Acquisitions and Dispositions (Summary of Significant Assumptions Utilized in Estimates) (Details) (USD $)	6 Months Ended
	Jun. 30, 2013 months
Minimum [Member]
Fair Value Inputs, Discount Rate	6.82%
Fair Value Inputs, Cap Rate	5.10%
Lease-up period (months)	12
Minimum [Member] | Industrial [Member]
Rental rate per square foot	$ 2.95
Minimum [Member] | Medical Office [Member]
Rental rate per square foot	18.00
Maximum [Member]
Fair Value Inputs, Discount Rate	9.67%
Fair Value Inputs, Cap Rate	7.67%
Lease-up period (months)	24
Maximum [Member] | Industrial [Member]
Rental rate per square foot	6.84
Maximum [Member] | Medical Office [Member]
Rental rate per square foot	$ 18.00