v3.25.2
Segment information - Information about Company's Segments (Detail) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Segment Reporting Information [Line Items]        
Net Interest Income $ 1,713,000 $ 1,718,000 $ 3,408,000 $ 3,398,000
Noninterest income 683,000 584,000 1,294,000 1,164,000
Provision for credit losses 125,000 150,000 255,000 350,000
Provision for credit losses 105,000 150,000 235,000 350,000
Salaries and employee benefits 813,000 764,000 1,700,000 1,597,000
Depreciation and amortization     164,000 159,000
Income before taxes 935,000 855,000 1,696,000 1,519,000
Income tax expense (benefit) 219,000 200,000 396,000 333,000
Net income (loss) 716,000 655,000 1,300,000 1,186,000
Operating Segments        
Segment Reporting Information [Line Items]        
Net Interest Income 1,713,000 1,718,000 3,408,000 3,398,000
Noninterest income 683,000 584,000 1,294,000 1,164,000
Total revenue 2,396,000 2,302,000 4,702,000 4,562,000
Salaries and employee benefits 813,000 764,000 1,700,000 1,597,000
Depreciation and amortization 124,000 127,000 254,000 257,000
Other direct expenses 399,000 406,000 797,000 839,000
Indirect expense 0 0 0 0
Income before taxes 935,000 855,000 1,696,000 1,519,000
Income tax expense (benefit) 219,000 200,000 396,000 333,000
Average total assets 210,261,000 211,981,000 209,296,000 211,729,000
Commercial Bank | Operating Segments        
Segment Reporting Information [Line Items]        
Net Interest Income 531,000 553,000 1,060,000 1,101,000
Noninterest income 205,000 164,000 378,000 315,000
Total revenue 736,000 717,000 1,438,000 1,416,000
Provision for credit losses     96,000 154,000
Provision for credit losses 60,000 77,000    
Salaries and employee benefits 150,000 154,000 301,000 300,000
Depreciation and amortization 11,000 10,000 21,000 19,000
Other direct expenses 73,000 68,000 140,000 134,000
Indirect expense 129,000 127,000 252,000 251,000
Income before taxes 313,000 281,000 628,000 558,000
Income tax expense (benefit) 82,000 76,000 166,000 152,000
Net income (loss) 231,000 205,000 462,000 406,000
Average total assets 78,497,000 81,198,000 78,927,000 81,140,000
Retail Bank | Operating Segments        
Segment Reporting Information [Line Items]        
Net Interest Income 988,000 1,090,000 1,960,000 2,161,000
Noninterest income 234,000 204,000 442,000 401,000
Total revenue 1,222,000 1,294,000 2,402,000 2,562,000
Provision for credit losses     150,000 128,000
Provision for credit losses 71,000 60,000    
Salaries and employee benefits 201,000 191,000 397,000 381,000
Depreciation and amortization 60,000 63,000 122,000 128,000
Other direct expenses 95,000 93,000 194,000 193,000
Indirect expense 292,000 252,000 571,000 496,000
Income before taxes 503,000 635,000 968,000 1,236,000
Income tax expense (benefit) 128,000 163,000 246,000 318,000
Net income (loss) 375,000 472,000 722,000 918,000
Average total assets 55,995,000 52,950,000 55,193,000 52,591,000
Institutional Services and Wealth Management | Operating Segments        
Segment Reporting Information [Line Items]        
Net Interest Income 166,000 194,000 337,000 380,000
Noninterest income 225,000 207,000 434,000 398,000
Total revenue 391,000 401,000 771,000 778,000
Provision for credit losses     5,000 3,000
Provision for credit losses 2,000 3,000    
Salaries and employee benefits 107,000 103,000 213,000 203,000
Depreciation and amortization 2,000 3,000 4,000 5,000
Other direct expenses 26,000 23,000 52,000 51,000
Indirect expense 82,000 74,000 163,000 149,000
Income before taxes 172,000 195,000 334,000 367,000
Income tax expense (benefit) 44,000 51,000 85,000 95,000
Net income (loss) 128,000 144,000 249,000 272,000
Average total assets 4,272,000 3,668,000 4,187,000 3,652,000
All Other | Operating Segments        
Segment Reporting Information [Line Items]        
Net Interest Income 28,000 (119,000) 51,000 (244,000)
Noninterest income 19,000 9,000 40,000 50,000
Total revenue 47,000 (110,000) 91,000 (194,000)
Provision for credit losses     4,000 65,000
Provision for credit losses (8,000) 10,000    
Salaries and employee benefits 355,000 316,000 789,000 713,000
Depreciation and amortization 51,000 51,000 107,000 105,000
Other direct expenses 205,000 222,000 411,000 461,000
Indirect expense (503,000) (453,000) (986,000) (896,000)
Income before taxes (53,000) (256,000) (234,000) (642,000)
Income tax expense (benefit) (35,000) (90,000) (101,000) (232,000)
Net income (loss) (18,000) (166,000) (133,000) (410,000)
Average total assets $ 71,497,000 $ 74,165,000 $ 70,989,000 $ 74,346,000