Accumulated Other Comprehensive Income (Loss) - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net increase (decrease) in other comprehensive income (loss)	$ (84,929)	$ 21,898	$ (42,292)	$ 61,095
Currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net increase (decrease) in other comprehensive income (loss)	$ (105,727)	$ 51,067	$ (63,738)	$ 105,336

Amount after tax of other comprehensive income (loss) attributable to parent entity.

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