Accrued Warranty Costs - Changes in Product Warranty Obligation (Accrued Warranty Costs) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Disclosure Accrued Product Warranty Costs [Abstract]
Balance at beginning of period	$ 7,297	$ 6,172
Amounts charged to costs and expenses	2,227	1,990
Costs incurred	(1,946)	(1,676)
Balance at end of period	$ 7,578	$ 6,486