| In millions, except per share items | Jun-30-17 | Mar-31-17 | Dec-31-16 | Sep-30-16 | Jun-30-16 | Mar-31-16 | Dec-31-15 | Sep-30-15 |
| | 10-Q | 10-Q | 10-K | 10-Q | 10-Q | 10-Q | 10-K | 10-Q |
| Revenues: | | | | | | | | |
| Base rent | 363.3 | 353.8 | 345.0 | 332.0 | 320.2 | 309.5 | 298.6 | 294.8 |
| Recoveries from tenants | 180.6 | 176.3 | 169.7 | 161.3 | 152.1 | 144.9 | 139.5 | 135.0 |
| Other revenues | 12.2 | 14.0 | 14.0 | 9.6 | 11.6 | 14.8 | 14.3 | 14.6 |
| Total revenues | 556.2 | 544.0 | 528.7 | 502.9 | 483.9 | 469.2 | 452.4 | 444.5 |
| Total revenues growth | 14.9% | 15.9% | 16.9% | 13.2% | 11.3% | 11.0% | 8.3% | 8.7% |
| Expenses: | | | | | | | | |
| Property operating costs | 161.8 | 158.3 | 154.1 | 148.8 | 142.8 | 134.5 | 130.1 | 124.7 |
| Real estate taxes and insurance | 19.1 | 19.9 | 20.2 | 21.1 | 21.5 | 22.7 | 21.3 | 19.6 |
| Depreciation and amortization | 112.8 | 110.1 | 107.8 | 106.1 | 105.0 | 104.9 | 104.0 | 102.8 |
| General and administrative | 25.3 | 24.3 | 23.0 | 21.2 | 20.1 | 19.3 | 18.1 | 17.7 |
| Business Combination, Acquisition Related Costs | 7.1 | | | | | | | |
| Other expenses | 10.3 | 12.1 | 11.8 | 7.4 | 9.6 | 12.0 | 16.9 | 21.0 |
| Total expenses | 336.3 | 324.7 | 316.8 | 427.0 | 421.4 | 415.8 | 412.8 | 285.8 |
| Operating income | 219.9 | 219.3 | 211.9 | 75.9 | 62.5 | 53.5 | 39.6 | 158.7 |
| Operating margin | 39.5% | 40.3% | 40.1% | 15.1% | 12.9% | 11.4% | 8.7% | 35.7% |
| |
| Interest: | | | | | | | | |
| Expense incurred | -48.4 | -48.2 | -48.3 | -47.6 | -46.3 | -43.8 | -40.5 | -38.0 |
| Amortization of deferred financing costs | -3.6 | -3.7 | -3.7 | -3.7 | -3.6 | -3.4 | -3.2 | -2.9 |
| Gain on sale of real estate | | | | 22.8 | 23.1 | | | |
| Net income | 166.4 | 189.0 | 181.4 | 46.3 | 35.7 | 6.3 | -4.1 | 117.6 |
| Net income attributable to redeemable noncontrolling interests – operating partnership | 80.5 | 77.6 | 77.8 | 62.9 | 63.5 | 66.3 | 68.1 | -12.9 |
| Net income attributable to controlling interests | 144.9 | 164.5 | 157.2 | 47.1 | 37.1 | 10.5 | 1.9 | 100.3 |
| Preferred stock dividends | -13.6 | -17.3 | -20.7 | -24.2 | -27.4 | -27.2 | -27.2 | -27.2 |
| Other Preferred Stock Dividends and Adjustments | | | | -12.5 | -8.8 | | | |
| Net income attributable to common shares | 127.6 | 134.8 | 124.0 | 10.4 | 0.9 | -16.7 | -25.3 | 73.1 |
| Net income attributable to common units | 149.1 | 159.3 | 148.2 | 9.6 | -0.5 | -21.0 | -31.3 | 67.4 |
| |
| Earnings per share – basic: | | | | | | | | |
| Net income attributable to common shares | $1.68 | $1.79 | $1.69 | $0.01 | ($0.08) | ($0.28) | ($0.40) | $1.11 |
| |
| Weighted average common shares outstanding | 75.6 | 74.8 | 72.4 | 70.4 | 67.9 | 65.6 | 65.2 | 65.3 |
| |
| Earnings per share – diluted: | | | | | | | | |
| Net income attributable to common shares | $1.64 | $1.75 | $1.66 | $0.00 | ($0.08) | ($0.27) | ($0.39) | $1.10 |
| Weighted average common shares outstanding | 76.5 | 75.7 | 73.3 | 71.1 | 68.5 | 66.1 | 65.7 | 66.0 |
| |
| Dividends declared per common share | $1.47 | $1.44 | | $1.41 | $1.36 | $1.31 | | $1.26 |
| |
| Earnings per unit – basic: | | | | | | | | |
| Net income attributable to common units | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| |
| Weighted average common units outstanding | | | | | | | | |
| Earnings per unit – diluted: | | | | | | | | |
| Net income attributable to common units | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| |
| Weighted average limited partnership units outstanding, diluted | | | | | | | | |
| Distributions declared per unit | | | | | | | | |