CONDENSED CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Revenues:
Rental income	$ 112,055	$ 111,852
Residents fees and services	79,442	75,056
Total revenues	191,497	186,908
Expenses:
Property operating expenses	77,802	73,679
Depreciation	38,355	37,703
General and administrative	8,290	8,648
Acquisition related costs	122	1,903
Impairment of assets		1,304
Total expenses	124,569	123,237
Operating income	66,928	63,671
Interest and other income	105	173
Interest expense	(28,900)	(29,564)
Income from continuing operations before income tax expense and equity in earnings of an investee	38,133	34,280
Income tax expense	(191)	(140)
Equity in (losses) / earnings of an investee	(97)	76
Income from continuing operations	37,845	34,216
Discontinued operations:
Income from discontinued operations	1,300	1,019
Impairment of assets from discontinued operations	(721)
Income before gain on sale of properties	38,424	35,235
Gain on sale of properties	156
Net income	38,580	35,235
Other comprehensive income:
Change in net unrealized (loss) / gain on investments	(1,921)	8,764
Share of comprehensive income (loss) of an investee	19	(8)
Comprehensive income	$ 36,678	$ 43,991
Weighted average shares outstanding (in shares)	188,176	184,605
Income from continuing operations per share (in dollars per share)	$ 0.21	$ 0.18
Income from discontinued operations per share (in dollars per share)		$ 0.01
Net income per share (in dollars per share)	$ 0.21	$ 0.19