Debt Discount Beneficial Conversion Feature

No definition available.

Name:	ncty_DebtDiscountBeneficialConversionFeature
Namespace Prefix:	ncty_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying amount of debt instrument and interest payable.

+ References

No definition available.

+ Details

Name:	ncty_DebtInstrumentCarryingAmountAndInterestPayable
Namespace Prefix:	ncty_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Adjustments to price per share of the conversion feature embedded in the debt instrument.

+ References

No definition available.

+ Details

Name:	ncty_DebtInstrumentConvertibleAdjustmentsToConversionPrice
Namespace Prefix:	ncty_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of tranches under the convertible debt instrument.

+ References

No definition available.

+ Details

Name:	ncty_DebtInstrumentConvertibleNumberOfTranches
Namespace Prefix:	ncty_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Extension of Maturity, Period

+ References

No definition available.

+ Details

Name:	ncty_DebtInstrumentExtensionOfMaturityPeriod
Namespace Prefix:	ncty_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of subsidiaries disposed off by the company.

+ References

No definition available.

+ Details

Name:	ncty_NumberOfSubsidiariesDisposedOff
Namespace Prefix:	ncty_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Carrying value as of the balance sheet date of the portion of long-term debt due within one year or the operating cycle if longer identified as Convertible Notes Payable. Convertible Notes Payable is a written promise to pay a note which can be exchanged for a specified amount of another, related security, at the option of the issuer and the holder.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.20)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_ConvertibleNotesPayableCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Year of expiration or mandatory redemption of the financial instrument issued in exchange for the original debt being converted in a noncash or part noncash transaction, in CCYY format.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4332-108586

+ Details

Name:	us-gaap_DebtConversionConvertedInstrumentExpirationOrDueDateYear
Namespace Prefix:	us-gaap_
Data Type:	us-types:gYearListItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of equity instruments that the holder of the debt instrument would receive if the debt was converted to equity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21521-112644

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21506-112644

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(5))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentConvertibleNumberOfEquityInstruments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

Aggregate amount of interest paid or due on all long-term debt.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.8)
-URI http://asc.fasb.org/extlink&oid=116637391&loc=SL114874048-224260

+ Details

Name:	us-gaap_InterestExpenseLongTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3291-108585

+ Details

Name:	us-gaap_RepaymentsOfLongTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Carrying amount of financial assets accounted for as secured borrowings recognized in the transferor's statement of financial position at the end of each period presented.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 1A
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=109249958&loc=SL6224234-111729

+ Details

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

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=ncty_The9ComputerC9iShanghaiAndShanghaiKaieMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DisposalGroupClassificationAxis=us-gaap_DiscontinuedOperationsHeldforsaleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=ncty_TwelvePercentConvertibleSeniorNotesDueTwoThousandEighteenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

CONVERTIBLE NOTES - Net Carrying Value at Date of Issuance (Details)						1 Months Ended		12 Months Ended
	Feb. 21, 2020 USD ($)	Jan. 01, 2020 USD ($)	Sep. 26, 2019 USD ($) subsidiary	Nov. 24, 2015 USD ($)	Nov. 24, 2015 USD ($)	Feb. 29, 2020 CNY (¥) subsidiary	Sep. 30, 2019 subsidiary	Dec. 31, 2019 USD ($) tranche $ / shares	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2016 USD ($)	Dec. 31, 2019 CNY (¥) tranche	Sep. 26, 2019 CNY (¥)	Nov. 24, 2015 CNY (¥)
Debt Instrument [Line Items]
Number of subsidiaries disposed off \| subsidiary							3
Remaining outstanding balance of convertible notes								$ 59,485,752		¥ 375,257,140			¥ 414,127,908
Beneficial conversion feature				$ 8,100,000	$ 8,100,000
Subsequent Event
Debt Instrument [Line Items]
Number of subsidiaries disposed off \| subsidiary						3
The9 Computer, C9I Shanghai and Shanghai Kaie
Debt Instrument [Line Items]
Number of subsidiaries disposed off \| subsidiary			3
Total consideration			$ 70,800,000											¥ 493,000,000
The9 Computer, C9I Shanghai and Shanghai Kaie \| Held for sale
Debt Instrument [Line Items]
Total consideration			$ 70,800,000											¥ 493,000,000
The9 Computer, C9I Shanghai and Shanghai Kaie \| Held for sale \| Subsequent Event
Debt Instrument [Line Items]
Total consideration \| ¥						¥ 443,700,000
12% Convertible Senior Notes Due 2018
Debt Instrument [Line Items]
Principal amount				$ 40,050,000	$ 40,050,000
Notes due date				2018
Notes extension				2 years	2 years
Interest rate (as a percent)				12.00%	12.00%										12.00%
Total net book value as secured notes \| ¥															¥ 14,100,000
Convertible shares of Group's ADS												11,695,513
Beneficial conversion feature				$ 8,112,556	$ 8,112,556
Carrying amount of convertible notes and interest payable								59,500,000		375,300,000			¥ 414,100,000
Interest expense recognized related to convertible note								$ 4,800,000	¥ 33,200,000	¥ 98,300,000	¥ 77,000,000
Number of tranches \| tranche								3					3
Adjustment to conversion price \| $ / shares								$ 0
12% Convertible Senior Notes Due 2018 \| Subsequent Event
Debt Instrument [Line Items]
Repayment of convertible notes	$ 4,800,000	$ 4,800,000
Remaining outstanding balance of convertible notes	$ 55,500,000	$ 55,500,000