Accumulated Other Comprehensive Income (Loss) - Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Accumulated Other Comprehensive Income Loss [Line Items]
Marketable securities, Balance at beginning of period	$ 1.6	$ 2.1	$ 1.6	$ 2.8
Marketable securities, Other comprehensive loss - unrealized losses arising during the period	(0.3)	(0.2)	(0.3)	(0.9)
Marketable securities, Balance at end of period	1.3	1.9	1.3	1.9
Currency translation adjustment, Balance at beginning of period	(61.6)	53.6	(22.6)	59.2
Currency translation adjustment, Other comprehensive loss	(9.3)	(37.2)	(48.3)	(42.8)
Currency translation adjustment, Balance at end of period	(70.9)	16.4	(70.9)	16.4
Balance at beginning of period	(183.3)	(11.7)	(148.6)	(8.0)
Other comprehensive loss	(10.0)	(36.1)	(44.7)	(39.8)
Balance at end of period	(193.3)	(47.8)	(193.3)	(47.8)
Interest Rate Swap
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive loss	(2.3)		(2.3)
Balance at end of period	(2.3)		(2.3)
Defined Benefit Pension Plans
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at beginning of period	(127.2)	(73.3)	(132.0)	(76.5)
Other comprehensive income— amortization of prior service cost and net losses included in net periodic pension cost	2.2	1.6	7.0	4.8
Balance at end of period	(125.0)	(71.7)	(125.0)	(71.7)
OPEB
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at beginning of period	3.9	5.9	4.4	6.5
Other comprehensive loss - amortization of prior service credit	(0.3)	(0.3)	(0.8)	(0.9)
Balance at end of period	$ 3.6	$ 5.6	$ 3.6	$ 5.6