CONDENSED CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Revenues:
Rental income	$ 112,297	$ 108,407	$ 224,150	$ 215,435
Residents fees and services	74,631	35,986	149,687	71,554
Total revenues	186,928	144,393	373,837	286,989
Expenses:
Property operating expenses	74,484	39,818	148,163	78,304
Depreciation	38,296	34,624	75,999	67,397
General and administrative	8,168	8,068	16,816	15,753
Acquisition related costs	292	1,829	2,187	2,694
Impairment of assets	4,371		5,675	3,071
Total expenses	125,611	84,339	248,840	167,219
Operating income	61,317	60,054	124,997	119,770
Interest and other income	397	227	570	709
Interest expense	(29,567)	(28,120)	(59,131)	(57,009)
Loss on early extinguishment of debt	(105)		(105)
Equity in earnings of an investee	79	76	155	121
Income before income tax expense	32,121	32,237	66,486	63,591
Income tax expense	(140)	(43)	(280)	(247)
Income from continuing operations	31,981	32,194	66,206	63,344
Discontinued operations:
Income from discontinued operations	1,513	1,057	2,523	2,259
Impairment of assets from discontinued operations	(27,896)		(27,896)
Net income	5,598	33,251	40,833	65,603
Other comprehensive income:
Change in net unrealized gain / loss on investments	(4,404)	(1,315)	4,360	916
Share of comprehensive income of an investee	(73)	(3)	(81)	(4)
Comprehensive income	$ 1,121	$ 31,933	$ 45,112	$ 66,515
Weighted average shares outstanding (in shares)	188,081	162,670	186,350	162,659
Income from continuing operations per share (in dollars per share)	$ 0.17	$ 0.20	$ 0.36	$ 0.39
(Loss) income from discontinued operations per share (in dollars per share)	$ (0.14)		$ (0.14)	$ 0.01
Net income per share (in dollars per share)	$ 0.03	$ 0.20	$ 0.22	$ 0.40