SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Depreciation, Depletion, Accretion and Amortization Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]
Depreciation	$ 276,814	$ 250,835	$ 238,237
Depletion	23,260	19,342	17,812
Accretion	10,776	11,415	11,059
Amortization of leaseholds	472	608	267
Amortization of intangible	34,924	23,765	17,565
Total	$ 346,246	$ 305,965	$ 284,940

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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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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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