Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
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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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Fair value as of the balance sheet date of all foreign currency derivative assets designated as cash flow hedging instruments.

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Fair value as of the balance sheet date of all foreign currency derivative liabilities designated as cash flow hedging instruments.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Amount before tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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Amount of tax expense (benefit) allocated to other comprehensive income (loss) attributable to parent entity.

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Accumulated Other Comprehensive Income (Details) $ in Thousands, € in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 EUR (€)	May 31, 2018 EUR (€)	Dec. 31, 2017 USD ($)	Dec. 31, 2017 EUR (€)	Nov. 30, 2016 EUR (€)
Components of comprehensive income
Net income	$ 6,638	$ 5,278	$ 10,900	$ 9,898
Mark to market of foreign exchange hedges	(72)	391	(116)	440
Deferred income tax (expense) benefit	17	(143)	27	(161)
Comprehensive income	6,583	$ 5,526	10,811	$ 10,177
Foreign exchange hedges assets							$ 111
Foreign exchange hedges liabilities	$ 3		$ 3
Prepaid expenses and other current assets
Components of comprehensive income
Foreign exchange hedges assets							83
Other assets, net
Components of comprehensive income
Foreign exchange hedges assets							$ 28
Foreign Exchange Contract
Components of comprehensive income
Foreign exchange hedges liabilities \| €					€ 0.7
Foreign Exchange Contract \| Designated as Hedging Instrument
Components of comprehensive income
Notional amount \| €					€ 2.9	€ 2.2		€ 2.2	€ 5.5