XML 114 R96.htm IDEA: XBRL DOCUMENT v3.8.0.1
Repurchase of shares - Additional Information (Detail) - $ / shares
1 Months Ended 12 Months Ended
Feb. 10, 2017
Jan. 13, 2017
Nov. 30, 2016
Oct. 27, 2016
Apr. 14, 2016
Dec. 31, 2017
Mar. 31, 2017
Dec. 30, 2016
Sep. 30, 2016
Aug. 30, 2016
Jul. 29, 2016
Jun. 30, 2016
May 31, 2016
Mar. 30, 2016
Dec. 31, 2016
Share Repurchase Program, 2016 [Member]                              
Equity, Class of Treasury Stock [Line Items]                              
Total Number of ADS Purchased     21,229 31,400 457,900     173,312 15,467 229,695 555,357 111,459 449,696 408,985 2,454,500
Average Price Paid Per Share     $ 4.61 $ 5.11 $ 6.61     $ 4.02 $ 5.33 $ 5.83 $ 5.33 $ 5.24 $ 6.28 $ 6.22  
Share Repurchase Program 2017 [Member]                              
Equity, Class of Treasury Stock [Line Items]                              
Total Number of ADS Purchased 5,553 994       93,070 86,523                
Average Price Paid Per Share $ 3.75 $ 4.34         $ 3.86