Other Assets (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011
Future Amortization of Intangible Assets and Liabilities
2012	$ 3,024
2013	2,881
2014	2,745
2015	2,618
2016	1,691
Thereafter	5,161
Total of aggregate amortization of intangible assets and liabilities	18,120
Weighted average remaining lease term (In Years)	10 years
Below Market Rents [Member]
Future Amortization of Intangible Assets and Liabilities
2012	(274)
2013	(249)
2014	(244)
2015	(231)
2016	(200)
Thereafter	(562)
Total of aggregate amortization of intangible assets and liabilities	(1,760)
Weighted average remaining lease term (In Years)	8 years
Above Market Ground Lease [Member]
Future Amortization of Intangible Assets and Liabilities
2012	(9)
2013	(9)
2014	(9)
2015	(9)
2016	(9)
Thereafter	(633)
Total of aggregate amortization of intangible assets and liabilities	(678)
Weighted average remaining lease term (In Years)	75 years
Above Market Rents [Member]
Future Amortization of Intangible Assets and Liabilities
2012	674
2013	674
2014	674
2015	658
2016	390
Thereafter	1,344
Total of aggregate amortization of intangible assets and liabilities	4,414
Weighted average remaining lease term (In Years)	8 years
In Place Leases [Member]
Future Amortization of Intangible Assets and Liabilities
2012	2,633
2013	2,465
2014	2,324
2015	2,200
2016	1,510
Thereafter	5,012
Total of aggregate amortization of intangible assets and liabilities	$ 16,144
Weighted average remaining lease term (In Years)	8 years