Acquisitions and Dispositions (Summary of Significant Assumptions Utilized in Estimates) (Details)	9 Months Ended
	Sep. 30, 2017 $ / sqft
Minimum [Member]
Property, Plant and Equipment [Line Items]
Exit capitalization rate	4.10%
Maximum [Member]
Property, Plant and Equipment [Line Items]
Exit capitalization rate	5.32%
Industrial [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Net rental rate per square foot	3.50
Industrial [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Net rental rate per square foot	10.00