Long-Term Debt - Summary of Long-Term Debt (Details) - USD ($) $ in Millions			6 Months Ended	12 Months Ended
		Feb. 23, 2018	Jun. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity			$ 143.6
Senior Notes [Abstract]
Other			3.0	$ 3.8
Less unamortized debt issuance costs	[1]		(16.0)	(18.4)
Total long-term debt			1,324.8	1,211.3
Less current portion of long-term debt			2.1	1.8
Total long-term debt, excluding current portion			1,322.7	1,209.5
Revolving Credit Facility
Debt Instrument [Line Items]
Maturity date		Feb. 23, 2023
Long-term Line of Credit			$ 110.3	$ 0.0
Senior Notes [Abstract]
Weighted average interest rate			2.80%	4.30%
7.625% Notes
Summary of Long-term debt
Borrowings under Notes	[2]		$ 350.9	$ 351.1
Senior Notes [Abstract]
Fixed rate			7.625%	7.625%
Effective interest rate			8.10%	8.10%
Notes Due April 2023 at Fixed Rate of 7.75% Interest Payments
Summary of Long-term debt
Borrowings under Notes			$ 325.0	$ 325.0
Senior Notes [Abstract]
Fixed rate			7.75%	7.75%
Effective interest rate			8.10%	8.10%
Notes Due January Two Thousand Twenty One at Fixed Rated Eleven Point Five Percentage Interest Payments [Member]
Summary of Long-term debt
Borrowings under Notes			$ 550.0	$ 550.0
Capital Lease Obligations
Senior Notes [Abstract]
Finance lease obligations, at various interest rates, interest and monthly principal payments			3.9	2.7
Less unamortized discounts
Senior Notes [Abstract]
Less unamortized discounts			$ (2.3)	$ (2.9)
Notes due April twenty twenty-five at Eleven percent interest payments [Member]
Senior Notes [Abstract]
Fixed rate			11.00%	11.00%
Effective interest rate			11.30%	11.20%
Interest Expense | Fair Value Hedging
Senior Notes [Abstract]
Liabilities, fair value adjustment			$ 0.9	$ 1.1

[1] Deferred debt issuance costs are being amortized by the effective interest rate method over the lives of the related debt instruments. These amounts are net of accumulated amortization of $18.1 million and $15.7 million at June 30, 2020 and December 31, 2019, respectively.

[2] The balance includes a fair value interest rate hedge adjustment, which increased the debt balance by $0.9 million and $1.1 million as of June 30, 2020 and December 31, 2019, respectively.