Activity in Warranty Accrual for Product Warranty (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance, beginning of the period	$ 263,181	$ 243,634	$ 254,554	$ 236,131
Provision	39,802	42,415	88,055	88,240
Amounts charged to the accrual	(40,924)	(37,654)	(80,550)	(75,976)
Balance, end of the period	$ 262,059	$ 248,395	$ 262,059	$ 248,395