Partnership Income, Expenses and Cash Distributions Cash Distributions (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Distribution Made to Member or Limited Partner [Line Items]
Distribution Made to Member or Limited Partner, Distributions Paid, Per Unit	$ 0.5000	$ 0.5000	$ 0.5000