Consolidated Statements of Comprehensive Income (Loss) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net income (loss)	$ 75.6	$ (54.7)	$ 11.2
Other comprehensive income (loss), net of tax:
Foreign currency translation loss	(0.1)	(0.1)	0
Defined benefit plans:
Net (loss) gain arising from remeasurement during the period, net of tax of ($25.0), $30.7, ($5.1)	(45.4)	56.8	(9.2)
Net prior service credit, net of tax of $6.1	0	11.3	0
Amortization of prior service benefits included in net income (loss), net of tax of ($5.4), ($5.2), ($4.8)	(9.8)	(8.7)	(8.3)
Amortization of net actuarial loss included in net income (loss), net of tax of $8.0, $10.1, $9.5	14.7	17.5	16.7
Reclassification adjustment for curtailment gain included in net income (loss), net of tax of ($0.2)	0	(0.4)	0
Total other comprehensive (loss) income, net of tax	(40.6)	76.4	(0.8)
Total comprehensive income	$ 35.0	$ 21.7	$ 10.4