ACQUISITIONS OF REAL ESTATE PROPERTY (Details) $ / shares in Units, $ in Thousands	1 Months Ended			3 Months Ended		6 Months Ended		12 Months Ended
	Apr. 30, 2015 USD ($)	Jan. 31, 2015 USD ($) property $ / shares shares	Aug. 31, 2014 CAD property	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) property	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($) property shares	Jul. 31, 2014 CAD	Aug. 31, 2004 CAD
Business Acquisition [Line Items]
Revenues				$ 891,322	$ 751,254	$ 1,775,346	$ 1,492,724
Acquisition-related costs				14,585	9,599	49,757	20,359
Total net real estate property				21,365,096		21,365,096		$ 18,985,559
Triple-Net Leased Properties
Business Acquisition [Line Items]
Revenues				261,701	243,871	529,043	482,865
Senior Living Operations
Business Acquisition [Line Items]
Revenues				454,645	374,473	901,559	745,534
MOB Operations
Business Acquisition [Line Items]
Revenues				148,152	$ 117,612	294,000	237,487
2015 Acquisitions
Business Acquisition [Line Items]
Total cash used						1,262,809
Assumed mortgage debt				177,857		177,857
Revenues						144,800
NOI						86,900
Business acquisition, related costs incurred				41,600		41,600
Acquisition-related costs						30,800	$ 2,600
2015 Acquisitions | Triple-Net Leased Properties
Business Acquisition [Line Items]
Assumed mortgage debt				0		0
2015 Acquisitions | Senior Living Operations
Business Acquisition [Line Items]
Assumed mortgage debt				77,940		77,940
2015 Acquisitions | MOB Operations
Business Acquisition [Line Items]
Assumed mortgage debt				$ 99,917		99,917
Ardent Health Services
Business Acquisition [Line Items]
Total cash used	$ 1,750,000
American Realty Capital Healthcare Trust
Business Acquisition [Line Items]
Number of real estate properties acquired | property		152
Business combination, consideration transferred, stock conversion ratio, per acquiree share		0.1688
Business combination, consideration transferred, price per acquiree share | $ / shares		$ 11.33
Total cash used		$ 11,000
Assumed mortgage debt		167,000
Repayments of debt		$ 730,000
Other Acquisitions
Business Acquisition [Line Items]
Business acquisition, equity interest issued, number of shares | shares								148,241
Business combination, other investments								$ 812,000
Payment for early repayment of debt at closing								$ 18,800
Other Acquisitions | Triple-Net Leased Properties
Business Acquisition [Line Items]
Business combination, other investments						$ 512,000
Other Acquisitions | Seniors Housing Communities And Hospitals | Triple-Net Leased Properties
Business Acquisition [Line Items]
Number of real estate properties acquired | property						10
Other Acquisitions | Seniors Housing Communities
Business Acquisition [Line Items]
Number of real estate properties acquired | property						1
Other Acquisitions | Seniors Housing Communities | Triple-Net Leased Properties
Business Acquisition [Line Items]
Number of real estate properties acquired | property								26
Other Acquisitions | Seniors Housing Communities | Senior Living Operations
Business Acquisition [Line Items]
Number of real estate properties acquired | property								4
Other Acquisitions | Private Hospitals | Triple-Net Leased Properties
Business Acquisition [Line Items]
Number of real estate properties acquired | property								3
Other Acquisitions | Skilled Nursing Facilities | Triple-Net Leased Properties
Business Acquisition [Line Items]
Number of real estate properties acquired | property						12
Other Acquisitions | Medical Office Buildings | MOB Operations
Business Acquisition [Line Items]
Number of real estate properties acquired | property						1
2014 Acquisitions
Business Acquisition [Line Items]
Total cash used								$ 1,468,724
Assumed mortgage debt								241,077
2014 Acquisitions | Triple-Net Leased Properties
Business Acquisition [Line Items]
Total cash used								599,782
Assumed mortgage debt								12,927
2014 Acquisitions | Senior Living Operations
Business Acquisition [Line Items]
Total cash used								868,942
Assumed mortgage debt								228,150
Holiday Retirement
Business Acquisition [Line Items]
Assumed mortgage debt | CAD										CAD 193,700,000
Business combination, other investments | CAD			CAD 957,000,000
Payment for early repayment of debt at closing | CAD			CAD 26,900,000
Holiday Retirement | Unsecured Term Loan | Unsecured Term Loan Due 2015
Business Acquisition [Line Items]
Loan amount | CAD									CAD 791,000,000.0
Holiday Retirement | Seniors Housing Communities
Business Acquisition [Line Items]
Number of real estate properties acquired | property			29
2014 Development Projects
Business Acquisition [Line Items]
Total net real estate property								$ 41,200
2014 Development Projects | Seniors Housing Communities
Business Acquisition [Line Items]
Number of real estate properties completed | property								1
2014 Development Projects | Medical Office Buildings
Business Acquisition [Line Items]
Number of real estate properties completed | property								2
Common Stock Par Value | American Realty Capital Healthcare Trust
Business Acquisition [Line Items]
Business acquisition, equity interest issued, number of shares | shares		28,400,000
Limited Partnership Units | American Realty Capital Healthcare Trust
Business Acquisition [Line Items]
Business acquisition, equity interest issued, number of shares | shares		1,100,000
Hospitals | Ardent Health Services
Business Acquisition [Line Items]
Business combination, expected parent ownership interest after deconsolidation (up to 9.9%)	9.90%