Refers to the annual percent of decline in premium prepayments.

No definition available.

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Namespace Prefix:	metc_
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Balance Type:	na
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- Definition

Annual percentage of premium prepayment.

+ References

No definition available.

+ Details

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Namespace Prefix:	metc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the amount of monthly installments under a debt agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	metc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Number of installments.

+ References

No definition available.

+ Details

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Namespace Prefix:	metc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

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Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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Balance Type:	na
Period Type:	instant

- 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.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Namespace Prefix:	us-gaap_
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Balance Type:	credit
Period Type:	instant

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Name:	us-gaap_DebtInstrumentAxis=us-gaap_UnsecuredDebtMember
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Note 4 - Debt (Details) - USD ($) $ in Millions			6 Months Ended
Note 4 - Debt (Details) - USD ($) $ in Millions	Apr. 16, 2020	Nov. 02, 2018	Jun. 30, 2021	Jul. 13, 2021
Senior Unsecured Notes Offering
Debt
Aggregate principal amount				$ 34.5
Interest rate				9.00%
Equipment Loan
Debt
Long-term Debt, Total			$ 3.0
KeyBank National Association \| Revolving Credit Facility
Debt
Line of Credit Facility, Maximum Borrowing Capacity		$ 30.0
Amount of remaining availability			30.0
KeyBank National Association \| Revolving Credit Facility \| London Interbank Offered Rate (LIBOR)
Debt
Debt Instrument, Basis Spread on Variable Rate		2.00%
KeyBank National Association \| Revolving Credit Facility \| Base Rate
Debt
Debt Instrument, Basis Spread on Variable Rate		1.50%
KeyBank National Association \| Revolving Credit Facility \| Fed Funds Effective Rate Overnight Index Swap Rate
Debt
Debt Instrument, Basis Spread on Variable Rate		0.50%
KeyBank National Association \| Letter of Credit
Debt
Line of Credit Facility, Maximum Borrowing Capacity		$ 3.0
KeyBank National Association \| Term Loan
Debt
Aggregate principal amount		$ 10.0
Debt Instrument, Monthly Installment, Amount			278.0
Long-term Debt, Total			$ 5.0
KeyBank National Association \| Term Loan \| London Interbank Offered Rate (LIBOR)
Debt
Debt Instrument, Basis Spread on Variable Rate			5.15%
KeyBank National Association \| Equipment Loan
Debt
Aggregate principal amount	$ 4.7
Debt Instrument, Monthly Installment, Amount	$ 147.0
Number Of Monthly Installments	36 months
Annual percent of premium prepayment	3.00%
Annual premium decline in premium prepayment	1.00%
Interest rate	7.45%