Discontinued Operations (Details) (USD $) In Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010	Sep. 30, 2011		Sep. 30, 2010	Dec. 31, 2010
Discontinued Operations [Abstract]
Rental and other revenues	$ 480		$ 535	$ 1,593		$ 3,092
Operating expenses:
Rental property and other expenses	211		166	570		1,214
Depreciation and amortization	0		98	127		647
Total operating expenses	211		264	697		1,861
Other Income	0		1	1		2
Income from discontinued operations	269		272	897		1,233
Net gains/(losses) on disposition of discontinued operations	2,573		0	2,573		(86)
Total discontinued operations	2,842		272	3,470		1,147
Assets:
Land	0			0			2,788
Buildings and tenant improvements	0			0			12,707
Land held for development	0			0			2,766
Total real estate assets	0			0			18,261
Less accumulated depreciation	0			0			(5,012)
Net real estate assets	0			0			13,249
Deferred leasing costs, net	0			0			58
Accrued straight line rents receivable	0			0			257
Prepaid expenses and other assets	0			0			43
Real estate and other assets, net, held for sale	0			0			13,607
Tenant security deposits, deferred rents and accrued costs	$ 0	[1]		$ 0	[1]		$ 11	[1]

[1] (1) Included in accounts payable, accrued expenses and other liabilities.