Schedule of Notional Amount of Derivatives (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Intercompany Foreign Currency Balance [Line Items]
Notional amounts, Buy Position	$ (16.8)	$ (16.0)
Notional amounts, Sell Position	47.3	69.3
Notional amounts, Net Total	30.5	53.3
Japanese Yen
Intercompany Foreign Currency Balance [Line Items]
Notional amounts, Sell Position	36.3	50.8
Notional amounts, Net Total	36.3	50.8
Taiwan Dollar
Intercompany Foreign Currency Balance [Line Items]
Notional amounts, Buy Position		(0.8)
Notional amounts, Sell Position	4.2	6.3
Notional amounts, Net Total	4.2	5.5
British Pound Sterling
Intercompany Foreign Currency Balance [Line Items]
Notional amounts, Sell Position	5.5	10.1
Notional amounts, Net Total	5.5	10.1
Euro
Intercompany Foreign Currency Balance [Line Items]
Notional amounts, Buy Position	(16.8)	(15.2)
Notional amounts, Sell Position	1.3	2.1
Notional amounts, Net Total	$ (15.5)	$ (13.1)