Financial Instruments - Marketable Securities and Financial Instruments on Fair Value Basis (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, current	$ 2.0	$ 2.7
Marketable securities, noncurrent	254.9	255.6
Currency forward contracts	(1.2)	(4.2)
Interest rate swap	$ (3.5)
Quoted Prices in Active Markets (Level 1)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, current		1.7
Marketable securities, noncurrent	$ 3.5	2.5
Currency forward contracts	(1.2)	(4.2)
Significant Other Observable Inputs (Level 2)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, current	2.0	1.0
Marketable securities, noncurrent	1.4	$ 3.1
Interest rate swap	$ (3.5)
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, current
Marketable securities, noncurrent	$ 250.0	$ 250.0