Other Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Other Liabilities Disclosure [Abstract]
Subsidence Liability	$ 105,322	$ 96,623
Accrued Compensation and Benefits	73,763	67,893
Accrued Other Taxes	12,276	10,551
Deferred Revenue	9,517	966
Accrued Interest	6,283	7,942
Other	10,457	10,427
Current Portion of Long-Term Liabilities:
Asset Retirement Obligations	28,571	29,644
Postretirement Benefits Other than Pensions	19,327	22,436
Pneumoconiosis Benefits	15,071	12,723
Workers' Compensation	10,019	10,451
Total Other Accrued Liabilities	$ 290,606	$ 269,656