Acquisitions of Real Estate Property (Details)	1 Months Ended	3 Months Ended								12 Months Ended			1 Months Ended		12 Months Ended										1 Months Ended			12 Months Ended			1 Months Ended			1 Months Ended		12 Months Ended												12 Months Ended									1 Months Ended				12 Months Ended							1 Months Ended	12 Months Ended		1 Months Ended		12 Months Ended
	Aug. 31, 2012 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Sep. 30, 2013 USD ($)	Jun. 30, 2013 USD ($)	Mar. 31, 2013 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Sep. 30, 2014 Unsecured Debt Unsecured term loan due 2015 CAD	Jul. 31, 2014 Unsecured Debt Unsecured term loan due 2015 CAD	Dec. 31, 2014 Triple Net Leased Properties USD ($)	Dec. 31, 2013 Triple Net Leased Properties USD ($)	Dec. 31, 2012 Triple Net Leased Properties USD ($)	Dec. 31, 2014 Senior Living Operations USD ($)	Dec. 31, 2013 Senior Living Operations USD ($)	Dec. 31, 2012 Senior Living Operations USD ($)	Dec. 31, 2014 MOB Operations USD ($)	Dec. 31, 2013 MOB Operations USD ($)	Dec. 31, 2012 MOB Operations USD ($)	Dec. 31, 2014 American Realty Capital Healthcare Trust USD ($)	Jan. 31, 2015 American Realty Capital Healthcare Trust Subsequent Event USD ($)	Jan. 31, 2015 American Realty Capital Healthcare Trust Common Stock Subsequent Event	Jan. 31, 2015 American Realty Capital Healthcare Trust Limited Partnership Units Subsequent Event	Dec. 31, 2014 2014 Acquisitions USD ($)	Dec. 31, 2014 2014 Acquisitions Triple Net Leased Properties USD ($)	Dec. 31, 2014 2014 Acquisitions Senior Living Operations USD ($)	Aug. 31, 2014 Holiday Retirement CAD	Aug. 31, 2004 Holiday Retirement CAD	Jul. 31, 2014 Holiday Retirement Unsecured Debt Unsecured term loan due 2015 CAD	Aug. 31, 2014 Holiday Retirement Seniors Housing Communities property	Dec. 31, 2014 Development Projects, 2014 USD ($)	Dec. 31, 2014 Development Projects, 2014 Seniors Housing Communities property	Dec. 31, 2014 Development Projects, 2014 Medical Office Buildings property	Dec. 31, 2014 2013 Acquisitions USD ($)	Dec. 31, 2013 2013 Acquisitions USD ($)	Dec. 31, 2014 2013 Acquisitions Triple Net Leased Properties USD ($)	Dec. 31, 2013 2013 Acquisitions Triple Net Leased Properties Seniors Housing Communities property	Dec. 31, 2014 2013 Acquisitions Senior Living Operations USD ($)	Dec. 31, 2014 2013 Acquisitions Senior Living Operations Seniors Housing Communities property	Dec. 31, 2013 2013 Acquisitions Senior Living Operations Seniors Housing Communities property	Dec. 31, 2014 2013 Acquisitions MOB Operations USD ($)	Dec. 31, 2013 2013 Acquisitions MOB Operations Medical Office Buildings property	Dec. 31, 2013 Development Projects, 2013 USD ($)	Dec. 31, 2013 Development Projects, 2013 Seniors Housing Communities property	Dec. 31, 2013 Development Projects, 2013 Medical Office Buildings property	Dec. 31, 2013 Development Projects, 2013 Hospitals property	Dec. 31, 2013 2012 Acquisitions USD ($)	Dec. 31, 2013 2012 Acquisitions Triple Net Leased Properties USD ($)	Dec. 31, 2013 2012 Acquisitions Senior Living Operations USD ($)	Dec. 31, 2013 2012 Acquisitions MOB Operations USD ($)	Dec. 31, 2012 ATRIA	Dec. 31, 2012 Funds Previously Managed by LFREI USD ($)	Apr. 30, 2012 Cogdell Spencer Inc USD ($)	Apr. 30, 2012 Cogdell Spencer Inc Medical Office Buildings property	May 31, 2012 SUNRISE Seniors Housing Communities property	Dec. 31, 2012 Development Projects, 2012 USD ($)	Dec. 31, 2012 Development Projects, 2012 Seniors Housing Communities property	Dec. 31, 2012 Development Projects, 2012 Medical Office Buildings property	Dec. 31, 2014 Other Acquisitions USD ($)	Dec. 31, 2013 Other Acquisitions Seniors Housing Communities property	Dec. 31, 2013 Other Acquisitions Skilled Nursing Facilities property	Dec. 31, 2013 Other Acquisitions Medical Office Buildings property	Dec. 31, 2013 Other Acquisitions Medical Office Buildings Unconsolidated Properties property	Feb. 13, 2015 Other Acquisitions Triple Net Leased Properties Subsequent Event USD ($)	Dec. 31, 2014 Other Acquisitions Triple Net Leased Properties Seniors Housing Communities property	Dec. 31, 2014 Other Acquisitions Triple Net Leased Properties Private Hospitals property	Feb. 13, 2015 Other Acquisitions Triple Net Leased Properties Skilled Nursing Facilities Subsequent Event property	Feb. 13, 2015 Other Acquisitions Triple Net Leased Properties Seniors Housing Communities and Hospitals Subsequent Event property	Dec. 31, 2014 Other Acquisitions Senior Living Operations Seniors Housing Communities property
Business Acquisition [Line Items]
Number of real estate properties acquired																																		29							27			24		11												71	16					21	2	44	36		26	3	12	5	4
Number of real estate properties acquired, previously capital leases																																											8	8
Business combination, consideration transferred																															957,000,000								$ 1,800,000,000																		$ 760,000,000						$ 812,000,000					$ 320,000,000
Business combination, consideration transferred, price per acquiree share																									$ 11.33
Business combination, consideration transferred, stock conversion ratio, per acquiree share																									0.1688
Business acquisition, equity interest issued, number of shares																										28,400,000	1,100,000
Payments to acquire businesses	350,000,000																								11,000,000			1,468,358,000	599,782,000	868,576,000								1,581,487,000		808,287,000		627,249,000			145,951,000						1,586,504,000	172,061,000	481,508,000	932,935,000
Business combination, notes payable and other debt assumed																									167,000,000			241,077,000	12,927,000	228,150,000		193,700,000						41,436,000		36,300,000		5,136,000			0						412,825,000	57,219,000	0	355,606,000			203,800,000
Business combination, repayment of debt													660,000,000												740,000,000
Early debt repayment costs																															26,900,000																																18,800,000
Debt instrument, face amount														791,000,000																			791,000,000
Number of real estate properties completed																																				1	2											2	1	1											2	3
Net real estate property		18,985,559,000				18,075,586,000				18,985,559,000	18,075,586,000																								41,200,000												65,500,000													116,900,000
Revenues		803,987,000	779,035,000	751,254,000	741,470,000	733,185,000	711,249,000	684,109,000	682,909,000	3,075,746,000	2,811,452,000	2,469,615,000			974,942,000	881,745,000	824,320,000	1,552,951,000	1,406,005,000	1,227,124,000	486,147,000	462,184,000	377,152,000					75,900,000
NOI																												41,500,000
Settlement of capital lease obligation										142,200,000
Business acquisition, transaction costs																								8,800,000				26,200,000
Merger-related expenses and deal costs										45,051,000	21,634,000	63,183,000																23,800,000
Ownership interests in properties accounted for under the equity method (as a percent)									5.00%																																														34.00%
Common stock acquired in business combination, shares		7,000				3,712,000				7,000	3,712,000																																													3,700,000
Preacquisition contingency, amount of settlement																																																								44,000,000
Number of real estate properties acquired, managed by property management business																																																										44
Business combination, joint venture partners' share of net debt assumed																																																									$ 36,300,000
Business combination, right to receive cash, per share of common stock outstanding (in dollars per share)																																																									$ 4.25
Preferred stock, dividend rate, percentage																																																									8.50%
Business combination, consideration transferred per share of preferred stock (in dollars per share)																																																									$ 25.00