Schedule of Changes in Benefit Obligations, Plan Assets and Funded Status of Defined Benefit Pension and Post-Retirement Benefit Plans (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]
Curtailment	$ 12.3
Plan assets at beginning of year	767.0
Plan assets at end of year	799.7
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation (ABO) at December 31	978.7		895.1
PBO at beginning of year	(906.5)		(862.1)
Service cost	(7.8)		(9.1)		(8.6)
Interest cost	(43.6)		(44.1)
Plan amendments			(1.6)
Actuarial (loss) gain including assumption changes	(90.3)		(52.0)
Benefits paid	60.5		60.4
Curtailment			2.0
PBO at end of year	(987.7)		(906.5)		(862.1)
Plan assets at beginning of year	768.6		640.8
Actual return on plan assets	91.2		11.3
Contribution by the company	1.2		176.9
Plan assets at end of year	800.5		768.6		640.8
Funded status	(187.2)		(137.9)
Non-current liabilities	(187.2)		(137.9)
Net pension liability at end of year	(187.2)	[1]	(137.9)	[1]
Net actuarial loss (gain)	567.9		532.0
Prior service cost	(8.1)		(8.9)
Total recognized in accumulated other comprehensive loss	559.8		523.1
Pension Benefits | Change During Period, Fair Value Disclosure
Defined Benefit Plan Disclosure [Line Items]
Benefits paid	(60.5)		(60.4)
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
PBO at beginning of year	(12.7)		(14.9)
Service cost	(0.1)		(0.1)		(0.2)
Interest cost	(0.5)		(0.7)
Participant contributions	(0.3)		(0.3)
Actuarial (loss) gain including assumption changes	1.1		1.9
Benefits paid	1.1		1.4
PBO at end of year	(11.4)		(12.7)		(14.9)
Contribution by the company	0.8		1.1
Funded status	(11.4)		(12.7)
Current liabilities	(0.8)		(1.1)
Non-current liabilities	(10.6)		(11.6)
Net pension liability at end of year	(11.4)		(12.7)
Net actuarial loss (gain)	(3.5)		(2.8)
Total recognized in accumulated other comprehensive loss	(3.5)		(2.8)
Postretirement Benefits | Change During Period, Fair Value Disclosure
Defined Benefit Plan Disclosure [Line Items]
Participant contributions	0.3		0.3
Benefits paid	$ (1.1)		$ (1.4)

[1] In addition, the company has recorded a liability for a foreign pension plan of $2.9 million and $1.6 million at December 31, 2012 and 2011, respectively and an accumulated other comprehensive loss of $2.3 million and $2.1 million at December 31, 2012 and 2011, respectively.