v3.26.1
Segment information - Information about Company's Segments (Detail) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Segment Reporting Information [Line Items]    
Net Interest Income $ 1,752,000 $ 1,695,000
Noninterest income 689,000 611,000
Provision for credit losses 140,000 130,000
Provision for credit losses 125,000 130,000
Salaries and employee benefits 914,000 887,000
Depreciation and amortization 79,000 83,000
Income before taxes 863,000 761,000
Income tax expense (benefit) 199,000 177,000
Net income (loss) 664,000 584,000
Operating Segments    
Segment Reporting Information [Line Items]    
Net Interest Income 1,752,000 1,695,000
Noninterest income 689,000 611,000
Total revenue 2,441,000 2,306,000
Salaries and employee benefits 914,000 887,000
Depreciation and amortization 97,000 130,000
Other direct expenses 427,000 398,000
Indirect expense 0 0
Income before taxes 863,000 761,000
Income tax expense (benefit) 199,000 177,000
Average total assets 213,828,000 208,321,000
Commercial Bank | Operating Segments    
Segment Reporting Information [Line Items]    
Net Interest Income 535,000 529,000
Noninterest income 193,000 173,000
Total revenue 728,000 702,000
Provision for credit losses 29,000 36,000
Salaries and employee benefits 145,000 151,000
Depreciation and amortization 10,000 10,000
Other direct expenses 78,000 67,000
Indirect expense 127,000 123,000
Income before taxes 339,000 315,000
Income tax expense (benefit) 89,000 84,000
Net income (loss) 250,000 231,000
Average total assets 78,804,000 79,362,000
Retail Bank | Operating Segments    
Segment Reporting Information [Line Items]    
Net Interest Income 950,000 972,000
Noninterest income 217,000 208,000
Total revenue 1,167,000 1,180,000
Provision for credit losses 82,000 79,000
Salaries and employee benefits 197,000 196,000
Depreciation and amortization 36,000 62,000
Other direct expenses 103,000 99,000
Indirect expense 289,000 279,000
Income before taxes 460,000 465,000
Income tax expense (benefit) 116,000 118,000
Net income (loss) 344,000 347,000
Average total assets 58,821,000 54,381,000
Institutional Services and Wealth Management | Operating Segments    
Segment Reporting Information [Line Items]    
Net Interest Income 156,000 171,000
Noninterest income 221,000 209,000
Total revenue 377,000 380,000
Provision for credit losses 0 3,000
Salaries and employee benefits 109,000 106,000
Depreciation and amortization 2,000 2,000
Other direct expenses 35,000 26,000
Indirect expense 80,000 81,000
Income before taxes 151,000 162,000
Income tax expense (benefit) 39,000 41,000
Net income (loss) 112,000 121,000
Average total assets 4,744,000 4,102,000
All Other | Operating Segments    
Segment Reporting Information [Line Items]    
Net Interest Income 111,000 23,000
Noninterest income 58,000 21,000
Total revenue 169,000 44,000
Provision for credit losses 29,000 12,000
Salaries and employee benefits 463,000 434,000
Depreciation and amortization 49,000 56,000
Other direct expenses 211,000 206,000
Indirect expense (496,000) (483,000)
Income before taxes (87,000) (181,000)
Income tax expense (benefit) (45,000) (66,000)
Net income (loss) (42,000) (115,000)
Average total assets $ 71,459,000 $ 70,476,000