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Stock Based Compensation - Additional Information (Detail) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]        
Share-based compensation expense $ 20,637 $ 11,484 $ 56,538 $ 37,289