ASSET RETIREMENT OBLIGATIONS - Estimated Payments (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Estimated payments of asset retirement obligations:
2022	$ 7,582
2023	2,232
2024	558
2025	3,788
2026	7,256
Thereafter	208,021
Aggregate undiscounted asset retirement obligations	229,437
Effect of discounting	(98,338)	$ (102,100)
Total asset retirement obligations	131,099	127,898	$ 137,514
Less: current portion	(7,582)
Asset retirement obligations	123,517	121,487
Surety bonds outstanding to performance of reclamation obligations	$ 173,900	$ 171,100

Undiscounted amount of estimated future payments of asset retirement obligations.

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- Definition

Amount necessary to reduce estimated payments of asset retirement obligations to present value.

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No definition available.

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- Definition

Amount of surety bonds that are available for the future payment of reclamation obligations.

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No definition available.

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- Definition

Amount of estimated payments of asset retirement obligations in the fifth fiscal year following the latest fiscal year.

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No definition available.

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Amount of estimated payments of asset retirement obligations in the fourth fiscal year following the latest fiscal year.

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No definition available.

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Amount of estimated payments of asset retirement obligations in the next fiscal year following the latest fiscal year.

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No definition available.

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Amount of estimated payments of asset retirement obligations after the fifth fiscal year following the latest fiscal year.

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Amount of estimated payments of asset retirement obligations in the third fiscal year following the latest fiscal year.

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Amount of estimated payments of asset retirement obligations in the second fiscal year following the latest fiscal year.

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- Definition

The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

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Current portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

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Noncurrent portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

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