Workers Compensation Expense - Worker's compensation expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Accrued Workers' Compensation [Line Items]
Service cost	$ 5,991	$ 7,796	$ 7,564
Interest cost	$ 4,610	$ 4,439	$ 5,115
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Nonoperating Income (Expense)	Nonoperating Income (Expense)	Nonoperating Income (Expense)
Net amortization	$ 628	$ 2,363	$ 1,189
Total workers' compensation expense
Accrued Workers' Compensation [Line Items]
Total workers' compensation expense	7,446	18,523	26,790
Occupational disease
Accrued Workers' Compensation [Line Items]
Service cost	5,991	7,796
Interest cost	4,610	4,439
Net benefit (credit) cost	11,229	14,598	13,868
Traumatic injury claims and assessments
Accrued Workers' Compensation [Line Items]
Traumatic injury claims and assessments	$ (3,783)	$ 3,925	$ 12,922