Loans and Leases Loans and Leases (Credit Rating) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans and leases	$ 29,240,959	$ 28,322,780
Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
2020	1,301,213
2019	4,621,544
2018	3,427,113
2017	2,671,228
2016	2,085,121
Prior	3,452,034
Revolving loans	1,321,513
Revolving loans converted to term loans	6,716
Total loans and leases	18,886,482
Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	487,710
2019	1,893,663
2018	1,367,883
2017	1,059,455
2016	776,283
Prior	1,383,336
Revolving loans	2,656,203
Revolving loans converted to term loans	169,592
Total loans and leases	9,794,125
Consumer And PCD Portfolio Segments
Financing Receivable, Credit Quality Indicator [Line Items]
2020	1,799,304
2019	6,551,659
2018	4,842,076
2017	3,774,162
2016	2,899,664
Prior	5,175,451
Revolving loans	3,994,597
Revolving loans converted to term loans	204,046
Total loans and leases	29,240,959
Construction and land development | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
2020	96,709
2019	383,343
2018	274,699
2017	182,081
2016	32,935
Prior	19,328
Revolving loans	24,922
Revolving loans converted to term loans	0
Total loans and leases	1,014,017
Construction and land development | Commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2020	94,980
2019	382,104
2018	267,188
2017	176,674
2016	32,927
Prior	18,191
Revolving loans	24,922
Revolving loans converted to term loans	0
Total loans and leases	996,986
Construction and land development | Commercial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2020	91
2019	0
2018	350
2017	5,407
2016	0
Prior	440
Revolving loans	0
Revolving loans converted to term loans	0
Total loans and leases	6,288
Construction and land development | Commercial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2020	1,638
2019	1,239
2018	7,161
2017	0
2016	8
Prior	697
Revolving loans	0
Revolving loans converted to term loans	0
Total loans and leases	10,743
Construction and land development | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	36,802
2019	212,432
2018	68,748
2017	19,336
2016	8,810
Prior	11,748
Revolving loans	5,314
Revolving loans converted to term loans	0
Total loans and leases	363,190
Owner occupied commercial mortgage | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
2020	649,500
2019	2,249,093
2018	1,900,442
2017	1,572,252
2016	1,294,682
Prior	2,271,799
Revolving loans	138,153
Revolving loans converted to term loans	211
Total loans and leases	10,076,132
Owner occupied commercial mortgage | Commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2020	647,821
2019	2,230,133
2018	1,860,144
2017	1,537,841
2016	1,261,880
Prior	2,195,573
Revolving loans	126,108
Revolving loans converted to term loans	139
Total loans and leases	9,859,639
Owner occupied commercial mortgage | Commercial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	8,201
2018	26,827
2017	14,694
2016	18,763
Prior	35,475
Revolving loans	4,129
Revolving loans converted to term loans	0
Total loans and leases	108,089
Owner occupied commercial mortgage | Commercial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2020	1,679
2019	10,759
2018	13,471
2017	19,717
2016	14,039
Prior	40,751
Revolving loans	7,916
Revolving loans converted to term loans	72
Total loans and leases	108,404
Non-owner occupied commercial mortgage | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
2020	201,269
2019	683,873
2018	544,531
2017	454,264
2016	414,953
Prior	713,689
Revolving loans	45,656
Revolving loans converted to term loans	0
Total loans and leases	3,058,235
Non-owner occupied commercial mortgage | Commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2020	200,770
2019	680,203
2018	532,550
2017	452,508
2016	404,537
Prior	704,861
Revolving loans	43,379
Revolving loans converted to term loans	0
Total loans and leases	3,018,808
Non-owner occupied commercial mortgage | Commercial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	1,849
2018	10,042
2017	933
2016	5,971
Prior	7,485
Revolving loans	798
Revolving loans converted to term loans	0
Total loans and leases	27,078
Non-owner occupied commercial mortgage | Commercial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2020	499
2019	1,821
2018	1,939
2017	823
2016	4,445
Prior	1,343
Revolving loans	1,479
Revolving loans converted to term loans	0
Total loans and leases	12,349
Commercial and industrial | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
2020	353,735
2019	1,305,235
2018	707,441
2017	462,631
2016	342,551
Prior	447,218
Revolving loans	1,112,782
Revolving loans converted to term loans	6,505
Total loans and leases	4,738,098
Commercial and industrial | Commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2020	348,311
2019	1,299,423
2018	698,386
2017	450,781
2016	336,295
Prior	436,325
Revolving loans	1,013,228
Revolving loans converted to term loans	5,616
Total loans and leases	4,588,365
Commercial and industrial | Commercial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2020	1,389
2019	1,501
2018	4,647
2017	6,052
2016	3,081
Prior	3,238
Revolving loans	9,913
Revolving loans converted to term loans	73
Total loans and leases	29,894
Commercial and industrial | Commercial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2020	4,035
2019	4,311
2018	4,408
2017	5,798
2016	3,175
Prior	7,655
Revolving loans	19,632
Revolving loans converted to term loans	816
Total loans and leases	49,830
Commercial and industrial | Commercial | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
Prior	0
Revolving loans	3
Revolving loans converted to term loans	0
Total loans and leases	3
Commercial and industrial | Commercial | Ungraded
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
Prior	0
Revolving loans	70,006
Revolving loans converted to term loans	0
Total loans and leases	70,006
Residential mortgage | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	308,407
2019	1,167,724
2018	959,247
2017	864,120
2016	664,948
Prior	1,307,649
Revolving loans	27,317
Revolving loans converted to term loans	0
Total loans and leases	5,299,412
Revolving mortgage | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
Prior	0
Revolving loans	2,193,052
Revolving loans converted to term loans	169,592
Total loans and leases	2,362,644
Consumer auto | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	132,051
2019	463,576
2018	319,085
2017	164,929
2016	90,140
Prior	31,371
Revolving loans	0
Revolving loans converted to term loans	0
Total loans and leases	1,201,152
Consumer other | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	10,450
2019	49,931
2018	20,803
2017	11,070
2016	12,385
Prior	32,568
Revolving loans	430,520
Revolving loans converted to term loans	0
Total loans and leases	567,727
PCD Loans
Financing Receivable, Credit Quality Indicator [Line Items]
2020	10,381
2019	36,452
2018	47,080
2017	43,479
2016	38,260
Prior	340,081
Revolving loans	16,881
Revolving loans converted to term loans	27,738
Total loans and leases	560,352
Current | Construction and land development | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	36,285
2019	208,509
2018	67,438
2017	19,024
2016	8,720
Prior	10,255
Revolving loans	5,314
Revolving loans converted to term loans	0
Total loans and leases	355,545
Current | Residential mortgage | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	308,079
2019	1,163,902
2018	948,832
2017	851,257
2016	652,297
Prior	1,272,796
Revolving loans	24,177
Revolving loans converted to term loans	0
Total loans and leases	5,221,340
Current | Revolving mortgage | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
Prior	0
Revolving loans	2,184,215
Revolving loans converted to term loans	156,841
Total loans and leases	2,341,056
Current | Consumer auto | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	132,008
2019	461,232
2018	316,446
2017	163,033
2016	89,287
Prior	30,805
Revolving loans	0
Revolving loans converted to term loans	0
Total loans and leases	1,192,811
Current | Consumer other | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	10,371
2019	49,571
2018	20,504
2017	11,024
2016	12,296
Prior	32,561
Revolving loans	423,402
Revolving loans converted to term loans	0
Total loans and leases	559,729
Current | PCD Loans
Financing Receivable, Credit Quality Indicator [Line Items]
2020	9,871
2019	28,888
2018	39,500
2017	40,406
2016	34,571
Prior	301,337
Revolving loans	16,310
Revolving loans converted to term loans	25,200
Total loans and leases	496,083
30 to 59 Days past due | Construction and land development | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	517
2019	3,923
2018	1,310
2017	312
2016	3
Prior	24
Revolving loans	0
Revolving loans converted to term loans	0
Total loans and leases	6,089
30 to 59 Days past due | Residential mortgage | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	328
2019	2,491
2018	6,910
2017	6,515
2016	5,023
Prior	18,840
Revolving loans	42
Revolving loans converted to term loans	0
Total loans and leases	40,149
30 to 59 Days past due | Revolving mortgage | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
Prior	0
Revolving loans	6,155
Revolving loans converted to term loans	3,990
Total loans and leases	10,145
30 to 59 Days past due | Consumer auto | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	43
2019	1,739
2018	1,703
2017	1,346
2016	472
Prior	372
Revolving loans	0
Revolving loans converted to term loans	0
Total loans and leases	5,675
30 to 59 Days past due | Consumer other | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	79
2019	260
2018	129
2017	35
2016	89
Prior	7
Revolving loans	3,048
Revolving loans converted to term loans	0
Total loans and leases	3,647
30 to 59 Days past due | PCD Loans
Financing Receivable, Credit Quality Indicator [Line Items]
2020	56
2019	4,291
2018	2,471
2017	1,104
2016	306
Prior	18,759
Revolving loans	181
Revolving loans converted to term loans	460
Total loans and leases	27,628
60 to 89 Days past due | Residential mortgage | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	684
2018	117
2017	538
2016	2,081
Prior	4,469
Revolving loans	126
Revolving loans converted to term loans	0
Total loans and leases	8,015
60 to 89 Days past due | Revolving mortgage | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
Prior	0
Revolving loans	476
Revolving loans converted to term loans	2,934
Total loans and leases	3,410
60 to 89 Days past due | Consumer auto | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	261
2018	376
2017	252
2016	184
Prior	108
Revolving loans	0
Revolving loans converted to term loans	0
Total loans and leases	1,181
60 to 89 Days past due | Consumer other | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	59
2018	139
2017	6
2016	0
Prior	0
Revolving loans	1,854
Revolving loans converted to term loans	0
Total loans and leases	2,058
60 to 89 Days past due | PCD Loans
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	2,202
2018	105
2017	285
2016	0
Prior	5,677
Revolving loans	90
Revolving loans converted to term loans	321
Total loans and leases	8,680
90 Days or greater | Construction and land development | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	87
Prior	1,469
Revolving loans	0
Revolving loans converted to term loans	0
Total loans and leases	1,556
90 Days or greater | Residential mortgage | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	647
2018	3,388
2017	5,810
2016	5,547
Prior	11,544
Revolving loans	2,972
Revolving loans converted to term loans	0
Total loans and leases	29,908
90 Days or greater | Revolving mortgage | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
Prior	0
Revolving loans	2,206
Revolving loans converted to term loans	5,827
Total loans and leases	8,033
90 Days or greater | Consumer auto | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	344
2018	560
2017	298
2016	197
Prior	86
Revolving loans	0
Revolving loans converted to term loans	0
Total loans and leases	1,485
90 Days or greater | Consumer other | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	41
2018	31
2017	5
2016	0
Prior	0
Revolving loans	2,216
Revolving loans converted to term loans	0
Total loans and leases	2,293
90 Days or greater | PCD Loans
Financing Receivable, Credit Quality Indicator [Line Items]
2020	454
2019	1,071
2018	5,004
2017	1,684
2016	3,383
Prior	14,308
Revolving loans	300
Revolving loans converted to term loans	1,757
Total loans and leases	$ 27,961