DEBT (Narrative) (Details) - USD ($)				1 Months Ended							12 Months Ended
		Feb. 23, 2018	Feb. 20, 2018	Jan. 31, 2018	Dec. 31, 2017		Jul. 31, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2015	Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Debt Instrument [Line Items]
Net interest expense											$ 143,226,000		$ 125,748,000
Discounts and debt issuance costs											9,808,000		4,418,000
Total long-term debt - face value					$ 2,881,529,000						2,881,529,000		2,004,065,000
Long term debt					2,854,865,000						2,854,865,000		1,982,889,000
Repayments of long term debt							$ 565,560,000				1,463,308,000		130,000		$ 695,060,000
Proceeds from issuance of long-term debt											2,200,000,000		0		400,000,000
Net noncash expense					4,228,000		3,029,000				7,257,000				7,274,000
Purchase amount					1,087,401,000						1,087,401,000
Repayments of debt											1,087,536,000		130,000		530,923,000
Cost of debt purchase											(140,772,000)		0		(67,075,000)
Premium for repayments of debt							43,020,000				139,187,000				59,293,000
Transaction costs for repayments of debt							$ 28,000				1,586,000				508,000
Combined charge, component of interest expense											148,030,000				$ 67,075,000
Total short-term debt					0						$ 0		0
Term Loan Due 2018 [Member]
Debt Instrument [Line Items]
Debt issued, term											6 months
Total short-term debt					$ 350,000,000						$ 350,000,000
Debt Exchange Offer, March 2018 [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Total long-term debt - face value			$ 350,000,000
Proceeds from issuance of long-term debt			0
LIBOR [Member] | Term Loan Due 2018 [Member]
Debt Instrument [Line Items]
Applicable margin on borrowing rate					1.25%
3.90% notes due 2027 [Member]
Debt Instrument [Line Items]
Net proceeds									$ 345,450,000
7.50% notes due 2021 [Member]
Debt Instrument [Line Items]
Face value					$ 564,889,000						$ 564,889,000
Repayments of debt					662,613,000
Premium for repayments of debt					96,167,000
Transaction costs for repayments of debt					1,558,000
7.50% notes due 2021 [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Face value				$ 35,111,000
Repayments of debt				40,719,000
Premium for repayments of debt				$ 5,608,000
Bank Line of Credit [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity													750,000,000
Commitment fee											0.15%
Available borrowing capacity					456,761,000						$ 456,761,000
Total long-term debt - face value													235,000,000
Long term debt					250,000,000						$ 250,000,000
Bank Line of Credit [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Applicable margin on borrowing rate											1.25%
Bank Line of Credit [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Applicable margin on borrowing rate											0.25%
Bank Line of Credit [Member] | Maximum, Upon Certain Acquisitions [Member]
Debt Instrument [Line Items]
Debt to EBITDA ratio											3.75
Standby Letters of Credit [Member]
Debt Instrument [Line Items]
Outstanding standby letters of credit					43,239,000						$ 43,239,000
Period of standby letters of credit											1 year
Standby Letters of Credit [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Applicable margin on borrowing rate											0.175%
Minimum [Member] | Bank Line of Credit [Member]
Debt Instrument [Line Items]
EBITDA to net cash interest expense ratio											3.0
Commitment fee											0.10%
Minimum [Member] | Bank Line of Credit [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Applicable margin on borrowing rate											1.00%
Minimum [Member] | Bank Line of Credit [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Applicable margin on borrowing rate											0.00%
Maximum [Member] | Bank Line of Credit [Member]
Debt Instrument [Line Items]
Debt to EBITDA ratio											3.5
Commitment fee											0.25%
Maximum [Member] | Bank Line of Credit [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Applicable margin on borrowing rate											1.75%
Maximum [Member] | Bank Line of Credit [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Applicable margin on borrowing rate											0.75%
Term Loan Due 2018 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value	[1],[2]				350,000,000						$ 350,000,000		0
Maturity year											2018
Term Loan Due 2018 [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Repayments of long term debt		$ 350,000,000
Notes [Member]
Debt Instrument [Line Items]
Total long-term debt - face value					2,631,529,000						$ 2,631,529,000
Face value								$ 1,000,000,000
Net proceeds								989,512,000
Notes [Member] | 3.90% notes due 2027 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value					$ 400,000,000						$ 400,000,000		0
Maturity year											2027
Face value								$ 400,000,000
Interest rate					3.90%			3.90%	3.90%		3.90%
Notes [Member] | 3.90% notes due 2027 [Member] | June 2017 Issuance [Member]
Debt Instrument [Line Items]
Face value								$ 50,000,000
Notes [Member] | 3.90% notes due 2027 [Member] | March 2017 Issuance [Member]
Debt Instrument [Line Items]
Face value									$ 350,000,000
Notes [Member] | Delayed draw term loan [Member]
Debt Instrument [Line Items]
Total long-term debt - face value					$ 250,000,000	[1]		250,000,000			$ 250,000,000	[1]	0	[1]
Maturity year											2021
Notes [Member] | Delayed draw term loan [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Repayments of long term debt		$ 250,000,000
Notes [Member] | Delayed draw term loan [Member] | Quarters 5 - 8 [Member]
Debt Instrument [Line Items]
Required periodic principal payment											$ 1,562,500
Notes [Member] | Delayed draw term loan [Member] | Quarters 9 - 12 [Member]
Debt Instrument [Line Items]
Required periodic principal payment											3,125,000
Notes [Member] | Delayed draw term loan [Member] | Quarters 13 - 19 [Member]
Debt Instrument [Line Items]
Required periodic principal payment											4,687,500
Notes [Member] | Delayed draw term loan [Member] | Quarter 20 [Member]
Debt Instrument [Line Items]
Required periodic principal payment											$ 198,437,500
Notes [Member] | 10.125% notes due 2015 [Member]
Debt Instrument [Line Items]
Maturity year											2015
Repayments of long term debt										$ 150,000,000
Interest rate										10.125%					10.125%
Notes [Member] | 6.40% notes due 2017 [Member]
Debt Instrument [Line Items]
Maturity year											2017
Interest rate										6.40%					6.40%
Purchase amount										$ 218,633,000					$ 218,633,000
Principal percentage															100.00%
Notes [Member] | 6.50% notes due 2016 [Member]
Debt Instrument [Line Items]
Maturity year											2016
Interest rate										6.50%					6.50%
Purchase amount										$ 125,001,000					$ 125,001,000
Principal percentage															100.00%
Notes [Member] | Investment-Grade Type Covenants Governed [Member]
Debt Instrument [Line Items]
Total long-term debt - face value					2,031,299,000						$ 2,031,299,000
Notes [Member] | 4.50% notes due 2047 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value					$ 700,000,000						$ 700,000,000		0
Maturity year											2047
Face value								$ 700,000,000
Interest rate					4.50%			4.50%			4.50%
Notes [Member] | 4.50% notes due 2025 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value					$ 400,000,000						$ 400,000,000		$ 400,000,000
Maturity year											2025
Face value										$ 400,000,000					$ 400,000,000
Interest rate					4.50%					4.50%	4.50%		4.50%		4.50%
Net proceeds															$ 395,207,000
Notes [Member] | Floating-Rate Notes Due 2020 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value					$ 250,000,000						$ 250,000,000		$ 0
Maturity year											2020
Face value								$ 250,000,000
Notes [Member] | 10.375% notes due 2018 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value					0			$ 250,000,000			$ 0		$ 250,000,000
Maturity year											2018
Interest rate								10.375%					10.375%
Notes [Member] | 7.00% notes due 2018 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value					0			$ 272,512,000			$ 0		$ 272,512,000
Maturity year											2018
Interest rate								7.00%		7.00%			7.00%		7.00%
Purchase amount										$ 127,488,000					$ 127,488,000
Principal percentage															33.00%
Notes [Member] | 7.50% notes due 2021 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value					$ 35,111,000						$ 35,111,000		$ 600,000,000
Maturity year											2021
Interest rate					7.50%						7.50%		7.50%
Notes [Member] | 4.70% notes due 2048 [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Maturity year		2048
Face value		$ 350,000,000
Interest rate		4.70%
Notes [Member] | Floating-Rate Notes Due 2021 [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Maturity year		2021
Face value		$ 500,000,000
Notes [Member] | 7.15% notes due 2037 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value					$ 240,188,000						$ 240,188,000		$ 240,188,000
Maturity year											2037
Interest rate					7.15%						7.15%		7.15%
Notes [Member] | 7.15% notes due 2037 [Member] | Debt Exchange Offer, March 2018 [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Total long-term debt - face value			$ 240,188,000
Industrial Revenue Bonds [Member]
Debt Instrument [Line Items]
Maturity year											2022
Repayments of long term debt															$ 14,000,000
Bank Line of Credit [Member]
Debt Instrument [Line Items]
Maturity date											Dec. 31, 2021
Total long-term debt - face value	[1],[3]				$ 250,000,000						$ 250,000,000		$ 235,000,000
Bank Line of Credit [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Repayments of long term debt		$ 250,000,000

[1] Non-publicly traded debt.

[2] This short-term loan was refinanced on a long-term basis in February 2018 as discussed below

[3] Borrowings on the bank line of credit are classified as short-term debt if we intend to repay within twelve months and as long-term debt otherwise.