Loans receivable, net (Loans Receivable Maturity Due) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Loans receivable, net
2021	$ 22,096
2022	532
2023	93
2024	93
2025	96
2026 and thereafter	807
Total loans	$ 23,717	$ 41,179

The amount represents loans receivable maturity due of after five years

No definition available.

Name:	sgoc_LoansReceivableMaturityDueAfterFiveYears
Namespace Prefix:	sgoc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The amount represents loans receivable maturity due of four year

No definition available.

Name:	sgoc_LoansReceivableMaturityDueFiveYear
Namespace Prefix:	sgoc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The amount represents loans receivable maturity due of four year

No definition available.

Name:	sgoc_LoansReceivableMaturityDueFourYear
Namespace Prefix:	sgoc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The amount represents loans receivable maturity due of one year

No definition available.

Name:	sgoc_LoansReceivableMaturityDueOneYear
Namespace Prefix:	sgoc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The amount represents loans receivable maturity due of three year

No definition available.

Name:	sgoc_LoansReceivableMaturityDueThreeYear
Namespace Prefix:	sgoc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The amount represents loans receivable maturity due of two year

No definition available.

Name:	sgoc_LoansReceivableMaturityDueTwoYear
Namespace Prefix:	sgoc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The amount represent notes and loans receivable total

No definition available.

Name:	sgoc_NotesAndLoansReceivableTotal
Namespace Prefix:	sgoc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

No definition available.

Name:	us-gaap_LoansAndLeasesReceivableDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration