Segment Information Building Acquisitions and Dispositions (Details) (USD $)	3 Months Ended	6 Months Ended
	Jun. 30, 2014 bldg	Jun. 30, 2014 bldg
Land, Buildings and Improvements [Member]
Property, Plant and Equipment [Line Items]
Number of real estate properties acquired	6	8
Total purchase price	$ 53,200,000	$ 90,900,000
Number of Real Estate Properties Sold		52
Proceeds from Sale of Property		366,900,000
Land [Member]
Property, Plant and Equipment [Line Items]
Number of Real Estate Properties Sold		19
Equity Method Investee [Member]
Property, Plant and Equipment [Line Items]
Equity Method Investment, Ownership Percentage	25.00%	25.00%
Not Discontinued Operations [Member] | Other Segments [Member] | Land, Buildings and Improvements [Member]
Property, Plant and Equipment [Line Items]
Number of Real Estate Properties Sold		4
Proceeds from Sale of Property		37,300,000
Not Discontinued Operations [Member] | Other Segments [Member] | Equity Method Investee [Member] | Land, Buildings and Improvements [Member]
Property, Plant and Equipment [Line Items]
Number of Real Estate Properties Sold	3
Proceeds from Sale of Property	$ 32,200,000