XML 75 R58.htm IDEA: XBRL DOCUMENT
v3.20.2

Derivatives and Hedging-Disclosures and Fair Value Measurements - Additional Information (Detail) gal in Millions, $ in Millions | 12 Months Ended
--- | ---
Sep. 30, 2020 USD ($) gal | Sep. 30, 2019 USD ($) gal
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Hedging positions and payable amounts secured under credit facility | $ 11.1 | $ 7.7
Prepaid expense and other current assets |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Aggregated cash posted as collateral in normal course of business | 0.1 |
Interest rate swap |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Notional Value | 64.0 | 45.0
Fair Value | $ (3.1) | $ (2.0)
Percentage of market risk exposure of long term debt | 52.00% |
Call Option |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Derivative activity volume | gal | 8.5 | 6.1
Notional Value | $ 17.4 | $ 15.6
Fair Value | $ 0.1 | $ 0.1
Call Option | Synthetic calls |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Derivative activity volume | gal | 80.7 | 81.0
Notional Value | $ 123.4 | $ 165.4
Fair Value | $ (8.6) | $ (7.2)
Put Option |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Derivative activity volume | gal | 5.1 | 5.9
Notional Value | $ 4.2 | $ 7.7
Fair Value | $ 0.2 | $ 28.0
Swap Contracts Bought |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Derivative activity volume | gal | 11.3 | 15.5
Notional Value | $ 16.0 | $ 29.7
Fair Value | $ (2.6) | $ (1.0)
Swap Contracts Bought | Short |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Derivative activity volume | gal | 19.2 |
Notional Value | $ 22.7 |
Swap Contracts Bought | Short | Maximum |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Fair Value | $ 0.1 |
Swap Contracts Bought | Long |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Derivative activity volume | gal |  | 1.3
Notional Value |  | $ 2.4
Fair Value |  | $ (0.1)
Future Contracts | Short |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Derivative activity volume | gal | 11.1 | 67.5
Notional Value | $ 14.3 | $ 124.9
Fair Value | $ 0.7 | $ 0.2
Future Contracts | Long |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Derivative activity volume | gal | 3.8 | 45.2
Notional Value | $ 5.4 | $ 83.2
Fair Value | $ (0.4) | $ (0.9)
Hedge its Internal Fuel Usage and Other Related Activities Call Options and Swap Contracts Bought |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |
Derivative activity volume | gal | 7.0 | 4.2
Notional Value | $ 10.7 | $ 7.4
Fair Value | $ (0.4) | $ (0.3)

X
- Definition Carrying amount as of the balance sheet date of cash collateral held for borrowed securities, for which the cash is restricted as to withdrawal or usage. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.1) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.(a),2) -URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910 + Details
Name: | us-gaap_CashCollateralForBorrowedSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of hedged item in hedging relationship. Excludes hedged asset or liability. + References No definition available. + Details
Name: | us-gaap_DerivativeAmountOfHedgedItem
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition Fair value of the assets less the liabilities of a derivative or group of derivatives. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13433-108611 + Details
Name: | us-gaap_DerivativeFairValueOfDerivativeNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Nominal volume used to calculate payments on a derivative instrument. + References No definition available. + Details
Name: | us-gaap_DerivativeNonmonetaryNotionalAmountVolume
Namespace Prefix: | us-gaap_
Data Type: | num:volumeItemType
Balance Type: | na
Period Type: | duration

X
- Definition Nominal or face amount used to calculate payment on derivative. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959 + Details
Name: | us-gaap_DerivativeNotionalAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of an entity's outstanding debt that is designated as a hedged item in cash flow, fair value, or net investment hedge. + References No definition available. + Details
Name: | us-gaap_PercentageOfDebtHedgedByInterestRateDerivatives
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=us-gaap_PrepaidExpensesAndOtherCurrentAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_OptionIndexedToIssuersEquityTypeAxis=us-gaap_CallOptionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ReserveQuantitiesByTypeOfReserveAxis=srt_SyntheticOilMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_OptionIndexedToIssuersEquityTypeAxis=us-gaap_PutOptionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=sgu_SwapContractOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PositionAxis=us-gaap_ShortMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PositionAxis=us-gaap_LongMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_FutureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=sgu_InternalFuelUsageCallAndSwapContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |