Changes in Warranty Liabilities (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
Warranty Liability [Line Items]
Balance, beginning of the period	$ 16,660	$ 15,103	$ 17,358	$ 16,238
Provision for warranties	1,668	3,353	3,143	3,442
Warranty costs paid	(1,982)	(3,118)	(4,155)	(4,342)
Balance, end of the period	$ 16,346	$ 15,338	$ 16,346	$ 15,338