Contingencies - Additional Information (Detail) In Millions, unless otherwise specified	3 Months Ended			1 Months Ended
	Mar. 31, 2015 BRL	May 31, 2012 USD ($)	Jun. 30, 2010 USD ($)	Nov. 22, 2011 Court-Imposed Interest, Fees or Inflation Adjustments Maximum USD ($)	Nov. 22, 2011 Court-Imposed Interest, Fees or Inflation Adjustments Maximum BRL
Loss Contingencies [Line Items]
Damages asserted by BK	20.8			$ 57.0
Total ordered damages granted to Bk				8.2	26.7
Accrual for Environmental Loss Contingencies			100
Business combination, recognized identifiable assets acquired and liabilities assumed, contingent liability		$ 2.9