DEBT (Narrative) (Details) (USD $)	1 Months Ended	6 Months Ended				1 Months Ended		6 Months Ended												6 Months Ended
	Mar. 31, 2014	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Jun. 30, 2011	Jun. 30, 2013 Medium-term Notes	Jan. 31, 2013 Medium-term Notes	Jun. 30, 2014 6.50% notes due 2016	Jun. 30, 2013 6.50% notes due 2016	Jun. 30, 2013 7.50% notes due 2021	Jun. 30, 2013 10.125% notes due 2015	Jun. 30, 2013 10.375% notes due 2018	Jun. 30, 2013 7.00% notes due 2018	Jun. 30, 2014 6.40% notes due 2017	Jun. 30, 2013 6.40% notes due 2017	Jun. 30, 2013 7.15% notes due 2037	Jun. 30, 2014 Line of Credit	Dec. 31, 2013 Line of Credit	Jun. 30, 2013 Line of Credit	Jun. 30, 2014 Line of Credit Minimum	Jun. 30, 2014 Line of Credit Maximum
Debt Instrument [Line Items]
Required periodic principal payment		$ 0				$ 140,444,000	$ 10,000,000
Debt instrument face amount					500,000,000
Debt purchased, amount		506,366,000						374,999,000						131,367,000
Maturity year								2016	2016	2021	2015	2018	2018	2017	2017	2037
Interest rate					6.50%	6.30%	8.70%	6.50%	6.50%	7.50%	10.125%	10.375%	7.00%	6.40%	6.40%	7.15%
Amount of bank credit facility																	500,000,000
Facility expiration date																	Mar. 25, 2019
Borrowing capacity		446,732,000
Applicable margin for LIBOR based borrowing																	2.00%			1.50%	2.25%
Total consideration paid for debt	579,659,000	579,694,000	161,477,000
Short-term line of credit		0	100,000,000	0													0	0	100,000,000
Premium paid for purchase of debt		71,829,000
Transaction cost related to termination of debt		1,464,000
Other benefit related to debt purchase		344,000
Cost of debt purchase		$ 72,949,000	$ 0