Fair Value of Derivative Instruments (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Designated as Hedging Instrument
Derivative [Line Items]
Asset Derivatives, Fair Value	$ 0.7		$ 0.3
Amount of Gains (Loss) Recognized in OCI from Derivatives	0.3	(0.1)
Designated as Hedging Instrument | Diesel Fuel Contracts | Other Comprehensive Income (Loss)
Derivative [Line Items]
Amount of Gains (Loss) Recognized in OCI from Derivatives	0.1	0.4
Designated as Hedging Instrument | Diesel Fuel Contracts | Other Current Assets
Derivative [Line Items]
Asset Derivatives, Notional Amount	7.1
Asset Derivatives, Fair Value	0.5		0.2
Designated as Hedging Instrument | Foreign Exchange Contract | Other Comprehensive Income (Loss)
Derivative [Line Items]
Amount of Gains (Loss) Recognized in OCI from Derivatives	0.2	(0.5)
Designated as Hedging Instrument | Foreign Exchange Contract | Other Current Assets
Derivative [Line Items]
Asset Derivatives, Notional Amount	22.8
Asset Derivatives, Fair Value	0.2		0.1
Not Designated as Hedging Instrument
Derivative [Line Items]
Asset Derivatives, Fair Value	3.5		0.9
Amount of Gain (Loss) Recognized in Income	4.6	1.5
Not Designated as Hedging Instrument | Foreign Exchange Contract | Selling, General And Administrative Expenses
Derivative [Line Items]
Amount of Gain (Loss) Recognized in Income	0	0.1
Not Designated as Hedging Instrument | Foreign Exchange Contract | Other Current Assets
Derivative [Line Items]
Asset Derivatives, Notional Amount	2.4
Asset Derivatives, Fair Value	0		0
Not Designated as Hedging Instrument | Equity Derivatives | Selling, General And Administrative Expenses
Derivative [Line Items]
Amount of Gain (Loss) Recognized in Income	4.6	1.4
Not Designated as Hedging Instrument | Equity Derivatives | Other Current Assets
Derivative [Line Items]
Asset Derivatives, Notional Amount	23.6
Asset Derivatives, Fair Value	$ 3.5		$ 0.9