Recapitalization Transaction - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands				12 Months Ended
		May 29, 2020	May 28, 2020	Dec. 31, 2021	Dec. 31, 2020		Jan. 19, 2021	Oct. 06, 2020	Jul. 01, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Cash		$ 68,900		$ 12,342	$ 56,363
Common stock, shares issued (in shares)		50,160,042		60,433,395	59,901,306
Common stock, shares outstanding (in shares)		50,160,042	2,900,000	60,433,395	59,901,306
Percentage of stock issued to creditors		1.00%
Proceeds from sale of royalty to Sprott		$ 30,000		$ 0	$ 30,000
Smelter royalty obligation, percentage		1.50%
Restricted cash				34,293	$ 39,677
Common Stock
Business Acquisition [Line Items]
Common shares issued (in shares)	[1]				101
Exchange of Seller's 1.25 Lien Notes for HYMC common stock
Business Acquisition [Line Items]
Debt converted				0	$ 48,459
Debt conversion, number of shares issued		4,845,920
Exchange of Seller's 1.5 Lien Notes for HYMC common stock
Business Acquisition [Line Items]
Debt converted				$ 0	$ 160,254
Debt conversion, number of shares issued		16,025,316
2.0 Lien Notes to common stock
Business Acquisition [Line Items]
Common stock, shares issued (in shares)			2,900,000
Debt conversion, number of shares issued			132,800,000
Transaction consideration (in shares)			15,100,000
Stock surrendered (in shares)			3,500,000	3,511,820
Notes payable | Conversion of 1.25 Lien Notes to New Subordinated Notes
Business Acquisition [Line Items]
Debt conversion, amount		$ 80,000
First Lien Agreement | Notes payable
Business Acquisition [Line Items]
Amount of debt repurchased		125,500
Promissory Note | Notes payable
Business Acquisition [Line Items]
Amount of debt repurchased		6,900
1.25 Lien Notes | Notes payable | Exchange of Seller's 1.25 Lien Notes for HYMC common stock
Business Acquisition [Line Items]
Debt converted		48,500
1.25 Lien Notes | Notes payable | Conversion of 1.25 Lien Notes to New Subordinated Notes
Business Acquisition [Line Items]
Debt converted		80,000
1.5 Lien Notes | Notes payable | Exchange of Seller's 1.5 Lien Notes for HYMC common stock
Business Acquisition [Line Items]
Debt converted		$ 145,700
Repurchase price (percent)		110.00%
2.0 Lien Notes | Notes payable | 2.0 Lien Notes to common stock
Business Acquisition [Line Items]
Debt converted		$ 221,300	$ 221,300
The 1.25 Lien notes | Conversion of 1.25 Lien Notes to New Subordinated Notes
Business Acquisition [Line Items]
Debt converted		80,000
Sprott credit agreement, noncurrent portion
Business Acquisition [Line Items]
Stated amount of borrowing		$ 70,000
Debt, original issue discount (percent)		2.00%
Sprott credit agreement, noncurrent portion | Credit facility
Business Acquisition [Line Items]
Stated amount of borrowing		$ 70,000
Debt, original issue discount (percent)		2.00%
SPAC Trust
Business Acquisition [Line Items]
Number of shares issued (in shares)		1,200,000
Proceeds from private placement and forward purchase contract		$ 10,400
Cantor Fitzgerald & Co.
Business Acquisition [Line Items]
Cash payment to underwriter		2,500
Payment for stock that had not been redeemed		$ 2,000
Cantor Fitzgerald & Co. | Common Stock
Business Acquisition [Line Items]
Number of shares issued (in shares)		40,000.00
Holders of Seller's phantom unit
Business Acquisition [Line Items]
Payment of deferred additional interest		$ 1,800
Payment of transaction costs		7,400
Seller
Business Acquisition [Line Items]
Restricted cash		$ 2,300
Warrants, exercise price 11.50
Business Acquisition [Line Items]
Outstanding warrants (in shares)		34,289,999
Warrants, exercise price (in dollars per share)		$ 11.50
Number of securities called by warrants (in shares)		34,289,999
Warrants, exercise price 44.82
Business Acquisition [Line Items]
Outstanding warrants (in shares)		12,721,623
Warrants, exercise price (in dollars per share)		$ 44.82
Number of securities called by warrants (in shares)		3,210,213
5-Year Public Warrants
Business Acquisition [Line Items]
Outstanding warrants (in shares)		7,740,000		24,811,068	24,401,483					20,800,000
Warrants, exercise price (in dollars per share)		$ 11.50		$ 11.50				$ 11.50
Number of securities called by warrants (in shares)								3,249,999
Number of securities called by each warrant (in shares)								1
5-Year Public Warrants | SPAC Trust
Business Acquisition [Line Items]
Outstanding warrants (in shares)		27,900,000
Warrants, exercise price (in dollars per share)		$ 11.50
Seller Warrants
Business Acquisition [Line Items]
Outstanding warrants (in shares)		12,700,000		12,721,901	12,721,901				12,700,000	12,721,901
Warrants, exercise price (in dollars per share)				$ 40.31	$ 41.26		$ 40.31		$ 44.82
Number of securities called by warrants (in shares)				3,569,129	3,487,168		3,569,051		3,210,213
Number of securities called by each warrant (in shares)				0.28055	0.27411		0.28055		0.2523
Private placement
Business Acquisition [Line Items]
Number of shares issued (in shares)		7,600,000
Offering price (in dollars per share)		$ 10.00
Proceeds from private placement and forward purchase contract		$ 76,000		$ 0	$ 75,963
Private placement | Common Stock
Business Acquisition [Line Items]
Common shares issued (in shares)	[1]				7,596,309
Private placement | 5-Year Public Warrants
Business Acquisition [Line Items]
Warrants, exercise price (in dollars per share)		$ 11.50
Number of securities called by warrants (in shares)		3,250,000
Number of warrants issued (in shares)		3,250,000
Forward Purchase Contract
Business Acquisition [Line Items]
Number of securities called by warrants (in shares)		2,500,000
Number of shares issued (in shares)		3,125,000
Proceeds from private placement and forward purchase contract		$ 25,000
Number of shares converted		5,200,000
Forward Purchase Contract | Class B common stock
Business Acquisition [Line Items]
Shares surrendered as transaction consideration (in shares)		3,500,000
Forward Purchase Contract | 5-Year Public Warrants
Business Acquisition [Line Items]
Warrants, exercise price (in dollars per share)		$ 11.50
Number of warrants issued (in shares)		2,500,000
Sprott credit agreement, noncurrent portion | Common Stock
Business Acquisition [Line Items]
Common shares issued (in shares)		496,634			496,634	[1]
MUDS
Business Acquisition [Line Items]
Common stock, shares issued (in shares)		50,160,042
Common stock, shares outstanding (in shares)		50,160,042
Cash acquired		$ 10,400
Liabilities assumed		$ 6,900

[1] Retroactively restated January 1, 2020 and March 31, 2020 for the reverse recapitalization as described in Note 2 - Summary of Significant Accounting Policies, and the restated reclassification of the Company's 5-Year Private Warrants as described in Note 12 - Warrant Liabilities.