Restricted Net Assets - Additional Information (Detail) ¥ in Thousands, $ in Thousands |
12 Months Ended | |||
|---|---|---|---|---|
|
Dec. 31, 2017
CNY (¥)
|
Dec. 31, 2017
USD ($)
|
Dec. 31, 2016
CNY (¥)
|
Dec. 31, 2015
CNY (¥)
|
|
| Restricted Net Assets [Abstract] | ||||
| Percentage of after tax profits allocated to general reserve | 10.00% | |||
| Percentage of maximum limit of registered capital to discontinue general reserve | 50.00% | |||
| Appropriated retained earnings | ¥ 51,847 | $ 7,969 | ¥ 36,000 | ¥ 19,175 |
| Restricted net assets | ¥ 6,789,409 | $ 1,043,513 | ¥ 5,165,673 |