Liability for Warranty Returns - Summary of Warranty Expense and Write-Off Activity (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Product Warranties Disclosures [Abstract]
Balance at beginning of period	$ 8,988	$ 9,042	$ 8,548	$ 8,739
Plus: Amounts charged to cost and expenses	3,055	1,431	2,314	2,329
Less: Deductions	(2,863)	(1,538)	(1,682)	(2,133)
Balance at end of period	$ 9,180	$ 8,935	$ 9,180	$ 8,935