Product Warranties - Summary of Changes in Product Warranties Reserve (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Product Warranties Disclosures [Abstract]
Warranty reserve, beginning of period	$ 97,190	$ 77,341	$ 101,507	$ 62,742
Provision	12,103	15,798	35,556	49,701
Payments	(14,981)	(11,403)	(42,751)	(30,707)
Warranty reserve, end of period	$ 94,312	$ 81,736	$ 94,312	$ 81,736