| In millions, except per share items | Jun-30-23 | Mar-31-23 | Sep-30-22 | Jun-30-22 | Mar-31-22 | Sep-30-21 | Jun-30-21 | Mar-31-21 |
| | 10-Q | 10-Q | 10-Q | 10-Q | 10-Q | 10-Q | 10-Q | 10-Q |
| Interest Income | | | | | | | | |
| Interest and fees on loans | 52.4 | 47.0 | 38.5 | 33.2 | 31.9 | 34.0 | 33.1 | 34.3 |
| |
| Interest and dividends on investment securities: | | | | | | | | |
| Taxable | 11.8 | 11.8 | 9.6 | 7.5 | 6.2 | 6.1 | 5.9 | 5.2 |
| Tax-exempt | 1.0 | 1.2 | 1.2 | 1.2 | 1.2 | 1.3 | 1.3 | 1.3 |
| Interest on deposits in depository institutions | 2.6 | 1.6 | 1.5 | 0.8 | 0.2 | 0.2 | 0.2 | 0.1 |
| Total Interest Income | 67.7 | 61.5 | 50.8 | 42.7 | 39.6 | 41.6 | 40.5 | 40.9 |
| |
| Interest Expense | | | | | | | | |
| Interest on deposits | 8.6 | 5.7 | 1.6 | 1.3 | 1.5 | 2.0 | 2.5 | 3.3 |
| Interest on customer repurchase agreements | 3.0 | 2.4 | 0.4 | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 |
| Interest on FHLB long-term advances | 0.6 | | | | | | | |
| Total Interest Expense | 12.2 | 8.1 | 2.0 | 1.5 | 1.6 | 2.1 | 2.6 | 3.4 |
| Net Interest Income | 55.5 | 53.5 | 48.8 | 41.3 | 37.9 | 39.5 | 37.9 | 37.5 |
| |
| Provision for (recovery of) credit losses | | | | | | | | |
| Net Interest Income After Provision for (Recovery of) Credit Losses | 55.1 | 50.5 | 48.1 | 41.3 | 38.7 | 40.2 | 39.9 | 38.0 |
| |
| Non-Interest Income | | | | | | | | |
| Gains on sale of investment securities, net | | 1.1 | 0.0 | | -0.7 | 0.1 | 0.4 | 0.2 |
| Unrealized gains (losses) recognized on equity securities still held, net | -0.3 | 0.4 | 0.0 | -0.6 | -0.7 | 0.1 | | |
| |
| Revenue from contract with customer | | | | | | | | |
| Bank owned life insurance | 3.2 | 0.8 | 0.8 | 1.0 | 2.0 | 0.7 | 0.9 | 1.5 |
| Other income | 1.0 | 1.3 | 0.8 | 1.2 | 0.8 | 1.4 | 0.9 | 0.8 |
| Total Non-Interest Income | 20.3 | 18.7 | 18.2 | 17.8 | 17.4 | 17.9 | 17.4 | 16.6 |
| |
| Non-Interest Expense | | | | | | | | |
| Salaries and employee benefits | 18.4 | 17.7 | 17.4 | 16.4 | 15.6 | 15.3 | 15.6 | 15.7 |
| Occupancy related expense | 2.8 | 2.6 | 2.7 | 2.6 | 2.7 | 2.5 | 2.5 | 2.6 |
| Equipment and software related expense | 2.9 | 3.1 | 2.9 | 2.7 | 2.8 | 2.6 | 2.7 | 2.5 |
| FDIC insurance expense | 0.7 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 |
| Advertising | 1.0 | 0.8 | 0.9 | 1.0 | 0.8 | 0.8 | 0.8 | 0.9 |
| Bankcard expenses | 1.7 | 1.5 | 1.4 | 1.7 | 1.6 | 1.5 | 1.7 | 1.6 |
| Postage, delivery, and statement mailings | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 |
| Office supplies | 0.6 | 0.4 | 0.5 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 |
| Legal and professional fees | 0.6 | 0.5 | 0.5 | 0.5 | 0.5 | 0.6 | 0.6 | 0.7 |
| Telecommunications | 0.6 | 0.6 | 0.7 | 0.8 | 0.6 | 0.8 | 0.7 | 0.7 |
| |
| Repossessed asset losses (gains), net of expenses | | | | | | | | |
| Merger related expenses | | 5.6 | | | | | | |
| Other expenses | 4.8 | 4.7 | 3.6 | 3.7 | 3.4 | 3.8 | 3.7 | 3.7 |
| Total Non-Interest Expense | 34.8 | 38.6 | 31.5 | 30.7 | 29.5 | 29.2 | 29.6 | 29.8 |
| Income Before Income Taxes | 40.6 | 30.6 | 34.8 | 28.5 | 26.6 | 29.0 | 27.8 | 24.8 |
| Income tax expense | 7.9 | 6.3 | 7.4 | 5.8 | 5.3 | 6.3 | 5.6 | 5.0 |
| Net Income Available to Common Shareholders | 32.7 | 24.3 | 27.4 | 22.7 | 21.3 | 22.7 | 22.1 | 19.8 |
| |
| Weighted Average Number of Shares Outstanding Reconciliation [Abstract] | | | | | | | | |
| Average shares outstanding, basic (in shares) | 15.0 | 14.8 | 14.8 | 14.9 | 15.0 | 15.3 | 15.6 | 15.7 |
| Effect of dilutive securities (in shares) | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| Average shares outstanding, diluted (in shares) | 15.0 | 14.8 | 14.8 | 14.9 | 15.0 | 15.3 | 15.6 | 15.7 |
| |
| Earnings Per Share [Abstract] | | | | | | | | |
| Basic earnings per common share (in dollars per share) | $2.16 | $1.63 | $1.84 | $1.51 | $1.41 | $1.47 | $1.41 | $1.25 |
| Diluted earnings per common share (in dollars per share) | $2.16 | $1.63 | $1.83 | $1.51 | $1.41 | $1.47 | $1.41 | $1.25 |