| In millions, except per share items | Dec-31-22 | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 |
| | 10-K | 10-K | 10-K | 10-K | 10-K |
| Interest and dividend income: | | | | | |
| Interest and fees on loans | 476.0 | 367.6 | 372.2 | 402.1 | 369.1 |
| Interest on federal funds sold and other short-term investments | 3.3 | 1.9 | 1.8 | 3.0 | 3.4 |
| Total interest and dividend income | 605.2 | 435.2 | 413.3 | 445.0 | 415.2 |
| |
| Interest expense: | | | | | |
| Interest on deposits | 28.6 | 5.2 | 11.3 | 27.3 | 17.4 |
| Interest on borrowings | 8.5 | 0.2 | 0.8 | 6.5 | 7.7 |
| Total interest expense | 37.1 | 5.3 | 12.1 | 33.8 | 25.1 |
| Net interest income | 568.1 | 429.8 | 401.3 | 411.3 | 390.0 |
| Net interest income after provision for allowance for loan losses | 550.1 | 439.5 | 362.5 | 405.0 | 374.9 |
| |
| Noninterest income (loss): | | | | | |
| Insurance commissions | 99.2 | 94.7 | 94.5 | 90.6 | 91.9 |
| Service charges on deposit accounts | 30.4 | 24.3 | 21.6 | 27.0 | 26.9 |
| Trust and investment advisory fees | 23.6 | 24.6 | 21.1 | 19.7 | 19.1 |
| Debit card processing fees | 12.6 | 12.1 | 10.3 | 10.5 | 16.2 |
| Other | 18.0 | 16.9 | 14.6 | 16.2 | 20.5 |
| Total noninterest income (loss) | 176.2 | 193.2 | 178.4 | 182.3 | 180.6 |
| |
| Noninterest expense: | | | | | |
| Salaries and employee benefits | 298.2 | 295.9 | 261.8 | 252.2 | 239.3 |
| Office occupancy and equipment | 40.8 | 40.5 | 33.8 | 36.5 | 35.5 |
| Data processing | 57.3 | 50.8 | 45.3 | 45.9 | 45.3 |
| Professional services | 16.8 | 21.9 | 16.4 | 16.0 | 14.8 |
| Marketing expenses | 9.5 | 8.7 | 8.9 | 9.6 | 11.1 |
| Loan expenses | 6.4 | 9.1 | 9.2 | 4.6 | 3.9 |
| FDIC insurance | 6.3 | 4.2 | 3.7 | 1.9 | 4.2 |
| Amortization of intangible assets | 3.9 | 2.5 | 2.9 | 3.5 | 3.9 |
| Other | 30.5 | 10.3 | 27.7 | 26.3 | 26.8 |
| Total noninterest expense | 469.6 | 444.0 | 504.9 | 412.7 | 397.9 |
| Income (loss) before income tax expense (benefit) | 256.7 | 188.7 | 35.9 | 174.6 | 157.6 |
| Income tax expense (benefit) | 56.9 | 34.0 | 13.2 | 39.5 | 34.9 |
| Net income (loss) | 199.8 | 154.7 | 22.7 | 135.1 | 122.7 |
| |
| Basic earnings per share (in dollars per share) | $1.21 | $0.90 | $0.13 | | |
| Diluted earnings per share (in dollars per share) | $1.21 | $0.90 | $0.13 | | |