Stockholders' Equity (Deficit) Accumulated Other Comprehensive Income and Redeemable Noncontrolling Interest - Schedule of Changes in Accumulated Other Comprehensive Income (Loss) (Detail) (USD $) In Millions, unless otherwise specified			6 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2014 Foreign Currency Translation [Member]	Jun. 30, 2014 Benefit Plan Liabilities [Member]	Jun. 30, 2014 Unrealized Gain (Loss) on Available-For-Sale Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss) net of tax, beginning balance	$ (193.5)	$ (189.9)	$ (18.3)	$ (174.9)	$ 3.3
Other comprehensive income (loss) before reclassifications			(0.7)		(3.3)
Reclassification from accumulated other comprehensive income, period net of tax				0.4
Net current-period other comprehensive income (loss)			(0.7)	0.4	(3.3)
Accumulated other comprehensive income (loss) net of tax, ending balance	$ (193.5)	$ (189.9)	$ (19.0)	$ (174.5)