XML 92 R69.htm IDEA: XBRL DOCUMENT v3.21.1
BUSINESS ACQUISITION - Acquisitions of after-sales service centers (Details) - Acquisitions of after-sales service centers
12 Months Ended
Dec. 31, 2018
item
Business Acquisition [Line Items]  
Equity interest subscribed 70.00%
Number of equal annual installments after the successful offering 4
Shanghai Zhoushuo [Member]  
Business Acquisition [Line Items]  
Number of acquisition completed 3