Recent Acquisitions of Real Estate Recent Acquisition of Real Estate (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 Property	Dec. 31, 2018 Property	Dec. 31, 2017 USD ($) Property	Dec. 31, 2016 USD ($)
Business Acquisition [Line Items]
Number of real estate properties acquired | Property	9	3	3
Two Years Prior Acquisitions
Business Acquisition [Line Items]
Acquisition related expenses and fees excluded from pro forma net loss			$ 10.0
Three Years Prior Acquisitions
Business Acquisition [Line Items]
Acquisition related expenses and fees included in pro forma net loss				$ 10.0