Accounting Policies (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011 Segment Property Year State Province License LeaseRenewal	Sep. 30, 2010	Dec. 31, 2010 Property Year
Accounting Policies (Textuals) [Abstract]
Straight line rent receivable	$ 95,500,000		$ 95,500,000		$ 86,300,000
Notice period to cancel lease agreements by the resident			30 days
Term of resident lease agreements, Minimum			12 months
Term of resident lease agreements, Maximum			18 months
REIT share amount	0.7866		0.7866
Fair value of operating partnership units exceeding cost	92,800,000		92,800,000
Percentage of partnership interest units held by class B unitholders	70.90%		70.90%
Maximum percentage of ownership interest can be held in Entities	100.00%		100.00%
Number of properties having controlling interests owned through joint ventures			29		6
Noncontrolling interest share in properties owned through joint ventures	84,507,000		84,507,000		3,479,000
Net income (loss) attributable to noncontrolling interest, net of tax	$ (901,000)	$ 996,000	$ (781,000)	$ 2,443,000
Class A Units [Member]
Property, Plant and Equipment [Line Items]
Limited partnership units held by third party investors	2,375,027		2,375,027
Percentage of ownership interest on total units outstanding	29.10%		29.10%
Class B Units [Member]
Property, Plant and Equipment [Line Items]
Limited partnership units outstanding	5,795,210		5,795,210