Discontinued Operations (Schedule Of Properties Identified As Held For Sale) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended		0 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Jul. 10, 2013 106 Allen Road [Member]	Jun. 30, 2013 106 Allen Road [Member] item sqft
Long Lived Assets Held-for-sale [Line Items]
Number of Buildings				1	[1]
Rentable Square Feet				132,010	[1]
Gross Book Value				$ 17,895	[1]
Accumulated Depreciation				(5,044)	[1]
Net Book Value	12,851	60,863		12,851	[1]
Sales proceeds	$ 165,513		$ 18,000

[1] On July 10, 2013, the Company sold this property for approximately $18.0 million.