Equity and Capital Noncontrolling Interest of Preferred Units (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Class of Stock [Line Items]
Distributions Paid To Preferred Unit Holders	7.45%
Preferred Units, Outstanding	500,000	500,000
Series D preferred units, par value	$ 50,000,000	$ 50,000,000