CONDENSED CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues:
Rental income	$ 112,319	$ 113,756	$ 336,468	$ 329,191
Residents fees and services	74,946	42,352	224,634	113,906
Total revenues	187,265	156,108	561,102	443,097
Expenses:
Property operating expenses	74,729	46,805	222,893	125,109
Depreciation	38,473	35,276	114,472	102,673
General and administrative	7,798	8,352	24,615	24,106
Acquisition related costs	396	4,297	2,590	6,814
Impairment of assets			5,675	3,071
Total expenses	121,396	94,730	370,245	261,773
Operating income	65,869	61,378	190,857	181,324
Interest and other income	42	248	612	957
Interest expense	(29,405)	(30,417)	(88,536)	(87,426)
Loss on early extinguishment of debt	(692)	(6,349)	(797)	(6,349)
Loss on lease terminations		(104)		(104)
Gain (loss) on sale of properties	1,141	(101)	1,141	(101)
Equity in earnings of an investee	64	115	219	236
Income before income tax expense	37,019	24,770	103,496	88,537
Income tax expense	(125)	(43)	(405)	(290)
Income from continuing operations	36,894	24,727	103,091	88,247
Discontinued operations:
Income from discontinued operations	1,231	919	3,762	3,001
Impairment of assets from discontinued operations			(27,896)
Net income	38,125	25,646	78,957	91,248
Other comprehensive income:
Change in net unrealized (loss) / gain on investments	(2,166)	7,499	2,195	8,416
Share of comprehensive income of an investee	13	35	(68)	31
Comprehensive income	$ 35,972	$ 33,180	$ 81,084	$ 99,695
Weighted average shares outstanding (in shares)	188,102	174,690	186,942	166,698
Income from continuing operations per share (in dollars per share)	$ 0.20	$ 0.14	$ 0.55	$ 0.53
Income (loss) from discontinued operations per share (in dollars per share)		$ 0.01	$ (0.13)	$ 0.02
Net income per share (in dollars per share)	$ 0.20	$ 0.15	$ 0.42	$ 0.55