Investments in Unconsolidated Real Estate Joint Ventures Management, Leasing and Marketing Fees (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Management, Leasing and Marketing Fees [Line Items]
Management and Leasing Fees Paid by Unconsolidated Joint Ventures	$ 1,958	$ 1,927	$ 1,921
Marketing Fees Paid by Unconsolidated Joint Venture	163	154	147
Total Management, Leasing and Marketing Fees Paid by Unconsolidated Joint Ventures	$ 2,121	$ 2,081	$ 2,068