| 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 INCOME | | | | | | | | |
| Interest and fees on loans | 278.0 | 219.0 | 213.1 | 220.8 | 208.6 | 163.7 | 121.3 | 117.9 |
| |
| Interest on investment securities: | | | | | | | | |
| Taxable interest income | 53.5 | 32.1 | 20.4 | 19.9 | 10.6 | 7.0 | 6.2 | 6.3 |
| Tax-exempt interest income | 4.4 | 2.4 | 0.7 | 1.0 | 1.5 | 1.7 | 1.7 | 1.8 |
| Other, principally overnight investments | 5.0 | 2.4 | 3.4 | 8.4 | 10.5 | 5.0 | 1.8 | 0.7 |
| Total interest income | 341.0 | 255.9 | 237.7 | 250.1 | 231.2 | 177.4 | 131.0 | 126.7 |
| |
| INTEREST EXPENSE | | | | | | | | |
| Interest on borrowings | 4.8 | 1.6 | 3.3 | 8.9 | 9.3 | 5.1 | 2.4 | 1.6 |
| Total interest expense | 16.1 | 9.5 | 19.6 | 33.9 | 23.8 | 12.7 | 7.6 | 6.9 |
| Net interest income | 324.9 | 246.4 | 218.1 | 216.2 | 207.4 | 164.7 | 123.4 | 119.7 |
| Total provision for credit losses | 12.4 | 15.0 | 35.0 | 2.3 | -3.6 | 0.7 | 0.0 | -0.8 |
| Net interest income after provision for credit losses | 312.5 | 231.4 | 183.1 | 213.9 | 211.0 | 164.0 | 123.4 | 120.5 |
| |
| NONINTEREST INCOME | | | | | | | | |
| Service charges on deposit accounts | 15.5 | 12.3 | 11.1 | 13.0 | 12.7 | 11.9 | 10.6 | 11.6 |
| Fees from presold mortgage loans | 2.1 | 11.0 | 14.2 | 3.9 | 2.7 | 5.7 | | |
| Commissions from sales of financial products | 5.2 | 6.9 | 8.8 | 8.5 | 8.7 | 5.3 | 3.8 | 2.6 |
| SBA consulting fees | 2.6 | 7.2 | 8.6 | 3.9 | 4.7 | 4.0 | | |
| SBA loan sale gains | 5.1 | 7.3 | 8.0 | 8.3 | 10.4 | 5.5 | | |
| Bank-owned life insurance income | 3.8 | 2.9 | 2.5 | 2.6 | 2.5 | 2.3 | 2.1 | 1.7 |
| Other gains, net | 7.3 | 1.6 | -0.1 | -0.2 | 0.7 | 0.4 | 0.0 | -0.5 |
| Total noninterest income | 68.0 | 73.6 | 81.3 | 59.5 | 58.9 | 49.2 | 25.6 | 45.5 |
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| NONINTEREST EXPENSE | | | | | | | | |
| Salaries expense | 96.3 | 86.8 | 84.9 | 79.1 | 75.1 | 66.8 | 51.3 | 47.7 |
| |
| Employee benefits expense | | | | | | | | |
| Total personnel expense | 96.3 | 86.8 | 84.9 | 79.1 | 75.1 | 66.8 | 51.3 | 47.7 |
| Occupancy expense | 12.8 | 11.5 | 11.3 | 11.1 | 10.8 | 9.7 | 7.8 | 7.4 |
| Equipment related expenses | 5.8 | 4.5 | 4.3 | 5.0 | 5.6 | 4.5 | 3.6 | 3.7 |
| Merger and acquisition expenses | 5.1 | 16.8 | | 0.2 | 2.4 | 8.1 | 1.4 | |
| Intangibles amortization expense | 3.7 | 3.5 | 4.0 | 4.9 | 5.9 | 4.0 | 1.2 | 0.7 |
| Other operating expenses | 50.5 | 45.0 | 40.3 | 39.1 | 39.3 | 36.6 | 29.9 | 29.5 |
| Total noninterest expenses | 195.2 | 184.7 | 161.3 | 157.2 | 156.5 | 145.5 | 106.8 | 98.1 |
| Income before income taxes | 185.2 | 120.3 | 103.1 | 116.3 | | | | |
| Income tax expense | 38.3 | 24.7 | 21.7 | 24.2 | 24.2 | 21.8 | 14.6 | 14.1 |
| Net income | 146.9 | 95.6 | 81.5 | 92.0 | 89.3 | 46.0 | 27.5 | 27.0 |
| |
| Earnings per common share: | | | | | | | | |
| Basic (in dollars per share) | $4.12 | $3.19 | $2.81 | $3.10 | $3.02 | $1.82 | $1.37 | $1.34 |
| Diluted (in dollars per share) | $4.12 | $3.19 | $2.81 | $3.10 | $3.01 | $1.82 | $1.33 | $1.30 |
| |
| Dividends declared per common share (in dollars per share) | $0.88 | $0.80 | $0.72 | $0.54 | $0.40 | $0.32 | $0.32 | $0.32 |
| |
| Weighted average common shares outstanding: | | | | | | | | |
| Basic (in shares) | 35.5 | 29.9 | 28.8 | 29.5 | 29.6 | 25.2 | 20.0 | 19.8 |
| Diluted (in shares) | 35.7 | 30.0 | 29.0 | 29.7 | 29.7 | 25.3 | 20.7 | 20.5 |