Note 5 - Long-term Debt (Details Textual) $ in Thousands	Aug. 23, 2022 USD ($)	Dec. 31, 2024 USD ($)
Long-Term Debt, Maturity, Year One		$ 5,625
Long-Term Debt, Maturity, Year Two		6,563
Long-Term Debt, Maturity, Year Three		74,500
Credit Agreement [Member]
Long-Term Debt, Maturity, Year One		5,600
Long-Term Debt, Maturity, Year Two		6,600
Long-Term Debt, Maturity, Year Three		$ 52,500
Debt Instrument Covenant Fixed Charge Coverage Ratio	1.25
Debt Instrument Covenant, Net Leverage Ratio	4
Credit Agreement [Member] \| PNC Bank [Member]
Line of Credit Facility, Additional Capacity Available	$ 75,000
Debt, Weighted Average Interest Rate		5.50%
Credit Agreement [Member] \| PNC Bank [Member] \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] \| Minimum [Member]
Debt Instrument, Basis Spread on Variable Rate	0.10%
Credit Agreement [Member] \| PNC Bank [Member] \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] \| Maximum [Member]
Debt Instrument, Basis Spread on Variable Rate	0.25%
Credit Agreement [Member] \| PNC Bank [Member] \| Adjusted Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] \| Minimum [Member]
Debt Instrument, Basis Spread on Variable Rate	1.00%
Credit Agreement [Member] \| PNC Bank [Member] \| Adjusted Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] \| Maximum [Member]
Debt Instrument, Basis Spread on Variable Rate	2.00%
Credit Agreement [Member] \| Revolving Credit Facility [Member]
Letters of Credit Outstanding, Amount		$ 0
Credit Agreement [Member] \| Revolving Credit Facility [Member] \| PNC Bank [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 125,000
Credit Agreement [Member] \| Revolving Credit Facility [Member] \| PNC Bank [Member] \| Minimum [Member]
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.125%
Credit Agreement [Member] \| Revolving Credit Facility [Member] \| PNC Bank [Member] \| Maximum [Member]
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.25%
Credit Agreement [Member] \| Term Loan [Member] \| PNC Bank [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 75,000

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

Ratio that the net leverage ratio cannot exceed to comply with the debt covenant.

+ References

No definition available.

+ Details

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

- Definition

The maximum amount of additional borrowing capacity under a line of credit that is available as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	sgc_LineOfCreditFacilityAdditionalCapacityAvailable
Namespace Prefix:	sgc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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

- 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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ 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:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04(a))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1E
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1E

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-SubTopic 10
-Topic 470
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481544/470-10-50-1

+ Details

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

- Definition

Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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

- Definition

Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember
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_VariableRateAxis=sgc_AdjustedSecuredOvernightFinancingRateSOFROvernightIndexSwapRateMember
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_CreditFacilityAxis=sgc_TermLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: