Business combinations - Other acquisition (Details) ¥ in Millions, $ in Millions	1 Months Ended	12 Months Ended
Apr. 30, 2020 CNY (¥)	Dec. 31, 2022 CNY (¥)	Dec. 31, 2022 HKD ($)
Business combinations
Cash consideration	¥ 23.8
Other acquisition
Business combinations
Cash consideration		¥ 8.7	$ 9.5
Percentage of equity interest acquired		30.00%	30.00%
Percentage of equity interest held before the business combination		55.00%	55.00%

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.

No definition available.

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- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

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- Definition

Percentage of equity in the acquiree held by the acquirer immediately before the acquisition date in a business combination.

+ References

No definition available.

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- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
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-URI https://asc.fasb.org/extlink&oid=126975305&loc=d3e6927-128479

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-Section 45
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