FAIR VALUE MEASUREMENTS - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities (Other assets)	$ 8,746	$ 8,499
Derivative contracts		38,576
Assets, Fair Value, Total	8,746	47,075
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities (Other assets)	8,746	8,499
Derivative contracts		0
Assets, Fair Value, Total	8,746	8,499
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities (Other assets)	0	0
Derivative contracts		36,603
Assets, Fair Value, Total	0	36,603
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities (Other assets)	0	0
Derivative contracts		1,973
Assets, Fair Value, Total	$ 0	$ 1,973