SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Narrative) (Details) $ in Thousands	12 Months Ended			24 Months Ended
	Dec. 31, 2017 USD ($) state item factor	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2018 USD ($)
Change in Accounting Estimate [Line Items]
State of incorporation	New Jersey
Number of states | state	20
Number of demographic factors | factor	3
Excess tax benefits from share-based compensation	$ 0	$ 0	$ 18,376
Net gains of the Rabbi Trust investments	2,441	2,741	(1,517)
Unrealized net gains (losses) of the Rabbi Trust investments	$ (3,618)	1,599	(1,769)
Number of Rabbi Trust estabished | item	2
Number of Facilities | item	8
Income tax receivables	$ 106,980	10,201
Bad debt expense	812	(1,190)	1,450
Write-offs of accounts receivables	1,384	1,544	1,483
Capitalized software costs	4,446	4,732
Capitalized software costs during the year	1,988	152	1,482
Goodwill	3,122,321	3,094,824	3,094,824
Loss on impairment of long-lived assets	$ 0	10,506	5,190
Assets, Fair Value Disclosure, Nonrecurring		$ 0
Percentage of goodwill in total assets	33.00%	37.00%
Percentage of net property, plant & equipment in total assets	41.00%
Percentage of net other intangible assets in total assets	11.00%
Number of Reporting Units | item	17
Proceeds from sale of future production				$ 226,926
Amortization term of proceeds from sale of future production	25 years
Stripping costs	$ 65,944	$ 55,987	50,409
Capitalized pre-production stripping costs	81,241	70,227
Spread between the amount accrued and the maximum environmental loss	3,105
Maximum self-insurance coverage per occurrence for losses related to workers' compensation	2,000
Maximum self-insurance coverage per occurrence for automotive and general/product liability	$ 3,000
Accounting Standards Codification Topic 740 - Income Taxes recognition threshold for uncertain tax positions	50.00%
Goodwill impairment charges	$ 0	0	0
Net Cash Provided By Used In Financing Activities	503,440	(304,585)	(67,009)
Excess tax benefits from share-based compensation			18,376
Investing cash flows	(1,269,491)	(357,194)	(308,592)
Asset Retirement Obligation	$ 218,117	223,872	226,594
Goodwill [Member]
Change in Accounting Estimate [Line Items]
Number of Reporting Units | item	9
Accounting Standards Update 2016-09 [Member]
Change in Accounting Estimate [Line Items]
Tax reduction from net excess tax benefits from share based compensation	$ 22,962	24,847
Excess tax benefits from share-based compensation			18,115
Accounting Standards Update 2016-09 [Member] | Federal [Member]
Change in Accounting Estimate [Line Items]
Tax reduction from net excess tax benefits from share based compensation	20,740	22,443
Accounting Standards Update 2016-09 [Member] | State [Member]
Change in Accounting Estimate [Line Items]
Tax reduction from net excess tax benefits from share based compensation	2,222	$ 2,404
ASU 2015-11 [Member]
Change in Accounting Estimate [Line Items]
LIFO method used for percentage of inventory		66.00%
ASU 2017-07 [Member]
Change in Accounting Estimate [Line Items]
All other components	$ (8,102)	$ (13,715)	11,339
Minimum [Member] | Machinery and Equipment [Member]
Change in Accounting Estimate [Line Items]
Estimated service lives	3 years
Minimum [Member] | Buildings [Member]
Change in Accounting Estimate [Line Items]
Estimated service lives	7 years
Minimum [Member] | Land Improvements [Member]
Change in Accounting Estimate [Line Items]
Estimated service lives	8 years
Maximum [Member] | Machinery and Equipment [Member]
Change in Accounting Estimate [Line Items]
Estimated service lives	35 years
Maximum [Member] | Buildings [Member]
Change in Accounting Estimate [Line Items]
Estimated service lives	20 years
Maximum [Member] | Land Improvements [Member]
Change in Accounting Estimate [Line Items]
Estimated service lives	20 years
Forecast [Member]
Change in Accounting Estimate [Line Items]
Estimated deferred revenue to be recognized in the next 12 months					$ 8,080
Restatement Adjustment [Member] | Accounting Standards Update 2016-18 [Member]
Change in Accounting Estimate [Line Items]
Investing cash flows	$ 4,033	$ (7,883)	(1,150)
Restatement Adjustment [Member] | Accounting Standards Update 2016-09, Gross Excess Tax Benefits Reclassified [Member]
Change in Accounting Estimate [Line Items]
Excess tax benefits from share-based compensation			$ 18,376