Pension and Other Postretirement Benefit Plans (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Pension Benefits [Member]
Assets and liabilities:
Liability - current	$ (0.7)	$ (0.8)
Liability - long term	(29.9)	(20.0)
Accumulated other comprehensive income:
Prior service cost (credit)	1.2	1.1
Net actuarial loss (gain)	34.8	22.8
Other Postretirement Benefit Plans, Defined Benefit [Member]
Assets and liabilities:
Liability - current	0	0
Liability - long term	(0.2)	(0.3)
Accumulated other comprehensive income:
Prior service cost (credit)	0	0
Net actuarial loss (gain)	$ 0	$ 0