| Quarterly Financial Information [Text Block] |
15. Quarterly Financial Data (unaudited) Summarized quarterly financial data, for the years ended December 31, 2014 and 2013, is as follows: | | | | | | | | | | | | | | | | | | | | | (in thousands, except per share amounts) | First | | Second | | Third | | Fourth | | Total (a) | 2014: | | | | | | | | | | Revenues | $ | 205,929 |
| | $ | 208,492 |
| | $ | 213,098 |
| | $ | 216,459 |
| | $ | 843,978 |
| Net income attributable to common shareholders | 40,036 |
| | 35,272 |
| | 38,283 |
| | 178,498 |
| | 292,089 |
| Net income attributable to common shareholders per share – basic | 0.45 |
| (b) | 0.40 |
| (c) | 0.43 |
| (d) | 1.99 |
| (e) | 3.29 |
| Net income attributable to common shareholders per share – diluted | 0.45 |
| (b) | 0.40 |
| (c) | 0.43 |
| (d) | 1.98 |
| (e) | 3.27 |
| 2013: | | | | | | | | | | Revenues | $ | 189,811 |
| | $ | 194,983 |
| | $ | 199,740 |
| | $ | 204,317 |
| | $ | 788,851 |
| Net income attributable to common shareholders | 63,476 |
| | 72,172 |
| | 70,720 |
| | 129,996 |
| | 336,364 |
| Net income attributable to common shareholders per share – basic | 0.72 |
| (f) | 0.82 |
| (g) | 0.80 |
| (h) | 1.47 |
| (i) | 3.82 |
| Net income attributable to common shareholders per share – diluted | 0.72 |
| (f) | 0.81 |
| (g) | 0.79 |
| (h) | 1.46 |
| (i) | 3.78 |
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| | (a) | Net income per share is computed independently for each of the quarters presented. Therefore, the sum of quarterly net income per share amounts may not equal the total computed for the year. |
| | (b) | Includes a $3,566, or $0.04 basic and diluted per share, impact related to our proportionate gain on sale of an operating property by each of our funds, which is included in equity in income of joint ventures. |
| | (c) | Includes a $1,447, or $0.02 basic and diluted per share, impact related to a gain on sale of land, and a $1,152, or $0.01 basic and diluted per share, impact related to an impairment charge associated with land holdings |
| | (d) | Includes a $1,808, or $0.02 basic and diluted per share, impact related to a gain on sale of land. |
| | (e) | Includes a $155,680, or $1.76 basic and $1.73 diluted per share, impact related to the gain on sale of operating properties, and a $10,000, or $0.11 basic and diluted per share, impact related to incentive compensation expense as a result of joint venture restructuring. |
| | (f) | Includes a $31,783, or $0.37 basic and $0.36 diluted per share, impact related to the gain on sale of discontinued operations. |
| | (g) | Includes a $24,866, or $0.29 basic and $0.28 diluted per share, impact related to the gain on sale of discontinued operations, and a $13,032, or $0.15 basic and diluted per share, impact related to our proportionate gain on sale of 14 joint venture communities included in equity in income of joint ventures. |
| | (h) | Includes an $34,410, or $0.39 basic and diluted per share, impact related to the gain on sale of discontinued operations. |
| | (i) | Includes a $91,101, or $1.04 basic and $1.03 diluted per share, impact related to the gain on sale of discontinued operations and a $3,245, or $0.04 basic and diluted per share, impact related to our proportionate gain on sale of two operating properties by one of our unconsolidated joint ventures included in equity in income of joint ventures. |
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