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Derivative instruments and hedging activities (Narrative) (Details)
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3 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
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Mar. 31, 2015
USD ($)
|
Mar. 31, 2014
USD ($)
|
Mar. 31, 2015
Foreign Exchange Contract [Member]
Other current assets [Member]
Not Designated as Hedging Instrument [Member]
USD ($)
|
Mar. 31, 2015
Foreign Exchange Contract [Member]
Other current assets [Member]
Not Designated as Hedging Instrument [Member]
EUR (€)
|
Dec. 31, 2014
Foreign Exchange Contract [Member]
Other current assets [Member]
Not Designated as Hedging Instrument [Member]
USD ($)
|
Mar. 31, 2015
Foreign Exchange Contract [Member]
Accrued expenses and other current liabilities [Member]
Designated as Hedging Instrument [Member]
Cash Flow Hedge [Member]
USD ($)
|
Dec. 31, 2014
Foreign Exchange Contract [Member]
Accrued expenses and other current liabilities [Member]
Designated as Hedging Instrument [Member]
Cash Flow Hedge [Member]
USD ($)
|
Mar. 31, 2015
Foreign Exchange Contract [Member]
Accrued expenses and other current liabilities [Member]
Not Designated as Hedging Instrument [Member]
USD ($)
|
Mar. 31, 2015
Foreign Exchange Contract [Member]
Accrued expenses and other current liabilities [Member]
Not Designated as Hedging Instrument [Member]
ILS
|
Dec. 31, 2014
Foreign Exchange Contract [Member]
Accrued expenses and other current liabilities [Member]
Not Designated as Hedging Instrument [Member]
USD ($)
|
|
| Derivatives, Fair Value [Line Items] | ||||||||||
| Assets derivatives - Notional amount | $ 46,050,000 | € 39,400,000 | $ 45,000,000 | |||||||
| Liability derivatives - Notional amount | 38,794,000 | 38,426,000 | 12,686,000 | 46,100,000 | 18,424,000 | |||||
| Gain (loss) on derivative instrument | 4,200,000 | (1,000,000) | ||||||||
| Fair value adjustments on derivatives designated as cash flow hedges | $ 380,000 | $ (128,000) | ||||||||