Loans - Accruing And Non-Accruing Loans By Class (Details) - USD ($) $ in Thousands	Mar. 31, 2020		Dec. 31, 2019		Mar. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	$ 33,125,848		$ 30,841,035
Total Accruing	33,188,490		30,898,946
Current, Non-Accruing	126,237		100,382
Total Non-Accruing	189,813		162,165
Total loans, net of unearned income	33,378,303	[1]	31,061,111	[1]	$ 27,990,048
Allowance for loan losses	444,490		200,307		184,911	$ 180,424
30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	48,498		36,052
Past Due, Non-Accruing	9,354		20,217
90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	14,144		21,859
Past Due, Non-Accruing	54,222		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	22,011,134		19,967,302
Total Accruing	22,028,349		19,976,779
Current, Non-Accruing	60,387		36,564
Total Non-Accruing	96,081		74,312
Total loans, net of unearned income	22,124,430		20,051,091		17,176,112
Allowance for loan losses	254,516		122,486		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	17,049		7,442
Past Due, Non-Accruing	2,505		14,385
Commercial | Commercial, financial, and industrial | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	166		2,035
Past Due, Non-Accruing	33,189		23,363
Commercial | Commercial, financial, and industrial | C&I
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	16,081,865		15,314,292
Total Accruing	16,099,080		15,321,684
Current, Non-Accruing	60,387		36,564
Total Non-Accruing	96,081		74,312
Total loans, net of unearned income	16,195,161		15,395,996
Nonaccrual, no allowance	36,100
Commercial | Commercial, financial, and industrial | C&I | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	17,049		7,155
Past Due, Non-Accruing	2,505		14,385
Commercial | Commercial, financial, and industrial | C&I | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	166		237
Past Due, Non-Accruing	33,189		23,363
Commercial | Commercial, financial, and industrial | Loans to Mortgage Companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	5,713,914		4,410,883
Total Accruing	5,713,914		4,410,883
Current, Non-Accruing	0		0
Total Non-Accruing	0		0
Total loans, net of unearned income	5,713,914		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	0		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	215,355		218,287
Total Accruing	215,355		218,287
Current, Non-Accruing	0		0
Total Non-Accruing	0		0
Total loans, net of unearned income	215,355		218,287
Allowance for loan losses	18,900		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	4,637,044		4,334,283
Total Accruing	4,637,502		4,335,192
Current, Non-Accruing	29		0
Total Non-Accruing	2,190		1,825
Total loans, net of unearned income	4,639,692		4,337,017		3,946,943
Allowance for loan losses	47,625		36,112		34,382	31,311
Commercial | Commercial real estate | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	458		814
Past Due, Non-Accruing	844		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	1,317		1,340
Commercial | Commercial real estate | Income CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	4,562,822		4,242,044
Total Accruing	4,563,241		4,242,723
Current, Non-Accruing	29		0
Total Non-Accruing	2,162		1,359
Total loans, net of unearned income	4,565,403		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	419		679
Past Due, Non-Accruing	816		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	1,317		1,340
Commercial | Commercial real estate | Residential CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	74,222		87,487
Total Accruing	74,261		87,494
Current, Non-Accruing	0		0
Total Non-Accruing	28		466
Total loans, net of unearned income	74,289		87,960
Commercial | Commercial real estate | Residential CRE | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	39		7
Past Due, Non-Accruing	28		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	5,988,115		6,048,510
Total Accruing	6,028,201		6,091,445
Current, Non-Accruing	65,668		63,717
Total Non-Accruing	91,182		85,694
Total loans, net of unearned income	6,119,383		6,177,139		6,360,763
Allowance for loan losses	123,022		28,443		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	27,954		24,820
Past Due, Non-Accruing	5,967		5,303
Consumer | Consumer Real Estate (a) | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	12,132		18,115
Past Due, Non-Accruing	19,547		16,674
Consumer | Consumer Real Estate (a) | HELOC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	1,186,834		1,217,344
Total Accruing	1,202,875		1,232,169
Current, Non-Accruing	41,506		43,007
Total Non-Accruing	51,177		54,706
Total loans, net of unearned income	1,254,052		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	10,213		9,156
Past Due, Non-Accruing	3,547		4,227
Consumer | Consumer Real Estate (a) | HELOC | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	5,828		5,669
Past Due, Non-Accruing	6,124		7,472
Consumer | Consumer Real Estate (a) | R/E Installment Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	4,801,281		4,812,446
Total Accruing	4,825,326		4,834,510
Current, Non-Accruing	24,162		20,710
Total Non-Accruing	40,005		30,988
Total loans, net of unearned income	4,865,331		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	17,741		12,894
Past Due, Non-Accruing	2,420		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	6,304		9,170
Past Due, Non-Accruing	13,423		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	489,555		490,940
Total Accruing	494,438		495,530
Current, Non-Accruing	153		101
Total Non-Accruing	360		334
Total loans, net of unearned income	494,798		495,864		506,230
Allowance for loan losses	19,327		13,266		$ 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	3,037		2,976
Past Due, Non-Accruing	38		44
Consumer | Credit Card and Other | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past Due, Accruing	1,846		1,614
Past Due, Non-Accruing	169		189
Consumer | Credit Card and Other | Credit Card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, Accruing	189,247		198,917
Total Accruing	192,855		201,171
Current, Non-Accruing	0		0
Total Non-Accruing	0		0
Total loans, net of unearned income	192,855		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	1,893		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	1,715		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	300,308		291,700
Total Accruing	301,583		293,839
Current, Non-Accruing	153		101
Total Non-Accruing	360		334
Total loans, net of unearned income	301,943		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	1,144		1,802
Past Due, Non-Accruing	38		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	131		337
Past Due, Non-Accruing	$ 169		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] March 31, 2020 and December 31, 2019 include $20.8 million and $18.8 million, respectively, of held-to-maturity consumer mortgage loans secured by residential real estate in process of foreclosure.