XML 59 R48.htm IDEA: XBRL DOCUMENT v3.10.0.1
Share-based Compensation - Summary of Additional Stock Option Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]        
Weighted-average grant date fair value per share   $ 8.72 $ 12.39 $ 8.90
Intrinsic value of options exercised $ 574 $ 78 $ 1,604 $ 4,802
Fair value of stock options that vested   $ 258 $ 199 $ 559