v3.21.2

Summary of significant accounting policies (Intangible assets) (Details) | 12 Months Ended
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Dec. 31, 2020
Trademarks of GFS (Member) |
Finite-Lived Intangible Asset, Useful Life | 10 years
Service Contracts of GFS (Member) |
Finite-Lived Intangible Asset, Useful Life | 1 year
Non-competition agreements of Apiguru (Member) |
Finite-Lived Intangible Asset, Useful Life | 3 years

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- Definition Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_FiniteLivedIntangibleAssetUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=sgoc_TrademarksOfGfsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=sgoc_ServiceContractsOfGfsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=sgoc_NonCompetitionAgreementsOfApiguruMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |