Amounts Due From/To Related Parties - Additional Information - (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
Dec. 31, 2017	Oct. 31, 2017
Related Party Transaction [Line Items]
Disposal of a subsidiary to a related party	¥ 1,000
Shangde Jiaxun
Related Party Transaction [Line Items]
Disposal of a subsidiary to a related party	1,000	¥ 1,000
Gain on disposition of assets	¥ 178

Amount of gain (loss) on sale or disposal of assets, including but not limited to property plant and equipment, intangible assets and equity in securities of subsidiaries or equity method investee.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585

Name:	us-gaap_GainLossOnDispositionOfAssets1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration