Fixed Assets, Mineral Leaseholds, and Asset Retirement Obligations (Mineral Leaseholds) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fixed Assets And Asset Retirement Obligations [Abstract]
Mineral leaseholds	$ 566,019	$ 566,019
Less: Accumulated depletion	(26,645)	(25,499)
Mineral leaseholds, net of accumulated depletion	$ 539,374	$ 540,520

Carrying amount at the balance sheet date of mineral properties, gross of adjustments.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-SubTopic 10
-Topic 360
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482099/360-10-50-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 932
-SubTopic 360
-Name Accounting Standards Codification
-Section 25
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482479/932-360-25-7

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 932
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482274/932-235-50-4

Name:	us-gaap_MineralPropertiesGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant