OTHER COMPREHENSIVE INCOME (Amounts Reclassified from Accumulated Other Comprehensive Income to Earnings) (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense										$ 295,522	$ 134,076	$ 220,588
Cost of revenues										2,889,735	2,591,850	2,564,648
Selling, administrative and general expenses										323,918	314,986	286,844
Benefit from income taxes										(232,075)	124,851	94,943
Total		$ 327,546	$ 108,579	$ 120,139	$ 44,921	$ 112,600	$ 142,024	$ 124,709	$ 40,158	601,185	419,491	221,177
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total										4,016	1,276	17,813
Reclassification Adjustment for Cash Flow Hedge Losses [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense										3,070	2,008	9,759
Benefit from income taxes										(1,208)	(814)	(3,931)
Total	[1]									1,862	1,194	5,828
Amortization of Pension and Postretirement Plan Actuarial Loss and Prior Service Cost [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of revenues										2,376	109	15,916
Selling, administrative and general expenses										539	25	3,608
Benefit from income taxes										(761)	(52)	(7,539)
Total	[2]									2,154	82	11,985
Cash Flow Hedges [Member] | Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Loss reclassified from AOCI										3,070	$ 2,008	9,759
Cash Flow Hedges [Member] | Debt [Member] | Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Loss reclassified from AOCI										$ 1,405		$ 7,208

[1] Totals for 2017 and 2015 include the acceleration of deferred losses on interest rate derivatives (see Note 5) referable to debt purchases (see Note 6).

[2] Total for 2015 includes a one-time settlement loss resulting from a lump sum payment to a former employee (see Note 10).