Commitments and Contingent Liabilities - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Loss Contingencies [Line Items]
Operating leases, rental expense	$ 24.0	$ 26.3	$ 24.9
Contingency reserve for litigation	11.1
Minimum
Loss Contingencies [Line Items]
Time-frame over which the accrued amounts may be paid out, in years	15
Maximum
Loss Contingencies [Line Items]
Time-frame over which the accrued amounts may be paid out, in years	20
Accrued Liabilities
Loss Contingencies [Line Items]
Waste disposed accrued liability	1.9
Other Liability
Loss Contingencies [Line Items]
Waste disposed accrued liability	$ 6.9