Income Taxes - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended	3 Months Ended
	Mar. 31, 2013	Sep. 30, 2013 Mexico [Member]	Jun. 30, 2013 Mexico [Member] 2007 Tax year [Member]	Sep. 30, 2013 Mexico [Member] 2004 Tax Year [Member]	Sep. 30, 2013 Mexico [Member] 2006 Tax Year [Member]
Income Taxes [Line Items]
Tax expense increase (decrease)	$ (27.5)
Total tax assessment including interest and penalty				22.9	24.4
Net cash cost on settlement of tax liability		3.7
Increase in uncertain tax position due to tax settlement		13.2
Change in interest on uncertain tax positions		5.0
Change in penalties on uncertain tax positions		2.7
Reduction in uncertain tax positions related to statute of limitations expirations			4.3
Reversal of accrued interest on uncertain tax position			1.5
Reversal of accrued penalty on uncertain tax position			$ 0.6