SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Depreciation, Depletion, Accretion and Amortization Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]
Depreciation	$ 315,136	$ 300,613	$ 276,814
Depletion	21,011	22,421	23,260
Accretion	12,432	10,992	10,776
Amortization of finance leases	1,616	29	472
Amortization of intangibles	46,611	40,541	34,924
Total	$ 396,806	$ 374,596	$ 346,246

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- Definition

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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- Definition

The expense charged against earnings for the periodic recognition of capitalized leases. This element may apply to energy companies that lease mineral producing properties and to other enterprises that capitalize property, plant, or equipment obtained through capital leases.

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Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability.

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- Definition

The noncash expense charged against earnings to recognize the consumption of natural resources.

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- Definition

The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

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