Accumulated Other Comprehensive Loss - Summary of Changes in Accumulated Other Comprehensive Loss by Component (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Accumulated Other Comprehinsive Income [Roll Forward]
Beginning balance	$ (47.2)	$ (50.3)	$ (54.1)	$ (34.1)
Other comprehensive income before reclassifications	(9.8)	7.1	(3.9)	(10.4)
Amounts reclassified from accumulated other comprehensive income loss	0.9	1.0	1.9	2.3
Net current-period other comprehensive income(loss)	(8.9)	8.1	(2.0)	(8.1)
Ending balance	(56.1)	(42.2)	(56.1)	(42.2)
Unrealized Translation Adjustments [Member]
Accumulated Other Comprehinsive Income [Roll Forward]
Beginning balance	1.0	(0.5)	(4.9)	17.0
Other comprehensive income before reclassifications	(9.8)	7.1	(3.9)	(10.4)
Amounts reclassified from accumulated other comprehensive income loss	(0.2)		(0.2)	0.0
Net current-period other comprehensive income(loss)	(10.0)	7.1	(4.1)	(10.4)
Ending balance	(9.0)	6.6	(9.0)	6.6
Pension and Other Postretirement Plans [Member]
Accumulated Other Comprehinsive Income [Roll Forward]
Beginning balance	(48.2)	(49.8)	(49.2)	(51.1)
Amounts reclassified from accumulated other comprehensive income loss	1.1	1.0	2.1	2.3
Net current-period other comprehensive income(loss)	1.1	1.0	2.1	2.3
Ending balance	$ (47.1)	$ (48.8)	$ (47.1)	$ (48.8)