Loans - Accruing And Non-Accruing Loans By Class (Details) - USD ($) $ in Thousands	Sep. 30, 2018		Dec. 31, 2017		Sep. 30, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net of unearned income	$ 27,350,214	[1]	$ 27,658,929	[1]	$ 20,166,091
Accruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	27,108,765		27,435,858
Total Accruing	27,203,857		27,528,310
Accruing | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	53,613		50,884
Accruing | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	41,479		41,568
Non-Accruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	101,712		70,040
Total Non- Accruing	146,357		130,619
Non-Accruing | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	8,425		13,654
Non-Accruing | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	36,220		46,925
Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net of unearned income	16,044,145		16,057,273
Commercial Portfolio Segment | General C&I
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net of unearned income	13,645,749		13,550,990
Commercial Portfolio Segment | Loans to Mortgage Companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net of unearned income	2,092,366		2,099,961
Commercial Portfolio Segment | TRUPs
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net of unearned income	256,287		306,915
Valuation allowance	20,500		25,500
Commercial Portfolio Segment | Purchased credit-impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net of unearned income	49,743		99,407
Commercial Portfolio Segment | Accruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	15,978,736		15,996,404
Total Accruing	16,002,021		16,026,120
Commercial Portfolio Segment | Accruing | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	9,586		10,264
Commercial Portfolio Segment | Accruing | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	13,699		19,452
Commercial Portfolio Segment | Accruing | General C&I
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	13,597,235		13,514,752
Total Accruing	13,606,561		13,522,904
Commercial Portfolio Segment | Accruing | General C&I | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	9,202		8,057
Commercial Portfolio Segment | Accruing | General C&I | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	124		95
Commercial Portfolio Segment | Accruing | Loans to Mortgage Companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	2,092,366		2,099,961
Total Accruing	2,092,366		2,099,961
Commercial Portfolio Segment | Accruing | Loans to Mortgage Companies | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	0		0
Commercial Portfolio Segment | Accruing | Loans to Mortgage Companies | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	0		0
Commercial Portfolio Segment | Accruing | TRUPs
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	253,351		303,848
Total Accruing	253,351		303,848
Commercial Portfolio Segment | Accruing | TRUPs | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	0		0
Commercial Portfolio Segment | Accruing | TRUPs | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	0		0
Commercial Portfolio Segment | Accruing | Purchased credit-impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	35,784		77,843
Total Accruing	49,743		99,407
Commercial Portfolio Segment | Accruing | Purchased credit-impaired loans | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	384		2,207
Commercial Portfolio Segment | Accruing | Purchased credit-impaired loans | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	13,575		19,357
Commercial Portfolio Segment | Non-Accruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	25,713		1,761
Total Non- Accruing	42,124		31,153
Commercial Portfolio Segment | Non-Accruing | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	1,284		7,019
Commercial Portfolio Segment | Non-Accruing | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	15,127		22,373
Commercial Portfolio Segment | Non-Accruing | General C&I
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	25,713		1,761
Total Non- Accruing	39,188		28,086
Commercial Portfolio Segment | Non-Accruing | General C&I | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	1,284		7,019
Commercial Portfolio Segment | Non-Accruing | General C&I | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	12,191		19,306
Commercial Portfolio Segment | Non-Accruing | Loans to Mortgage Companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	0		0
Total Non- Accruing	0		0
Commercial Portfolio Segment | Non-Accruing | Loans to Mortgage Companies | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	0		0
Commercial Portfolio Segment | Non-Accruing | Loans to Mortgage Companies | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	0		0
Commercial Portfolio Segment | Non-Accruing | TRUPs
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	0		0
Total Non- Accruing	2,936		3,067
Commercial Portfolio Segment | Non-Accruing | TRUPs | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	0		0
Commercial Portfolio Segment | Non-Accruing | TRUPs | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	2,936		3,067
Commercial Portfolio Segment | Non-Accruing | Purchased credit-impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	0		0
Total Non- Accruing	0		0
Commercial Portfolio Segment | Non-Accruing | Purchased credit-impaired loans | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	0		0
Commercial Portfolio Segment | Non-Accruing | Purchased credit-impaired loans | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	0		0
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net of unearned income	4,237,036		4,214,695
Commercial real estate | Income CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net of unearned income	4,048,925		4,078,948
Commercial real estate | Residential CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net of unearned income	164,915		99,635
Commercial real estate | Purchased credit-impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net of unearned income	23,196		36,112
Commercial real estate | Accruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	4,227,508		4,207,123
Total Accruing	4,236,030		4,213,302
Commercial real estate | Accruing | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	8,417		3,926
Commercial real estate | Accruing | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	105		2,253
Commercial real estate | Accruing | Income CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	4,041,797		4,077,106
Total Accruing	4,048,449		4,078,346
Commercial real estate | Accruing | Income CRE | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	6,652		1,240
Commercial real estate | Accruing | Income CRE | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	0		0
Commercial real estate | Accruing | Residential CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	164,338		98,844
Total Accruing	164,385		98,844
Commercial real estate | Accruing | Residential CRE | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	47		0
Commercial real estate | Accruing | Residential CRE | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	0		0
Commercial real estate | Accruing | Purchased credit-impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	21,373		31,173
Total Accruing	23,196		36,112
Commercial real estate | Accruing | Purchased credit-impaired loans | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	1,718		2,686
Commercial real estate | Accruing | Purchased credit-impaired loans | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	105		2,253
Commercial real estate | Non-Accruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	70		56
Total Non- Accruing	1,006		1,393
Commercial real estate | Non-Accruing | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	37		0
Commercial real estate | Non-Accruing | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	899		1,337
Commercial real estate | Non-Accruing | Income CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	35		56
Total Non- Accruing	476		602
Commercial real estate | Non-Accruing | Income CRE | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	37		0
Commercial real estate | Non-Accruing | Income CRE | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	404		546
Commercial real estate | Non-Accruing | Residential CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	35		0
Total Non- Accruing	530		791
Commercial real estate | Non-Accruing | Residential CRE | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	0		0
Commercial real estate | Non-Accruing | Residential CRE | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	495		791
Commercial real estate | Non-Accruing | Purchased credit-impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	0		0
Total Non- Accruing	0		0
Commercial real estate | Non-Accruing | Purchased credit-impaired loans | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	0		0
Commercial real estate | Non-Accruing | Purchased credit-impaired loans | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	0		0
Consumer real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net of unearned income	6,191,183		6,367,755
Consumer real estate | HELOC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net of unearned income	1,578,460		1,823,710
Consumer real estate | R/E Installment Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net of unearned income	4,578,389		4,505,515
Consumer real estate | Purchased credit-impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net of unearned income	34,334		38,530
Consumer real estate | Accruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	6,065,415		6,254,801
Total Accruing	6,110,984		6,296,268
Consumer real estate | Accruing | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	25,354		27,034
Consumer real estate | Accruing | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	20,215		14,433
Consumer real estate | Accruing | HELOC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	1,495,298		1,743,776
Total Accruing	1,518,411		1,771,222
Consumer real estate | Accruing | HELOC | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	14,582		17,744
Consumer real estate | Accruing | HELOC | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	8,531		9,702
Consumer real estate | Accruing | R/E Installment Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	4,541,642		4,475,669
Total Accruing	4,558,239		4,486,516
Consumer real estate | Accruing | R/E Installment Loans | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	8,589		7,274
Consumer real estate | Accruing | R/E Installment Loans | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	8,008		3,573
Consumer real estate | Accruing | Purchased credit-impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	28,475		35,356
Total Accruing	34,334		38,530
Consumer real estate | Accruing | Purchased credit-impaired loans | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	2,183		2,016
Consumer real estate | Accruing | Purchased credit-impaired loans | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	3,676		1,158
Consumer real estate | Non-Accruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	63,619		54,947
Total Non- Accruing	80,199		71,487
Consumer real estate | Non-Accruing | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	6,277		5,583
Consumer real estate | Non-Accruing | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	10,303		10,957
Consumer real estate | Non-Accruing | HELOC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	48,400		40,508
Total Non- Accruing	60,049		52,488
Consumer real estate | Non-Accruing | HELOC | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	4,038		3,626
Consumer real estate | Non-Accruing | HELOC | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	7,611		8,354
Consumer real estate | Non-Accruing | R/E Installment Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	15,219		14,439
Total Non- Accruing	20,150		18,999
Consumer real estate | Non-Accruing | R/E Installment Loans | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	2,239		1,957
Consumer real estate | Non-Accruing | R/E Installment Loans | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	2,692		2,603
Consumer real estate | Non-Accruing | Purchased credit-impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	0		0
Total Non- Accruing	0		0
Consumer real estate | Non-Accruing | Purchased credit-impaired loans | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	0		0
Consumer real estate | Non-Accruing | Purchased credit-impaired loans | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	0		0
Permanent mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net of unearned income	347,054		399,307
Permanent mortgage | Accruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	315,746		365,527
Total Accruing	324,732		372,917
Permanent mortgage | Accruing | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	4,051		3,930
Permanent mortgage | Accruing | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	4,935		3,460
Permanent mortgage | Non-Accruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	12,217		13,245
Total Non- Accruing	22,322		26,390
Permanent mortgage | Non-Accruing | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	749		1,052
Permanent mortgage | Non-Accruing | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	9,356		12,093
Credit Card And Other Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net of unearned income	530,796		619,899
Credit Card And Other Portfolio Segment | Credit card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net of unearned income	196,051		196,364
Credit Card And Other Portfolio Segment | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net of unearned income	332,174		418,035
Credit Card And Other Portfolio Segment | Purchased credit-impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, net of unearned income	2,571		5,500
Credit Card And Other Portfolio Segment | Accruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	521,360		612,003
Total Accruing	530,090		619,703
Credit Card And Other Portfolio Segment | Accruing | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	6,205		5,730
Credit Card And Other Portfolio Segment | Accruing | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	2,525		1,970
Credit Card And Other Portfolio Segment | Accruing | Credit card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	193,681		193,940
Total Accruing	196,051		196,364
Credit Card And Other Portfolio Segment | Accruing | Credit card | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	1,292		1,371
Credit Card And Other Portfolio Segment | Accruing | Credit card | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	1,078		1,053
Credit Card And Other Portfolio Segment | Accruing | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	326,672		415,070
Total Accruing	331,468		417,839
Credit Card And Other Portfolio Segment | Accruing | Other | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	4,078		2,666
Credit Card And Other Portfolio Segment | Accruing | Other | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	718		103
Credit Card And Other Portfolio Segment | Accruing | Purchased credit-impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	1,007		2,993
Total Accruing	2,571		5,500
Credit Card And Other Portfolio Segment | Accruing | Purchased credit-impaired loans | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	835		1,693
Credit Card And Other Portfolio Segment | Accruing | Purchased credit-impaired loans | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	729		814
Credit Card And Other Portfolio Segment | Non-Accruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	93		31
Total Non- Accruing	706		196
Credit Card And Other Portfolio Segment | Non-Accruing | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	78		0
Credit Card And Other Portfolio Segment | Non-Accruing | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	535		165
Credit Card And Other Portfolio Segment | Non-Accruing | Credit card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	0		0
Total Non- Accruing	0		0
Credit Card And Other Portfolio Segment | Non-Accruing | Credit card | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	0		0
Credit Card And Other Portfolio Segment | Non-Accruing | Credit card | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	0		0
Credit Card And Other Portfolio Segment | Non-Accruing | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	93		31
Total Non- Accruing	706		196
Credit Card And Other Portfolio Segment | Non-Accruing | Other | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	78		0
Credit Card And Other Portfolio Segment | Non-Accruing | Other | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	535		165
Credit Card And Other Portfolio Segment | Non-Accruing | Purchased credit-impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	0		0
Total Non- Accruing	0		0
Credit Card And Other Portfolio Segment | Non-Accruing | Purchased credit-impaired loans | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	0		0
Credit Card And Other Portfolio Segment | Non-Accruing | Purchased credit-impaired loans | 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due	$ 0		$ 0

[1] September 30, 2018 and December 31, 2017 include $20.8 million and $22.7 million, respectively, of held-to-maturity consumer mortgage loans secured by residential real estate in process of foreclosure.