Real Estate Assets, Discontinued Operations and Assets Held for Sale (Table Illustration of Number of Properties in Discontinued Operations) (Details) - buildings	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Continuing Operations, Number of In-service Properties Held for Sale	0
Continuing Operations, Number of Real Estate Properties Sold	1	28
Total Properties Sold or Classified as Held for Sale	29