v3.25.4

Other Matters - Sale of Marketable Equity Securities (Details) - USD ($) $ in Millions |  | 9 Months Ended
--- | --- | ---
Mar. 31, 2025 | Dec. 31, 2025 | Dec. 31, 2025
Marketable Securities [Abstract] |  |  |
Number of shares owned | 1,468,337 |  |
Proceeds from sale of marketable equity securities |  | $ 6.0 |
Realized (gain) loss on sale of marketable equity securities | $ (0.8) | $ 0.6 | $ (0.2)

X
- Definition Number of Shares Owned + References No definition available. + Details
Name: | ngl_NumberOfSharesOwned
Namespace Prefix: | ngl_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_MarketableSecuritiesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of realized gain (loss) on investment in marketable security. + References No definition available. + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash inflow associated with the aggregate amount received by the entity through sale or maturity of marketable securities (held-to-maturity or available-for-sale) during the period. + References No definition available. + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration