Acquisitions (Details 2) (USD $)		12 Months Ended		0 Months Ended			12 Months Ended		12 Months Ended			0 Months Ended								1 Months Ended			1 Months Ended
	Mar. 31, 2013	Mar. 31, 2013 Common units	Mar. 31, 2012 Common units	Nov. 02, 2012 Pecos	Mar. 31, 2013 Pecos	Mar. 31, 2013 Pecos Trade names	Mar. 31, 2013 Pecos Customer relationships	Mar. 31, 2013 Pecos Vehicles and related equipment	Mar. 31, 2013 Pecos Vehicles and related equipment Minimum	Mar. 31, 2013 Pecos Vehicles and related equipment Maximum	Mar. 31, 2013 Pecos Other	Nov. 12, 2012 Pecos Call agreement Common units	Nov. 02, 2011 Pecos Call agreement Common units Minimum	Nov. 02, 2012 Pecos Call agreement Common units Maximum	Nov. 02, 2011 Pecos Call agreement Common units Maximum	Mar. 31, 2013 High Sierra	Jun. 19, 2012 High Sierra	Jun. 19, 2012 High Sierra Trade names	Jun. 19, 2012 High Sierra Customer relationships	Jun. 30, 2012 High Sierra Customer relationships Minimum	Jun. 30, 2012 High Sierra Customer relationships Maximum	Jun. 19, 2012 High Sierra Vehicles and related equipment	Jun. 30, 2012 High Sierra Vehicles and related equipment Minimum	Jun. 30, 2012 High Sierra Vehicles and related equipment Maximum
Acquisitions
Cash acquired				$ 2,200,000
Amount of additional consideration payable	5,000,000			10,200,000
Number of common units issued to acquire ownership interests (in shares)		24,250,258	14,432,031									1,834,414
General and administrative expense					600,000											3,700,000
Estimated fair value of the assets acquired and liabilities assumed
Accounts receivable					73,704,000												395,311,000
Inventory					1,903,000												43,575,000
Other current assets					1,425,000												11,131,000
Property, plant and equipment								19,193,000			2,562,000											20,968,000
Useful life of property, plant and equipment									5 years	10 years													5 years	10 years
Intangible assets						1,000,000	8,000,000											13,000,000	245,000,000
Useful life of intangible assets							5 years													5 years	17 years
Goodwill					86,661,000												220,884,000
Accounts payable and accrued liabilities					(51,827,000)
Long-term debt					(10,234,000)												(2,537,000)
Consideration paid, net of cash acquired					132,387,000												654,045,000
Consideration paid for acquisition
Cash paid, net of cash received pursuant to call agreement	14,000,000			132,400,000	87,444,000											239,251
Value of common units issued pursuant to call agreement					44,943,000							45,000,000	45,000,000	60,000,000	60,000,000	414,794
Total consideration paid					$ 132,387,000											$ 654,045