Real Estate Properties (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								3 Months Ended		1 Months Ended														1 Months Ended
	Mar. 31, 2013 property item	Mar. 31, 2012	Mar. 31, 2013 Five Star	Mar. 31, 2013 Managed Senior Living Communities Five Star item	Mar. 31, 2013 Senior living communities Five Star item	Mar. 31, 2013 Acquisition Five Star	Mar. 31, 2013 Acquisition MOB item sqft	Jan. 31, 2013 Acquisition Senior Living Leased Community Stellar Senior Living, LLC	Mar. 31, 2013 Land Acquisition MOB	Mar. 31, 2013 Buildings and improvements Acquisition MOB	Feb. 28, 2013 WA Acquisition MOB item sqft	Jan. 31, 2013 WA Acquisition Senior Living Leased Community item	Feb. 28, 2013 WA Land Acquisition MOB	Jan. 31, 2013 WA Land Acquisition Senior Living Leased Community	Feb. 28, 2013 WA Buildings and improvements Acquisition MOB	Jan. 31, 2013 WA Buildings and improvements Acquisition Senior Living Leased Community	Jan. 31, 2013 WA Furniture, fixtures and equipment Acquisition Senior Living Leased Community	Mar. 31, 2013 Hattiesburg, MS Acquisition MOB item sqft	Mar. 31, 2013 Hattiesburg, MS Land Acquisition MOB	Mar. 31, 2013 Hattiesburg, MS Buildings and improvements Acquisition MOB	Apr. 30, 2013 Cherry Hill, NJ Agreement to acquire MOB sqft	Mar. 31, 2013 Pittsburgh, PA Triple Net Senior Living Communities	Dec. 31, 2012 Pittsburgh, PA Triple Net Senior Living Communities	Mar. 31, 2013 Pittsburgh, PA Sale Triple Net Senior Living Communities item	Apr. 30, 2013 Cumming, GA Agreement to acquire Managed Senior Living Communities item
Real Estate Properties
Number of properties owned	395
Number of states in which properties are located	40
Real Estate Properties
Number of properties acquired or agreed to be acquired							3				2	1						1							1
Number of units												150													93
Aggregate purchase price of properties acquired, excluding closing costs							$ 52,600				$ 38,000	$ 22,350						$ 14,600			$ 21,500				$ 22,030
Intangible assets recorded related to acquisition												1,039
Assumption of mortgage notes payable	12,266											12,266
Fair value of mortgage notes payable												13,306
Premium on Assumed Debt												1,040
Area of real estate properties acquired (in square feet)							217,000				144,900							71,824			53,976
Intangible lease liabilities recorded							10,765				8,442							2,323
Intangible lease assets recorded							2,222				1,539							683
Property plant and equipment recorded									6,908	36,930			5,639	5,120	25,239	16,562	669		1,269	11,691
Number of properties classified as held for sale	1																							1
Real estate properties, held for sale																						850	850
Impairment of asset charges recorded	1,304	3,071
Real estate improvements purchased			8,171			8,171
Increase or decrease in annual lease rent payable			654			656
Annual lease rent payable								$ 1,732
Number of properties acquired, referred to as managed properties				39	39