WORKERS' COMPENSATION AND PNEUMOCONIOSIS - Workers' Compensation Liability (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Reconciliation of changes in the workers' compensation liability
Beginning balance	$ 53,384	$ 49,539
Accruals increase	1,748	1,961
Payments	(2,571)	(3,473)
Interest accretion	319	401
Ending balance	52,880	$ 48,428
Receivables for traumatic injury claims	$ 7,700

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 additional amounts accrued during the period.

+ References

No definition available.

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- References

No definition available.

+ Details

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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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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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://fasb.org/us-gaap/role/ref/legacyRef
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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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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