Real Estate Investments - Nonmonetary Exchange Narrative (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2017 USD ($) property	Jun. 30, 2017 USD ($) property	Jun. 30, 2016 property
Real Estate [Line Items]
Number of real estate properties disposed | property		1
Red Lobster [Member]
Real Estate [Line Items]
Number of real estate properties disposed | property	15	20	24
Fair value of assets disposed | $	$ 50.1	$ 50.1
Gain on acquisition and disposition of assets | $	$ 7.4
Bob Evans [Member]
Real Estate [Line Items]
Number of real estate properties acquired | property	22
Fair value of properties acquired | $	$ 50.1