Goodwill - Additional Information (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Additions due to acquisitions	¥ 612,239
Goodwill impaired related to reporting unit	¥ 0	¥ 0

Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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