Goodwill and Intangible Assets (Narrative) (Detail) $ in Millions	3 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2015 USD ($) Segment	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Goodwill And Intangible Assets [Line Items]
Number of reporting units | Segment		7
Estimated cost of capital, minimum	9.50%	9.50%
Estimated cost of capital, maximum	13.50%	13.50%
Estimated cost of capital, weighted	10.70%	10.70%
Hypothetical decrease to fair values of each reporting unit				10.00%
Net intangible assets	$ 327.0	$ 327.0		$ 353.5
Intangibles with indefinite useful lives	27.6	27.6
Estimated amortization expense for intangible assets, current year	8.0	8.0
Estimated amortization expense for intangible assets, year 2015	30.5	30.5
Estimated amortization expense for intangible assets, year 2016	29.7	29.7
Estimated amortization expense for intangible assets, year 2017	26.9	26.9
Estimated amortization expense for intangible assets, year 2018	24.3	24.3
Estimated amortization expense for intangible assets, year 2019 and thereafter	180.0	$ 180.0
Goodwill, Purchase Accounting Adjustments	$ 0.0		$ (13.9)
MEI Conlux Holdings [Member]
Goodwill And Intangible Assets [Line Items]
Proceeds Received Related To Adjustment Of Working Capital				6.1
Goodwill, Purchase Accounting Adjustments				$ 7.8