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Summary of Significant of Accounting Policies - Estimated Useful Lives of Intangible Asset (Detail)	12 Months Ended
	Dec. 31, 2017
Platform
Finite Lived Intangible Asset useful life	5 years
Minimum [Member] | Customer relationship
Finite Lived Intangible Asset useful life	2 years
Minimum [Member] | Trademarks
Finite Lived Intangible Asset useful life	3 years
Minimum [Member] | Technology
Finite Lived Intangible Asset useful life	1 year
Minimum [Member] | Online game licenses
Finite Lived Intangible Asset useful life	1 year
Minimum [Member] | User base
Finite Lived Intangible Asset useful life	1 year
Minimum [Member] | Domain names
Finite Lived Intangible Asset useful life	1 year
Maximum [Member] | Customer relationship
Finite Lived Intangible Asset useful life	6 years
Maximum [Member] | Trademarks
Finite Lived Intangible Asset useful life	10 years
Maximum [Member] | Technology
Finite Lived Intangible Asset useful life	10 years
Maximum [Member] | Online game licenses
Finite Lived Intangible Asset useful life	5 years
Maximum [Member] | User base
Finite Lived Intangible Asset useful life	3 years
Maximum [Member] | Domain names
Finite Lived Intangible Asset useful life	10 years

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- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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- Details

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