Pension and Post-Retirement Benefits - Components of Net Periodic Benefit Costs (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Net periodic benefit (income) costs:
Net periodic benefit costs	$ (1.3)	$ (0.1)	$ (0.4)
Pension Plans
Net periodic benefit (income) costs:
Service cost	0.2	0.2
Interest cost	7.5	6.9
Expected return on plan assets	(10.4)	(9.5)
Amortization of actuarial loss	1.2	2.1
Net periodic benefit costs	(1.5)	(0.3)
Other Post-Retirement Benefit Plans
Net periodic benefit (income) costs:
Service cost	0	0
Interest cost	0.2	0.1
Expected return on plan assets	0	0
Amortization of actuarial loss	0	0.1
Net periodic benefit costs	$ 0.2	$ 0.2