Financial Instruments - Balance Sheet Location (Details) - Fair Value, Measurements, Recurring [Member] - Fair Value, Inputs, Level 2 [Member] - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Assets [Abstract]
Foreign currency cash flow hedges - asset	$ 4,059	$ 358
Liabilities [Abstract]
Foreign currency cash flow hedges - liability	$ 1,290	$ 2,243

Fair value portion of liability contracts related to the exchange of different currencies, including, but not limited to, foreign currency options, forward (delivery or nondelivery) contracts, and swaps entered into.

No definition available.

Name:	us-gaap_ForeignCurrencyContractsLiabilityFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant