| Cover | 12 Months Ended |
| Dec. 31, 2022 | |
| Document Information [Line Items] | |
| Document Type | DEF 14A |
| Amendment Flag | false |
| Entity Information [Line Items] | |
| Entity Registrant Name | Warrior Met Coal, Inc. |
| Entity Central Index Key | 0001691303 |
| Pay vs Performance Disclosure Unit_pure in Millions | 12 Months Ended | ||
| Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($) | |
| Pay vs Performance Disclosure [Table] | |||
| Pay vs Performance [Table Text Block] | PAY VERSUS PERFORMANCE In accordance with rules adopted by the Securities and Exchange Commission pursuant to the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010, we provide the following disclosure regarding executive compensation for our principal executive officer (“PEO”) and Non-PEO ars Year Summary ($)(1) Compensation to PEO ($)(1)(2)(3) Average SCT Non-PEO ($)(1) Average Non-PEO ($)(1)(2)(3) Value of Initial Based on: ($)(4) Net Income ($) (in Adjusted ($)(4) (in TSR Peer 2022 6,508,776 11,156,444 2,363,124 3,440,123 175.72 178.99 641.3 994.2 2021 5,679,932 5,192,986 2,087,322 2,044,041 124.60 157.75 150.9 457.0 2020 4,343,999 4,426,909 1,612,982 1,716,748 102.25 116.44 (35.8 ) 108.3 (1) The PEO for each of 2022, 2021 and 2020 was Walter J. Scheller, III. The non-PEO (2) The amounts shown for Compensation Actually Paid have been calculated in accordance with Item 402(v) of Regulation S-K (3) Compensation Actually Paid reflects the exclusions and inclusions of certain amounts for the PEO and the Non-PEO Year Summary Exclusion of Stock Inclusion of Equity Compensation 2022 6,508,776 (3,453,483 ) 8,101,151 11,156,444 2021 5,679,932 (3,160,870 ) 2,673,924 5,192,986 2020 4,343,999 (2,023,959 ) 2,106,869 4,426,909 Year Average Summary Non-PEO Average Exclusion of Non-PEO Average Inclusion of Equity Values for Non-PEO Average Non-PEO 2022 2,363,124 (1,022,091 ) 2,099,090 3,440,123 2021 2,087,322 (831,457 ) 788,176 2,044,041 2020 1,612,982 (526,416 ) 630,182 1,716,748 The amounts in the Inclusion of Equity Values columns in the tables above are derived from the amounts set forth in the following tables: Year Year-End Change in Change in Total- Inclusion of 2022 7,349,174 267,335 484,642 8,101,151 2021 2,497,465 111,743 64,716 2,673,924 2020 2,128,756 6,251 (28,138 ) 2,106,869 Year Average Year-End for Non-PEO Average Change in Awards for Non-PEO Average Change in for Non-PEO Total-Average for Non-PEO 2022 1,887,371 87,462 124,257 2,099,090 2021 778,192 35,573 (25,589 ) 788,176 2020 552,815 85,209 (7,842 ) 630,182 (4) The Peer Group TSR set forth in this table utilizes the S&P Metals and Mining Index, which we also utilize in the stock performance graph required by Item 201(e) of Regulation S-K (5) We determined Adjusted EBITDA to be the most important financial performance measure used to link Company performance to Compensation Actually Paid to our PEO and Non-PEO | ||
| Company Selected Measure Name | Adjusted EBITDA | ||
| Named Executive Officers, Footnote [Text Block] | The PEO for each of 2022, 2021 and 2020 was Walter J. Scheller, III. The non-PEO | ||
| Peer Group Issuers, Footnote [Text Block] | The Peer Group TSR set forth in this table utilizes the S&P Metals and Mining Index, which we also utilize in the stock performance graph required by Item 201(e) of Regulation S-K | ||
| PEO Total Compensation Amount | $ 6,508,776 | $ 5,679,932 | $ 4,343,999 |
| PEO Actually Paid Compensation Amount | $ 11,156,444 | 5,192,986 | 4,426,909 |
| Adjustment To PEO Compensation, Footnote [Text Block] | Year Summary Exclusion of Stock Inclusion of Equity Compensation 2022 6,508,776 (3,453,483 ) 8,101,151 11,156,444 2021 5,679,932 (3,160,870 ) 2,673,924 5,192,986 2020 4,343,999 (2,023,959 ) 2,106,869 4,426,909 | ||
| Non-PEO NEO Average Total Compensation Amount | $ 2,363,124 | 2,087,322 | 1,612,982 |
| Non-PEO NEO Average Compensation Actually Paid Amount | $ 3,440,123 | 2,044,041 | 1,716,748 |
| Adjustment to Non-PEO NEO Compensation Footnote [Text Block] | Year Average Summary Non-PEO Average Exclusion of Non-PEO Average Inclusion of Equity Values for Non-PEO Average Non-PEO 2022 2,363,124 (1,022,091 ) 2,099,090 3,440,123 2021 2,087,322 (831,457 ) 788,176 2,044,041 2020 1,612,982 (526,416 ) 630,182 1,716,748 | ||
| Compensation Actually Paid vs. Total Shareholder Return [Text Block] | Description of Relationship Between PEO and Other NEO Compensation Actually Paid and Company Total Shareholder Return (“TSR”) The following chart sets forth the relationship between Compensation Actually Paid to our PEO, the average of Compensation Actually Paid to our other NEOs, and the Company’s cumulative TSR over the three most recently completed fiscal years. PEO and Average Non-PEO NEO Compensation Actually Paid Versus Company TSR | ||
| Compensation Actually Paid vs. Net Income [Text Block] | Description of Relationship Between PEO and Other NEO Compensation Actually Paid and Net Income The following chart sets forth the relationship between Compensation Actually Paid to our PEO, the average of Compensation Actually Paid to our other NEOs, and our Net Income during the three most recently completed fiscal years. PEO and Average Non-PEO NEO Compensation Actually Paid Versus Net Income | ||
| Compensation Actually Paid vs. Company Selected Measure [Text Block] | Description of Relationship Between PEO and Other NEO Compensation Actually Paid and Adjusted EBITDA The following chart sets forth the relationship between Compensation Actually Paid to our PEO, the average of Compensation Actually Paid to our other NEOs, and our Adjusted EBITDA during the three most recently completed fiscal years. PEO and Average Non-PEO NEO Compensation Actually Paid Versus Adjusted EBITDA | ||
| Total Shareholder Return Vs Peer Group [Text Block] | Description of Relationship Between Company TSR and Peer Group TSR The following chart compares our cumulative TSR over the three most recently completed fiscal years to that of the S&P Metals & Mining Index over the same period. | ||
| Tabular List [Table Text Block] | Tabular List of Most Important Financial Performance Measures The following table presents the financial performance measures that the Co mpany c onsid Performance Measure Rationale for Use in the Company’s Definition Adjusted EBITDA Adjusted EBITDA is used as a supplemental financial measure by management and by external users of our financial statements, such as investors, industry analysts, lenders and ratings agencies, to assess: (i) our operating performance as compared to the operating performance of other companies in the coal industry, without regard to financing methods, historical cost basis or capital structure; and (ii) the viability of acquisitions and other capital expenditure projects and the returns on investment of various investment opportunities, such as Blue Creek. “Adjusted EBITDA” is a non-GAAP non-cash non-cash non-cash non-cash mark-to-market Capital expenditures This metric reflects management’s focus on operational efficiency. Money spent by the Company on acquiring fixed assets, such as machinery and equipment Cash cost of production per metric ton This metric reflects management’s focus on our key business strategy of maintaining and further improving our low-cost Represents production costs divided by metric tons produced Continuous miner feet of advance This metric reflects management’s focus on operational efficiency. Represents the number of feet the continuous miner advances during a period Longwall feet of advance This metric reflects management’s focus on operational efficiency. Represents the number of feet the longwall advances during a period Metrics tons of production This metric reflects managements focus on maximizing profitable production. Metric tons of metallurgical coal produced from Mine 4 and Mine 7 Safety rate Our dedication to safety is at the core of all of our overall operations as we work to further reduce workplace incidents by focusing on policy awareness and accident prevention. Total reportable incidence rate (TRIR) | ||
| Total Shareholder Return Amount | $ 175.72 | 124.6 | 102.25 |
| Peer Group Total Shareholder Return Amount | 178.99 | 157.75 | 116.44 |
| Net Income (Loss) | $ 641,300,000 | $ 150,900,000 | $ (35,800,000) |
| Company Selected Measure Amount | 994.2 | 457 | 108.3 |
| PEO Name | Walter J. Scheller, III | ||
| Measure [Axis]: 1 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Adjusted EBITDA | ||
| Measure [Axis]: 2 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Capital expenditures | ||
| Measure [Axis]: 3 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Cash cost of production per metric ton | ||
| Measure [Axis]: 4 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Continuous miner feet of advance | ||
| Measure [Axis]: 5 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Longwall feet of advance | ||
| Measure [Axis]: 6 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Metrics tons of production | ||
| Measure [Axis]: 7 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Safety rate | ||
| PEO [Member] | Stock Awards [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | $ (3,453,483) | $ (3,160,870) | $ (2,023,959) |
| PEO [Member] | Equity Values [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 8,101,151 | 2,673,924 | 2,106,869 |
| Year-End Fair Value of Equity Awards Granted During Year That Remained Unvested as of Last Day of Year for PEO | 7,349,174 | 2,497,465 | 2,128,756 |
| Change in Fair Value from Last Day of Prior Year to Last Day of Year of Unvested Equity Awards for PEO | 267,335 | 111,743 | 6,251 |
| Change in Fair Value from Last Day of Prior Year to Vesting Date of Unvested Equity Awards that Vested During Year for PEO | 484,642 | 64,716 | (28,138) |
| Non-PEO NEO [Member] | Stock Awards [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (1,022,091) | (831,457) | (526,416) |
| Non-PEO NEO [Member] | Equity Values [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 2,099,090 | 788,176 | 630,182 |
| Year-End Fair Value of Equity Awards Granted During Year That Remained Unvested as of Last Day of Year for PEO | 1,887,371 | 778,192 | 552,815 |
| Change in Fair Value from Last Day of Prior Year to Last Day of Year of Unvested Equity Awards for PEO | 87,462 | 35,573 | 85,209 |
| Change in Fair Value from Last Day of Prior Year to Vesting Date of Unvested Equity Awards that Vested During Year for PEO | $ 124,257 | $ (25,589) | $ (7,842) |
