Foreign Currency Transaction Exposure - Summary (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Currency Transaction Gains (Losses) [Line Items]
Net transaction (losses) gains	$ (5,438)	$ 8,318
Operating (loss) income
Currency Transaction Gains (Losses) [Line Items]
Net transaction (losses) gains	(3,770)	7,731
Other non-operating (expense) income, net
Currency Transaction Gains (Losses) [Line Items]
Net transaction (losses) gains	$ (1,668)	$ 587

Amount before tax of foreign currency transaction realized and unrealized gain (loss) recognized in the income statement.

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