DERIVATIVE INSTRUMENTS - Effect of Derivative Instruments Designated Cash Flow Hedges on Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Derivative Instruments, Gain (Loss) [Roll Forward]
Balance, Beginning of Period			$ 962,306
Balance, End of Period	$ 1,341,905		1,341,905
Cash Flow
Derivative Instruments, Gain (Loss) [Roll Forward]
Balance, Beginning of Period	8,511	$ 2,479	(4,512)	$ 1,871
Amount of Gain (Loss) Recognized in AOCI	19,335	(1,500)	27,314	(914)
Amount of Gain (Loss) Reclassified from AOCI into Earnings	13,394	44	8,351	(22)
Balance, End of Period	14,452	935	14,452	935
Cash Flow \| Interest rate swap \| Interest (expense)
Derivative Instruments, Gain (Loss) [Roll Forward]
Balance, Beginning of Period	16,188	2,479	592	1,871
Amount of Gain (Loss) Recognized in AOCI	6,306	(1,500)	21,247	(914)
Amount of Gain (Loss) Reclassified from AOCI into Earnings	150	44	(505)	(22)
Balance, End of Period	22,344	$ 935	22,344	$ 935
Cash Flow \| Cross-currency swap \| Other income (expense)
Derivative Instruments, Gain (Loss) [Roll Forward]
Balance, Beginning of Period	(7,677)		(5,104)
Amount of Gain (Loss) Recognized in AOCI	13,029		6,067
Amount of Gain (Loss) Reclassified from AOCI into Earnings	13,244		8,856
Balance, End of Period	$ (7,892)		$ (7,892)

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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- Definition

Amount before tax and reclassification adjustments of other comprehensive income (loss) attributable to parent.

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- Definition

Amount, after tax, of reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

+ References

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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