| In millions, except per share items | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 | Dec-31-14 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Revenues: | | | | | | | | |
| Rental and related revenue | 1,025.7 | 929.2 | 855.8 | | | | | |
| General contractor and service fee revenue | 80.3 | 64.0 | 117.9 | 162.6 | 94.4 | 88.8 | 133.4 | 224.5 |
| Revenues, total | 1,105.9 | 993.2 | 973.8 | 947.9 | 780.9 | 730.5 | 792.2 | 1,046.9 |
| Revenues, total growth | 11.3% | 2.0% | 2.7% | 21.4% | 6.9% | -7.8% | -24.3% | 8.1% |
| Expenses: | | | | | | | | |
| Rental expenses | 85.8 | 76.6 | 75.6 | 71.4 | 62.9 | 74.3 | 93.4 | |
| Real estate taxes | 159.6 | 149.3 | 129.5 | 125.3 | 109.0 | 98.9 | 95.7 | |
| General contractor and other services expenses | 68.1 | 58.0 | 111.6 | 153.9 | 89.5 | 80.5 | 119.2 | 200.0 |
| Depreciation and amortization | 362.1 | 353.0 | 327.2 | 312.2 | 273.6 | 242.6 | 245.8 | 346.3 |
| Costs and expenses, total | 675.6 | 636.9 | 643.9 | 662.8 | 2,337.8 | 496.3 | 1,323.1 | 797.6 |
| |
| Other operating activities: | | | | | | | | |
| Equity in earnings of unconsolidated joint ventures | 32.8 | 11.9 | 31.4 | 21.4 | 63.3 | 47.4 | -3.3 | |
| Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal | 585.7 | 127.7 | 234.7 | 205.0 | 113.7 | 162.1 | 229.7 | 162.7 |
| Other Operating Income (Expense), Net | -3.6 | -8.2 | -5.3 | -5.2 | -4.2 | -3.9 | -5.9 | -7.2 |
| Impairment charges | | 5.6 | | | 4.5 | 18.0 | 22.9 | 49.1 |
| General and administrative expenses | 69.6 | 62.4 | 60.9 | 56.2 | 54.9 | 55.4 | 58.6 | 49.4 |
| Other Operating Activities, Net | 544.9 | 61.6 | 194.9 | 175.3 | 142.6 | 199.1 | 174.0 | 161.8 |
| Operating income | 975.2 | 417.8 | 524.8 | 460.4 | 388.6 | 433.3 | 412.1 | 411.1 |
| Operating margin | 88.2% | 42.1% | 53.9% | 48.6% | 49.8% | 59.3% | 52.0% | 39.3% |
| |
| Other income (expenses): | | | | | | | | |
| Interest and other income, net | 4.5 | 1.7 | 9.9 | 17.2 | 14.7 | 4.0 | 4.7 | 1.2 |
| Interest expense | -84.8 | -93.4 | -89.8 | -85.0 | -87.0 | -112.8 | -138.3 | -196.2 |
| Loss on debt extinguishment | -17.9 | -32.9 | -6.3 | -0.4 | -26.1 | -33.9 | -85.7 | -0.3 |
| Income before income taxes | 880.2 | 297.5 | 440.9 | 392.2 | 290.2 | 297.8 | 184.3 | 214.7 |
| Income tax expense | -18.5 | 5.1 | -8.7 | -8.8 | 0.4 | 0.6 | 3.9 | 0.8 |
| Net income | 861.6 | 302.6 | 432.2 | 383.4 | 290.6 | 298.4 | 188.2 | 215.6 |
| |
| Net income attributable to noncontrolling interests | | | | | | | | |
| Net income attributable to noncontrolling interests | 8.7 | -2.8 | -3.7 | -3.5 | -19.9 | -3.1 | -6.6 | -2.9 |
| Net income attributable to common shareholders | 852.9 | 299.9 | 429.0 | 383.7 | 1,634.4 | 312.1 | 615.3 | 204.9 |
| |
| Weighted average number of common shares/units outstanding | 377.7 | 370.1 | 362.2 | 357.6 | 355.8 | 349.9 | 345.1 | 335.8 |
| Weighted average number of common shares/units and potential dilutive securities | 383.5 | 374.2 | 367.3 | 363.3 | 362.0 | 357.1 | 352.2 | 340.4 |
| |
| Basic net income per common share/unit: | | | | | | | | |
| Continuing operations attributable to common shareholders/unitholders | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| |
| Diluted net income per common share/unit: | | | | | | | | |
| Continuing operations attributable to common shareholders/unitholders | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| |
| Comprehensive income: | | | | | | | | |
| Net income | 861.6 | 302.8 | 432.6 | 387.3 | 1,654.3 | 315.3 | 621.9 | 246.5 |
| |
| Comprehensive income | | | | | | | | |