DEBT (Narrative) (Details)	1 Months Ended			3 Months Ended			9 Months Ended
	Mar. 31, 2018 USD ($)	Feb. 28, 2018 USD ($)	Jan. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)		Mar. 31, 2018 USD ($)	Sep. 30, 2019 USD ($) item		Sep. 30, 2018 USD ($)		Dec. 31, 2018 USD ($)		Dec. 31, 2017 USD ($)
Debt Instrument [Line Items]
Discounts and debt issuance costs							$ 3,730,000		$ 3,927,000
Total long-term debt - face value				$ 2,846,402,000			2,846,378,000		2,846,402,000		$ 2,846,396,000
Repayments of long term debt							$ 17,000		892,049,000
Net proceeds		$ 846,029,000
Net noncash expense						$ 466,000
Premium for repayments of debt						5,608,000
Transaction costs for repayments of debt						1,314,000
Combined charge, component of interest expense				7,388,000					7,388,000
Term Loan Due 2018 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value													$ 350,000,000
Maturity year							2018
Investment-Grade Type Covenants Governed [Member]
Debt Instrument [Line Items]
Number of indentures with customary investment-grade type covenants | item							3
7.50% notes due 2021 [Member]
Debt Instrument [Line Items]
Maturity year							2021
Bank Line of Credit [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity							$ 750,000,000
Commitment fee							0.15%
Available borrowing capacity							$ 696,750,000
Maturity year							2021
Borrowings							$ 0
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							$ 53,250,000
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%
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%
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%
Notes [Member]
Debt Instrument [Line Items]
Total long-term debt - face value							$ 2,846,378,000
Notes [Member] | Term Loan Due 2018 [Member]
Debt Instrument [Line Items]
Maturity year							2021
Notes [Member] | Term Loan Due 2021 [Member] | Term Loan Due 2018 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value													250,000,000
Notes [Member] | Investment-Grade Type Covenants Governed [Member]
Debt Instrument [Line Items]
Total long-term debt - face value							$ 2,846,187,000
Notes [Member] | 7.50% notes due 2021 [Member]
Debt Instrument [Line Items]
Face value			$ 35,111,000
Interest rate			7.50%
Net noncash expense			$ 263,000
Repayments of debt			40,719,000
Premium for repayments of debt			$ 5,608,000
Notes [Member] | 4.70% notes due 2048 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value				460,949,000			$ 460,948,000		460,949,000		$ 460,949,000
Maturity year							2048
Face value	$ 460,949,000	$ 350,000,000				$ 460,949,000
Interest rate		4.70%					4.70%				4.70%
Net noncash expense		$ 203,000
Premium for repayments of debt	38,164,000
Notes [Member] | Floating-Rate Notes Due 2021 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value				500,000,000			$ 500,000,000		500,000,000		$ 500,000,000
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				129,239,000			$ 129,239,000		129,239,000		129,239,000		240,188,000
Maturity year							2037
Repayments of long term debt	$ 110,949,000
Interest rate	7.15%					7.15%	7.15%
Transaction costs for repayments of debt	$ 1,314,000
Bank Line of Credit [Member]
Debt Instrument [Line Items]
Total long-term debt - face value				$ 0	[1]		$ 0	[1]	$ 0	[1]	$ 0	[1]	$ 250,000,000
Maturity year							2021

[1] 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 if we have the intent and ability to extend payment beyond twelve months.