| In millions, except per share items | Dec-31-22 | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Interest and dividend income: | | | | | | | | |
| Taxable | 12.1 | 8.9 | 7.8 | 6.6 | 6.4 | 5.1 | 4.6 | 6.8 |
| |
| Securities: | | | | | | | | |
| Taxable | 12.1 | 8.9 | 7.8 | 6.6 | 6.4 | 5.1 | 4.6 | 6.8 |
| Nontaxable | 19.1 | 16.2 | 14.9 | 13.9 | 13.7 | 11.3 | 9.7 | 7.8 |
| Interest-bearing deposits at financial institutions | 1.1 | 0.2 | 0.7 | 3.9 | 1.3 | 0.9 | 0.4 | 0.3 |
| Restricted investment securities | 2.1 | 1.0 | 1.0 | 1.2 | 1.1 | 0.6 | 0.5 | 0.5 |
| Federal funds sold | 0.4 | 0.0 | 0.0 | 0.2 | 0.3 | 0.1 | 0.0 | 0.0 |
| Total interest and dividend income | 292.6 | 200.2 | 198.4 | 216.1 | 182.9 | 135.5 | 106.5 | 90.0 |
| |
| Interest expense: | | | | | | | | |
| Deposits | 42.4 | 13.3 | 23.3 | 50.9 | 30.7 | 13.0 | 6.0 | 4.5 |
| Short-term borrowings | 0.3 | 0.0 | 0.1 | 0.4 | 0.3 | 0.1 | 0.1 | 0.2 |
| Federal Home Loan Bank advances | 7.0 | 0.1 | 1.1 | 2.9 | 4.2 | 2.0 | 1.3 | 3.5 |
| Subordinated notes | 9.2 | 6.3 | 4.7 | 3.6 | 0.1 | 1.5 | 1.2 | 1.3 |
| Junior subordinated debentures | 9.2 | 6.3 | 4.7 | 3.6 | 0.1 | 1.5 | 1.2 | 1.3 |
| Total interest expense | 61.5 | 21.9 | 31.4 | 60.5 | 40.5 | 19.5 | 12.0 | 13.7 |
| Net interest income | 231.1 | 178.2 | 167.0 | 155.6 | 142.4 | 116.1 | 94.5 | 76.3 |
| Provision for credit losses | 8.3 | 3.5 | 55.7 | 7.1 | 12.7 | 8.5 | 7.5 | 6.9 |
| Net interest income after provision for credit losses | 222.8 | 174.7 | 111.2 | 148.5 | 129.7 | 107.6 | 87.0 | 69.4 |
| |
| Noninterest income: | | | | | | | | |
| Gains on sales of residential real estate loans, net | 2.4 | 4.4 | 4.7 | 2.6 | 0.9 | 0.4 | 0.4 | 0.3 |
| Gains on sales of government guaranteed portions of loans, net | 0.1 | 0.2 | 0.2 | 0.7 | | | | |
| Earnings on bank-owned life insurance | 2.1 | 1.8 | 1.9 | 2.0 | 1.6 | 1.8 | 1.8 | 1.8 |
| Other | 1.4 | 3.9 | 2.6 | 5.4 | 3.8 | 3.3 | 2.9 | 3.1 |
| Total noninterest income | 80.7 | 100.4 | 113.8 | 78.8 | 41.5 | 30.5 | 31.0 | 24.4 |
| |
| Noninterest expense: | | | | | | | | |
| Salaries and employee benefits | 115.4 | 100.9 | 96.3 | 92.1 | 69.0 | 55.7 | 46.3 | 43.0 |
| Occupancy and equipment expense | 22.0 | 15.9 | 16.5 | 15.1 | 12.9 | 10.9 | 8.4 | 7.0 |
| Professional and data processing fees | 16.3 | 14.6 | 14.6 | 13.4 | 11.5 | 10.8 | 7.1 | 5.5 |
| Acquisition costs | 3.7 | 0.6 | | | 1.8 | 1.1 | 1.4 | |
| Post-acquisition compensation, transition and integration costs | 5.5 | | 0.2 | 3.6 | 2.1 | 4.3 | 1.0 | |
| FDIC insurance, other insurance and regulatory fees | 5.8 | 4.5 | 4.2 | 3.0 | 3.6 | 2.8 | 2.5 | 2.7 |
| Loan/lease expense | 1.8 | 1.7 | 1.4 | 1.1 | 1.5 | 1.2 | 0.7 | 0.9 |
| Advertising and marketing | 5.0 | 4.3 | 3.3 | 4.5 | 3.6 | 2.6 | 2.1 | 1.9 |
| Bank service charges | 2.3 | 2.2 | 2.0 | 2.0 | 1.8 | 1.8 | 1.7 | 1.5 |
| Correspondent banking expense | 0.8 | 0.8 | 0.8 | 0.8 | 0.8 | 0.8 | 0.8 | 0.7 |
| Intangibles amortization | 2.9 | 2.0 | 2.1 | 2.3 | 1.7 | 1.0 | 0.4 | 0.2 |
| Other | 2.6 | 2.7 | 1.3 | 6.8 | 6.4 | 4.5 | 3.8 | 3.7 |
| Total noninterest expense | 190.0 | 153.7 | 151.8 | 155.2 | 119.1 | 97.4 | 81.5 | 73.2 |
| Federal and state income tax expense | 14.5 | 22.6 | 12.7 | 14.6 | 9.0 | 4.9 | 8.9 | 3.7 |
| Net income | 99.1 | 98.9 | 60.6 | 57.4 | 43.1 | 35.7 | 27.7 | 16.9 |
| |
| Basic earnings per common share | $5.94 | $6.30 | $3.84 | $3.65 | $2.92 | $2.68 | $2.20 | $1.64 |
| Diluted earnings per common share | $5.87 | $6.20 | $3.80 | $3.60 | $2.86 | $2.61 | $2.17 | $1.61 |
| |
| Weighted average common shares outstanding | 16.7 | 15.7 | 15.8 | 15.7 | 14.8 | 13.3 | 12.6 | 10.3 |
| Weighted average common and common equivalent shares outstanding | 16.9 | 15.9 | 16.0 | 16.0 | 15.1 | 13.7 | 12.8 | 10.5 |
| |
| Cash dividends declared per common share | $0.24 | $0.24 | $0.24 | $0.24 | $0.24 | $0.20 | $0.16 | $0.08 |