Lease Obligations - Schedule of Future Minimum Lease Commitments (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Finance Leases
2021, remaining three months	$ 43,600
2022	133,400
2023	81,800
2024	41,700
2025	12,400
Thereafter	1,000
Total minimum lease payments	313,900
Less amounts representing interest	(12,200)
Total lease obligations, net of interest	301,700
Less current portion	140,800
Long-term portion of lease obligations, net of interest	$ 160,900
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Current portion of long-term debt, including finance leases
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Long-term debt, including finance leases
Operating Leases
2021, remaining three months	$ 31,500
2022	73,300
2023	43,400
2024	30,600
2025	19,100
Thereafter	25,000
Total minimum lease payments	222,900
Less amounts representing interest	(13,100)
Total lease obligations, net of interest	209,800
Less current portion	80,155	$ 72,481
Long-term portion of lease obligations, net of interest	$ 129,568	$ 116,506