DISPOSITIONS - Narrative (Details) $ in Millions	6 Months Ended
	Jun. 30, 2017 USD ($) property parcel	Jun. 30, 2016 USD ($)	Nov. 30, 2016 USD ($) property
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Vacant parcels sold | parcel	2
Proceeds from sale of real estate	$ 104.6
Gain on disposition	44.0
Potential proceeds from sale of property under agreement			$ 700.0
Impairment of real estate	$ 15.6	$ 14.5
Triple-Net Leased Properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties sold | property	10
Medical Office Buildings
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties sold | property	2
Skilled Nursing Facilities
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Potential properties for sale under agreement | property			36
Potential gain on sale of real estate	$ 600.0
Kindred
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Potential proceeds from sale of property under agreement			$ 700.0