Number of shares to sell for the disposal of assets and liabilities, including discontinued operation.

No definition available.

Name:	sgoc_DisposalGroupIncludingDiscontinuedOperationNumberOfSharesToSell
Namespace Prefix:	sgoc_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Percentage of ownership to sell for the disposal of assets and liabilities, including discontinued operation.

No definition available.

Name:	sgoc_DisposalGroupIncludingDiscontinuedOperationPercentageOfOwnershipToSell
Namespace Prefix:	sgoc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Percentage of ownership is used to pay to acquiree in business combination.

No definition available.

Name:	sgoc_PercentageOfOwnershipUsedToPayToAcquireeInBusinessCombination
Namespace Prefix:	sgoc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Principal amount of Notes to be surrendered in the disposal.

No definition available.

Name:	sgoc_PrincipalAmountToBeSurrenderedInDisposal
Namespace Prefix:	sgoc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Amount of consideration received or receivable for the disposal of assets and liabilities, including discontinued operation.

No definition available.

Name:	us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

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Data Type:	na
Balance Type:
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Name:	us-gaap_ShortTermDebtTypeAxis=sgoc_TwoThousandEighteenNotesMemberMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	srt_CounterpartyNameAxis=sgoc_HoPuiLungMember
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Data Type:	na
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Discontinued Operations (Additional Information) (Details) $ in Thousands, $ in Thousands						3 Months Ended	12 Months Ended
	Aug. 31, 2020 HKD ($) shares	Sep. 20, 2019 HKD ($) shares	Apr. 30, 2019 USD ($)	Apr. 25, 2019 USD ($) shares	Jun. 07, 2018 HKD ($)	Dec. 31, 2018	Dec. 31, 2019 USD ($)	Aug. 31, 2020 USD ($)	Sep. 20, 2019 USD ($)	Apr. 25, 2019 HKD ($)	Apr. 25, 2019 USD ($)	Jun. 07, 2018 USD ($)
Century Skyway Limited
Percentage of ownership used to pay to acquiree in business combination					49.00%
Consideration					$ 126,130		$ 12,750			$ 99,450	$ 12,750	$ 16,170
Percentage of ownership to sell in disposal						51.00%	51.00%
Number of shares to sell				5,100
Boca International Limited
Percentage of ownership used to pay to acquiree in business combination					49.00%
Consideration	$ 1,460				$ 184,840			$ 190				$ 23,700
Percentage of ownership to sell in disposal	51.00%
Number of shares to sell	94
Two Thousand Eighteen Notes Member [Member] \| Century Skyway Limited
Principal amount to be surrendered in the disposal \| $			$ 3,760	$ 3,760
Ho Pui Lung [Member] \| Century Skyway Limited
Consideration		$ 99,450							$ 12,750
Percentage of ownership to sell in disposal		51.00%
Number of shares to sell		5,100
Wong Yiu Tong [Member] \| Boca International Limited
Consideration	$ 1,460							$ 190
Percentage of ownership to sell in disposal	51.00%