Fair Value Measurements - Fair Value of Gross Position of Derivative Contracts in Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accrued current liabilities
Derivatives, Fair Value [Line Items]
Net amounts presented	$ (1,893)	$ 0
Other long-term liabilities
Derivatives, Fair Value [Line Items]
Net amounts presented	(1,334)	0
Other current assets
Derivatives, Fair Value [Line Items]
Net amounts presented	0	1,062
Designated as hedging instruments:
Derivatives, Fair Value [Line Items]
Gross amounts recognized	(2,808)	1,029
Gross amounts offset	168	0
Net amounts	(2,640)	1,029
Not designated as hedging instruments:
Derivatives, Fair Value [Line Items]
Gross amounts recognized	(684)	109
Gross amounts offset	97	(76)
Net amounts	$ (587)	$ 33

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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Fair value of the assets less the liabilities of a derivative or group of derivatives.

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