Unaudited Condensed Consolidating Guarantor and Non-Guarantor Financial Information - Unaudited Condensed Consolidating Statements of Comprehensive Income (Loss) (Details) - USD ($)	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Unaudited Condensed Consolidating Statement of Comprehensive Income (Loss)
Net income (loss)	$ 8,039,000	$ (169,289,000)
Other comprehensive income (loss)	37,000	(11,000)
Comprehensive income (loss)	8,076,000	(169,300,000)
Reportable Entity | NGL Energy Partners LP (Parent)
Unaudited Condensed Consolidating Statement of Comprehensive Income (Loss)
Net income (loss)	8,307,000	(168,546,000)
Comprehensive income (loss)	8,307,000	(168,546,000)
Reportable Entity | Guarantor Subsidiaries
Unaudited Condensed Consolidating Statement of Comprehensive Income (Loss)
Net income (loss)	34,096,000	(138,909,000)
Other comprehensive income (loss)	17,000	(1,000)
Comprehensive income (loss)	34,113,000	(138,910,000)
Reportable Entity | Non-Guarantor Subsidiaries
Unaudited Condensed Consolidating Statement of Comprehensive Income (Loss)
Net income (loss)	7,325,000	(2,390,000)
Other comprehensive income (loss)	20,000	(10,000)
Comprehensive income (loss)	7,345,000	(2,400,000)
Consolidating Adjustments
Unaudited Condensed Consolidating Statement of Comprehensive Income (Loss)
Net income (loss)	(41,689,000)	140,556,000
Comprehensive income (loss)	$ (41,689,000)	$ 140,556,000