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Warranties - Additional Information (Detail) - USD ($)
$ in Millions
9 Months Ended
Sep. 30, 2017
Dec. 31, 2016
Guarantor Obligations [Line Items]    
Warranty reserve balance $ 2.7 $ 2.6
Maximum [Member]    
Guarantor Obligations [Line Items]    
Warranty term 5 years  
Minimum [Member]    
Guarantor Obligations [Line Items]    
Warranty term 2 years