301		355
Loans and leases:
Loans acquired with deteriorated credit quality					19,933		27,934
Consumer & other, net
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	10,065	11,231	10,976	12,178
Charge-offs	(1,853)	(1,460)	(5,065)	(4,364)
Recoveries	570	532	1,765	1,701
Provision	793	911	1,899	1,699
Ending balance	9,575	11,214	9,575	11,214
Allowance for loans and leases:
Collectively evaluated for impairment					9,567		11,173
Individually evaluated for impairment					0		0
Total	$ 10,065	$ 11,231	$ 10,976	$ 12,178	9,575	$ 10,976	11,214
Loans and leases:
Collectively evaluated for impairment					494,414		603,752
Individually evaluated for impairment					0		0
Total					494,721		604,159
Consumer & other, net | Receivables Acquired with Deteriorated Credit Quality
Allowance for loans and leases:
Loans acquired with deteriorated credit quality					8		41
Loans and leases:
Loans acquired with deteriorated credit quality					$ 307		$ 407