Real Estate Investments, Net - Revenue from External Customers and Long-Lived Assets, by Geographical Areas (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Entity-wide revenue percentage	62.10%	63.00%
Michigan
Revenues from External Customers and Long-Lived Assets [Line Items]
Entity-wide revenue percentage	14.00%	14.60%
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Entity-wide revenue percentage	17.40%	18.20%