DEBT (Debt) (Details) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2017		Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016		Sep. 30, 2016
Debt Instrument [Line Items]
Total short-term debt		$ 0				$ 0		$ 0
Total long-term debt - face value		2,846,541				2,004,065		2,004,184
Unamortized discounts and debt issuance costs		(31,748)				(21,176)		(20,414)
Total long-term debt - book value		2,814,793				1,982,889		1,983,770
Less current maturities		4,827				138		131
Total long-term debt - reported value		2,809,966				1,982,751		1,983,639
Estimated fair value of long-term debt		3,068,236				2,243,213		2,305,065
Bank Line of Credit [Member]
Debt Instrument [Line Items]
Total short-term debt	[1],[2],[3]	$ 0				0		0
Maturity date		Dec. 31, 2021
Bank Line of Credit [Member]
Debt Instrument [Line Items]
Total long-term debt - face value	[1],[2],[3]	$ 0				235,000		235,000
Maturity date		Dec. 31, 2021
Notes [Member] | 7.00% notes due 2018 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 0		$ 272,512		272,512		272,512
Interest rate		7.00%		7.00%
Maturity year		2018
Notes [Member] | 10.375% notes due 2018 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 0		$ 250,000		250,000		250,000
Interest rate		10.375%		10.375%
Maturity year		2018
Notes [Member] | Floating-Rate Notes Due 2020 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 250,000				0		0
Maturity year		2020
Effective interest rate		2.13%
Notes [Member] | 7.50% notes due 2021 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 600,000				600,000		600,000
Interest rate		7.50%
Maturity year		2021
Effective interest rate		7.75%
Notes [Member] | 8.85% notes due 2021 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 6,000				6,000		6,000
Interest rate		8.85%
Maturity year		2021
Effective interest rate		8.88%
Notes [Member] | Delayed draw term loan [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 250,000	[2],[3]	$ 250,000		0	[2],[3]	0	[2],[3]
Maturity year		2021
Effective interest rate	[2],[3]	2.49%
Notes [Member] | 4.50% notes due 2025 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 400,000				400,000		400,000
Interest rate		4.50%
Maturity year		2025
Effective interest rate		4.65%
Notes [Member] | 3.90% notes due 2027 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 400,000				0		0
Interest rate		3.90%		3.90%	3.90%
Maturity year		2027
Effective interest rate		4.00%
Notes [Member] | 7.15% notes due 2037 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 240,188				240,188		240,188
Interest rate		7.15%
Maturity year		2037
Effective interest rate		8.05%
Notes [Member] | 4.50% notes due 2047 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 700,000				0		0
Interest rate		4.50%		4.50%
Maturity year		2047
Effective interest rate		4.59%
Other Notes [Member]
Debt Instrument [Line Items]
Total long-term debt - face value	[2]	$ 353				$ 365		$ 484
Effective interest rate	[2]	6.31%

[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 otherwise.

[2] Non-publicly traded debt.

[3] The effective interest rate is the spread over LIBOR as of the most recent balance sheet date.