Name:	ncty_IndefiniteLivedIntangibleAssetsAdditionsFromExchange
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Data Type:	xbrli:monetaryItemType
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Amount of increase in assets, excluding financial assets and goodwill, lacking physical substance with an indefinite life, from interest income earned.

No definition available.

Name:	ncty_IndefiniteLivedIntangibleAssetsInterestIncome
Namespace Prefix:	ncty_
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

Amount of realized gains (losses) on assets, excluding financial assets and goodwill, lacking physical substance with an indefinite life.

No definition available.

Name:	ncty_IndefiniteLivedIntangibleAssetsRealizedGainLoss
Namespace Prefix:	ncty_
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Period Type:	duration

Amount of increase in assets, excluding financial assets and goodwill, lacking physical substance with an indefinite life, through receipt from games.

No definition available.

Name:	ncty_IndefiniteLivedIntangibleAssetsReceiptFromGames
Namespace Prefix:	ncty_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Amount of increase in assets, excluding financial assets and goodwill, lacking physical substance with an indefinite life, through receipt from NFT business.

No definition available.

Name:	ncty_IndefiniteLivedIntangibleAssetsReceiptFromNftBusiness
Namespace Prefix:	ncty_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Amount of decrease in assets, excluding financial assets and goodwill, lacking physical substance with an indefinite life, through used in operating activities.

No definition available.

Name:	ncty_IndefiniteLivedIntangibleAssetsUsedInOperatingActivities
Namespace Prefix:	ncty_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of impairment loss resulting from write-down of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit to fair value.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=66006027&loc=d3e16373-109275

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

Name:	us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.