| In millions, except per share items | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 | Dec-31-14 | Dec-31-13 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Interest income and dividends | | | | | | | |
| Loans, including fees | 157.2 | 131.9 | 100.5 | 78.2 | 53.6 | 33.6 | 20.1 |
| |
| Securities: | | | | | | | |
| Taxable | 17.5 | 26.5 | 21.3 | 15.3 | 12.4 | 9.5 | 4.7 |
| Tax-Exempt | 5.6 | 7.4 | 8.6 | 5.6 | 2.3 | 0.1 | 0.1 |
| Dividends on restricted equity securities | 1.2 | 1.2 | 0.9 | 0.5 | 0.4 | 0.2 | 0.1 |
| Federal funds sold and other | 3.2 | 2.9 | 1.2 | 0.3 | 0.1 | 0.1 | 0.0 |
| Total interest income | 184.7 | 169.9 | 132.5 | 99.9 | 68.7 | 43.4 | 25.0 |
| |
| Interest expense | | | | | | | |
| Deposits | 61.3 | 53.3 | 27.5 | 14.2 | 8.7 | 5.3 | 3.7 |
| Federal funds purchased and repurchase agreements | 0.3 | 0.4 | 0.4 | 0.3 | 0.3 | 0.2 | 0.1 |
| Subordinated notes | 4.3 | 4.3 | 4.3 | 2.9 | | | |
| Total interest expense | 73.5 | 64.4 | 35.4 | 18.3 | 9.3 | 5.7 | 3.9 |
| Net interest income | 111.2 | 105.5 | 97.0 | 81.6 | 59.4 | 37.7 | 21.0 |
| Provision for loan losses | 32.0 | 2.3 | 4.3 | 5.2 | 5.0 | 2.4 | 0.9 |
| Net interest income after provision for loan losses | 79.1 | 103.2 | 92.7 | 76.3 | 54.4 | 35.3 | 20.1 |
| |
| Noninterest income | | | | | | | |
| Total noninterest income | | | | | | | |
| Net (loss) gain on sale of loans held for investment | -2.0 | | 0.2 | 7.2 | 7.0 | 5.8 | 4.4 |
| Total noninterest income | 17.8 | 10.7 | 14.7 | 15.1 | 12.9 | 10.0 | 13.8 |
| |
| Noninterest expense | | | | | | | |
| Salaries and employee benefits | 50.8 | 43.8 | 35.3 | 30.0 | 24.0 | 19.2 | 13.1 |
| Occupancy and equipment | 13.1 | 11.6 | 9.2 | 7.6 | 6.6 | 4.7 | 2.8 |
| Professional fees | 4.4 | 4.4 | 3.4 | 3.5 | 2.4 | 2.0 | 0.6 |
| Amortization of core deposit intangible | 0.5 | 0.6 | 0.5 | | | | |
| Other | 10.1 | 8.4 | 7.8 | 7.6 | 7.0 | 4.5 | 2.3 |
| Total noninterest expense | 81.9 | 73.5 | 60.8 | 51.7 | 42.1 | 31.7 | 19.7 |
| Income before income tax expense | 15.0 | 40.4 | 46.6 | 39.8 | 25.1 | 13.5 | 7.3 |
| Income tax expense | 0.2 | 5.9 | 18.5 | 11.7 | 9.0 | 5.1 | 2.7 |
| Net income | 14.8 | 34.5 | 28.1 | 28.1 | 16.1 | | |
| Earnings attributable to noncontrolling interest | 0.0 | 0.0 | 0.0 | | | | |
| Net income available to common shareholders | 14.8 | 34.5 | 28.1 | 28.0 | 16.0 | 8.3 | 4.5 |
| |
| Earnings per share: | | | | | | | |
| Basic (in dollars per share) | $1.01 | $2.44 | $2.14 | $2.56 | $1.62 | $1.32 | $1.13 |
| Diluted (in dollars per share) | $0.98 | $2.34 | $2.04 | $2.42 | $1.54 | $1.27 | $1.10 |