Acquisitions and Dispositions (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Proceeds from land and depreciated property sales, net	$ 70,673,000	$ 61,931,000
Business Combination, Acquisition Related Costs	14,000	319,000
Gain Loss On Business Combinations Excluding Acquisitions Costs		(962,000)
Income Tax Expense (Benefit)	2,674,000	0
Discontinued Operation, Tax Effect of Discontinued Operation	$ 2,977,000	$ 0
Other Two Thousand Fourteen Acquisitions [Member] [Domain] [Member] [Member]
Weighted average remaining life of property (years)	3 years 9 months 29 days
Atlanta Georgia [Member] | Industrial [Member] | Other Two Thousand Fourteen Acquisitions [Member] [Domain] [Member] [Member]
Number of real estate properties acquired	1