Discontinued Operations (Details)	3 Months Ended
	Mar. 31, 2015 sqft		Mar. 31, 2014
Promenade Bolingbrook [Member]
Summary of rental properties included in discontinued operations
Area of Real Estate Property	771,000
Period disposed	Q2-2014 (1)	[1]
Period status	0		Yes
Quartermaster Plaza [Member]
Summary of rental properties included in discontinued operations
Area of Real Estate Property	456,000
Period disposed	Q1-2014
Period status	0		Yes
Mesa del Sol - 5600 University SE [Member]
Summary of rental properties included in discontinued operations
Area of Real Estate Property	87,000
Period disposed	Q1-2014
Period status	0		Yes

[1] Classified as held for sale as of March 31, 2014.