Related Party Transactions - Significant Related Party Transactions (Detail) - Ping An Group [Member] ¥ in Thousands, $ in Thousands |
12 Months Ended | ||||||||
|---|---|---|---|---|---|---|---|---|---|
|
Dec. 31, 2017
CNY (¥)
|
Dec. 31, 2017
USD ($)
|
Dec. 31, 2016
CNY (¥)
|
Dec. 31, 2015
CNY (¥)
|
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| Related Party Transaction [Line Items] | |||||||||
| Significant related party transactions, interest income | ¥ 35,049 | $ 5,387 | ¥ 3,564 | ¥ 0 | |||||
| Sales of New Vehicles [Member] | |||||||||
| Related Party Transaction [Line Items] | |||||||||
| Significant related party transactions, sales | 0 | 0 | 21,938 | 0 | |||||
| Rental Property Management And Other Miscellaneous Services [Member] | |||||||||
| Related Party Transaction [Line Items] | |||||||||
| Significant related party transactions, service provided | [1] | 55,220 | 8,487 | 21,594 | 0 | ||||
| Commission Fee And Advertising Services Member [Member] | |||||||||
| Related Party Transaction [Line Items] | |||||||||
| Significant related party transactions, service provided | [2] | ¥ 21,171 | $ 3,254 | ¥ 0 | ¥ 0 | ||||
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