Revenues and Deferred Revenue - Schedule of Movement of the Deferred Revenue (Details) ¥ in Thousands, $ in Thousands	12 Months Ended
Dec. 31, 2018 CNY (¥)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2018 USD ($)
Disaggregation Of Revenue [Abstract]
Beginning balance (current and noncurrent)	¥ 2,110,428	¥ 727,569
Additions	3,214,400	2,381,755
Deductions	(2,038,803)	(998,896)
Ending balance (current and noncurrent)	3,286,025	2,110,428
Deferred revenue, current	1,765,085	1,325,954	$ 256,721
Deferred revenue, non-current	¥ 1,520,940	¥ 784,474	$ 221,212

Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable, classified as noncurrent.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
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-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130549-203045

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82913815&loc=SL49130531-203044

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant