Restricted cash - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025	Dec. 31, 2025
Restricted Cash and Cash Equivalent Item [Line Items]
Restricted cash	$ 14,598		$ 14,598		$ 22,493
Guarantor obligations	58,900		58,900		58,900
Interest income	2,108	$ 1,131	5,792	$ 2,531
Surety bond cash collateral
Restricted Cash and Cash Equivalent Item [Line Items]
Restricted cash	14,500		14,500		$ 22,400
Restricted Cash
Restricted Cash and Cash Equivalent Item [Line Items]
Interest income	100	$ 300	400	$ 800
Surety bond, Hycroft Mine financial requirements
Restricted Cash and Cash Equivalent Item [Line Items]
Guarantor obligations	58,300		58,300
Surety Bond, Hycroft Mine financial requirements, water well field and exploration
Restricted Cash and Cash Equivalent Item [Line Items]
Guarantor obligations	$ 600		$ 600