Workers' Compensation Expense (Occupational Disease Costs Activity and Assumptions) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Self Insurance Reserve [Roll Forward]
Service cost	$ 5,991	$ 7,796	$ 7,564
Interest cost	$ 4,610	$ 4,439	5,115
Discount Rate
Self Insurance Reserve [Roll Forward]
Discount rate	0.0521	0.0282
Occupational disease
Self Insurance Reserve [Roll Forward]
Beginning of period	$ 167,585	$ 183,001
Service cost	5,991	7,796
Interest cost	4,610	4,439
Actuarial (gain) loss	(48,859)	(21,245)
Benefit and administrative payments	(9,319)	(6,406)
End of period	$ 120,008	$ 167,585	$ 183,001