v3.26.1
Business Segment Reporting - Schedule of Business Segment Financial Results (Detail) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Segment Reporting Information [Line Items]        
Net interest income $ 532,525 $ 467,024 $ 1,066,891 $ 864,663
Provision for credit losses 28,000 21,000 55,000 107,000
Noninterest income 245,505 222,185 450,298 388,383
Salaries and employee benefits 227,162 213,551 446,843 434,949
Processing fees 43,073 43,638 85,132 84,488
Bankcard 11,873 12,363 23,714 25,158
Amortization of other intangible assets 23,460 25,268 46,920 42,750
Noninterest expense 399,633 393,168 780,516 777,955
Income before income taxes 350,397 275,041 681,673 368,091
Income tax expense (benefit) 72,827 57,647 142,665 69,364
NET INCOME 277,570 217,394 539,008 298,727
Operating Segments [Member]        
Segment Reporting Information [Line Items]        
Net interest income 532,525 467,024 1,066,891 864,663
Provision for credit losses 28,000 21,000 55,000 107,000
Noninterest income 245,505 222,185 450,298 388,383
Salaries and employee benefits 145,687 140,413 292,675 277,183
Processing fees 19,706 18,496 38,785 37,251
Bankcard 11,826 12,375 23,697 25,171
Amortization of other intangible assets 2,047 1,879 4,095 3,768
Allocated technology, service, overhead 177,982 177,072 341,898 362,906
Other segment items 42,385 42,933 79,366 71,676
Noninterest expense 399,633 393,168 780,516 777,955
Income before income taxes 350,397 275,041 681,673 368,091
Income tax expense (benefit) 72,827 57,647 142,665 69,364
NET INCOME 277,570 217,394 539,008 298,727
Average assets 70,407,000 66,872,000 70,416,000 63,440,000
Commercial Banking [Member] | Operating Segments [Member]        
Segment Reporting Information [Line Items]        
Net interest income 362,575 322,619 727,917 596,536
Provision for credit losses 24,733 18,334 48,510 85,085
Noninterest income 51,939 43,219 98,228 80,438
Salaries and employee benefits 53,977 53,685 110,403 107,271
Processing fees 4,328 3,770 8,355 7,434
Bankcard 2,833 3,620 5,682 6,793
Allocated technology, service, overhead 93,137 95,114 178,773 196,240
Other segment items 14,978 14,459 31,492 25,922
Noninterest expense 169,253 170,648 334,705 343,660
Income before income taxes 220,528 176,856 442,930 248,229
Income tax expense (benefit) 45,835 37,068 92,699 46,777
NET INCOME 174,693 139,788 350,231 201,452
Average assets 35,374,000 33,917,000 35,133,000 31,979,000
Institutional Banking [Member] | Operating Segments [Member]        
Segment Reporting Information [Line Items]        
Net interest income 79,048 66,331 156,336 127,489
Provision for credit losses 627 430 1,125 865
Noninterest income 129,191 107,998 251,020 211,792
Salaries and employee benefits 53,327 47,278 103,965 94,464
Processing fees 10,579 9,778 21,249 20,425
Bankcard 6,318 5,424 12,830 11,461
Amortization of other intangible assets 1,972 1,776 3,945 3,562
Allocated technology, service, overhead 38,829 31,921 72,705 64,165
Other segment items 11,502 8,960 20,764 18,325
Noninterest expense 122,527 105,137 235,458 212,402
Income before income taxes 85,085 68,762 170,773 126,014
Income tax expense (benefit) 17,684 14,412 35,741 23,746
NET INCOME 67,401 54,350 135,032 102,268
Average assets 21,070,000 18,978,000 21,266,000 18,658,000
Personal Banking [Member] | Operating Segments [Member]        
Segment Reporting Information [Line Items]        
Net interest income 90,902 78,074 182,638 140,638
Provision for credit losses 2,640 2,236 5,365 21,050
Noninterest income 64,375 70,968 101,050 96,153
Salaries and employee benefits 38,383 39,450 78,307 75,448
Processing fees 4,799 4,948 9,181 9,392
Bankcard 2,675 3,331 5,185 6,917
Amortization of other intangible assets 75 103 150 206
Allocated technology, service, overhead 46,016 50,037 90,420 102,501
Other segment items 15,905 19,514 27,110 27,429
Noninterest expense 107,853 117,383 210,353 221,893
Income before income taxes 44,784 29,423 67,970 (6,152)
Income tax expense (benefit) 9,308 6,167 14,225 (1,159)
NET INCOME 35,476 23,256 53,745 (4,993)
Average assets $ 13,963,000 $ 13,977,000 $ 14,017,000 $ 12,803,000