Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Effect of Fourth Quarter Events [Line Items]
Total revenues	$ 3,848,079	$ 3,406,641	$ 3,045,538	$ 2,721,970	$ 2,325,440	$ 2,685,006	$ 3,193,195	$ 3,538,469	$ 13,022,228	$ 11,742,110	$ 16,802,057
Total cost of sales	3,598,717	3,228,022	2,928,730	2,566,440	2,077,160	2,433,500	3,005,826	3,322,551	12,321,909	10,839,037	15,958,207
Net income (loss)	26,486	1,293	(66,658)	182,753	(206,985)	50,995	(6,100)	(25,007)	143,874	(187,097)	50,193
Net income (loss) attributable to NGL Energy Partners LP	$ 25,745	$ 976	$ (66,599)	$ 176,920	$ (204,132)	$ 44,157	$ (9,597)	$ (29,357)	$ 137,042	$ (198,929)	$ 37,306
Basic income (loss) per common unit (in dollars per unit)	$ 0.14	$ (0.07)	$ (0.71)	$ 1.66	$ (1.94)	$ 0.27	$ (0.25)	$ (0.43)	$ 0.99	$ (2.35)	$ (0.05)
Diluted income (loss) per common unit (in dollars per unit)	$ 0.14	$ (0.07)	$ (0.71)	$ 1.38	$ (1.94)	$ 0.22	$ (0.25)	$ (0.43)	$ 0.95	$ (2.35)	$ (0.05)
Basic weighted average common units outstanding (in units)	114,131,764	107,966,901	106,186,389	104,169,573	104,930,260	105,338,200	105,189,463	103,888,281	108,091,486	104,838,886	86,359,300
Diluted weighted average common units outstanding (in units)	120,198,802	107,966,901	106,186,389	128,453,733	104,930,260	106,194,547	105,189,463	103,888,281	111,850,621	104,838,886	86,359,300
Operating segment
Effect of Fourth Quarter Events [Line Items]
Asset impairment charges					$ 64,700