Derivatives - Notional Amounts - Not Designated as Hedges (Details) - USD ($)
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Not Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount $ 14,620,000 $ 40,165,000  
Gain (Loss) 195,000 (54,000)  
Foreign exchange forward      
Derivative [Line Items]      
Gain (Loss) 2,573,000 1,112,000 $ 338,000
Foreign exchange forward | Not Designated as Hedging Instrument      
Derivative [Line Items]      
Gain (Loss) 195,000 (54,000)  
AUD / USD | Not Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 5,800,000 8,051,000  
Gain (Loss) 204,000 337,000  
CAD / USD | Not Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 0 5,762,000  
Gain (Loss) 0 (4,000)  
CNY / USD | Not Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 5,556,000 9,943,000  
Gain (Loss) (24,000) (441,000)  
EUR / USD | Not Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 0 2,118,000  
Gain (Loss) 0 53,000  
DKK / USD | Not Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 0 7,927,000  
Gain (Loss) 0 125,000  
GBP / USD | Not Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 0 4,526,000  
Gain (Loss) 0 (106,000)  
NZD / AUD | Not Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 3,264,000 0  
Gain (Loss) 15,000 0  
NOK / USD | Not Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 0 1,838,000  
Gain (Loss) $ 0 $ (18,000)