v3.21.2

Summary of significant accounting policies (Intangible assets) (Details)	12 Months Ended
	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

X

- 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

X

- Details

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

X

- 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: