Benefit Plans - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Percentage of U.S. and U.K. benefit obligation	77.00%
Percentage of U.S. and U.K. plan assets	90.00%
Contributions to defined contribution plans	$ 17.4	$ 17.7	$ 14.8
Other benefit plans obligations	3.9	3.8
Post Sixty Five Retiree Medical Plan | Effective January One Twenty Thirteen
Defined Benefit Plan Disclosure [Line Items]
US postretirement medical plan amendment	50.00%
Post Sixty Five Retiree Medical Plan | Effective January One Twenty Fourteen
Defined Benefit Plan Disclosure [Line Items]
US postretirement medical plan amendment	100.00%
Pre Sixty Five Retiree Medical Plan
Defined Benefit Plan Disclosure [Line Items]
US postretirement medical plan amendment	100.00%
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Amortization of net gains (losses)	4.0
Amortization of net prior service cost (credit)	0
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Amortization of net gains (losses)	1.0
Amortization of net prior service cost (credit)	1.4
U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	76.9	74.9
Expected contribution by employer in 2013	1.8
Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	243.8	206.6
Expected contribution by employer in 2013	$ 6.1