2018 Dispositions Activity (Details) - 2018 Dispositions $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) property parcel
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of vacant parcels sold | parcel	2
Proceeds from sale of real estate | $	$ 348.6
Gain on the sale of real estate | $	$ 46.2
Medical Office Buildings
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties sold	11
Senior Living Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties sold	7
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	5