| In millions, except per share items | Jun-30-23 | Mar-31-23 | Dec-31-22 | Sep-30-22 | Jun-30-22 | Mar-31-22 | Dec-31-21 | Sep-30-21 |
| | 10-Q | 10-Q | 8-K | 8-K | 10-Q | 10-Q | 8-K | 10-Q |
| Operating activities | | | | | | | | |
| Net income (loss) | 48.7 | -194.1 | | | 51.2 | 51.5 | | 37.1 |
| |
| Adjustments to reconcile net income to net cash provided by operating activities | | | | | | | | |
| Provision for allowance for loan losses | 7.5 | | | | 0.6 | | | |
| Depreciation and amortization | 3.8 | 3.7 | | | 3.5 | 3.8 | | 3.3 |
| Amortization (accretion) of deferred loan fees and premiums, net | 1.7 | 0.7 | | | -2.1 | -2.7 | | |
| Deferred income tax (benefit) expense | -3.8 | -73.1 | | | 0.7 | 14.1 | | 0.2 |
| Amortization of investment security premiums and discounts, net | 1.3 | 2.6 | | | 4.3 | 4.7 | | 4.7 |
| Right-of-use asset amortization | 3.0 | 3.1 | | | 3.3 | 3.3 | | 3.0 |
| Share-based compensation | 4.7 | 3.0 | | | 2.9 | 1.6 | | 2.2 |
| Increase in cash surrender value of bank-owned life insurance | -1.0 | -1.0 | | | -0.9 | -0.9 | | -0.5 |
| Loss on sale of securities available for sale, net | | 333.2 | | | 0.1 | 2.2 | | |
| Accretion of gains from terminated interest rate swaps | | 0.0 | | | -3.1 | -5.3 | | -7.9 |
| Employee Stock Ownership Plan expense | 1.8 | 1.7 | | | 2.4 | 2.6 | | |
| Other | 0.3 | 0.0 | | | -0.7 | 1.0 | | |
| |
| Change in: | | | | | | | | |
| Loans held for sale | 0.3 | 1.4 | | | 0.4 | 0.0 | | |
| Prepaid pension expense | 1.2 | 1.2 | | | -0.5 | -7.7 | | 0.8 |
| Other assets | -36.4 | -8.8 | | | 9.2 | 40.3 | | 24.5 |
| Other liabilities | 39.2 | 26.7 | | | 25.7 | -39.8 | | 5.9 |
| Net cash provided by operating activities | 72.4 | 100.5 | | | 97.4 | 68.4 | | 67.5 |
| |
| Investing activities | | | | | | | | |
| Proceeds from sales of securities available for sale | | 1,899.7 | | | 5.6 | 232.6 | | |
| Proceeds from maturities and principal paydowns of securities available for sale | 99.6 | 130.6 | | | 261.7 | 362.7 | | 192.0 |
| Purchases of securities available for sale | | | | | -199.2 | -471.5 | | -1,065.0 |
| Proceeds from maturities and principal paydowns of securities held to maturity | 6.2 | 5.6 | | | 4.8 | 0.4 | | |
| Purchases of securities held to maturity | | | | | -97.8 | -395.8 | | |
| Proceeds from sale of Federal Home Loan Bank stock | 62.9 | 105.7 | | | 5.2 | | | |
| Purchases of Federal Home Loan Bank stock | -44.6 | -109.5 | | | | | | |
| Contributions to low income housing tax credit investments | -8.2 | -10.9 | | | -5.6 | -5.6 | | -5.6 |
| Contributions to other equity investments | -0.1 | -0.4 | | | -0.5 | | | -0.4 |
| Distributions from other equity investments | 0.1 | 0.1 | | | 0.1 | 0.6 | | 0.1 |
| Net increase in outstanding loans, excluding loan purchases | -355.3 | | | | -117.7 | | | |
| Purchases of loans | | -32.0 | | | | | | |
| Proceeds from life insurance policies | | | | | 0.7 | 19.7 | | |
| Acquisitions, net of cash and cash equivalents acquired | | | | | | -5.2 | | |
| Purchased banking premises and equipment | -1.0 | -1.2 | | | -1.6 | -3.3 | | -2.0 |
| Proceeds from sale of premises held for sale | | | | | 3.8 | 8.4 | | |
| Net cash provided by (used in) investing activities | -172.5 | 1,919.6 | | | -240.3 | -157.3 | | -767.2 |
| |
| Financing activities | | | | | | | | |
| Net decrease in demand, savings, interest checking, and money market investment deposit accounts | -744.5 | -775.8 | | | -190.7 | -155.4 | | |
| Net increase (decrease) in time deposits | 383.8 | 343.0 | | | -38.3 | -80.1 | | |
| Net (decrease) increase in borrowed funds | -389.6 | | | | 8.8 | | | |
| Contingent consideration paid | -0.3 | -0.4 | | | -0.1 | -0.1 | | -0.1 |
| Payments for repurchases of common stock | | | | | -81.2 | -60.6 | | |
| Dividends declared and paid to common shareholders | -16.2 | -16.2 | | | -16.5 | -16.9 | | -13.8 |
| Net cash used in financing activities | -1,164.3 | -51.8 | | | -318.7 | -312.4 | | 387.3 |
| Net increase (decrease) in cash, cash equivalents, and restricted cash | -1,264.3 | 1,968.3 | | | -461.6 | -401.3 | | |
| |
| Supplemental disclosure of cash flow information | | | | | | | | |
| Cash paid during the period for: | | | | | | | | |
| Interest paid on deposits and borrowings | 58.4 | 46.7 | | | 3.1 | 3.3 | | 0.8 |
| Income taxes | 15.8 | 5.9 | | | 14.5 | 5.5 | | 7.3 |
| Non-cash activities | | | | | | | | |
| Net increase in capital commitments relating to low income housing tax credit projects | 38.0 | 51.5 | | | 6.4 | 0.5 | | 13.8 |
| Net decrease in operating lease right-of-use assets and operating lease liabilities relating to lease remeasurements/modifications | -4.4 | | | | | | | |