Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Accumulated balances for each classification of comprehensive income (loss)
Balance at the beginning of the period	$ (43.7)	$ (48.0)	$ (35.5)	$ (45.0)
Other comprehensive income (loss) before reclassifications	11.5	4.7	1.6	0.3
Amounts reclassified from accumulated other comprehensive loss	1.4	1.2	4.0	3.5
Income tax expense	(0.6)	(0.5)	(1.5)	(1.4)
Net Other comprehensive income (loss)	12.3	5.5	4.1	2.4
Balance at the end of the period	(31.4)	(42.6)	(31.4)	(42.6)
Accrued post-retirement benefit liability
Accumulated balances for each classification of comprehensive income (loss)
Balance at the beginning of the period	(31.7)	(39.1)	(34.1)	(40.7)
Other comprehensive income (loss) before reclassifications			0.5
Amounts reclassified from accumulated other comprehensive loss	1.5	1.3	4.4	3.9
Income tax expense	(0.6)	(0.5)	(1.6)	(1.5)
Net Other comprehensive income (loss)	0.9	0.8	3.3	2.4
Balance at the end of the period	(30.8)	(38.3)	(30.8)	(38.3)
Foreign currency translation
Accumulated balances for each classification of comprehensive income (loss)
Balance at the beginning of the period	(13.1)	(10.3)	(2.7)	(5.9)
Other comprehensive income (loss) before reclassifications	11.5	4.7	1.1	0.3
Net Other comprehensive income (loss)	11.5	4.7	1.1	0.3
Balance at the end of the period	(1.6)	(5.6)	(1.6)	(5.6)
Hedging activities
Accumulated balances for each classification of comprehensive income (loss)
Balance at the beginning of the period	1.1	1.4	1.3	1.6
Amounts reclassified from accumulated other comprehensive loss	(0.1)	(0.1)	(0.4)	(0.4)
Income tax expense			0.1	0.1
Net Other comprehensive income (loss)	(0.1)	(0.1)	(0.3)	(0.3)
Balance at the end of the period	$ 1.0	$ 1.3	$ 1.0	$ 1.3