FAIR VALUE MEASUREMENTS (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Financial Assets (Liabilities):
Derivative instruments — assets	$ 1,119	$ 10,745
Derivative instruments — liabilities	$ (28,399)
Senior Notes 5.875% [Member]
Financial Assets (Liabilities):
Interest rate (as a percent)	5.875%	5.875%
Senior Notes 5.875% [Member] | Fair Value, Inputs, Level 1 [Member]
Financial Assets (Liabilities):
Interest rate (as a percent)	5.875%	5.875%
Senior Notes 4.375% [Member]
Financial Assets (Liabilities):
Interest rate (as a percent)	4.375%	4.375%
Senior Notes 4.375% [Member] | Fair Value, Inputs, Level 1 [Member]
Financial Assets (Liabilities):
Interest rate (as a percent)	4.375%	4.375%
Carrying Amount [Member]
Financial Assets (Liabilities):
Derivative instruments — assets	$ 1,119	$ 11,246
Derivative instruments — liabilities	(31,608)
Carrying Amount [Member] | Senior Notes 5.875% [Member]
Financial Assets (Liabilities):
Long-term debt	(750,000)	(750,000)
Carrying Amount [Member] | Senior Notes 4.375% [Member]
Financial Assets (Liabilities):
Long-term debt	(750,000)	(750,000)
Fair Value [Member]
Financial Assets (Liabilities):
Derivative instruments — assets	1,119	11,246
Derivative instruments — liabilities	(31,608)
Fair Value [Member] | Senior Notes 5.875% [Member]
Financial Assets (Liabilities):
Long-term debt	(788,475)	(723,750)
Fair Value [Member] | Senior Notes 4.375% [Member]
Financial Assets (Liabilities):
Long-term debt	$ (780,000)	$ (683,318)