Fair Value of Derivative Instruments (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Derivatives, Fair Value [Line Items]
Derivatives assets	$ 15.2	$ 12.6
Derivatives liabilities	2.4	6.8
Derivatives designated as accounting hedges
Derivatives, Fair Value [Line Items]
Derivatives assets	13.8	11.5
Derivatives liabilities	1.7	4.5
Derivatives designated as accounting hedges | Interest rate swaps | Other Assets
Derivatives, Fair Value [Line Items]
Derivatives assets	13.8	11.5
Derivatives designated as accounting hedges | Interest rate swaps | Accounts payable and accrued liabilities
Derivatives, Fair Value [Line Items]
Derivatives liabilities	0.7	4.5
Derivatives designated as accounting hedges | Foreign exchange forward | Net Investment Hedging | Accounts payable and accrued liabilities
Derivatives, Fair Value [Line Items]
Derivatives liabilities	1.0
Derivatives not designated as accounting hedges | Foreign exchange forward | Other Current Assets
Derivatives, Fair Value [Line Items]
Derivatives assets	1.4	1.1
Derivatives not designated as accounting hedges | Foreign exchange forward | Accounts payable and accrued liabilities
Derivatives, Fair Value [Line Items]
Derivatives liabilities	$ 0.7	$ 2.3