Summary of Changes in Benefit Obligations and Fair Value of Plan Assets for Post-Retirement Plans (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule Of Pension And Other Retirement Benefits Expected Benefit Payments [Line Items]
Pension and retirement benefits liability-current	$ (7.0)	$ (4.4)
Pension and retirement benefits liability-non current	(164.0)	(213.3)
Pension Plans
Schedule Of Pension And Other Retirement Benefits Expected Benefit Payments [Line Items]
Benefit obligation, beginning of the period	356.3	298.8
Service cost	19.8	18.9	(15.1)
Interest cost	13.5	13.1	(13.1)
Plan participants' contributions	0	0
Benefits paid	5.3	5.7
Actuarial gain (loss)	0.7	11.0
Benefit obligation, end of the period	347.1	356.3	298.8
Beginning Balance	167.6	133.0
Actual return on plan assets	23.0	19.0
Benefits paid	(5.3)	(5.7)
Employer contributions		21.3
Plan participants' contributions	0	0
Ending Balance	204.6	167.6	133.0
Funded status of the plans	(142.5)	(188.7)
Pension and retirement benefits liability-current	(6.2)	(3.6)
Pension and retirement benefits liability-non current	(136.3)	(185.1)
Net amount recognized	(142.5)	(188.7)
Accumulated benefit obligation, end of the period	298.5	298.4
Assumption changes	(37.9)	20.2
Other Retirement Plans
Schedule Of Pension And Other Retirement Benefits Expected Benefit Payments [Line Items]
Benefit obligation, beginning of the period	21.8	20.2
Service cost	1.7	1.5	(1.1)
Interest cost	0.8	0.7	(0.8)
Plan participants' contributions	0.3	0.3
Benefits paid	0.6	1.0
Actuarial gain (loss)	(1.0)	(1.1)
Benefit obligation, end of the period	20.7	21.8	20.2
Beginning Balance	0	0
Actual return on plan assets	0	0
Benefits paid	(0.6)	(1.0)
Employer contributions	0.6	0.7
Plan participants' contributions	(0.3)	(0.3)
Ending Balance	0	0	0
Funded status of the plans	(20.7)	(21.8)
Pension and retirement benefits liability-current	(0.8)	(0.8)
Pension and retirement benefits liability-non current	(19.9)	(21.0)
Net amount recognized	(20.7)	(21.8)
Assumption changes	$ (2.3)	$ 1.2