Current report of foreign issuer pursuant to Rules 13a-16 and 15d-16 Amendments

Derivative instruments and hedging activities (Narrative) (Details)

v3.5.0.2
Derivative instruments and hedging activities (Narrative) (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Dec. 31, 2015
Derivatives, Fair Value [Line Items]          
Gain (loss) on derivative instrument $ 100 $ (200) $ (2,300) $ 3,400  
Other current assets [Member] | Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member]          
Derivatives, Fair Value [Line Items]          
Assets derivatives - Notional amount 24,572   24,572   $ 54,586
Other current assets [Member] | Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member] | Conversion To Euro [Member]          
Derivatives, Fair Value [Line Items]          
Assets derivatives - Notional amount 32,100   32,100    
Other current assets [Member] | Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member] | Conversion To NIS [Member]          
Derivatives, Fair Value [Line Items]          
Assets derivatives - Notional amount 4,100   4,100    
Other current assets [Member] | Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member] | Conversion To Yen [Member]          
Derivatives, Fair Value [Line Items]          
Assets derivatives - Notional amount 10,600   10,600    
Other current assets [Member] | Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member]          
Derivatives, Fair Value [Line Items]          
Assets derivatives - Notional amount 7,780   7,780   $ 2,700
Other current assets [Member] | Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member] | Conversion To NIS [Member]          
Derivatives, Fair Value [Line Items]          
Assets derivatives - Notional amount $ 9,800   $ 9,800