SEGMENT INFORMATION - Capital Expenditures (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Segment Reporting Information [Line Items]
Capital expenditures	$ 78,949	$ 232,792	$ 151,057	$ 1,359,969
Operating Segments | Triple-Net Leased Properties
Segment Reporting Information [Line Items]
Capital expenditures	15,949	102,971	56,650	559,989
Operating Segments | Senior Living Operations
Segment Reporting Information [Line Items]
Capital expenditures	24,808	29,374	43,802	311,806
Operating Segments | MOB operations
Segment Reporting Information [Line Items]
Capital expenditures	$ 38,192	$ 100,447	$ 50,605	$ 488,174