Long-term Debt - Summary of Long-term Debt (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015	Nov. 30, 2015	Feb. 28, 2015
Debt Instrument [Line Items]
Total senior debt	$ 90.6	$ 91.8	$ 93.1
Total senior secured notes	450.0	449.4	449.4	$ 448.2
Convertible subordinated debentures, bearing interest at 4.0625% per annum, interest payments due in June and December, maturing in December 2039	84.8	84.8	84.8	99.4
Total convertible subordinated notes	84.8	84.8	84.8
Capital lease, payable in monthly installments, maturing in March 2017	0.2	0.3	0.4
Total other debt	0.2	13.0	13.1
Total debt, net of deferred financing costs	625.6	639.0	640.4
Less: Amounts due within one year	(5.2)	(5.3)	(5.3)	$ (5.2)
Total long-term debt, net of deferred financing costs	620.4	633.7	635.1
Term Loan [Member]
Debt Instrument [Line Items]
Total senior debt	91.3	92.5	93.8
Unamortized deferred financing costs	(0.7)	(0.7)	(0.7)
7.125% Second-Priority Senior Secured Notes [Member]
Debt Instrument [Line Items]
Unamortized deferred financing costs	(10.0)	(10.6)	(10.6)
Total senior secured notes	460.0	460.0	460.0
2.25% Convertible Subordinated Debentures [Member]
Debt Instrument [Line Items]
Convertible subordinated debentures, bearing interest at 2.25% per annum, interest payments due in May and November, maturing in November 2024	0.2	0.2	0.2
4 1/16% Convertible Subordinated Debentures [Member]
Debt Instrument [Line Items]
Convertible subordinated debentures, bearing interest at 4.0625% per annum, interest payments due in June and December, maturing in December 2039	84.6	84.6	84.6
Delayed Draw Term Loan [Member]
Debt Instrument [Line Items]
Delayed draw term loan	0.0	13.0	13.0
Other Debt [Member]
Debt Instrument [Line Items]
Unamortized deferred financing costs	$ 0.0	$ (0.3)	$ (0.3)