Condensed Consolidating Guarantor and Non-Guarantor Financial Information (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2014	Mar. 31, 2014
CURRENT ASSETS:
Cash and cash equivalents	$ 43,506	$ 41,303	$ 39,679	$ 10,440
Accounts receivable - trade, net of allowance for doubtful accounts	905,196	1,024,226
Accounts receivable - affiliates	18,740	17,198
Inventories	489,064	441,762
Prepaid expenses and other current assets	130,889	120,855
Total current assets	1,587,395	1,645,344
PROPERTY, PLANT AND EQUIPMENT, net of accumulated depreciation	1,743,584	1,617,389
GOODWILL	1,451,654	1,402,761
INTANGIBLE ASSETS, net of accumulated amortization	1,251,478	1,288,343
INVESTMENTS IN UNCONSOLIDATED ENTITIES	474,221	472,673
LOAN RECEIVABLE-AFFILIATE	23,775	8,154
OTHER NONCURRENT ASSETS	110,544	112,837
Total assets	6,642,651	6,547,501
CURRENT LIABILITIES:
Accounts payable - trade	755,062	833,380
Accounts payable - affiliates	25,592	25,794
Accrued expenses and other payables	237,407	195,116
Advance payments received from customers	66,706	54,234
Current maturities of long-term debt	3,933	4,472
Total current liabilities	1,088,700	1,112,996
LONG-TERM DEBT, net of current maturities	2,968,069	2,745,299
OTHER NONCURRENT LIABILITIES	17,082	16,086
EQUITY :
Partners' equity	2,021,755	2,125,903
Accumulated other comprehensive loss	(117)	(109)
Noncontrolling interests	547,162	547,326
Total equity	2,568,800	2,673,120
Total liabilities and equity	6,642,651	6,547,501
Reportable Entity | NGL Energy Partners LP (Parent)
CURRENT ASSETS:
Cash and cash equivalents	22,693	29,115	31,399	1,181
Accounts receivable - affiliates	11	5
Total current assets	22,704	29,120
INTANGIBLE ASSETS, net of accumulated amortization	16,936	17,834
NET INTERCOMPANY RECEIVABLES (PAYABLES)	1,371,288	1,363,792
INVESTMENTS IN CONSOLIDATED SUBSIDIARIES	1,727,335	1,834,738
Total assets	3,138,263	3,245,484
CURRENT LIABILITIES:
Accounts payable - affiliates	1
Accrued expenses and other payables	16,624	19,690
Total current liabilities	16,625	19,690
LONG-TERM DEBT, net of current maturities	1,100,000	1,100,000
EQUITY :
Partners' equity	2,021,638	2,125,794
Total equity	2,021,638	2,125,794
Total liabilities and equity	3,138,263	3,245,484
Reportable Entity | Guarantor Subsidiaries
CURRENT ASSETS:
Cash and cash equivalents	13,642	9,757	7,589	8,728
Accounts receivable - trade, net of allowance for doubtful accounts	889,449	1,007,001
Accounts receivable - affiliates	18,172	16,610
Inventories	487,313	440,026
Prepaid expenses and other current assets	113,594	104,528
Total current assets	1,522,170	1,577,922
PROPERTY, PLANT AND EQUIPMENT, net of accumulated depreciation	1,204,560	1,093,018
GOODWILL	1,419,487	1,372,690
INTANGIBLE ASSETS, net of accumulated amortization	1,170,731	1,195,896
INVESTMENTS IN UNCONSOLIDATED ENTITIES	217,636	217,600
NET INTERCOMPANY RECEIVABLES (PAYABLES)	(1,333,513)	(1,319,724)
INVESTMENTS IN CONSOLIDATED SUBSIDIARIES	73,107	56,690
LOAN RECEIVABLE-AFFILIATE	23,775	8,154
OTHER NONCURRENT ASSETS	107,651	110,120
Total assets	4,405,604	4,312,366
CURRENT LIABILITIES:
Accounts payable - trade	744,886	820,441
Accounts payable - affiliates	25,473	25,690
Accrued expenses and other payables	213,484	165,819
Advance payments received from customers	66,248	53,903
Current maturities of long-term debt	3,863	4,413
Total current liabilities	1,053,954	1,070,266
LONG-TERM DEBT, net of current maturities	1,610,868	1,395,100
OTHER NONCURRENT LIABILITIES	13,447	12,262
EQUITY :
Partners' equity	1,727,335	1,834,738
Total equity	1,727,335	1,834,738
Total liabilities and equity	4,405,604	4,312,366
Reportable Entity | Non-Guarantor Subsidiaries
CURRENT ASSETS:
Cash and cash equivalents	7,171	2,431	$ 691	$ 531
Accounts receivable - trade, net of allowance for doubtful accounts	15,747	17,225
Accounts receivable - affiliates	557	583
Inventories	1,751	1,736
Prepaid expenses and other current assets	17,295	16,327
Total current assets	42,521	38,302
PROPERTY, PLANT AND EQUIPMENT, net of accumulated depreciation	539,024	524,371
GOODWILL	32,167	30,071
INTANGIBLE ASSETS, net of accumulated amortization	63,811	74,613
INVESTMENTS IN UNCONSOLIDATED ENTITIES	256,585	255,073
NET INTERCOMPANY RECEIVABLES (PAYABLES)	(37,775)	(44,068)
OTHER NONCURRENT ASSETS	2,893	2,717
Total assets	899,226	881,079
CURRENT LIABILITIES:
Accounts payable - trade	10,176	12,939
Accounts payable - affiliates	118	104
Accrued expenses and other payables	7,299	9,607
Advance payments received from customers	458	331
Current maturities of long-term debt	70	59
Total current liabilities	18,121	23,040
LONG-TERM DEBT, net of current maturities	257,201	250,199
OTHER NONCURRENT LIABILITIES	3,635	3,824
EQUITY :
Partners' equity	620,386	604,125
Accumulated other comprehensive loss	(117)	(109)
Total equity	620,269	604,016
Total liabilities and equity	899,226	881,079
Consolidating Adjustments
CURRENT ASSETS:
INVESTMENTS IN CONSOLIDATED SUBSIDIARIES	(1,800,442)	(1,891,428)
Total assets	(1,800,442)	(1,891,428)
EQUITY :
Partners' equity	(2,347,604)	(2,438,754)
Noncontrolling interests	547,162	547,326
Total equity	(1,800,442)	(1,891,428)
Total liabilities and equity	$ (1,800,442)	$ (1,891,428)