| In millions, except per share items | Jun-30-23 | Dec-31-22 | Sep-30-22 | Jun-30-22 | Mar-31-22 | Dec-31-21 | Sep-30-21 | Jun-30-21 |
| | 10-Q | 10-K | 10-Q | 10-Q | 10-Q | 10-K | 10-Q | 10-Q |
| Cash Flows from Operating Activities: | | | | | | | | |
| Net income | 153.8 | 218.4 | 113.4 | 69.0 | -13.0 | -34.6 | -67.9 | -18.8 |
| Items included in net income not affecting cash flows: | | | | | | | | |
| Depreciation and amortization | | 28.4 | 27.7 | 27.3 | 27.0 | 27.0 | 25.8 | 17.1 |
| Loss on write-down of vessels and other assets | | | | | 1.7 | | | 3.5 |
| Amortization of debt discount and other deferred financing costs | | 1.6 | 1.7 | 1.1 | 0.9 | 0.7 | 0.5 | 0.5 |
| Amortization of time charter hire contracts acquired | | | 0.2 | 0.3 | 0.3 | 0.7 | 1.7 | |
| Deferred financing costs write-off | | 0.7 | 0.3 | 0.1 | 0.1 | | | |
| Stock compensation | 0.1 | 2.3 | 1.7 | 1.6 | 1.1 | 1.6 | 6.6 | 1.2 |
| Earnings of affiliated companies | | -0.3 | | -4.4 | -5.6 | -5.3 | -5.7 | -5.4 |
| Other - net | | -1.5 | -0.4 | -0.9 | 0.6 | 1.8 | 0.4 | 0.4 |
| Items included in net income/(loss) related to investing and financing activities: | | | | | | | | |
| Gain on disposal of vessels and other assets, net | | -10.3 | 0.1 | -8.1 | -3.1 | -4.7 | -9.1 | 0.5 |
| Loss on sale of investment in affiliated companies | | | 0.0 | 9.5 | | | | |
| Cash distributions from affiliated companies | | 0.9 | | | 2.3 | 3.1 | 3.2 | 0.8 |
| Payments for drydocking | | -7.0 | -10.5 | -8.2 | -17.6 | -18.6 | -9.1 | -6.1 |
| Insurance claims proceeds related to vessel operations | | 0.8 | 2.5 | 1.1 | 1.0 | 0.7 | 0.5 | 0.2 |
| Changes in operating assets and liabilities: | | | | | | | | |
| Decrease/(increase) in receivables | | -59.6 | -48.2 | -61.4 | -13.4 | -10.2 | 1.4 | -4.9 |
| Decrease in deferred revenue | | 1.6 | 1.0 | | | -0.8 | 2.1 | |
| Net change in inventories, prepaid expenses and other current assets and accounts payable, accrued expense, and other current and long-term liabilities | | 5.7 | 1.8 | 7.6 | -2.1 | 5.6 | -8.0 | 9.4 |
| Net cash provided by operating activities | 189.4 | 181.6 | 91.4 | 34.6 | -19.8 | -27.2 | -26.5 | -1.5 |
| |
| Cash Flows from Investing Activities: | | | | | | | | |
| Expenditures for vessels, vessel improvements and vessels under construction | | -116.0 | | -53.8 | | -78.0 | | |
| Proceeds from disposal of vessels and other assets | | | | 79.6 | | | | |
| Expenditures for other property | | 0.0 | -0.2 | -0.1 | -0.4 | -0.5 | -0.2 | -0.1 |
| Proceeds from sale of investment in affiliated companies | | | -1.1 | 140.1 | | | | |
| Investments in short term time deposits | | -25.0 | -80.0 | | | | | |
| Pool working capital deposits | | | | -0.8 | | | | |
| Net cash (used in)/provided by investing activities | | -9.2 | -112.5 | 179.2 | -14.6 | 17.1 | 137.2 | -17.6 |
| |
| Cash Flows from Financing Activities: | | | | | | | | |
| Issuance of debt, net of issuance and deferred financing costs | | | | | | | | |
| Borrowings on long term debt, net of lenders' fees and deferred financing costs | | -0.9 | | 641.1 | | 24.2 | 59.5 | |
| Repayments of debt | | -54.7 | -26.1 | -682.6 | -35.3 | -619.3 | 30.7 | -15.4 |
| Proceeds from sale and leaseback financing, net of issuance and deferred financing costs | | 19.2 | 28.7 | 39.7 | 20.4 | | | |
| Payments and advance payment on sale and leaseback financing and finance lease | | | | -18.8 | | | | |
| Payments of deferred financing costs | | 0.8 | -0.2 | -0.6 | | 166.6 | -166.6 | 0.0 |
| Cash dividends paid | | -55.0 | -5.9 | -6.0 | -3.0 | -3.0 | -34.6 | -1.7 |
| Repurchases of common stock | | | -20.0 | | | -16.7 | | |
| Cash paid to tax authority upon vesting or exercise of stock-based compensation | | -2.9 | -1.7 | -0.5 | -1.0 | | -0.1 | -0.5 |
| Net cash used in by financing activities | | -104.2 | -35.0 | -57.7 | 11.1 | -23.6 | -111.7 | -19.7 |
| Net (decrease)/increase in cash, cash equivalents and restricted cash | | | | 132.8 | | -116.7 | | |