Write-Off of Abandoned Development Projects and Demolition Costs (Details Textual) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Write-off of Abandoned Development Projects and Demolition Costs [Line Items]
Write-offs of abandoned development projects and demolition costs	$ 933,000	$ 657,000	$ 933,000	$ 13,553,000
Ten MetroTech Center [Member]
Write-off of Abandoned Development Projects and Demolition Costs [Line Items]
Non-capitalizable demolition costs	$ 650,000		$ 650,000