DEBT (Narrative) (Details) - USD ($)		1 Months Ended			3 Months Ended
		Jun. 30, 2015	Apr. 30, 2015	Mar. 31, 2015	Mar. 31, 2016	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2015	Jun. 30, 2011
Debt Instrument [Line Items]
Net interest expense					$ 1,096,000
Debt to EBITDA ratio					3.5
EBITDA to net cash interest expense ratio					3.0
Long term debt	[1]			$ 2,253,806,000	$ 1,981,556,000		$ 2,253,806,000	$ 1,980,464,000
Debt instrument face amount				2,277,137,000	2,004,194,000		2,277,137,000	2,004,198,000
Total consideration paid for debt			$ 385,024,000		5,000		145,918,000
Premium paid for purchase of debt			41,153,000
Transaction cost related to termination of debt			52,000
Other cost (benefit) related to debt purchase			$ 4,136,000
Cost of debt purchase					$ 0	$ 45,341,000	21,734,000
Period of letters of credit					1 year
10.125% notes due 2015 [Member]
Debt Instrument [Line Items]
Long term debt				150,000,000	$ 0		150,000,000	0
Interest rate					10.125%				10.125%
Maturity year					2015
4.50% notes due 2025 [Member]
Debt Instrument [Line Items]
Long term debt				400,000,000	$ 400,000,000		400,000,000	400,000,000
Debt instrument face amount				$ 400,000,000			$ 400,000,000
Interest rate				4.50%	4.50%		4.50%
Maturity year					2025		2025
Debt issued, net proceeds				$ 395,207,000
7.00% notes due 2018 [Member]
Debt Instrument [Line Items]
Long term debt				$ 272,697,000	$ 272,512,000		$ 272,697,000	272,512,000
Interest rate			7.00%	7.00%	7.00%		7.00%
Maturity year			2018		2018		2018
Debt purchased, amount			$ 185,000	$ 127,303,000			$ 127,303,000
Principal amount, percentage			1.00%	32.00%
Total consideration paid for debt				$ 145,899,000
Premium paid for purchase of debt				18,140,000			18,140,000
Transaction cost related to termination of debt				456,000
Other cost (benefit) related to debt purchase				3,138,000
Cost of debt purchase							21,734,000
6.40% notes due 2017 [Member]
Debt Instrument [Line Items]
Long term debt				218,633,000	$ 0		218,633,000	0
Interest rate			6.40%		6.40%
Maturity year			2017		2017
Debt purchased, amount			$ 218,633,000
Principal amount, percentage			100.00%
6.50% notes due 2016 [Member]
Debt Instrument [Line Items]
Long term debt				125,001,000	$ 0		125,001,000	0
Debt instrument face amount									$ 500,000,000
Interest rate			6.50%		6.50%				6.50%
Maturity year			2016		2016
Debt purchased, amount			$ 125,001,000
Principal amount, percentage			100.00%
Bank Line of Credit [Member]
Debt Instrument [Line Items]
Line of credit, maximum borrowing capacity		$ 500,000,000			$ 750,000,000	$ 500,000,000
Transaction fees		$ 2,589,000
Line of credit, expiration date					Jun. 01, 2020
Commitment fee					0.20%
Available borrowing capacity					$ 475,136,000
Long term debt					$ 235,000,000
Bank Line of Credit [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Applicable margin on borrowing rate					1.50%
Bank Line of Credit [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Applicable margin on borrowing rate					0.50%
Standby Letters of Credit [Member]
Debt Instrument [Line Items]
Other liabilities					$ 39,864,000
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]
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]
Commitment fee					0.35%
Maximum [Member] | Bank Line of Credit [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Applicable margin on borrowing rate					2.00%
Maximum [Member] | Bank Line of Credit [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Applicable margin on borrowing rate					1.00%
Other Notes [Member]
Debt Instrument [Line Items]
Long term debt					$ 494,000
Industrial Revenue Bonds [Member]
Debt Instrument [Line Items]
Long term debt				$ 14,000,000	$ 0		$ 14,000,000	$ 0
Maturity year					2022

[1] The debt balances as of March 31, 2015 have been adjusted to reflect our early adoption of ASU 2015-03 and related election as discussed in Note 1, caption Reclassifications.