Long-Term Debt and Finance Leases - Summary (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022	Dec. 20, 2021
Long-Term Debt and Capital Leases
Available borrowing capacity	$ 86.4
Long-term debt	871.9	$ 726.7
Finance lease obligations	$ 21.2	$ 20.6
Finance Lease, Liability, Statement of Financial Position	Long-term portion, Less current portion	Long-term portion, Less current portion
Total long-term debt and finance lease obligations	$ 893.1	$ 747.3
Debt issuance costs, net	(4.0)	(4.6)
Sub-total	889.1	742.7
Less current portion	(17.2)	(17.7)
Long-term portion	$ 871.9	725.0
Term B Loans
Long-Term Debt and Capital Leases
Effective interest rate (as a percent)	8.39%
Long-term debt	$ 712.9	717.7
Debt issuance costs, net	(3.1)	(3.5)
Net discount	4.3	5.0
Revolving Credit Facility
Long-Term Debt and Capital Leases
Available borrowing capacity	$ 86.4
Effective interest rate (as a percent)	8.13%
Long-term debt	$ 159.0	9.0
Debt issuance costs, net	(0.9)	$ (1.1)
Maximum borrowing capacity	250.0		$ 250.0
Outstanding letters of credit	$ 4.6