Derivative Financial Instruments (Details) $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($) Contract	Dec. 31, 2018 USD ($) Contract	Dec. 31, 2017 USD ($)
Foreign Currency Derivatives [Abstract]
Unrealized gains/(losses) related to foreign currency cash flow hedges included in accumulated other comprehensive loss	$ 0	$ 0
Cumulative translation adjustments included in accumulated other comprehensive loss	$ (85,300)	$ (79,900)	$ (66,400)
Foreign Currency Forward Contracts [Member] \| Not Designated as Hedging Instrument [Member]
Foreign Currency Derivatives [Abstract]
Number of contracts \| Contract	0	0
Gain (loss) recognized in income	$ 0	$ 0	(500)
Foreign Currency Forward Contracts [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedges [Member]
Foreign Currency Derivatives [Abstract]
Number of contracts \| Contract	0	0
Foreign Currency Forward Contracts [Member] \| Other Comprehensive Income (Loss) [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedges [Member]
Foreign Currency Derivatives [Abstract]
Gain (loss) recognized in other comprehensive loss	$ 0	$ (200)	(200)
Foreign Currency Forward Contracts [Member] \| Revenue [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedges [Member]
Foreign Currency Derivatives [Abstract]
Gain (loss) reclassified from accumulated other comprehensive loss into income	0	18	100
Foreign Currency Forward Contracts [Member] \| Selling Expenses [Member] \| Designated as Hedging Instrument [Member] \| Cash Flow Hedges [Member]
Foreign Currency Derivatives [Abstract]
Gain (loss) reclassified from accumulated other comprehensive loss into income	$ 0	$ 0	$ 400

Accumulated change, net of tax, in accumulated gains and losses from derivative instruments designated and qualifying as the effective portion of cash flow hedges. Includes an entity's share of an equity investee's Increase or Decrease in deferred hedging gains or losses.

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Accumulated adjustment, net of tax, that results from the process of translating subsidiary financial statements and foreign equity investments into the reporting currency from the functional currency of the reporting entity, net of reclassification of realized foreign currency translation gains or losses.

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Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

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Number of foreign currency exchange rate derivatives held by the entity at the reporting date.

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Amount before tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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