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

Derivative instruments and hedging activities (Narrative) (Details)

v3.3.0.814
Derivative instruments and hedging activities (Narrative) (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2015
Sep. 30, 2014
Sep. 30, 2015
Sep. 30, 2014
Dec. 31, 2014
Derivatives, Fair Value [Line Items]          
Gains (loss) on derivative instrument $ (200) $ 4,600 $ 3,400 $ 4,700  
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member] | Cash Flow Hedge [Member]          
Derivatives, Fair Value [Line Items]          
Assets derivatives - Notional amount 22,000   22,000    
Foreign Exchange Contract [Member] | Other current assets [Member] | Not Designated as Hedging Instrument [Member]          
Derivatives, Fair Value [Line Items]          
Assets derivatives - Notional amount 37,993   37,993   $ 45,000
Foreign Exchange Contract [Member] | Accrued expenses and other current liabilities [Member] | Designated as Hedging Instrument [Member] | Cash Flow Hedge [Member]          
Derivatives, Fair Value [Line Items]          
Assets derivatives - Notional amount 9,518   9,518  
Liability derivatives - Notional amount 12,500   12,500   $ 38,426
Foreign Exchange Contract [Member] | Accrued expenses and other current liabilities [Member] | Not Designated as Hedging Instrument [Member]          
Derivatives, Fair Value [Line Items]          
Liability derivatives - Notional amount $ 26,737   $ 26,737   $ 18,424