Tax Effects of Temporary Differences and Carryforwards that Gives Rise to Deferred Income Tax Assets and Liabilities (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Deferred tax assets:
Inventory reserves	$ 21.7	$ 18.3
Warranty reserves	12.5	9.3
Accrued liabilities	37.5	15.5
Net operating loss carryforward	22.4	19.6
Research and development credit carry forward	18.8	38.2
Alternative minimum tax credit carryforward	5.0	5.0
Other	5.6	4.7
Deferred Tax Assets, Gross, Total	123.5	110.6
Deferred tax liabilities:
Book to tax revenue differences	(31.7)	(37.5)
Intangible assets	(127.9)	(92.8)
Depreciation	(38.2)	(23.2)
Software development costs	(0.7)	(1.3)
Deferred Tax Liabilities, Net	(198.5)	(154.8)
Net deferred tax liability before valuation allowance	(75.0)	(44.2)
Valuation allowance	(26.5)	(20.1)
Net deferred tax liability	$ (101.5)	$ (64.3)