CONDENSED CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Per Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Revenues:
Rental income	$ 102,546	$ 80,961	$ 300,527	$ 242,173
Residents fees and services	10,731		11,575
Total revenues	113,277	80,961	312,102	242,173
Expenses:
Depreciation	28,824	22,505	82,120	67,139
Property operating expenses	19,754	4,599	40,572	13,138
General and administrative	6,608	5,545	19,618	16,439
Acquisition related costs	2,620	286	6,547	725
Impairment of assets	1,028		1,194	1,095
Total expenses	58,834	32,935	150,051	98,536
Operating income	54,443	48,026	162,051	143,637
Interest and other income	462	203	971	703
Interest expense	(24,730)	(20,226)	(70,837)	(59,155)
Loss on early extinguishment of debt			(427)	(2,433)
Gain on sale of properties		109	21,315	109
Equity in earnings (losses) of an investee	28	35	111	(17)
Income before income tax expense	30,203	28,147	113,184	82,844
Income tax expense	(207)	(69)	(365)	(223)
Net income	$ 29,996	$ 28,078	$ 112,819	$ 82,621
Weighted average shares outstanding (in shares)	153,385	127,423	145,745	127,404
Net income per share (in dollars per share)	$ 0.20	$ 0.22	$ 0.77	$ 0.65