Transactions with Affiliates (Details) (USD $)	12 Months Ended		0 Months Ended		12 Months Ended					12 Months Ended	0 Months Ended		12 Months Ended
	Mar. 31, 2013 item	Mar. 31, 2012	Jun. 19, 2012 High Sierra Energy, LP	Mar. 31, 2013 High Sierra	Mar. 31, 2013 SemGroup item	Mar. 31, 2012 SemGroup	Mar. 31, 2013 Other	Mar. 31, 2012 Other	Mar. 31, 2012 Osterman	Mar. 31, 2013 High Sierra Management	Jun. 19, 2012 General Partner	Jun. 19, 2012 General Partner High Sierra Energy, LP	Mar. 31, 2013 Retail segment management	Mar. 31, 2012 Retail segment management
Transactions with Affiliates
Right to appoint number of members to the Board of Directors of the entity's general partner by related party					2
Increase in property, plant and equipment										$ 3,100,000
Sales to related party					32,431,000	29,200,000				16,828,000
Purchase from related parties					60,425,000	23,800,000				60,942,000			273,000	300,000
Payments to SemGroup for services					256,000	700,000
Number of business combination transactions	2
Cash paid	14,000,000		91,800,000	239,251								50,000,000
Liabilities assumed in the form of non-compete agreements	5,000,000		97,400,000
Receivables from affiliates	22,883,000	2,282,000				1,878,000	96,000	404,000		22,787,000
Payables to related parties	6,900,000	9,462,000			4,601,000	4,699,000			4,763,000	2,299,000
Cash acquired			5,000,000
Common units issued			18,018,468								2,685,042
Amount paid											$ 50,000,000