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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-Section 13
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+ References

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+ References

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- Definition

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

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Derivative Financial Instruments - Additional Information (Detail) - Derivatives Not Designated as Hedging Instrument [Member] - Fair Value, Inputs, Level 2 [Member] - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Derivatives Fair Value [Line Items]
Foreign currency forward contracts, notional amount	$ 24,000,000		$ 24,000,000		$ 37,000,000
Other Expense [Member]
Derivatives Fair Value [Line Items]
Foreign currency forward contracts, gain (loss) related to changes in fair value			(1,000,000)
Other Expense [Member] \| Maximum [Member]
Derivatives Fair Value [Line Items]
Foreign currency forward contracts, gain (loss) related to changes in fair value	1,000,000	$ 1,000,000		$ 2,000,000
Prepaid and Other Current Assets [Member] \| Maximum [Member]
Derivatives Fair Value [Line Items]
Foreign currency forward contracts, assets	1,000,000		1,000,000		1,000,000
Other Current Liabilities [Member] \| Maximum [Member]
Derivatives Fair Value [Line Items]
Foreign currency forward contracts, liability	$ 1,000,000		$ 1,000,000		$ 1,000,000