Represents the fixed charge coverage ratio.

No definition available.

Name:	sgc_DebtInstrumentCovenantFixedChargeCoverageRatio
Namespace Prefix:	sgc_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

The maximum total debt to EBITDAX ratio required by the debt agreement.

+ References

No definition available.

+ Details

Name:	sgc_DebtInstrumentCovenantMaximumTotalDebtToEBITDAXRatio
Namespace Prefix:	sgc_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the debt instrument libor floor.

+ References

No definition available.

+ Details

Name:	sgc_DebtInstrumentLIBORFloor
Namespace Prefix:	sgc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the fee for available but unused credit capacity under the credit facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- 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=120381028&loc=d3e5070-113901

+ Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=sgc_CreditAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=sgc_TermLoan2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
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_LongtermDebtTypeAxis=sgc_TermLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=sgc_BBTMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
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:

Note 19 - Subsequent Events (Details Textual)			12 Months Ended
Note 19 - Subsequent Events (Details Textual)	Feb. 08, 2021 USD ($)	Feb. 01, 2021	Dec. 31, 2020 USD ($)	Dec. 31, 2019	May 02, 2018 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)			2 years
Credit Agreement [Member]
Fixed Charge Coverage Ratio			1.25
Debt Instrument, Covenant, Maximum Total Debt to EBITDAX Ratio			5.0
Credit Agreement [Member] \| Term Loan 2 [Member] \| London Interbank Offered Rate (LIBOR) [Member] \| Minimum [Member]
Debt Instrument, Basis Spread on Variable Rate			0.85%
Credit Agreement [Member] \| Term Loan 2 [Member] \| London Interbank Offered Rate (LIBOR) [Member] \| Maximum [Member]
Debt Instrument, Basis Spread on Variable Rate			1.65%
Credit Agreement [Member] \| Term Loan [Member] \| London Interbank Offered Rate (LIBOR) [Member] \| Minimum [Member]
Debt Instrument, Basis Spread on Variable Rate			0.68%
Credit Agreement [Member] \| Term Loan [Member] \| London Interbank Offered Rate (LIBOR) [Member] \| Maximum [Member]
Debt Instrument, Basis Spread on Variable Rate			1.50%
Credit Agreement [Member] \| Revolving Credit Facility [Member] \| BB&T [Member]
Line of Credit Facility, Maximum Borrowing Capacity			$ 75,000,000.0		$ 75,000,000
Subsequent Event [Member] \| Credit Agreement [Member]
Line of Credit Facility, Commitment Fee Amount	$ 250,000
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.15%
Fixed Charge Coverage Ratio	1.25
Debt Instrument, Covenant, Maximum Total Debt to EBITDAX Ratio	5.0
Subsequent Event [Member] \| Credit Agreement [Member] \| Revolving Credit Facility [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, LIBOR Floor	0.25%
Subsequent Event [Member] \| Credit Agreement [Member] \| Revolving Credit Facility [Member] \| BB&T [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 125,000,000.0
Subsequent Event [Member] \| Credit Agreement [Member] \| Revolving Credit Facility [Member] \| BB&T [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, LIBOR Floor	0.25%
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)				3 years
Restricted Stock [Member] \| Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)		5 years