DERIVATIVE INSTRUMENTS (Narrative) (Details)	1 Months Ended	3 Months Ended	12 Months Ended
	Aug. 31, 2011 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2007 USD ($) agreement	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Apr. 30, 2015	Jun. 30, 2011 USD ($)
Derivative [Line Items]
Number of forward starting interest rate swap agreements | agreement			15
Cash payments for (proceeds from) interest rate swap agreements	$ (25,382,000)		$ 89,777,000
Loss reclassified from AOCI		$ 2,700,000
Fixed-rate notes issued		$ 2,277,137,000			$ 2,004,194,000	$ 2,004,198,000
Gain component of the settlement	23,387,000
Accrued interest	$ 1,995,000
6.50% notes due 2016 [Member]
Derivative [Line Items]
Fixed-rate notes issued								$ 500,000,000
Interest rate					6.50%		6.50%	6.50%
10.125% notes due 2015 [Member]
Derivative [Line Items]
Interest rate					10.125%			10.125%
Interest Rate Swap Agreements [Member]
Derivative [Line Items]
Notional amount of interest rate swap agreements			$ 1,500,000,000
Interest Rate Swap Agreement One [Member]
Derivative [Line Items]
Notional amount of interest rate swap agreements								$ 500,000,000
Interest rate spread above London Interbank Offered Rate (LIBOR)								4.05%
Fixed interest rate under swap agreements								6.50%
Interest Rate Swap Agreement Two [Member]
Derivative [Line Items]
Notional amount of interest rate swap agreements								$ 150,000,000
Interest rate spread above London Interbank Offered Rate (LIBOR)								8.03%
Fixed interest rate under swap agreements								10.125%
Scenario, Forecast [Member]
Derivative [Line Items]
Estimated amount of pretax loss in AOCI reclassified to earnings for the next 12-month period				$ 2,049,000