Common shares earned percentage of initial target number shares awarded.

No definition available.

Name:	sif_CommonSharesEarnedPercentageOfInitialTargetNumberSharesAwarded
Namespace Prefix:	sif_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Common Shares Earned Percentage Of Initial Target Number Shares Awarded, Next Fiscal Year

+ References

No definition available.

+ Details

Name:	sif_CommonSharesEarnedPercentageOfInitialTargetNumberSharesAwardedNextFiscalYear
Namespace Prefix:	sif_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Common shares earned pursuant to award.

+ References

No definition available.

+ Details

Name:	sif_CommonSharesEarnedPursuantToAward
Namespace Prefix:	sif_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Outstanding share awards earned and issued at greater than the target number of shares.

+ References

No definition available.

+ Details

Name:	sif_OutstandingShareAwardsEarnedAndIssuedAtGreaterThanTargetNumberOfShares
Namespace Prefix:	sif_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Outstanding Share Awards Earned And Issued At Greater Than Target Number Of Shares, Next Fiscal Year

+ References

No definition available.

+ Details

Name:	sif_OutstandingShareAwardsEarnedAndIssuedAtGreaterThanTargetNumberOfSharesNextFiscalYear
Namespace Prefix:	sif_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Qualifying for the Award Period

+ References

No definition available.

+ Details

Name:	sif_ShareBasedCompensationArrangementBySharebasedPaymentAwardQualifyingForTheAwardPeriod
Namespace Prefix:	sif_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Share Based Compensation, Number Of Tranches

+ References

No definition available.

+ Details

Name:	sif_ShareBasedCompensationNumberOfTranches
Namespace Prefix:	sif_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5047-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.F)
-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_AllocatedShareBasedCompensationExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

+ References

+ Details

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(2)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- 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_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of shares authorized for issuance under share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_PlanNameAxis=sif_AmendedTwentySixteenPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=sif_TwoThousandAndSixteenLongTermIncentivePlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_PerformanceSharesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GranteeStatusAxis=us-gaap_ShareBasedPaymentArrangementEmployeeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=sif_PerformanceandRestrictedSharesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GranteeStatusAxis=us-gaap_ShareBasedPaymentArrangementNonemployeeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Stock-Based Compensation (Details) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2020 USD ($) shares	Mar. 31, 2019 USD ($)	Mar. 31, 2020 USD ($) tranche $ / shares shares	Mar. 31, 2019 USD ($)	Sep. 30, 2019	Jan. 30, 2020 shares
Amended 2016 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate number of shares that may be awarded (in shares)						550,000
2016 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate number of shares that may be awarded (in shares)	1,196,000		1,196,000
Exercise period for shares awarded under plan			10 years
Outstanding share awards that may be awarded (in shares)	524,000		524,000
Outstanding share awards earned and issued at greater than the target number of shares					200.00%
Outstanding share awards earned and issued at greater than the target number of shares next fiscal year			150.00%
Share-based compensation expense (benefit) \| $	$ 70	$ 190	$ 225	$ 426
Total unrecognized compensation cost related to performance and restricted shares \| $	$ 732		$ 732
Period of recognized compensation cost (in years)			1 year 7 months
2016 Plan \| Performance shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period (in years)			3 years
2016 Plan \| Performance shares \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares earned pursuant to award (in shares)			0
2016 Plan \| Performance shares \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares earned as percentage of initial target number shares awarded			200.00%
Common shares earned as percentage of initial target number shares awarded next fiscal year			150.00%
2016 Plan \| Restricted shares \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)			1 year
2016 Plan \| Restricted shares \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)			3 years
Key employees \| 2016 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of tranches in award \| tranche			2
Key employees \| 2016 Plan \| Performance shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted in period (in shares)			47,000
Key employees \| 2016 Plan \| Performance and Restricted Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted in period (in shares)			134,000
Vesting period (in years)			3 years
Shares granted in period, grant date fair value (in dollars per share) \| $ / shares			$ 2.50
Key employees \| 2016 Plan \| Restricted shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted in period (in shares)			87,000
Non-employee directors \| 2016 Plan \| Performance and Restricted Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted in period, grant date fair value (in dollars per share) \| $ / shares			$ 4.39
Non-employee directors \| 2016 Plan \| Restricted shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted in period (in shares)			57,000
Vested in period (in shares)			61,000