Name:	stg_PortionOfAfterTaxProfitToBeAllocatedToGeneralReserveUnderPrcLaw
Namespace Prefix:	stg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

The percentage of paid in capital that the general reserve would not surpass.

No definition available.

Name:	stg_RequiredGeneralReserveRegisteredCapitalRatioToDeForceCompulsoryNetProfitAllocationToGeneralReserve
Namespace Prefix:	stg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Required percentage of after tax profit allocated to statutory common reserve.

No definition available.

Name:	stg_RequiredPercentageOfAfterTaxProfitAllocatedToStatutoryCommonReserve
Namespace Prefix:	stg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Restricted net assets.

No definition available.

Name:	stg_RestrictedNetAssetsAbstract
Namespace Prefix:	stg_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Threshold percentage of statutory common reserve need to be made over entities registered capital.

No definition available.

Name:	stg_ThresholdPercentageOfStatutoryCommonReserveNeedToBeMadeOverEntitiesRegisteredCapital
Namespace Prefix:	stg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Amount of restricted net assets of consolidated and unconsolidated subsidiaries as of the end of the most recently completed fiscal year.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(e)(3)(ii))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690