Real Estate Properties (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended							9 Months Ended		9 Months Ended		1 Months Ended
	Sep. 30, 2013 item property	Sep. 30, 2012	Sep. 30, 2013 Managed Senior Living Communities Five Star item	Sep. 30, 2013 MOB item sqft	Sep. 30, 2012 MOB	Sep. 30, 2013 Senior living communities item	Dec. 31, 2012 Senior living communities item	Sep. 30, 2013 Acquisition MOB item sqft	Jan. 31, 2013 Acquisition Senior Living Leased Community Stellar Senior Living, LLC	Sep. 30, 2013 Land Acquisition MOB	Sep. 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	Aug. 31, 2013 GA Acquisition Managed Senior Living Communities Cumming item	Oct. 31, 2013 GA Acquisition Senior living communities Subsequent event item	Aug. 31, 2013 GA Land Acquisition Managed Senior Living Communities Cumming	Aug. 31, 2013 GA Buildings and improvements Acquisition Managed Senior Living Communities Cumming	Aug. 31, 2013 GA Furniture, fixtures and equipment Acquisition Managed Senior Living Communities Cumming	Oct. 31, 2013 Tennessee Acquisition Senior living communities Subsequent event item	Aug. 31, 2013 Boston, MA Acquisition MOB item sqft	Aug. 31, 2013 Boston, MA Land Acquisition MOB	Aug. 31, 2013 Boston, MA Buildings and improvements Acquisition MOB	Aug. 31, 2013 Verona, WI Agreement to acquire MOB item	Oct. 31, 2013 Tennessee and Georgia Acquisition Senior living communities Subsequent event item	Oct. 31, 2013 Orlando, FL Agreement to acquire MOB Subsequent event item sqft
Real Estate Properties
Number of properties owned	396
Number of states in which properties are located	40
Real Estate Properties
Number of properties acquired or agreed to be acquired								4				2	1						1			1	2				1	1			1	3	3
Number of units						744	120						150									93									68	213
Aggregate purchase price of properties acquired, excluding closing costs								$ 102,100				$ 38,000	$ 22,350						$ 14,600			$ 22,030						$ 49,500			$ 12,000	$ 29,000	$ 15,375
Intangible assets recorded related to acquisition													1,039									1,013
Assumption of mortgage notes payable	12,266	112,153											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)								322,000				144,900							71,824									105,462					62,826
Intangible lease liabilities recorded								10,765				8,442							2,323
Intangible lease assets recorded								2,222				1,539							683
Property plant and equipment recorded										11,508	81,830			5,639	5,120	25,239	16,562	669		1,269	11,691			1,548	18,666	803			4,600	44,900
Number of properties classified as held for sale	19			7		10	1
Number of properties impaired	11
Real estate properties, held for sale						94,891	850
Impairment of asset charges recorded	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			40
Property held for sale (in square feet)				831,499