Schedule II - Valuation and Qualifying Accounts and Reserves (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Warranty Reserve [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 37,692	$ 33,522	$ 33,841
Additions (Reductions) Charged to Cost and Expenses	4,268	10,852	8,515
Deductions	(6,961)	(6,682)	(8,834)
Balance at End of Period	34,999	37,692	33,522
Valuation Allowance of Deferred Tax Assets [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	4,061	4,582	4,465
Additions (Reductions) Charged to Cost and Expenses			117
Deductions	(965)	(521)
Balance at End of Period	$ 3,096	$ 4,061	$ 4,582