Subsequent Events (Narrative) (Details) (USD $)	0 Months Ended	9 Months Ended
	Oct. 26, 2011	Sep. 30, 2011
Number of properties acquired		1
Earliest redemption date	Nov. 28, 2011
Redemption of depository shares	4,200,000
Ratio of cumulative preferred share	1/1,000
Preferred Stock, Dividend Rate, Percentage	6.95%
Dividend Rate %	6.95%
Aggregate redemption amount pre-accrued dividends	$ 105,000,000
Income reclassified from common to preferred	3,508,000
Permanent noncontrolling interests in two affiliated partnerships	6,300,000
Subsequent Period Acquisitions [Member]
Contract acquisition cost to acquire real estate		$ 10,500,000