Equity And Accumulated Other Comprehensive Loss, Net (Narrative) (Details) (USD $)	3 Months Ended			3 Months Ended	1 Months Ended	9 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011	Mar. 31, 2012 Common Stock [Member]	Jun. 30, 2011 Equity Distribution Agreements [Member]	Sep. 30, 2011 Equity Distribution Agreements [Member]
Aggregate offering price of the distribution agreement maximum						$ 400,000,000
Aggregate shares issued from the distribution agreement						100,000
Net proceeds from sale of common stock (shares)				956,818	6,800,000
Gross proceeds from the sale of common stock	63,346,000	5,734,000			400,000,000
Net proceeds from sale of common stock	62,700,000				394,000,000	5,600,000
Issuance of common shares	1,000,000
Average price per share	$ 66.19
Commissions	600,000
Equity distribution agreements at an average price						$ 58.44
Payment of commissions to sales agents						100,000
Redemption value of OP units	322,800,000		291,500,000
Percentage of operating partnership common units issued	25.00%
Available indebtedness	$ 17,800,000