Other Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Other Liabilities Disclosure [Abstract]
Subsidence Liability	$ 107,253	$ 88,259
Accrued Compensation and Benefits	60,057	54,138
Accrued Other Taxes	43,458	6,973
Other	52,473	31,928
Current Portion of Long-Term Liabilities:
Asset Retirement Obligations	41,255	35,554
Pneumoconiosis Benefits	23,378	16,389
Postretirement Benefits Other than Pensions	22,045	17,887
Workers' Compensation	17,837	11,056
Total Other Accrued Liabilities	$ 367,756	$ 262,184