Financial Instruments - Balance Sheet Location (Details) - Fair Value, Measurements, Recurring [Member] - Level 2 [Member] - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Assets [Abstract]
Foreign currency cash flow hedges	$ 358	$ 1,058
Liabilities [Abstract]
Foreign currency cash flow hedges	$ 2,243	$ 705

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