Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013 Common units	Mar. 31, 2012 Common units	Mar. 31, 2013 Subordinated units	Mar. 31, 2012 Subordinated units
Accounts receivable - trade, allowance for doubtful accounts (in dollars)	$ 1,760	$ 818
PROPERTY, PLANT AND EQUIPMENT, accumulated depreciation (in dollars)	50,127	12,843
INTANGIBLE ASSETS, accumulated amortization (in dollars)	$ 44,155	$ 8,174
General partner, interest (as a percent)	0.10%	0.10%
General partner, notional units outstanding	53,676	29,245
Limited partners, interest (as a percent)	99.90%	99.90%
Units outstanding			47,703,313	23,296,253	5,919,346	5,919,346
Units issued			47,703,313	23,296,253	5,919,346	5,919,346