Commitments and Contingencies	3 Months Ended
Mar. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies (a) General Estimated losses from loss contingencies are accrued by a charge to income when information available indicates that it is probable that an asset has been impaired or a liability has been incurred and the amount of the loss can be reasonably estimated. If a loss contingency is not probable or reasonably estimable, disclosure of the loss contingency is made in the Condensed Consolidated Financial Statements when it is at least reasonably possible that a loss may be incurred and that the loss could be material. (b) Commitments and Contingencies Commitments The Company leases coal mining and other equipment under long-term financing and operating leases with varying terms. Refer to Note 9 for further information on leases. In addition, the Company leases mineral interests and surface rights from land owners under various terms and royalty rates. Coal royalty expense was $23,946 and $5,973 for the three months ended March 31, 2019 and 2018. Refer to Note 9 for further information on leases. Other Commitments The Company has obligations under certain coal purchase agreements that contain minimum quantities to be purchased in the remainder of 2019 and 2020 totaling an estimated $295,667 and $13,090, respectively, which includes an estimated $74,970 in 2019 related to contractually committed variable priced tons from vendors with historical performance resulting in less than 20% of the committed tonnage being delivered. The Company has obligations under certain coal transportation agreements that contain minimum quantities to be shipped in 2019 and 2020 totaling $3,450 and $15,473, respectively. The Company also has obligations under certain equipment purchase agreements that contain minimum quantities to be purchased in the remainder of 2019 and 2020, totaling $40,262 and $283, respectively. Contingencies Extensive regulation of the impacts of mining on the environment and of maintaining workplace safety has had and is expected to continue to have a significant effect on the Company’s costs of production and results of operations. Further regulations, legislation or litigation in these areas may also cause the Company’s sales or profitability to decline by increasing costs or by hindering the Company’s ability to continue mining at existing operations or to permit new operations. During the normal course of business, contract-related matters arise between the Company and its customers. When a loss related to such matters is considered probable and can reasonably be estimated, the Company records a liability. Per terms of the Back-to-Back Coal Supply Agreements, the Company is required to purchase and sell coal in the remainder of 2019 and 2020 totaling $12,205 and $9,175, respectively. For the three months ended March 31, 2019, the Company purchased and sold 369 tons, totaling $3,881, under the Back-to-Back Coal Supply Agreements. For the three months ended March 31, 2018, the Company purchased and sold 3,164 tons, totaling $33,749 under the Back-to-Back Coal Supply Agreements. In October 2018, the State of Wyoming Department of Revenue invoiced Blackjewel for approximately $7,800 in severance taxes owed by Blackjewel in connection with the Wyoming properties it previously acquired from the Company. The transfer of mining permits associated with these properties is pending. In connection with this invoice, the Department purported to assert liens over Contura Coal West, LLC, one of the Company’s subsidiaries. The Company believes that, in light of the sale of the Wyoming properties to Blackjewel, neither the Company nor its subsidiary is obligated to pay these severance taxes. On October 28, 2018, Blackjewel entered into a payment plan agreement with the State of Wyoming Department of Revenue to address the severance taxes owed by Blackjewel. Future Federal Income Tax Refunds As of March 31, 2019, the Company has recorded $68,774 of federal income tax receivable and $68,774 of federal deferred tax asset related to AMT Credits. In addition, the Company has recorded a non-current federal income tax receivable of $43,770 related to an NOL carryback claim. Because the federal government was a creditor in the Alpha Natural Resources, Inc. (“Predecessor Alpha”) bankruptcy proceedings, it is possible that the federal government could withhold some or all of the tax refund attributable to the NOL carryback claim and the refundable AMT Credits and assert a right to setoff the tax refund and refundable credits against its prepetition bankruptcy claims. (c) Guarantees and Financial Instruments with Off-Balance Sheet Risk In the normal course of business, the Company is a party to certain guarantees and financial instruments with off-balance sheet risk, such as bank letters of credit, performance or surety bonds, and other guarantees and indemnities related to the obligations of affiliated entities which are not reflected in the Company’s Condensed Consolidated Balance Sheets. However, the underlying liabilities that they secure, such as asset retirement obligations, workers’ compensation liabilities, and royalty obligations, are reflected in the Company’s Condensed Consolidated Balance Sheets. The Company is required to provide financial assurance in order to perform the post-mining reclamation required by its mining permits, pay its federal production royalties, pay workers’ compensation claims under workers’ compensation laws in various states, pay federal black lung benefits, and perform certain other obligations. In order to provide the required financial assurance, the Company generally uses surety bonds for post-mining reclamation and workers’ compensation obligations. The Company can also use bank letters of credit to collateralize certain obligations. As of March 31, 2019, the Company had outstanding surety bonds with a total face amount of $579,934 to secure various obligations and commitments, including $237,310 related to the PRB. To secure the Company’s reclamation-related obligations, the Company currently has $125,348 of collateral supporting these obligations. Once the permits associated with the PRB Transaction have been transferred, the Company estimates approximately $9,100 comprised of short-term restricted cash and short-term deposits will be returned to operating cash. Amounts included in restricted cash represent cash deposits that are restricted as to withdrawal as required by certain agreements entered into by the Company and provide collateral in the amounts of $95,506, $31,160, $85,455, $28,155, and $2,833 as of March 31, 2019 for securing the Company’s obligations under certain worker’s compensation, black lung, reclamation-related obligations, general liabilities, and financial guarantees, respectively, which have been written on the Company’s behalf. Additionally, the Company has $9,686 of short-term restricted cash held in escrow related to the Company’s contingent revenue obligation. Refer to Note 11 for further information regarding the contingent revenue obligation. The Company’s restricted cash is primarily invested in interest bearing accounts. This restricted cash is classified as both short-term and long-term on the Company’s Condensed Consolidated Balance Sheets. Amounts included in restricted investments consist of certificates of deposit, corporate bonds, and U.S. treasury bills that are restricted as to withdrawal as required by certain agreements entered into by the Company and provide collateral in the amounts of $1,888 and $28,438 as of March 31, 2019 for securing the Company’s obligations under certain worker’s compensation and reclamation-related obligations, respectively, which have been written on the Company’s behalf. These restricted investments are classified as long-term on the Company’s Condensed Consolidated Balance Sheets. Deposits represent cash deposits held at third parties as required by certain agreements entered into by the Company to provide cash collateral. At March 31, 2019, the Company had cash collateral in the form of deposits in the amounts of $11,456 and $3,156 to secure the Company’s obligations under reclamation-related obligations and various other operating agreements, respectively. These deposits are classified as both short-term and long-term on the Company’s Condensed Consolidated Balance Sheets. As of March 31, 2019, the Company had real property collateralizing $26,749 of reclamation bonds. The Company meets frequently with its surety providers and has discussions with certain providers regarding the extent of and the terms of their participation in the program. These discussions may cause the Company to shift surety bonds between providers or to alter the terms of their participation in our program. To the extent that surety bonds become unavailable or the Company’s surety bond providers require additional collateral, the Company would seek to secure its obligations with letters of credit, cash deposits or other suitable forms of collateral. The Company’s failure to maintain, or inability to acquire, surety bonds or to provide a suitable alternative would have a material adverse effect on its liquidity. These failures could result from a variety of factors including lack of availability, higher cost or unfavorable market terms of new surety bonds, and the exercise by third-party surety bond issuers of their right to refuse to renew the surety. WVDEP Settlement Agreement On November 6, 2018, Contura, the Alpha Companies and the West Virginia Department of Environmental Protection (the “WVDEP”) entered into a binding term sheet agreement (the “Term Sheet”) to resolve certain issues related to the issuance of the Dividend under the Permitting and Reclamation Plan Settlement Agreement for the State of West Virginia dated as of July 12, 2016 (amended by the First Amendment dated July 25, 2016 and by the Second Amendment dated October 23, 2017, the “Amended Settlement Agreement”). Pursuant to the Term Sheet, the WVDEP provided its consent to the Dividend. The Term Sheet also provides for the extension of the first lien mortgage and deed of trust in an office and associated real estate in Julian, West Virginia previously granted by ANR to the WVDEP to secure ANR’s obligations under the Amended Settlement Agreement until ANR and Contura complete the payments required under the Reclamation Funding Agreement dated as of July 12, 2016, by and among, ANR, Contura, WVDEP, and the regulatory agencies of Illinois, Tennessee, Kentucky and Virginia (the “Amended Reclamation Funding Agreement”). Contura is also obligated under the Term Sheet to continue to hold subject to the applicable Deposit Account Control Agreements referenced in the Amendment of Agreements dated as of October 23, 2017 by and between Contura and the WVDEP approximately $2,800 of certain cash collateral until ANR and Contura complete the payments required of them under the Amended Reclamation Funding Agreement. Concurrent with ANR’s issuance of the Dividend on November 8, 2018, pursuant to the Term Sheet, Contura posted cash collateral with WVDEP in the amount of $9,000, to secure Contura’s and ANR’s payment obligations under the Amended Reclamation Funding Agreement and the Amended Settlement Agreement (the “Payment Obligations”) until a performance bond was issued as described in the following sentence. During the fourth quarter of 2018, as required under the Term Sheet, Contura issued a performance bond to WVDEP in the amount of $35,000 to secure the Payment Obligations. The amount of such performance bond will decrease on a dollar to dollar basis after the Payment Obligations fall below $35,000. Upon issuance of the performance bond, the $9,000 cash collateral was released to Contura within the first quarter of 2019. Letters of Credit As of March 31, 2019, the Company had $28,700 letters of credit outstanding under the Amended and Restated Asset-Based Revolving Credit Agreement. Additionally, as of March 31, 2019, the Company had $135,746 letters of credit outstanding under the Amended and Restated Letter of Credit Agreement dated November 9, 2018 between ANR, Inc. and Citibank, N.A. and $11,876 letters of credit outstanding under the Credit and Security Agreement dated June 30, 2017, and related amendments, between ANR, Inc. and First Tennessee Bank National Association. (d) Legal Proceedings The Company is party to legal proceedings from time to time. These proceedings, as well as governmental examinations, could involve various business units and a variety of claims including, but not limited to, contract disputes, personal injury claims, property damage claims (including those resulting from blasting, trucking and flooding), environmental and safety issues, securities-related matters and employment matters. While some legal matters may specify the damages claimed by the plaintiffs, many seek an unquantified amount of damages. Even when the amount of damages claimed against the Company or its subsidiaries is stated, (i) the claimed amount may be exaggerated or unsupported; (ii) the claim may be based on a novel legal theory or involve a large number of parties; (iii) there may be uncertainty as to the likelihood of a class being certified or the ultimate size of the class; (iv) there may be uncertainty as to the outcome of pending appeals or motions; and/or (v) there may be significant factual issues to be resolved. As a result, if such legal matters arise in the future, the Company may be unable to estimate a range of possible loss for matters that have not yet progressed sufficiently through discovery and development of important factual information and legal issues. The Company records accruals based on an estimate of the ultimate outcome of these matters, but these estimates can be difficult to determine and involve significant judgment.

Commitments and Contingencies

(a) General

Estimated losses from loss contingencies are accrued by a charge to income when information available indicates that it is probable that an asset has been impaired or a liability has been incurred and the amount of the loss can be reasonably estimated.

If a loss contingency is not probable or reasonably estimable, disclosure of the loss contingency is made in the Condensed Consolidated Financial Statements when it is at least reasonably possible that a loss may be incurred and that the loss could be material.

(b) Commitments and Contingencies

Commitments

The Company leases coal mining and other equipment under long-term financing and operating leases with varying terms. Refer to Note 9 for further information on leases. In addition, the Company leases mineral interests and surface rights from land owners under various terms and royalty rates.

Coal royalty expense was $23,946 and $5,973 for the three months ended March 31, 2019 and 2018. Refer to Note 9 for further information on leases.

Other Commitments

The Company has obligations under certain coal purchase agreements that contain minimum quantities to be purchased in the remainder of 2019 and 2020 totaling an estimated $295,667 and $13,090, respectively, which includes an estimated $74,970 in 2019 related to contractually committed variable priced tons from vendors with historical performance resulting in less than 20% of the committed tonnage being delivered. The Company has obligations under certain coal transportation agreements that contain minimum quantities to be shipped in 2019 and 2020 totaling $3,450 and $15,473, respectively. The Company also has obligations under certain equipment purchase agreements that contain minimum quantities to be purchased in the remainder of 2019 and 2020, totaling $40,262 and $283, respectively.

Contingencies

Extensive regulation of the impacts of mining on the environment and of maintaining workplace safety has had and is expected to continue to have a significant effect on the Company’s costs of production and results of operations. Further regulations, legislation or litigation in these areas may also cause the Company’s sales or profitability to decline by increasing costs or by hindering the Company’s ability to continue mining at existing operations or to permit new operations.

During the normal course of business, contract-related matters arise between the Company and its customers. When a loss related to such matters is considered probable and can reasonably be estimated, the Company records a liability.

Per terms of the Back-to-Back Coal Supply Agreements, the Company is required to purchase and sell coal in the remainder of 2019 and 2020 totaling $12,205 and $9,175, respectively. For the three months ended March 31, 2019, the Company purchased and sold 369 tons, totaling $3,881, under the Back-to-Back Coal Supply Agreements. For the three months ended March 31, 2018, the Company purchased and sold 3,164 tons, totaling $33,749 under the Back-to-Back Coal Supply Agreements.

In October 2018, the State of Wyoming Department of Revenue invoiced Blackjewel for approximately $7,800 in severance taxes owed by Blackjewel in connection with the Wyoming properties it previously acquired from the Company. The transfer of mining permits associated with these properties is pending. In connection with this invoice, the Department purported to assert liens over Contura Coal West, LLC, one of the Company’s subsidiaries. The Company believes that, in light of the sale of the Wyoming properties to Blackjewel, neither the Company nor its subsidiary is obligated to pay these severance taxes. On October 28, 2018, Blackjewel entered into a payment plan agreement with the State of Wyoming Department of Revenue to address the severance taxes owed by Blackjewel.

Future Federal Income Tax Refunds

As of March 31, 2019, the Company has recorded $68,774 of federal income tax receivable and $68,774 of federal deferred tax asset related to AMT Credits. In addition, the Company has recorded a non-current federal income tax receivable of $43,770 related to an NOL carryback claim. Because the federal government was a creditor in the Alpha Natural Resources, Inc. (“Predecessor Alpha”) bankruptcy proceedings, it is possible that the federal government could withhold some or all of the tax refund attributable to the NOL carryback claim and the refundable AMT Credits and assert a right to setoff the tax refund and refundable credits against its prepetition bankruptcy claims.

In the normal course of business, the Company is a party to certain guarantees and financial instruments with off-balance sheet risk, such as bank letters of credit, performance or surety bonds, and other guarantees and indemnities related to the obligations of affiliated entities which are not reflected in the Company’s Condensed Consolidated Balance Sheets. However, the underlying liabilities that they secure, such as asset retirement obligations, workers’ compensation liabilities, and royalty obligations, are reflected in the Company’s Condensed Consolidated Balance Sheets.

The Company is required to provide financial assurance in order to perform the post-mining reclamation required by its mining permits, pay its federal production royalties, pay workers’ compensation claims under workers’ compensation laws in various states, pay federal black lung benefits, and perform certain other obligations. In order to provide the required financial assurance, the Company generally uses surety bonds for post-mining reclamation and workers’ compensation obligations. The Company can also use bank letters of credit to collateralize certain obligations.

As of March 31, 2019, the Company had outstanding surety bonds with a total face amount of $579,934 to secure various obligations and commitments, including $237,310 related to the PRB. To secure the Company’s reclamation-related obligations, the Company currently has $125,348 of collateral supporting these obligations. Once the permits associated with the PRB Transaction have been transferred, the Company estimates approximately $9,100 comprised of short-term restricted cash and short-term deposits will be returned to operating cash.

Amounts included in restricted cash represent cash deposits that are restricted as to withdrawal as required by certain agreements entered into by the Company and provide collateral in the amounts of $95,506, $31,160, $85,455, $28,155, and $2,833 as of March 31, 2019 for securing the Company’s obligations under certain worker’s compensation, black lung, reclamation-related obligations, general liabilities, and financial guarantees, respectively, which have been written on the Company’s behalf. Additionally, the Company has $9,686 of short-term restricted cash held in escrow related to the Company’s contingent revenue obligation. Refer to Note 11 for further information regarding the contingent revenue obligation. The Company’s restricted cash is primarily invested in interest bearing accounts. This restricted cash is classified as both short-term and long-term on the Company’s Condensed Consolidated Balance Sheets.

Amounts included in restricted investments consist of certificates of deposit, corporate bonds, and U.S. treasury bills that are restricted as to withdrawal as required by certain agreements entered into by the Company and provide collateral in the amounts of $1,888 and $28,438 as of March 31, 2019 for securing the Company’s obligations under certain worker’s compensation and reclamation-related obligations, respectively, which have been written on the Company’s behalf. These restricted investments are classified as long-term on the Company’s Condensed Consolidated Balance Sheets.

Deposits represent cash deposits held at third parties as required by certain agreements entered into by the Company to provide cash collateral. At March 31, 2019, the Company had cash collateral in the form of deposits in the amounts of $11,456 and $3,156 to secure the Company’s obligations under reclamation-related obligations and various other operating agreements, respectively. These deposits are classified as both short-term and long-term on the Company’s Condensed Consolidated Balance Sheets.

As of March 31, 2019, the Company had real property collateralizing $26,749 of reclamation bonds.

The Company meets frequently with its surety providers and has discussions with certain providers regarding the extent of and the terms of their participation in the program. These discussions may cause the Company to shift surety bonds between providers or to alter the terms of their participation in our program. To the extent that surety bonds become unavailable or the Company’s surety bond providers require additional collateral, the Company would seek to secure its obligations with letters of credit, cash deposits or other suitable forms of collateral. The Company’s failure to maintain, or inability to acquire, surety bonds or to provide a suitable alternative would have a material adverse effect on its liquidity. These failures could result from a variety of factors including lack of availability, higher cost or unfavorable market terms of new surety bonds, and the exercise by third-party surety bond issuers of their right to refuse to renew the surety.

WVDEP Settlement Agreement

On November 6, 2018, Contura, the Alpha Companies and the West Virginia Department of Environmental Protection (the “WVDEP”) entered into a binding term sheet agreement (the “Term Sheet”) to resolve certain issues related to the issuance of the Dividend under the Permitting and Reclamation Plan Settlement Agreement for the State of West Virginia dated as of July 12, 2016 (amended by the First Amendment dated July 25, 2016 and by the Second Amendment dated October 23, 2017, the “Amended Settlement Agreement”).

Pursuant to the Term Sheet, the WVDEP provided its consent to the Dividend. The Term Sheet also provides for the extension of the first lien mortgage and deed of trust in an office and associated real estate in Julian, West Virginia previously granted by ANR to the WVDEP to secure ANR’s obligations under the Amended Settlement Agreement until ANR and Contura complete the payments required under the Reclamation Funding Agreement dated as of July 12, 2016, by and among, ANR, Contura, WVDEP, and the regulatory agencies of Illinois, Tennessee, Kentucky and Virginia (the “Amended Reclamation Funding Agreement”). Contura is also obligated under the Term Sheet to continue to hold subject to the applicable Deposit Account Control Agreements referenced in the Amendment of Agreements dated as of October 23, 2017 by and between Contura and the WVDEP approximately $2,800 of certain cash collateral until ANR and Contura complete the payments required of them under the Amended Reclamation Funding Agreement.

Concurrent with ANR’s issuance of the Dividend on November 8, 2018, pursuant to the Term Sheet, Contura posted cash collateral with WVDEP in the amount of $9,000, to secure Contura’s and ANR’s payment obligations under the Amended Reclamation Funding Agreement and the Amended Settlement Agreement (the “Payment Obligations”) until a performance bond was issued as described in the following sentence. During the fourth quarter of 2018, as required under the Term Sheet, Contura issued a performance bond to WVDEP in the amount of $35,000 to secure the Payment Obligations. The amount of such performance bond will decrease on a dollar to dollar basis after the Payment Obligations fall below $35,000. Upon issuance of the performance bond, the $9,000 cash collateral was released to Contura within the first quarter of 2019.

Letters of Credit

As of March 31, 2019, the Company had $28,700 letters of credit outstanding under the Amended and Restated Asset-Based Revolving Credit Agreement. Additionally, as of March 31, 2019, the Company had $135,746 letters of credit outstanding under the Amended and Restated Letter of Credit Agreement dated November 9, 2018 between ANR, Inc. and Citibank, N.A. and $11,876 letters of credit outstanding under the Credit and Security Agreement dated June 30, 2017, and related amendments, between ANR, Inc. and First Tennessee Bank National Association.

(d) Legal Proceedings

The Company is party to legal proceedings from time to time. These proceedings, as well as governmental examinations, could involve various business units and a variety of claims including, but not limited to, contract disputes, personal injury claims, property damage claims (including those resulting from blasting, trucking and flooding), environmental and safety issues, securities-related matters and employment matters. While some legal matters may specify the damages claimed by the plaintiffs, many seek an unquantified amount of damages. Even when the amount of damages claimed against the Company or its subsidiaries is stated, (i) the claimed amount may be exaggerated or unsupported; (ii) the claim may be based on a novel legal theory or involve a large number of parties; (iii) there may be uncertainty as to the likelihood of a class being certified or the ultimate size of the class; (iv) there may be uncertainty as to the outcome of pending appeals or motions; and/or (v) there may be significant factual issues to be resolved. As a result, if such legal matters arise in the future, the Company may be unable to estimate a range of possible loss for matters that have not yet progressed sufficiently through discovery and development of important factual information and legal issues. The Company records accruals based on an estimate of the ultimate outcome of these matters, but these estimates can be difficult to determine and involve significant judgment.