Reconciliation of Segment Operating Income to Consolidated Income (Loss) Before Income Taxes (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income (loss)	$ 15.8	$ 38.0	$ (4.1)	$ 39.6
Interest expense	(2.3)	(2.6)	(4.3)	(5.3)
Other income (expense), net	(2.5)	14.1	(12.3)	9.2
Total income (loss) before income taxes	11.0	49.5	(20.7)	43.5
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income (loss)	30.5	61.5	26.9	84.3
Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income (loss)	$ (14.7)	$ (23.5)	$ (31.0)	$ (44.7)