Loans - Balances Of Commercial Loan Portfolio Classes, Disaggregated By PD Grade (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020		Dec. 31, 2019		Jun. 30, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collectively evaluated for impairment	$ 32,419,020				$ 29,343,285
Individually evaluated for impairment	289,917				300,726
Total loans, net of unearned income	32,708,937	[1]	$ 31,061,111	[1]	29,712,810
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collectively evaluated for impairment			24,273,207
Individually evaluated for impairment			84,001
C&I | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	4,203,052
2020, Collectively evaluated for impairment	4,181,906
2020, Individually evaluated for impairment	21,146
2019	4,009,508
2019, Collectively evaluated for impairment	4,002,895
2019, Individually evaluated for impairment	6,613
2018	1,781,274
2018, Collectively evaluated for impairment	1,768,820
2018, Individually evaluated for impairment	12,454
2017	1,329,918
2017, Collectively evaluated for impairment	1,307,923
2017, Individually evaluated for impairment	21,995
2016	1,022,537
2016, Collectively evaluated for impairment	1,020,628
2016, Individually evaluated for impairment	1,909
Prior to 2016	1,304,683
Prior to 2016, Collectively evaluated for impairment	1,282,569
Prior to 2016, Individually evaluated for impairment	22,114
Non-revolving loans	4,020,591
Non-revolving, collectively evaluated for impairment	4,020,591
Non-revolving, individually evaluated for impairment	0
Revolving Loans	3,612,908
Revolving, collectively evaluated for impairment	3,562,589
Revolving, individually evaluated for impairment	50,319
Revolving Loans converted to term loans (c)	109,422
Revolving loans converted to term loans, collectively evaluated for impairment	105,446
Revolving loans converted to term loan, Individually evaluated for impairment	3,976
Collectively evaluated for impairment	21,253,367				18,904,621
Individually evaluated for impairment	140,526				115,808
Total loans, net of unearned income	21,393,893		20,051,091		19,054,269
Revolving loan converted to term loan during period	22,700
C&I | C&I | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collectively evaluated for impairment			15,313,558
Individually evaluated for impairment			82,438
Total loans, net of unearned income	17,164,125		15,395,996
C&I | Loans to Mortgage Companies | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collectively evaluated for impairment			4,410,883
Individually evaluated for impairment			0
Total loans, net of unearned income	4,020,591		4,410,883
C&I | TRUPS | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Prior to 2016	209,200
Collectively evaluated for impairment			218,287
Individually evaluated for impairment			0
Total loans, net of unearned income	209,177		218,287
C&I | PD Grade 1 | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	2,078,712
2019	99,978
2018	121,167
2017	75,521
2016	106,700
Prior to 2016	108,574
Non-revolving loans	0
Revolving Loans	83,309
Revolving Loans converted to term loans (c)	56
Total loans, net of unearned income	2,674,017
C&I | PD Grade 2 | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	56,810
2019	223,191
2018	100,816
2017	79,318
2016	168,838
Prior to 2016	90,484
Non-revolving loans	0
Revolving Loans	95,035
Revolving Loans converted to term loans (c)	126
Total loans, net of unearned income	814,618
C&I | PD Grade 3 | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	42,983
2019	153,671
2018	49,176
2017	89,945
2016	30,381
Prior to 2016	97,338
Non-revolving loans	741,382
Revolving Loans	125,470
Revolving Loans converted to term loans (c)	3,490
Total loans, net of unearned income	1,333,836
C&I | PD Grade 3 | TRUPS | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Prior to 2016	3,300
C&I | PD Grade 4 | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	261,626
2019	335,130
2018	145,047
2017	122,185
2016	129,859
Prior to 2016	142,129
Non-revolving loans	685,876
Revolving Loans	259,379
Revolving Loans converted to term loans (c)	10,653
Total loans, net of unearned income	2,091,884
C&I | PD Grade 4 | TRUPS | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Prior to 2016	60,900
C&I | PD Grade 5 | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	304,710
2019	496,565
2018	220,632
2017	145,650
2016	96,325
Prior to 2016	163,676
Non-revolving loans	700,944
Revolving Loans	384,874
Revolving Loans converted to term loans (c)	12,654
Total loans, net of unearned income	2,526,030
C&I | PD Grade 5 | TRUPS | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Prior to 2016	47,900
C&I | PD Grade 6 | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	360,649
2019	714,704
2018	246,607
2017	195,634
2016	53,597
Prior to 2016	155,755
Non-revolving loans	1,198,775
Revolving Loans	667,570
Revolving Loans converted to term loans (c)	558
Total loans, net of unearned income	3,593,849
C&I | PD Grade 6 | TRUPS | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Prior to 2016	38,600
C&I | PD Grade 7 | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	309,088
2019	723,728
2018	339,953
2017	145,385
2016	100,069
Prior to 2016	171,016
Non-revolving loans	552,192
Revolving Loans	598,772
Revolving Loans converted to term loans (c)	48,291
Total loans, net of unearned income	2,988,494
C&I | PD Grade 7 | TRUPS | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Prior to 2016	13,400
C&I | PD Grade 8 | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	343,391
2019	593,106
2018	194,030
2017	175,289
2016	36,044
Prior to 2016	96,204
Non-revolving loans	93,900
Revolving Loans	379,261
Revolving Loans converted to term loans (c)	7,110
Total loans, net of unearned income	1,918,335
C&I | PD Grade 9 | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	171,524
2019	293,768
2018	89,519
2017	66,927
2016	65,539
Prior to 2016	75,753
Non-revolving loans	25,198
Revolving Loans	283,883
Revolving Loans converted to term loans (c)	10,670
Total loans, net of unearned income	1,082,781
C&I | PD Grade 9 | TRUPS | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Prior to 2016	20,700
C&I | PD Grade 10 | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	96,735
2019	171,901
2018	85,644
2017	60,721
2016	50,429
Prior to 2016	54,729
Non-revolving loans	15,325
Revolving Loans	227,301
Revolving Loans converted to term loans (c)	5,082
Total loans, net of unearned income	767,867
C&I | PD Grade 10 | TRUPS | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Prior to 2016	18,600
C&I | PD Grade 11 | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	53,872
2019	82,677
2018	74,977
2017	58,964
2016	70,190
Prior to 2016	38,059
Non-revolving loans	0
Revolving Loans	148,656
Revolving Loans converted to term loans (c)	3,233
Total loans, net of unearned income	530,628
C&I | PD Grade 12 | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	51,861
2019	33,083
2018	52,013
2017	47,162
2016	20,214
Prior to 2016	29,674
Non-revolving loans	6,999
Revolving Loans	95,943
Revolving Loans converted to term loans (c)	477
Total loans, net of unearned income	337,426
C&I | PD Grade 13 | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	39,047
2019	57,585
2018	10,231
2017	15,916
2016	51,816
Prior to 2016	45,984
Non-revolving loans	0
Revolving Loans	114,971
Revolving Loans converted to term loans (c)	498
Total loans, net of unearned income	336,048
C&I | PD Grade 13 | TRUPS | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Prior to 2016	5,800
C&I | PD Grade 14 15 16 | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	10,898
2019	23,808
2018	39,008
2017	29,306
2016	40,627
Prior to 2016	13,194
Non-revolving loans	0
Revolving Loans	98,165
Revolving Loans converted to term loans (c)	2,548
Total loans, net of unearned income	257,554
Commercial real estate | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collectively evaluated for impairment	4,813,181				3,852,027
Individually evaluated for impairment	160				1,777
Total loans, net of unearned income	4,813,341		4,337,017		$ 3,861,031
Commercial real estate | Income CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	1,061,575
2020, Collectively evaluated for impairment	1,061,575
2020, Individually evaluated for impairment	0
2019	1,510,795
2019, Collectively evaluated for impairment	1,510,795
2019, Individually evaluated for impairment	0
2018	659,682
2018, Collectively evaluated for impairment	659,682
2018, Individually evaluated for impairment	0
2017	571,891
2017, Collectively evaluated for impairment	571,891
2017, Individually evaluated for impairment	0
2016	348,257
2016, Collectively evaluated for impairment	348,257
2016, Individually evaluated for impairment	0
Prior to 2016	389,834
Prior to 2016, Collectively evaluated for impairment	389,674
Prior to 2016, Individually evaluated for impairment	160
Revolving Loans	209,206
Revolving, collectively evaluated for impairment	209,206
Revolving, individually evaluated for impairment	0
Revolving Loans converted to term loans (c)	17,483
Revolving loans converted to term loans, collectively evaluated for impairment	17,483
Revolving loans converted to term loan, Individually evaluated for impairment	0
Collectively evaluated for impairment	4,768,563		4,242,519
Individually evaluated for impairment	160		1,563
Total loans, net of unearned income	4,768,723		4,244,082
Commercial real estate | Residential CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	21,652
2020, Collectively evaluated for impairment	21,652
2020, Individually evaluated for impairment	0
2019	13,407
2019, Collectively evaluated for impairment	13,407
2019, Individually evaluated for impairment	0
2018	4,459
2018, Collectively evaluated for impairment	4,459
2018, Individually evaluated for impairment	0
2017	2,747
2017, Collectively evaluated for impairment	2,747
2017, Individually evaluated for impairment	0
2016	602
2016, Collectively evaluated for impairment	602
2016, Individually evaluated for impairment	0
Prior to 2016	1,638
Prior to 2016, Collectively evaluated for impairment	1,638
Prior to 2016, Individually evaluated for impairment	0
Revolving Loans	113
Revolving, collectively evaluated for impairment	113
Revolving, individually evaluated for impairment	0
Revolving Loans converted to term loans (c)	0
Revolving loans converted to term loans, collectively evaluated for impairment	0
Revolving loans converted to term loan, Individually evaluated for impairment	0
Collectively evaluated for impairment	44,618		87,960
Individually evaluated for impairment	0		0
Total loans, net of unearned income	44,618		$ 87,960
Commercial real estate | PD Grade 1 | Income CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	21,886
2019	0
2018	392
2017	106
2016	158
Prior to 2016	1,190
Revolving Loans	0
Revolving Loans converted to term loans (c)	0
Total loans, net of unearned income	23,732
Commercial real estate | PD Grade 1 | Residential CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
Prior to 2016	20
Revolving Loans	0
Revolving Loans converted to term loans (c)	0
Total loans, net of unearned income	20
Commercial real estate | PD Grade 2 | Income CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	7,798
2019	30,919
2018	405
2017	216
2016	617
Prior to 2016	3,145
Revolving Loans	0
Revolving Loans converted to term loans (c)	0
Total loans, net of unearned income	43,100
Commercial real estate | PD Grade 2 | Residential CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
Prior to 2016	0
Revolving Loans	0
Revolving Loans converted to term loans (c)	0
Total loans, net of unearned income	0
Commercial real estate | PD Grade 3 | Income CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	97,338
2019	212,413
2018	75,483
2017	34,863
2016	42,468
Prior to 2016	25,511
Revolving Loans	78,004
Revolving Loans converted to term loans (c)	181
Total loans, net of unearned income	566,261
Commercial real estate | PD Grade 3 | Residential CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	0
2019	151
2018	268
2017	482
2016	0
Prior to 2016	95
Revolving Loans	0
Revolving Loans converted to term loans (c)	0
Total loans, net of unearned income	996
Commercial real estate | PD Grade 4 | Income CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	90,915
2019	292,657
2018	100,058
2017	130,549
2016	94,836
Prior to 2016	45,975
Revolving Loans	839
Revolving Loans converted to term loans (c)	238
Total loans, net of unearned income	756,067
Commercial real estate | PD Grade 4 | Residential CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	0
2019	722
2018	0
2017	0
2016	0
Prior to 2016	106
Revolving Loans	0
Revolving Loans converted to term loans (c)	0
Total loans, net of unearned income	828
Commercial real estate | PD Grade 5 | Income CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	320,904
2019	279,229
2018	138,520
2017	152,573
2016	112,018
Prior to 2016	45,048
Revolving Loans	37,306
Revolving Loans converted to term loans (c)	6,224
Total loans, net of unearned income	1,091,822
Commercial real estate | PD Grade 5 | Residential CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	93
2019	0
2018	0
2017	0
2016	76
Prior to 2016	12
Revolving Loans	0
Revolving Loans converted to term loans (c)	0
Total loans, net of unearned income	181
Commercial real estate | PD Grade 6 | Income CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	264,892
2019	215,714
2018	125,075
2017	107,697
2016	33,716
Prior to 2016	119,742
Revolving Loans	37,800
Revolving Loans converted to term loans (c)	7,930
Total loans, net of unearned income	912,566
Commercial real estate | PD Grade 6 | Residential CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	14,512
2019	106
2018	43
2017	333
2016	30
Prior to 2016	234
Revolving Loans	0
Revolving Loans converted to term loans (c)	0
Total loans, net of unearned income	15,258
Commercial real estate | PD Grade 7 | Income CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	164,896
2019	293,784
2018	121,601
2017	64,796
2016	20,076
Prior to 2016	24,648
Revolving Loans	40,187
Revolving Loans converted to term loans (c)	1,224
Total loans, net of unearned income	731,212
Commercial real estate | PD Grade 7 | Residential CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	348
2019	470
2018	2,904
2017	1,776
2016	0
Prior to 2016	241
Revolving Loans	13
Revolving Loans converted to term loans (c)	0
Total loans, net of unearned income	5,752
Commercial real estate | PD Grade 8 | Income CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	23,028
2019	93,700
2018	55,579
2017	11,850
2016	28,382
Prior to 2016	50,403
Revolving Loans	6,845
Revolving Loans converted to term loans (c)	128
Total loans, net of unearned income	269,915
Commercial real estate | PD Grade 8 | Residential CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	467
2019	24
2018	443
2017	0
2016	6
Prior to 2016	89
Revolving Loans	100
Revolving Loans converted to term loans (c)	0
Total loans, net of unearned income	1,129
Commercial real estate | PD Grade 9 | Income CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	35,357
2019	36,942
2018	25,157
2017	22,936
2016	2,219
Prior to 2016	19,126
Revolving Loans	280
Revolving Loans converted to term loans (c)	0
Total loans, net of unearned income	142,017
Commercial real estate | PD Grade 9 | Residential CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	325
2019	520
2018	262
2017	0
2016	490
Prior to 2016	76
Revolving Loans	0
Revolving Loans converted to term loans (c)	0
Total loans, net of unearned income	1,673
Commercial real estate | PD Grade 10 | Income CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	23,623
2019	8,323
2018	7,323
2017	2,803
2016	9,125
Prior to 2016	17,320
Revolving Loans	0
Revolving Loans converted to term loans (c)	0
Total loans, net of unearned income	68,517
Commercial real estate | PD Grade 10 | Residential CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	179
2019	960
2018	277
2017	0
2016	0
Prior to 2016	6
Revolving Loans	0
Revolving Loans converted to term loans (c)	0
Total loans, net of unearned income	1,422
Commercial real estate | PD Grade 11 | Income CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	6,936
2019	21,414
2018	6,890
2017	7,347
2016	3,862
Prior to 2016	19,638
Revolving Loans	0
Revolving Loans converted to term loans (c)	1,330
Total loans, net of unearned income	67,417
Commercial real estate | PD Grade 11 | Residential CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	4,093
2019	8,660
2018	218
2017	156
2016	0
Prior to 2016	50
Revolving Loans	0
Revolving Loans converted to term loans (c)	0
Total loans, net of unearned income	13,177
Commercial real estate | PD Grade 12 | Income CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	2,962
2019	14,437
2018	2,383
2017	905
2016	652
Prior to 2016	13,476
Revolving Loans	64
Revolving Loans converted to term loans (c)	228
Total loans, net of unearned income	35,107
Commercial real estate | PD Grade 12 | Residential CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	154
2019	1,530
2018	44
2017	0
2016	0
Prior to 2016	538
Revolving Loans	0
Revolving Loans converted to term loans (c)	0
Total loans, net of unearned income	2,266
Commercial real estate | PD Grade 13 | Income CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	525
2019	455
2018	771
2017	16,185
2016	0
Prior to 2016	570
Revolving Loans	328
Revolving Loans converted to term loans (c)	0
Total loans, net of unearned income	18,834
Commercial real estate | PD Grade 13 | Residential CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	1,310
2019	0
2018	0
2017	0
2016	0
Prior to 2016	132
Revolving Loans	0
Revolving Loans converted to term loans (c)	0
Total loans, net of unearned income	1,442
Commercial real estate | PD Grade 14 15 16 | Income CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	515
2019	10,808
2018	45
2017	19,065
2016	128
Prior to 2016	3,882
Revolving Loans	7,553
Revolving Loans converted to term loans (c)	0
Total loans, net of unearned income	41,996
Commercial real estate | PD Grade 14 15 16 | Residential CRE | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
2020	171
2019	264
2018	0
2017	0
2016	0
Prior to 2016	39
Revolving Loans	0
Revolving Loans converted to term loans (c)	0
Total loans, net of unearned income	$ 474

[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.