Annual report pursuant to Section 13 and 15(d)

Employee Benefit Plan - Additional Information (Detail)

v3.19.3.a.u2
Employee Benefit Plan - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Share-based Payment Arrangement [Abstract]      
Participants contribution $ 19,000    
Employer contribution as a percentage of employee contributions 2.00%    
Employer contribution 25.00%    
Full vesting period of employer contribution 4 years    
Contribution expenses $ 12,200,000 $ 10,100,000 $ 7,900,000