Discontinued Operations and Assets Held for Sale (Table Illustration of Number of Properties in Discontinued Operations) (Details) - buildings	3 Months Ended	12 Months Ended
	Mar. 31, 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	5
Continuing Operations, Number of Real Estate Properties Sold	3	91
Continuing Operations, Number of Real Estate Properties Sold or Classified as Held for Sale	99
Number of Real Estate Properties Held for Sale	5
Number of Real Estate Properties Sold	3	153
Total Properties Sold or Classified as Held for Sale	161
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