Allowance for Credit Losses and Credit Quality - Schedule of Amortized Cost Basis of Loans and Leases by Year of Origination (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
2020	$ 5,328,285
2019	7,555,978
2018	5,125,619
2017	3,684,702
2016	2,232,784
2015 and Prior	4,098,272
Financing Receivable, Revolving, Converted to Term Loan	7,225,960
Revolving Loans and Leases Converted to Term Loans and Leases	284,224
Total	35,535,824	$ 34,497,464
Impaired Loans With No Valuation Allowance
Financing Receivable, Credit Quality Indicator [Line Items]
2020	2,515
2019	27,843
2018	26,622
2017	29,222
2016	22,502
2015 and Prior	114,677
Financing Receivable, Revolving, Converted to Term Loan	64,022
Revolving Loans and Leases Converted to Term Loans and Leases	4,048
Total	291,451
Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
2020	4,342,590
2019	5,679,995
2018	3,952,354
2017	2,807,759
2016	1,466,459
2015 and Prior	1,886,632
Financing Receivable, Revolving, Converted to Term Loan	4,172,566
Revolving Loans and Leases Converted to Term Loans and Leases	228,112
Total	24,536,467
Commercial | Impaired Loans With Valuation Allowance
Financing Receivable, Credit Quality Indicator [Line Items]
2020	835
2019	2,953
2018	1,202
2017	899
2016	233
2015 and Prior	871
Financing Receivable, Revolving, Converted to Term Loan	274
Revolving Loans and Leases Converted to Term Loans and Leases	0
Total	7,267
Commercial | Impaired Loans With No Valuation Allowance
Financing Receivable, Credit Quality Indicator [Line Items]
2020	1,499
2019	24,102
2018	22,479
2017	24,674
2016	20,112
2015 and Prior	54,864
Financing Receivable, Revolving, Converted to Term Loan	25,764
Revolving Loans and Leases Converted to Term Loans and Leases	967
Total	174,461
Commercial | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
2020	2,895,224
2019	2,385,854
2018	1,280,427
2017	751,073
2016	431,882
2015 and Prior	390,822
Financing Receivable, Revolving, Converted to Term Loan	4,023,501
Revolving Loans and Leases Converted to Term Loans and Leases	41,938
Total	12,200,721
Commercial | Commercial and industrial | Impaired Loans With Valuation Allowance
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	1,322
2018	3
2017	97
2016	15
2015 and Prior	284
Financing Receivable, Revolving, Converted to Term Loan	274
Revolving Loans and Leases Converted to Term Loans and Leases	0
Total	1,995
Commercial | Commercial and industrial | Impaired Loans With No Valuation Allowance
Financing Receivable, Credit Quality Indicator [Line Items]
2020	1,190
2019	19,942
2018	13,183
2017	12,758
2016	8,493
2015 and Prior	16,854
Financing Receivable, Revolving, Converted to Term Loan	25,764
Revolving Loans and Leases Converted to Term Loans and Leases	0
Total	98,184
Commercial | Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
2020	949,699
2019	2,408,045
2018	2,156,775
2017	1,730,618
2016	850,174
2015 and Prior	1,422,981
Financing Receivable, Revolving, Converted to Term Loan	110,052
Revolving Loans and Leases Converted to Term Loans and Leases	0
Total	9,628,344
Commercial | Commercial real estate | Impaired Loans With Valuation Allowance
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
2015 and Prior	373
Financing Receivable, Revolving, Converted to Term Loan	0
Revolving Loans and Leases Converted to Term Loans and Leases	0
Total	373
Commercial | Commercial real estate | Impaired Loans With No Valuation Allowance
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	219
2018	5,057
2017	7,427
2016	9,158
2015 and Prior	35,660
Financing Receivable, Revolving, Converted to Term Loan	0
Revolving Loans and Leases Converted to Term Loans and Leases	0
Total	57,521
Commercial | Lease financing
Financing Receivable, Credit Quality Indicator [Line Items]
2020	497,667
2019	886,096
2018	515,152
2017	326,068
2016	184,403
2015 and Prior	72,829
Financing Receivable, Revolving, Converted to Term Loan	39,013
Revolving Loans and Leases Converted to Term Loans and Leases	186,174
Total	2,707,402
Commercial | Lease financing | Impaired Loans With Valuation Allowance
Financing Receivable, Credit Quality Indicator [Line Items]
2020	835
2019	1,631
2018	1,199
2017	802
2016	218
2015 and Prior	214
Financing Receivable, Revolving, Converted to Term Loan	0
Revolving Loans and Leases Converted to Term Loans and Leases	0
Total	4,899
Commercial | Lease financing | Impaired Loans With No Valuation Allowance
Financing Receivable, Credit Quality Indicator [Line Items]
2020	309
2019	3,941
2018	4,239
2017	4,489
2016	2,461
2015 and Prior	2,350
Financing Receivable, Revolving, Converted to Term Loan	0
Revolving Loans and Leases Converted to Term Loans and Leases	967
Total	18,756
Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	985,695
2019	1,875,983
2018	1,173,265
2017	876,943
2016	766,325
2015 and Prior	2,211,640
Financing Receivable, Revolving, Converted to Term Loan	3,053,394
Revolving Loans and Leases Converted to Term Loans and Leases	56,112
Total	10,999,357
Consumer | Impaired Loans With Valuation Allowance
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
2015 and Prior	749
Financing Receivable, Revolving, Converted to Term Loan	0
Revolving Loans and Leases Converted to Term Loans and Leases	0
Total	749
Consumer | Impaired Loans With No Valuation Allowance
Financing Receivable, Credit Quality Indicator [Line Items]
2020	1,016
2019	3,741
2018	4,143
2017	4,548
2016	2,390
2015 and Prior	59,813
Financing Receivable, Revolving, Converted to Term Loan	38,258
Revolving Loans and Leases Converted to Term Loans and Leases	3,081
Total	116,990
Consumer | Residential mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
2020	815,179
2019	1,362,869
2018	873,848
2017	586,463
2016	564,846
2015 and Prior	1,903,029
Financing Receivable, Revolving, Converted to Term Loan	0
Revolving Loans and Leases Converted to Term Loans and Leases	16,884
Total	6,123,118
Consumer | Residential mortgage | Impaired Loans With Valuation Allowance
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
2015 and Prior	749
Financing Receivable, Revolving, Converted to Term Loan	0
Revolving Loans and Leases Converted to Term Loans and Leases	0
Total	749
Consumer | Residential mortgage | Impaired Loans With No Valuation Allowance
Financing Receivable, Credit Quality Indicator [Line Items]
2020	269
2019	1,788
2018	3,271
2017	3,865
2016	1,966
2015 and Prior	55,518
Financing Receivable, Revolving, Converted to Term Loan	0
Revolving Loans and Leases Converted to Term Loans and Leases	1,085
Total	67,762
Consumer | Consumer installment
Financing Receivable, Credit Quality Indicator [Line Items]
2020	149,266
2019	447,779
2018	236,733
2017	239,492
2016	164,373
2015 and Prior	160,498
Financing Receivable, Revolving, Converted to Term Loan	32,441
Revolving Loans and Leases Converted to Term Loans and Leases	73
Total	1,430,655
Consumer | Consumer installment | Impaired Loans With No Valuation Allowance
Financing Receivable, Credit Quality Indicator [Line Items]
2020	18
2019	196
2018	243
2017	329
2016	217
2015 and Prior	566
Financing Receivable, Revolving, Converted to Term Loan	99
Revolving Loans and Leases Converted to Term Loans and Leases	0
Total	1,668
Consumer | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
2020	21,250
2019	65,335
2018	62,684
2017	50,988
2016	37,106
2015 and Prior	148,113
Financing Receivable, Revolving, Converted to Term Loan	3,020,953
Revolving Loans and Leases Converted to Term Loans and Leases	39,155
Total	3,445,584
Consumer | Home equity | Impaired Loans With No Valuation Allowance
Financing Receivable, Credit Quality Indicator [Line Items]
2020	729
2019	1,757
2018	629
2017	354
2016	207
2015 and Prior	3,729
Financing Receivable, Revolving, Converted to Term Loan	38,159
Revolving Loans and Leases Converted to Term Loans and Leases	1,996
Total	47,560
Pass | Commercial | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
2020	2,870,840
2019	2,324,427
2018	1,178,500
2017	701,249
2016	401,396
2015 and Prior	358,937
Financing Receivable, Revolving, Converted to Term Loan	3,786,856
Revolving Loans and Leases Converted to Term Loans and Leases	41,929
Total	11,664,134
Pass | Commercial | Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
2020	947,705
2019	2,333,832
2018	2,105,250
2017	1,557,798
2016	791,144
2015 and Prior	1,274,833
Financing Receivable, Revolving, Converted to Term Loan	109,791
Revolving Loans and Leases Converted to Term Loans and Leases	0
Total	9,120,353
Pass | Commercial | Lease financing
Financing Receivable, Credit Quality Indicator [Line Items]
2020	492,516
2019	869,060
2018	504,714
2017	314,348
2016	177,670
2015 and Prior	67,231
Financing Receivable, Revolving, Converted to Term Loan	34,276
Revolving Loans and Leases Converted to Term Loans and Leases	176,789
Total	2,636,604
Pass | Consumer | Residential mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
2020	814,910
2019	1,360,556
2018	870,577
2017	582,465
2016	562,440
2015 and Prior	1,842,690
Financing Receivable, Revolving, Converted to Term Loan	0
Revolving Loans and Leases Converted to Term Loans and Leases	15,799
Total	6,049,437
Pass | Consumer | Consumer installment
Financing Receivable, Credit Quality Indicator [Line Items]
2020	149,212
2019	447,414
2018	236,490
2017	239,163
2016	164,156
2015 and Prior	159,931
Financing Receivable, Revolving, Converted to Term Loan	32,334
Revolving Loans and Leases Converted to Term Loans and Leases	73
Total	1,428,773
Pass | Consumer | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
2020	20,297
2019	63,096
2018	61,983
2017	50,597
2016	36,899
2015 and Prior	143,980
Financing Receivable, Revolving, Converted to Term Loan	2,981,806
Revolving Loans and Leases Converted to Term Loans and Leases	37,149
Total	3,395,807
Special Mention | Commercial | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
2020	21,404
2019	30,925
2018	68,788
2017	20,061
2016	6,686
2015 and Prior	8,298
Financing Receivable, Revolving, Converted to Term Loan	129,718
Revolving Loans and Leases Converted to Term Loans and Leases	0
Total	285,880
Special Mention | Commercial | Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
2020	1,994
2019	40,041
2018	42,127
2017	98,648
2016	42,644
2015 and Prior	77,196
Financing Receivable, Revolving, Converted to Term Loan	261
Revolving Loans and Leases Converted to Term Loans and Leases	0
Total	302,911
Special Mention | Commercial | Lease financing
Financing Receivable, Credit Quality Indicator [Line Items]
2020	1,390
2019	10,818
2018	4,742
2017	5,201
2016	3,270
2015 and Prior	2,120
Financing Receivable, Revolving, Converted to Term Loan	3,837
Revolving Loans and Leases Converted to Term Loans and Leases	6,173
Total	37,551
Special Mention | Consumer | Residential mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	391
2018	0
2017	0
2016	0
2015 and Prior	1,531
Financing Receivable, Revolving, Converted to Term Loan	0
Revolving Loans and Leases Converted to Term Loans and Leases	0
Total	1,922
Special Mention | Consumer | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	266
2018	0
2017	37
2016	0
2015 and Prior	372
Financing Receivable, Revolving, Converted to Term Loan	30
Revolving Loans and Leases Converted to Term Loans and Leases	0
Total	705
Substandard | Commercial | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
2020	2,980
2019	30,502
2018	33,139
2017	29,763
2016	23,800
2015 and Prior	23,587
Financing Receivable, Revolving, Converted to Term Loan	106,927
Revolving Loans and Leases Converted to Term Loans and Leases	9
Total	250,707
Substandard | Commercial | Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	34,172
2018	9,398
2017	74,172
2016	16,386
2015 and Prior	70,952
Financing Receivable, Revolving, Converted to Term Loan	0
Revolving Loans and Leases Converted to Term Loans and Leases	0
Total	205,080
Substandard | Commercial | Lease financing
Financing Receivable, Credit Quality Indicator [Line Items]
2020	3,761
2019	6,218
2018	5,696
2017	6,519
2016	3,463
2015 and Prior	3,478
Financing Receivable, Revolving, Converted to Term Loan	900
Revolving Loans and Leases Converted to Term Loans and Leases	3,212
Total	33,247
Substandard | Consumer | Residential mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
2020	269
2019	1,922
2018	3,271
2017	3,998
2016	2,406
2015 and Prior	58,808
Financing Receivable, Revolving, Converted to Term Loan	0
Revolving Loans and Leases Converted to Term Loans and Leases	1,085
Total	71,759
Substandard | Consumer | Consumer installment
Financing Receivable, Credit Quality Indicator [Line Items]
2020	54
2019	365
2018	243
2017	329
2016	217
2015 and Prior	567
Financing Receivable, Revolving, Converted to Term Loan	107
Revolving Loans and Leases Converted to Term Loans and Leases	0
Total	1,882
Substandard | Consumer | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
2020	953
2019	1,973
2018	701
2017	354
2016	207
2015 and Prior	3,761
Financing Receivable, Revolving, Converted to Term Loan	39,117
Revolving Loans and Leases Converted to Term Loans and Leases	2,006
Total	49,072
Financial Asset, Equal to or Greater than 90 Days Past Due | Impaired Loans With Valuation Allowance
Financing Receivable, Credit Quality Indicator [Line Items]
2020	835
2019	2,953
2018	1,202
2017	899
2016	233
2015 and Prior	1,620
Financing Receivable, Revolving, Converted to Term Loan	274
Revolving Loans and Leases Converted to Term Loans and Leases	0
Total	$ 8,016