Real Estate Properties (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended							6 Months Ended			6 Months Ended		1 Months Ended
	Jun. 30, 2013 property item	Jun. 30, 2013 property item	Jun. 30, 2012 item	Jun. 30, 2013 Managed Senior Living Communities Five Star item	Jun. 30, 2013 MOB sqft item	Jun. 30, 2012 MOB	Jun. 30, 2013 Senior living communities item	Dec. 31, 2012 Senior living communities item	Jun. 30, 2013 Senior living communities Five Star item	Jun. 30, 2013 Acquisition MOB item sqft	Jan. 31, 2013 Acquisition Senior Living Leased Community Stellar Senior Living, LLC	Jun. 30, 2013 Land Acquisition MOB	Jun. 30, 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 GA Agreement to acquire Managed Senior Living Communities Cumming item	Jul. 31, 2013 GA Agreement to acquire Managed Senior Living Communities Canton and Ellijay item	Jul. 31, 2013 Jefferson City, TN Agreement to acquire Managed Senior Living Communities item	Jul. 31, 2013 Boston, MA Agreement to acquire MOB sqft
Real Estate Properties
Number of properties owned	395	395
Number of states in which properties are located	40	40
Real Estate Properties
Number of properties acquired or agreed to be acquired										3				2	1						1			1	2	1
Number of units							856	120							150									93	153	60
Aggregate purchase price of properties acquired, excluding closing costs										$ 52,600				$ 38,000	$ 22,350						$ 14,600			$ 22,030	$ 19,100	$ 10,000	$ 49,500
Intangible assets recorded related to acquisition															1,039
Assumption of mortgage notes payable		12,266	56,789												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						105,462
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	18	18	1		7		11	1
Real estate properties, held for sale							42,551	850
Impairment of asset charges recorded	4,371	5,675	3,071		1,304	3,071	32,267
Annual lease rent payable											$ 1,732
Number of properties acquired, referred to as managed properties				39					39
Property held for sale (in square feet)					831,499