CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net (Loss) Income	$ (530,993)	$ (1,053,836)	$ 318,022
Other Comprehensive (Loss) Income, Net of Tax
Currency translation adjustments	(106,651)	191,267	(101,539)
Defined benefit pension plan adjustments	450	14,491	2,154
Net unrealized (losses) gains on available-for-sale security	(3,748)	(5,948)	3,149
Net unrealized gains (losses) on derivative instruments:
Unrealized holding gains (losses)	24,082	(55,377)	18,733
Reclassification adjustment for realized gains (losses) included in net (loss) income	8,427	16,810	(16,627)
Net unrealized gains (losses) on derivative instruments	32,509	(38,567)	2,106
Other Comprehensive (Loss) Income, Net of Tax	(77,440)	161,243	(94,130)
Comprehensive (Loss) Income	$ (608,433)	$ (892,593)	$ 223,892

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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