| 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 | 8-K | 10-K | 10-K | 10-K |
| CASH FLOWS FROM OPERATING ACTIVITIES: | | | | | | | | |
| Net loss | -34.8 | 13.3 | 1.1 | 22.3 | | 24.2 | -96.6 | -3.8 |
| Adjustments to reconcile net (loss) income to net cash used in operating activities: | | | | | | | | |
| Equity in earnings from unconsolidated entities | -21.5 | -6.2 | -42.4 | -2.3 | | -5.8 | 1.4 | |
| Return on investment from Gateway Commercial Venture | 0.4 | | 79.0 | | | | | |
| Deferred income taxes | -1.5 | 0.4 | 1.0 | 2.4 | | | | |
| Depreciation and amortization | 16.9 | 26.0 | 14.1 | 20.6 | | 1.5 | 3.0 | -0.2 |
| Gain on distribution from indirect Legacy Interest in Great Park Venture—related party | | -1.0 | | | | | | |
| Share-based compensation | 6.2 | 7.9 | 11.6 | 13.6 | | 18.4 | 27.7 | |
| Changes in operating assets and liabilities: | | | | | | | | |
| Inventories | -140.4 | -104.1 | -99.2 | -192.0 | | -64.5 | -61.7 | -39.9 |
| Related party assets | 2.4 | -0.4 | -10.0 | -19.4 | | 49.3 | 14.2 | -0.3 |
| Other assets | 2.7 | -1.3 | -0.1 | -3.9 | | -0.9 | -0.5 | 24.3 |
| Accounts payable and other liabilities | -22.5 | -18.3 | -32.3 | -4.2 | | 59.8 | 11.2 | -28.3 |
| Related party liabilities | 3.7 | 2.2 | -1.3 | -4.3 | | -34.5 | -15.5 | 1.1 |
| Net cash used in operating activities | -188.3 | -81.4 | -78.5 | -232.0 | | -58.1 | -124.6 | -41.4 |
| |
| CASH FLOWS FROM INVESTING ACTIVITIES: | | | | | | | | |
| Return of investment | | | | | | | | |
| Contribution to Valencia Landbank Venture | | | | | | | | |
| Distribution from indirect Legacy Interest in Great Park Venture—related party | | 1.0 | 1.7 | | | | | |
| Purchase of properties and equipment | -0.1 | -0.2 | -2.1 | -1.7 | | -0.2 | -1.1 | -0.8 |
| Net cash provided by investing activities | 64.0 | 75.3 | 52.9 | 0.3 | | -55.9 | 83.3 | 4.4 |
| |
| CASH FLOWS FROM FINANCING ACTIVITIES: | | | | | | | | |
| Reacquisition of share-based compensation awards for tax-withholding purposes | -2.7 | -2.0 | -5.5 | -4.1 | | -6.5 | -0.4 | |
| Payment of financing costs | | -0.7 | | -2.8 | | -10.6 | -0.1 | -0.3 |
| Related party reimbursement obligation | -6.5 | -19.4 | -13.5 | -0.3 | | | | |
| Tax distribution to noncontrolling interest | -0.4 | -4.4 | -4.6 | | | | | |
| Borrowings under revolving credit facility | 15.0 | | | | | | | |
| Repayments under revolving credit facility | -15.0 | | | | | | | |
| Net cash used in financing activities | -9.7 | -26.6 | -23.5 | 83.2 | | 900.2 | -5.0 | -6.6 |
| NET DECREASE IN CASH AND CASH EQUIVALENTS, AND RESTRICTED CASH | -134.0 | -32.7 | -49.1 | | | | | |