SEGMENT INFORMATION - Capital Expenditures (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Capital expenditures	$ 1,440,229	$ 1,363,289	$ 1,591,286	$ 2,723,258
Operating Segments | Triple-Net Leased Properties
Segment Reporting Information [Line Items]
Capital expenditures	12,992	1,318,868	69,642	1,878,857
Operating Segments | Senior Living Operations
Segment Reporting Information [Line Items]
Capital expenditures	26,495	34,104	70,297	345,910
Operating Segments | Office Operations
Segment Reporting Information [Line Items]
Capital expenditures	$ 1,400,742	$ 10,317	$ 1,451,347	$ 498,491