Related Parties (Narrative) (Details) (USD $)	1 Months Ended	3 Months Ended				6 Months Ended		12 Months Ended
	Mar. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Jun. 30, 2010	Mar. 31, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010	Apr. 30, 2011
Accounts receivable, related parties			$ 4,600,000			$ 4,600,000		$ 2,700,000
Accounts payable and accrued expenses, related parties			7,800,000			7,800,000		9,600,000
Management fees revenue, related parties			1,500,000	1,400,000		3,100,000	2,900,000
Debt assumed by unconsolidated joint venture					28,100,000
Proceeds from sale and disposition of property, net						43,013,000	17,248,000
Sale of unconsolidated joint venture interest		47.80%							50.00%
Gross sales proceeds received by unconsolidated real estate joint ventures	4,000,000	500,000						8,300,000
Property Contributed To Joint Venture [Member]
Value of property contributed to unconsolidated joint venture					47,300,000
Debt assumed by unconsolidated joint venture					28,100,000
Proceeds from sale and disposition of property, net					$ 14,000,000