Lease Obligations - Future Minimum Lease Commitments (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Finance Leases
2022	$ 143,400
2023	90,100
2024	50,000
2025	19,600
2026	1,500
Thereafter	0
Total minimum lease payments	304,600
Less amounts representing interest	(11,600)
Total lease obligations, net of interest	293,000
Less current portion	135,800
Long-term portion of lease obligations, net of interest	$ 157,200
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Current portion of long-term debt, including finance leases
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Long-term debt, including finance leases
Operating Leases
2022	$ 104,600
2023	65,500
2024	49,600
2025	32,500
2026	18,200
Thereafter	17,100
Total minimum lease payments	287,500
Less amounts representing interest	(15,700)
Total lease obligations, net of interest	271,800
Less current portion	95,426	$ 72,481
Long-term portion of lease obligations, net of interest	$ 176,378	$ 116,506