Share-based compensation (Summary of Restricted Share Units Activity) (Details) - $ / shares	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
2011 Incentive Scheme [Member] \| Parent [Member]
Number of restricted shares
Outstanding at the beginning of the period (in shares)	30,874,144	20,955,720	36,283,602
Granted (in shares)	11,977,794	22,090,030	1,530,008
Forfeited (in shares)	(5,115,304)	(4,007,728)	(4,628,202)
Vested (in shares)	(12,507,000)	(8,163,878)	(12,229,688)
Outstanding at the end of the period (in shares)	25,229,634	30,874,144	20,955,720
Expected to vest at the end of the period (in shares)	23,742,895
Weighted average grant-date fair value
Outstanding at the beginning of the period (in dollars per share)	$ 4.4969	$ 2.4320	$ 2.3535
Granted (in dollars per share)	4.7052	5.3001	1.8618
Forfeited (in dollars per share)	4.6843	2.5561	2.7386
Vested (in dollars per share)	3.6776	2.3227	2.0151
Outstanding at the end of the period (in dollars per share)	4.9639	$ 4.4969	$ 2.4320
Expected to vest at the end of the period (in dollars per share)	$ 4.9552
Huya 2017 Share Incentive Plan [Member] \| Restricted Stock Units (RSUs) [Member]
Number of restricted shares
Outstanding at the beginning of the period (in shares)	0
Granted (in shares)	4,193,685
Forfeited (in shares)	(76,500)
Vested (in shares)	(10,000)
Outstanding at the end of the period (in shares)	4,107,185	0
Expected to vest at the end of the period (in shares)	3,795,535
Weighted average grant-date fair value
Outstanding at the beginning of the period (in dollars per share)	$ 0
Granted (in dollars per share)	9.0242
Forfeited (in dollars per share)	7.1600
Vested (in dollars per share)	19.5900
Outstanding at the end of the period (in dollars per share)	9.0331	$ 0
Expected to vest at the end of the period (in dollars per share)	$ 8.9944

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(3)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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- Definition

Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

+ References

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-Publisher FASB
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-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ References

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

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The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

+ References

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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-Section 50
-Paragraph 2
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- Definition

The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

+ References

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-Publisher FASB
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- Definition

As of the balance sheet date, the weighted-average exercise price for awards that are expected to vest.

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As of the balance sheet date, the number of shares into which expected to vest stock options outstanding can be converted under the option plan.

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