XML 64 R50.htm IDEA: XBRL DOCUMENT v3.10.0.1
Commitments - Additional Information (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Leases [Abstract]      
Lease expense $ 7.9 $ 4.9 $ 4.5