Income Taxes - Changes in Valuation Allowance Attributable to Continuing Operations and Other Comprehensive Income (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Tax Disclosure [Abstract]
Continuing operations	$ (1.4)	$ (3.6)	$ (8.2)	$ (8.0)
Other comprehensive income	6.8	(3.4)	0	8.0
Change in valuation allowance	$ 5.4	$ (7.0)	$ (8.2)	$ 0

Amount of increase (decrease) in the valuation allowance for a specified deferred tax asset.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 45

-Paragraph 20

-URI http://asc.fasb.org/extlink&oid=37586315&loc=d3e32123-109318

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration