Other Events (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Other Commercial Events [Line Items]
Interest in unincorporated joint venture project	50.00%
Contribution to construction and development of joint venture	$ 17.0	$ 59.0	$ 72.0
Mine Reclamation and Closing Liability, Noncurrent	5.7
Millennium Mine
Other Commercial Events [Line Items]
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax	26.1
Wilkie Creek Mine
Other Commercial Events [Line Items]
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax	$ 24.6