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v3.20.4

Note 3 - Reserve for Sales Returns and Allowances (Tables) | 12 Months Ended
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Dec. 31, 2020
Notes Tables |
Reserve for Sales Returns and Allowances [Table Text Block] |
|  | Years Ended December 31, |
|  | 2020 |  |  | 2019 |  |  | 2018 |
Balance at the beginning of year |  | $ | 2,112 |  |  | $ | 1,893 |  |  | $ | 1,125 |
Provision for returns and allowances |  |  | 7,699 |  |  |  | 4,334 |  |  |  | 4,908 |
Actual returns and allowances paid to customers |  |  | (6,446 | ) |  |  | (4,115 | ) |  |  | (4,140 | )
Balance at the end of year |  | $ | 3,365 |  |  | $ | 2,112 |  |  | $ | 1,893 |

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- Definition Tabular disclosure of the reserve for sales returns and allowances + References No definition available. + Details
Name: | sgc_ReserveForSalesReturnsAndAllowancesTableTextBlock
Namespace Prefix: | sgc_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

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- References No definition available. + Details
Name: | us-gaap_TableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration