Defined Benefit Plan, Collateral

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- Definition

Guarantor, Collateral Held Directly or by Third Parties, Amount

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No definition available.

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- Definition

Income Tax Receivable, Operating Loss Carryforwards

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No definition available.

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- Definition

Income Tax Receivable, Operating Loss Carryforwards, Interest

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No definition available.

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- Definition

Other Commitment, to be Paid, after Year Four

+ References

No definition available.

+ Details

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- Definition

The current carrying amount of the liability for the freestanding or embedded guarantor's obligations under the guarantee or each group of similar guarantees.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121555522&loc=d3e12069-110248

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- Definition

Carrying amount as of the balance sheet date of income taxes previously overpaid to tax authorities (such as U.S. Federal, state and local tax authorities) representing refunds of overpayments or recoveries based on agreed-upon resolutions of disputes. Also called income tax refund receivable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(8))
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-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(10))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

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- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Amount of commitment classified as other to be paid in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

No definition available.

+ Details

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- Definition

Amount of commitment classified as other to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

No definition available.

+ Details

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- Definition

Amount of commitment classified as other to be paid in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

No definition available.

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- Definition

Amount of commitment classified as other to be paid in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

No definition available.

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- Definition

Amount of commitment classified as other to be paid in remainder of current fiscal year.

+ References

No definition available.

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- Definition

Amount of purchase arrangement to be paid in fourth fiscal year following current fiscal year. Includes, but is not limited to, recorded and unrecorded purchase obligations, long-term purchase commitment, and short-term purchase commitment. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

No definition available.

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- Definition

Amount of purchase arrangement to be paid in next fiscal year following current fiscal year. Includes, but is not limited to, recorded and unrecorded purchase obligations, long-term purchase commitment, and short-term purchase commitment. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

No definition available.

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- Definition

Amount of purchase arrangement to be paid in remainder of current fiscal year. Includes, but is not limited to, recorded and unrecorded purchase obligations, long-term purchase commitment, and short-term purchase commitment.

+ References

No definition available.

+ Details

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- Definition

Amount of expense related to royalty payments under a contractual arrangement such as payment for mineral and drilling rights and use of technology or intellectual property.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227

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Commitments and Contingencies (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Feb. 21, 2020	Feb. 20, 2020
Long-term Purchase Commitment [Line Items]
Coal royalty expense	$ 16,176	$ 21,868	$ 52,092	$ 73,119
Income tax receivable	66,129		66,129
Income tax receivable related to NOL carryback claim	64,160		64,160
Income tax receivable related to NOL carryback claim, interest receivable	5,126		5,126
Black Lung
Long-term Purchase Commitment [Line Items]
Collateral for self insurance black lunch obligations					$ 65,700	$ 2,600
Term Loan Credit Facility - due November 2025 \| Line of Credit
Long-term Purchase Commitment [Line Items]
Letters of credit outstanding	122,366		122,366
ANR, Inc. and Citibank, N.A. Credit Agreement \| Line of Credit
Long-term Purchase Commitment [Line Items]
Letters of credit outstanding	14,242		14,242
Credit and Security Agreement \| Line of Credit
Long-term Purchase Commitment [Line Items]
Letters of credit outstanding	613		613
Coal Purchase Agreements
Long-term Purchase Commitment [Line Items]
Minimum quantities to be purchased, 2020	15,670		15,670
Equipment Purchase Agreements
Long-term Purchase Commitment [Line Items]
Minimum quantities to be purchased, 2020	9,931		9,931
Minimum quantities to be purchased, 2021	8,968		8,968
Minimum quantities to be purchased, 2024	1,157		1,157
Shipping
Long-term Purchase Commitment [Line Items]
Minimum royalty obligations, 2021	8,793		8,793
Reclamation-related obligations
Long-term Purchase Commitment [Line Items]
Guarantees	349,772		349,772
Collateral supporting guarantees	113,470		113,470
Royalty Agreements \| Coal
Long-term Purchase Commitment [Line Items]
Minimum royalty obligations, 2020	1,784		1,784
Minimum royalty obligations, 2021	15,974		15,974
Minimum royalty obligations, 2022	14,081		14,081
Minimum royalty obligations, 2023	13,064		13,064
Minimum royalty obligations, 2024	11,110		11,110
Minimum royalty obligations, to be paid after 2024	$ 46,724		$ 46,724