Annual report pursuant to Section 13 and 15(d)

Commitments and Contingencies - Additional Information (Detail)

v3.10.0.1
Commitments and Contingencies - Additional Information (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]      
Rental expenses $ 7.4 $ 7.0 $ 6.6