SEGMENT INFORMATION - Capital Expenditures (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Segment Reporting Information [Line Items]
Capital expenditures	$ 309,130	$ 72,108
Operating Segments | Triple-Net Leased Properties
Segment Reporting Information [Line Items]
Capital expenditures	93,809	40,701
Operating Segments | Senior Living Operations
Segment Reporting Information [Line Items]
Capital expenditures	21,325	18,994
Operating Segments | Office Operations
Segment Reporting Information [Line Items]
Capital expenditures	$ 193,996	$ 12,413