Discontinued Operations and Assets Held for Sale (Table Illustration of Number of Properties in Discontinued Operations) (Details) - buildings	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Number of properties held for sale in discontinued operations	0
Number of properties sold in discontinued operations	0	62
Total number of properties in discontinued operations	62
Continuing Operations, Number of In-service Properties Held for Sale	1
Continuing Operations, Number of Real Estate Properties Sold	22	91
Continuing Operations, Number of Real Estate Properties Sold or Classified as Held for Sale	114
Number of Real Estate Properties Held for Sale	1
Number of Real Estate Properties Sold	22	153
Total Properties Sold or Classified as Held for Sale	176
Industrial [Member]
Number of properties held for sale in discontinued operations	0
Number of properties sold in discontinued operations	0	5
Total number of properties in discontinued operations	5
Medical Office [Member]
Number of properties held for sale in discontinued operations	0
Number of properties sold in discontinued operations	0	1
Total number of properties in discontinued operations	1
Non-reportable segment properties
Number of properties held for sale in discontinued operations	0
Number of properties sold in discontinued operations	0	56
Total number of properties in discontinued operations	56