Product Warranties - Summary of Changes in Product Warranties Reserve (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Product Warranty Accrual [Line Items]
Warranty reserve, beginning of period	$ 58,790	$ 62,804	$ 64,008	$ 69,787
Provision	11,870	11,474	27,587	23,247
Payments	(9,559)	(11,110)	(30,494)	(29,866)
Warranty reserve, end of period	$ 61,101	$ 63,168	$ 61,101	$ 63,168