Discontinued Operations - Additional Information (Details) - Cole Capital [Member] - Held-for-sale of Disposed of by Sale [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Feb. 01, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration paid at closing		$ 120.0
Contingent consideration, payment period	6 years
Contingent consideration, maximum consideration receivable		$ 80.0