Consolidated Statement of Equity and Comprehensive Income (Loss) (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Common stock/unit per share	$ 1.85	$ 1.85	$ 2.11
Parent Company [Member]
Common stock/unit per share	$ 1.8500	$ 1.8500	$ 1.85