Liability for Warranty Returns - Summary of Warranty Expense and Write-Off Activity (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Product Warranties Disclosures [Abstract]
Balance at beginning of period	$ 8,415	$ 8,977
Plus:Amounts charged to cost and expenses	1,905	2,770
Less:Deductions	(1,604)	(3,099)
Balance at end of period	$ 8,716	$ 8,648