Note 12 - Summary of Information About Stock Appreciation Rights Outstanding (Details)	12 Months Ended
Dec. 31, 2015 $ / shares shares
SARS 1 [Member] \| Minimum [Member]
Exercise price (in dollars per share)	$ 5.62
SARS 1 [Member] \| Maximum [Member]
Exercise price (in dollars per share)	$ 7.36
SARS 1 [Member]
SARS (in shares) \| shares	328,274
Weighted Average Remaining Contractual Life	1 year 339 days
Weighted Average Exercise Price (in dollars per share)	$ 6.43
SARS 2 [Member] \| Maximum [Member]
Exercise price (in dollars per share)	$ 18.66
SARS 2 [Member]
SARS (in shares) \| shares	53,292
Weighted Average Remaining Contractual Life	4 years 29 days
Weighted Average Exercise Price (in dollars per share)	$ 18.66
Stock Appreciation Rights (SARs) [Member] \| Minimum [Member]
Exercise price (in dollars per share)	5.62
Stock Appreciation Rights (SARs) [Member] \| Maximum [Member]
Exercise price (in dollars per share)	18.66
Stock Appreciation Rights (SARs) [Member]
Exercise price (in dollars per share)	$ 18.66
SARS (in shares) \| shares	381,566
Weighted Average Remaining Contractual Life	2 years 83 days
Weighted Average Exercise Price (in dollars per share)	$ 8.14

The weighted average exercise price for non-option equity instruments.

No definition available.

Name:	sgc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsNonOptionOutstandingWeightedAverageGrantDateFairValue
Namespace Prefix:	sgc_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted average remaining contractual term for equity-based awards excluding options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

+ Details

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

- Definition

Agreed-upon price for the exchange of the underlying asset relating to the share-based payment award.

+ References

No definition available.

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePrice
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of equity instruments other than options outstanding, including both vested and non-vested instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(ii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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

- Details

Name:	us-gaap_AwardTypeAxis=sgc_SARS1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=sgc_SARS2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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