Property, Plant and Equipment (Details) - USD ($) $ in Thousands		Sep. 30, 2024	Dec. 31, 2023
Property, plant and equipment
Operational Mining Properties Gross		$ 1,420,316	$ 1,358,189
Mineral Interest		833,564	809,912
Land		9,000	8,318
Buildings and Improvements, Gross	[1]	1,479,018	947,435
Property, Plant and Equipment, Gross		3,912,154	3,736,719
Accumulated depreciation and amortization	[2]	(2,152,700)	(2,048,431)
Construction in Progress, Gross	[3]	170,256	612,865
Property, plant and equipment and mining properties, net		$ 1,759,454	$ 1,688,288

[1] Includes $149.2 million and $127.6 million associated with facilities and equipment assets under finance leases at September 30, 2024 and December 31, 2023, respectively.

[2] Includes $54.1 million and $37.6 million of accumulated amortization related to assets under finance leases at September 30, 2024 and December 31, 2023, respectively.

[3] Includes $471.7 million of construction costs related to the Rochester expansion project at December 31, 2023.