Real Estate Investments - Assets Held for Sale (Details) $ in Millions				3 Months Ended	6 Months Ended
	Jun. 29, 2017 USD ($) ft²	Jun. 16, 2017 USD ($)	Mar. 31, 2017 USD ($)	Mar. 31, 2017 USD ($)	Jun. 30, 2017 USD ($) ft² property	Dec. 31, 2016 property
Real Estate [Line Items]
Number of properties held for sale | property					1	2
Number of properties reclassified to held for sale | property					3
Number of properties sold | property					4
PENNSYLVANIA | Inpatient Rehabilitation Facility
Real Estate [Line Items]
Area of real estate property held for sale | ft²					78,731
TEXAS | Inpatient Rehabilitation Facility
Real Estate [Line Items]
Area of real estate property held for sale | ft²	39,786
ILLINOIS | Medical Office Building
Real Estate [Line Items]
Area of real estate property held for sale | ft²					5,100
Impairment charge				$ 0.3
Real Estate Dispositions
Real Estate [Line Items]
Gain					$ 39.5
Real Estate Dispositions | TEXAS
Real Estate [Line Items]
Gain	$ 8.3		$ 15.8
Real Estate Dispositions | ILLINOIS
Real Estate [Line Items]
Gain		$ 0.0