Property, Plant and Equipment (Details) - USD ($) $ in Thousands		Sep. 30, 2025	Dec. 31, 2024
Property, plant and equipment
Operational Mining Properties Gross		$ 1,625,944	$ 1,502,457
Mineral Interest		1,683,564	833,564
Land		9,961	9,000
Buildings and Improvements, Gross	[1]	1,725,654	1,517,170
Property, Plant and Equipment, Gross		5,175,711	4,007,923
Accumulated depreciation and amortization	[2]	(2,403,444)	(2,190,307)
Construction in Progress, Gross		130,588	145,732
Property, plant and equipment and mining properties, net		$ 2,772,267	$ 1,817,616

[1] Includes $151.4 million and $170.1 million associated with facilities and equipment assets under finance leases at September 30, 2025 and December 31, 2024, respectively.

[2] Includes $81.5 million and $63.3 million of accumulated amortization related to assets under finance leases at September 30, 2025 and December 31, 2024, respectively.