XML 56 R45.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Investments - Schedule of Investments to be Available-for-sale (Detail) - USD ($) $ in Thousands | Dec. 31, 2018 | Sep. 30, 2018
--- | --- | ---
Schedule Of Available For Sale Securities [Line Items] |  |  |
Amortized Cost |  | $ 51,068 | $ 46,623
Gross Unrealized (Loss) |  | (815) | (1,204)
Fair Value | [1] | 50,253 | 45,419
Cash and Receivables |  |  |
Schedule Of Available For Sale Securities [Line Items] |  |  |
Amortized Cost |  | 416 | 350
Fair Value |  | 416 | 350
U.S. Government Sponsored Agencies |  |  |
Schedule Of Available For Sale Securities [Line Items] |  |  |
Amortized Cost |  | 16,208 | 10,735
Gross Unrealized (Loss) |  | (55) | (192)
Fair Value |  | 16,153 | 10,543
Corporate Debt Securities |  |  |
Schedule Of Available For Sale Securities [Line Items] |  |  |
Amortized Cost |  | 29,344 | 30,427
Gross Unrealized (Loss) |  | (701) | (928)
Fair Value |  | 28,643 | 29,499
Foreign Bonds and Notes |  |  |
Schedule Of Available For Sale Securities [Line Items] |  |  |
Amortized Cost |  | 5,100 | 5,111
Gross Unrealized (Loss) |  | (59) | (84)
Fair Value |  | $ 5,041 | $ 5,027
[1] | See Note 2 – Investments

X
- Definition Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109979856&loc=d3e26610-111562 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtSecurities
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_ScheduleOfAvailableForSaleSecuritiesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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

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

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

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