XML 58 R47.htm IDEA: XBRL DOCUMENT
v3.20.2

Derivatives and Hedging-Disclosures and Fair Value Measurements - Additional Information (Detail) gal in Millions, $ in Millions | 9 Months Ended |
--- | --- | ---
Jun. 30, 2020 USD ($) gal | Jun. 30, 2019 gal | Sep. 30, 2019 USD ($)
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 | $ | 0.5 |  |
Interest rate swap |  |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |  |
Notional Value | $ | $ 65.3 |  | 45.0
Percentage of market risk exposure of long term debt | 51.50% |  |
Fair Value | $ | $ (3.5) |  | $ (2.0)
Call Option |  |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |  |
Derivative activity volume | 6.3 | 3.6 |
Call Option | Synthetic calls |  |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |  |
Derivative activity volume | 59.5 | 58.6 |
Put Option |  |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |  |
Derivative activity volume | 3.5 | 3.1 |
Swap Contracts Bought |  |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |  |
Derivative activity volume | 8.2 | 6.9 |
Swap Contracts Bought | Short |  |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |  |
Derivative activity volume | 19.4 | 0.7 |
Swap Contracts Bought | Long |  |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |  |
Derivative activity volume |  | 1.3 |
Future Contracts | Short |  |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |  |
Derivative activity volume | 59.6 | 71.5 |
Future Contracts | Long |  |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |  |
Derivative activity volume | 57.2 | 55.4 |
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 | 7.9 | 7.8 |

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: | 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: |