SUPPLEMENTAL CASH FLOW INFORMATION (Supplemental Information Referable to Condensed Consolidated Statements of Cash Flows) (Details) - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020
SUPPLEMENTAL CASH FLOW INFORMATION [Abstract]
Interest (exclusive of amount capitalized)		$ 65,195	$ 60,741
Income taxes		87,416	9,055
Accrued liabilities for purchases of property, plant & equipment		27,018	10,994
Recognition of new and revised asset retirement obligations		1,770	55,858
Recognition of new and revised right-of-use assets for: Operating lease liabilities	[1]	56,974	25,083
Recognition of new and revised right-of-use assets for: Finance lease liabilities		3,265	4,991
Amounts referable to business acquisitions, Liabilities assumed		0	5,637
Amounts referable to business acquisitions, Consideration payable to seller		0	8,980
Amounts referable to business acquisitions, Fair value of noncash assets and liabilities exchanged		$ 0	$ 21,214

[1] The 2021 amount includes a modification to our headquarters office space lease to extend the lease term.