Dispositions, Assets Held for Sale and Discontinued Operations (Details Textuals) (USD $)	12 Months Ended
	Dec. 31, 2011 properties	Dec. 31, 2010 properties	Dec. 31, 2009 properties
Dispositions Assets Held for Sale and Discontinued Operations (Textuals) [Abstract]
Impairment charge to reduce the carrying value			$ 25,223,000
Impairment charge	12,194,000	947,000	25,223,000
Cash proceeds for sale	247,210,000	219,027,000	224,007,000
Sellers financing	0	(1,470,000)	0
Gain (loss) on sales of properties	61,160,000	36,115,000	43,394,000
Number of properties sold	42	38	36
Senior housing facilities [Member]
Dispositions Assets Held for Sale and Discontinued Operations (Textuals) [Abstract]
Number of real property facilities satisfying held for sale criteria	1
Number of facilities held for sale		16	2
Medical Facilities [Member]
Dispositions Assets Held for Sale and Discontinued Operations (Textuals) [Abstract]
Impairment charge to reduce the carrying value		947,000
Number of real property facilities satisfying held for sale criteria	5
Sellers financing	$ 0	$ (1,470,000)	$ 0
Number of facilities held for sale		1	8
Number of properties sold		7