XML 23 R37.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Derivatives and Hedging-Disclosures and Fair Value Measurements - Additional Information (Detail) (USD $) In Millions, unless otherwise specified | 6 Months Ended |
--- | --- | ---
Mar. 31, 2015 gal | Mar. 31, 2014 gal | Sep. 30, 2014
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |  |
Aggregated cash posted as collateral in normal course of business | 2.1 us-gaap_CashCollateralForBorrowedSecurities |  |
Hedging positions and payable amounts secured under credit facility | 12.2 us-gaap_DerivativeAmountOfHedgedItem |  | $ 14.9 us-gaap_DerivativeAmountOfHedgedItem
Call Option |  |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |  |
Derivative activity volume | 4,100,000 us-gaap_DerivativeNonmonetaryNotionalAmountVolume / us-gaap_OptionIndexedToIssuersEquityTypeAxis = us-gaap_CallOptionMember | 1,100,000 us-gaap_DerivativeNonmonetaryNotionalAmountVolume / us-gaap_OptionIndexedToIssuersEquityTypeAxis = us-gaap_CallOptionMember |
Put Option |  |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |  |
Derivative activity volume | 3,100,000 us-gaap_DerivativeNonmonetaryNotionalAmountVolume / us-gaap_OptionIndexedToIssuersEquityTypeAxis = us-gaap_PutOptionMember | 4,200,000 us-gaap_DerivativeNonmonetaryNotionalAmountVolume / us-gaap_OptionIndexedToIssuersEquityTypeAxis = us-gaap_PutOptionMember |
Inventory |  |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |  |
Derivative activity volume |  | 300,000 us-gaap_DerivativeNonmonetaryNotionalAmountVolume / us-gaap_DerivativeByNatureAxis = sgu_InventoryMember |
Swap Contracts Bought |  |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |  |
Derivative activity volume | 6,300,000 us-gaap_DerivativeNonmonetaryNotionalAmountVolume / us-gaap_DerivativeByNatureAxis = sgu_SwapContractOneMember | 6,300,000 us-gaap_DerivativeNonmonetaryNotionalAmountVolume / us-gaap_DerivativeByNatureAxis = sgu_SwapContractOneMember |
Synthetic calls |  |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |  |
Derivative activity volume | 54,700,000 us-gaap_DerivativeNonmonetaryNotionalAmountVolume / us-gaap_DerivativeByNatureAxis = us-gaap_SyntheticOilMember | 47,700,000 us-gaap_DerivativeNonmonetaryNotionalAmountVolume / us-gaap_DerivativeByNatureAxis = us-gaap_SyntheticOilMember |
Futures Contracts Sold |  |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |  |
Derivative activity volume | 54,700,000 us-gaap_DerivativeNonmonetaryNotionalAmountVolume / us-gaap_DerivativeByNatureAxis = sgu_FuturesContractsTwoMember | 60,000,000 us-gaap_DerivativeNonmonetaryNotionalAmountVolume / us-gaap_DerivativeByNatureAxis = sgu_FuturesContractsTwoMember |
Corresponding Long And Short Swap Contracts Bought |  |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |  |
Derivative activity volume |  | 33,100,000 us-gaap_DerivativeNonmonetaryNotionalAmountVolume / us-gaap_DerivativeByNatureAxis = sgu_CorrespondingLongAndShortSwapContractsBoughtMember |
Hedge its Internal Fuel Usage Swap Contracts Bought |  |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |  |
Derivative activity volume | 3,200,000 us-gaap_DerivativeNonmonetaryNotionalAmountVolume / us-gaap_DerivativeByNatureAxis = sgu_InternalFuelUsageSwapContractMember | 1,000,000 us-gaap_DerivativeNonmonetaryNotionalAmountVolume / us-gaap_DerivativeByNatureAxis = sgu_InternalFuelUsageSwapContractMember |
Futures Contracts Bought |  |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |  |
Derivative activity volume | 34,100,000 us-gaap_DerivativeNonmonetaryNotionalAmountVolume / us-gaap_DerivativeByNatureAxis = sgu_FuturesContractsOneMember | 46,200,000 us-gaap_DerivativeNonmonetaryNotionalAmountVolume / us-gaap_DerivativeByNatureAxis = sgu_FuturesContractsOneMember |

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