Loans - Accruing And Non-Accruing Loans By Class (Details) - USD ($) $ in Thousands	Jun. 30, 2020		Mar. 31, 2020	Dec. 31, 2019		Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	$ 32,441,292			$ 30,841,035
Total Accruing	32,482,946			30,898,946
Current, Non-Accruing	153,299			100,382
Total Non-Accruing	225,991			162,165
Total loans, net of unearned income	32,708,937	[1]		31,061,111	[1]	$ 29,712,810
Allowance for loan losses	537,881		$ 444,490	200,307		192,749	$ 184,911	$ 180,424
30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	27,156			36,052
Past Due, Non-Accruing	4,128			20,217
90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	14,498			21,859
Past Due, Non-Accruing	68,564			41,566
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses				158,598
Commercial | Commercial, financial, and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	21,260,765			19,967,302
Total Accruing	21,266,548			19,976,779
Current, Non-Accruing	79,022			36,564
Total Non-Accruing	127,345			74,312
Total loans, net of unearned income	21,393,893			20,051,091		19,054,269
Allowance for loan losses	318,722		254,516	122,486		116,096	103,713	98,947
Commercial | Commercial, financial, and industrial | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	5,496			7,442
Past Due, Non-Accruing	254			14,385
Commercial | Commercial, financial, and industrial | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	287			2,035
Past Due, Non-Accruing	48,069			23,363
Commercial | Commercial, financial, and industrial | C&I
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	17,031,822			15,314,292
Total Accruing	17,036,780			15,321,684
Current, Non-Accruing	79,022			36,564
Total Non-Accruing	127,345			74,312
Total loans, net of unearned income	17,164,125			15,395,996
Nonaccrual, no allowance	65,300
Commercial | Commercial, financial, and industrial | C&I | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	4,671			7,155
Past Due, Non-Accruing	254			14,385
Commercial | Commercial, financial, and industrial | C&I | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	287			237
Past Due, Non-Accruing	48,069			23,363
Commercial | Commercial, financial, and industrial | Loans to Mortgage Companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	4,019,766			4,410,883
Total Accruing	4,020,591			4,410,883
Current, Non-Accruing	0			0
Total Non-Accruing	0			0
Total loans, net of unearned income	4,020,591			4,410,883
Commercial | Commercial, financial, and industrial | Loans to Mortgage Companies | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	825			0
Past Due, Non-Accruing	0			0
Commercial | Commercial, financial, and industrial | Loans to Mortgage Companies | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	0			0
Past Due, Non-Accruing	0			0
Commercial | Commercial, financial, and industrial | TRUPS
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	209,177			218,287
Total Accruing	209,177			218,287
Current, Non-Accruing	0			0
Total Non-Accruing	0			0
Total loans, net of unearned income	209,177			218,287
Allowance for loan losses	18,400			19,100
Commercial | Commercial, financial, and industrial | TRUPS | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	0			0
Past Due, Non-Accruing	0			0
Commercial | Commercial, financial, and industrial | TRUPS | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	0			0
Past Due, Non-Accruing	0			0
Commercial | Commercial, financial, and industrial | C&I Purchase Credit Impaired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing				23,840
Total Accruing				25,925
Current, Non-Accruing				0
Total Non-Accruing				0
Total loans, net of unearned income				25,925
Commercial | Commercial, financial, and industrial | C&I Purchase Credit Impaired Loans | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing				287
Past Due, Non-Accruing				0
Commercial | Commercial, financial, and industrial | C&I Purchase Credit Impaired Loans | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing				1,798
Past Due, Non-Accruing				0
Commercial | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	4,811,179			4,334,283
Total Accruing	4,811,274			4,335,192
Current, Non-Accruing	797			0
Total Non-Accruing	2,067			1,825
Total loans, net of unearned income	4,813,341			4,337,017		3,861,031
Allowance for loan losses	57,285		47,625	36,112		32,953	34,382	31,311
Commercial | Commercial real estate | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	95			814
Past Due, Non-Accruing	0			485
Commercial | Commercial real estate | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	0			95
Past Due, Non-Accruing	1,270			1,340
Commercial | Commercial real estate | Income CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	4,766,561			4,242,044
Total Accruing	4,766,656			4,242,723
Current, Non-Accruing	797			0
Total Non-Accruing	2,067			1,359
Total loans, net of unearned income	4,768,723			4,244,082
Commercial | Commercial real estate | Income CRE | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	95			679
Past Due, Non-Accruing	0			19
Commercial | Commercial real estate | Income CRE | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	0			0
Past Due, Non-Accruing	1,270			1,340
Commercial | Commercial real estate | Residential CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	44,618			87,487
Total Accruing	44,618			87,494
Current, Non-Accruing	0			0
Total Non-Accruing	0			466
Total loans, net of unearned income	44,618			87,960
Commercial | Commercial real estate | Residential CRE | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	0			7
Past Due, Non-Accruing	0			466
Commercial | Commercial real estate | Residential CRE | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	0			0
Past Due, Non-Accruing	0			0
Commercial | Commercial real estate | CRE Purchase Credit Impaired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing				4,752
Total Accruing				4,975
Current, Non-Accruing				0
Total Non-Accruing				0
Total loans, net of unearned income				4,975
Commercial | Commercial real estate | CRE Purchase Credit Impaired Loans | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing				128
Past Due, Non-Accruing				0
Commercial | Commercial real estate | CRE Purchase Credit Impaired Loans | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing				95
Past Due, Non-Accruing				0
Consumer | Consumer Real Estate (a)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	5,923,755			6,048,510
Total Accruing	5,956,069			6,091,445
Current, Non-Accruing	73,394			63,717
Total Non-Accruing	96,324			85,694
Total loans, net of unearned income	6,052,393			6,177,139		6,303,134
Allowance for loan losses	143,757		123,022	28,443		31,532	34,154	37,439
Consumer | Consumer Real Estate (a) | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	19,514			24,820
Past Due, Non-Accruing	3,797			5,303
Consumer | Consumer Real Estate (a) | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	12,800			18,115
Past Due, Non-Accruing	19,133			16,674
Consumer | Consumer Real Estate (a) | HELOC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	1,136,288			1,217,344
Total Accruing	1,148,824			1,232,169
Current, Non-Accruing	41,608			43,007
Total Non-Accruing	48,636			54,706
Total loans, net of unearned income	1,197,460			1,286,875
Consumer | Consumer Real Estate (a) | HELOC | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	5,736			9,156
Past Due, Non-Accruing	1,720			4,227
Consumer | Consumer Real Estate (a) | HELOC | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	6,800			5,669
Past Due, Non-Accruing	5,308			7,472
Consumer | Consumer Real Estate (a) | R/E Installment Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	4,787,467			4,812,446
Total Accruing	4,807,245			4,834,510
Current, Non-Accruing	31,786			20,710
Total Non-Accruing	47,688			30,988
Total loans, net of unearned income	4,854,933			4,865,498
Consumer | Consumer Real Estate (a) | R/E Installment Loans | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	13,778			12,894
Past Due, Non-Accruing	2,077			1,076
Consumer | Consumer Real Estate (a) | R/E Installment Loans | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	6,000			9,170
Past Due, Non-Accruing	13,825			9,202
Consumer | Consumer Real Estate (a) | RE Installment Purchase Credit Impaired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing				18,720
Total Accruing				24,766
Current, Non-Accruing				0
Total Non-Accruing				0
Total loans, net of unearned income				24,766
Consumer | Consumer Real Estate (a) | RE Installment Purchase Credit Impaired Loans | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing				2,770
Past Due, Non-Accruing				0
Consumer | Consumer Real Estate (a) | RE Installment Purchase Credit Impaired Loans | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing				3,276
Past Due, Non-Accruing				0
Consumer | Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	445,593			490,940
Total Accruing	449,055			495,530
Current, Non-Accruing	86			101
Total Non-Accruing	255			334
Total loans, net of unearned income	449,310			495,864		494,376
Allowance for loan losses	18,117		$ 19,327	13,266		$ 12,168	$ 12,662	$ 12,727
Consumer | Credit Card and Other | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	2,051			2,976
Past Due, Non-Accruing	77			44
Consumer | Credit Card and Other | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	1,411			1,614
Past Due, Non-Accruing	92			189
Consumer | Credit Card and Other | Credit Card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	164,527			198,917
Total Accruing	167,344			201,171
Current, Non-Accruing	0			0
Total Non-Accruing	0			0
Total loans, net of unearned income	167,344			201,171
Consumer | Credit Card and Other | Credit Card | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	1,520			1,076
Past Due, Non-Accruing	0			0
Consumer | Credit Card and Other | Credit Card | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	1,297			1,178
Past Due, Non-Accruing	0			0
Consumer | Credit Card and Other | Other Consumer Loans Class
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	281,066			291,700
Total Accruing	281,711			293,839
Current, Non-Accruing	86			101
Total Non-Accruing	255			334
Total loans, net of unearned income	281,966			294,173
Consumer | Credit Card and Other | Other Consumer Loans Class | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	531			1,802
Past Due, Non-Accruing	77			44
Consumer | Credit Card and Other | Other Consumer Loans Class | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	114			337
Past Due, Non-Accruing	$ 92			189
Consumer | Credit Card and Other | Other Purchased Credit Impaired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing				323
Total Accruing				520
Current, Non-Accruing				0
Total Non-Accruing				0
Total loans, net of unearned income				520
Consumer | Credit Card and Other | Other Purchased Credit Impaired Loans | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing				98
Past Due, Non-Accruing				0
Consumer | Credit Card and Other | Other Purchased Credit Impaired Loans | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing				99
Past Due, Non-Accruing				$ 0

[1] June 30, 2020 and December 31, 2019 include $16.9 million and $18.8 million, respectively, of held-to-maturity consumer mortgage loans secured by residential real estate in process of foreclosure.