Summary of Significant Accounting Policies (Details) (USD $)	6 Months Ended		12 Months Ended
	Mar. 31, 2011	Sep. 30, 2010	Mar. 31, 2013	Mar. 31, 2012	Sep. 08, 2010
Basis of Presentation
Capital contribution by general partner					$ 1,000
Amortization related to intangible assets
Amortization of contract-based intangible assets	1,558,000		44,086,000	6,615,000
Advertising Costs
Advertising expense	300,000	100,000	1,100,000	800,000
Cost of sales - wholesale supply and marketing
Amortization related to intangible assets
Amortization of contract-based intangible assets	400,000		5,285,000	800,000
Cost of sales - wholesale supply and marketing | Contract-based intangibles
Amortization related to intangible assets
Amortization of contract-based intangible assets	$ 400,000	$ 400,000	$ 5,300,000	$ 800,000