Quarterly report pursuant to Section 13 or 15(d)

General - Additional Information (Detail)

v3.8.0.1
General - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2018
Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]    
Derivative effective dates Aug. 12, 2015  
Sales returns reserve $ 30.7 $ 43.4