WORKERS' COMPENSATION AND PNEUMOCONIOSIS - Liability (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Dec. 31, 2020
Reconciliation of changes in the workers' compensation liability
Beginning balance	$ 53,206	$ 54,233	$ 53,448	$ 54,739	$ 54,739
Accruals increase	2,271	1,565	4,546	3,237
Payments	(3,278)	(2,565)	(6,082)	(4,975)
Interest accretion	287	231	574	463
Valuation gain	(5,265)	(1,405)	(5,265)	(1,405)
Ending balance	47,221	$ 52,059	$ 47,221	$ 52,059	$ 53,448	$ 54,739
Estimated present value of future obligations and other information
Workers' compensation discount rate			4.22%	2.34%	2.41%	1.95%
Other long-term assets
Estimated present value of future obligations and other information
Receivables for traumatic injury claims	$ 5,700		$ 5,700

Represents the change in the liability for workers' compensation due to payments made during the period.

No definition available.

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- Definition

Represents the change in the liability for workers' compensation due to an adjustment for valuation gain or loss.

+ References

No definition available.

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- Definition

Represents the change in the liability for workers' compensation due to additional amounts accrued during the period.

+ References

No definition available.

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- References

No definition available.

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- Definition

Amount recognized for the passage of time, typically for liabilities, that have been discounted to their net present values. Excludes accretion associated with asset retirement obligations.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
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- References

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- Definition

Carrying amount due after one year of the balance sheet date (or one operating cycle, if longer) of amount due in settlement of a claim for reimbursement from an insurance company when the Company has suffered a loss covered under an insurance policy.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition

Percent discount applied to worker's compensation reserve liability to reduce the reserve to present value.

+ References

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-Name Accounting Standards Codification
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- Definition

Carrying value as of the balance sheet date of obligations and payables pertaining to claims incurred of a workers compensation nature.

+ References

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