Common Unit Repurchase and Retirement (Details Textual) (USD $)	1 Months Ended					3 Months Ended		9 Months Ended	12 Months Ended		23 Months Ended	1 Months Ended
	Feb. 29, 2012	Jan. 31, 2012	Dec. 31, 2011	Nov. 30, 2011	Oct. 31, 2011	Mar. 31, 2012	Dec. 31, 2011	Jun. 30, 2012	Sep. 30, 2011	Sep. 30, 2010	Jun. 30, 2012	Jul. 31, 2010 Plan II [Member]	Jul. 31, 2012 Plan III [Member]
Common Unit Repurchase and Retirement (Textual) [Abstract]
Repurchase of common units											7,250,000
Partnership's common units authorized for repurchase												7,000,000	3,000,000
Additional partnership's common units authorized for repurchase			250,000
Average Price Paid per Unit	$ 4.54	$ 4.63	$ 5.21	$ 4.95	$ 4.96	$ 4.62	$ 5.17	$ 4.94	$ 5.19	$ 4.44
Number of repurchased units acquired in private sale			1,750,000						1,500,000