Derivatives - Notional Amounts - 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)  
Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 164,358,000 213,164,000  
Unrealized Gain (Loss) 776,000 2,183,000  
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)  
USD / AUD | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 5,841,000 2,910,000  
Unrealized Gain (Loss) 316,000 (83,000)  
USD / CAD | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 2,604,000 3,893,000  
Unrealized Gain (Loss) (18,000) 181,000  
USD / CHF | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 370,000 0  
Unrealized Gain (Loss) 15,000 0  
USD / CNY | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 11,252,000 16,786,000  
Unrealized Gain (Loss) (301,000) (282,000)  
USD / EUR | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 60,387,000 72,758,000  
Unrealized Gain (Loss) 1,826,000 2,681,000  
USD / GBP | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 3,253,000 3,862,000  
Unrealized Gain (Loss) (75,000) 22,000  
USD / NZD | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 9,650,000 4,893,000  
Unrealized Gain (Loss) (64,000) 37,000  
USD / SEK | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 4,923,000 5,128,000  
Unrealized Gain (Loss) 146,000 39,000  
USD / MXP | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 6,148,000 8,494,000  
Unrealized Gain (Loss) (417,000) (284,000)  
EUR / AUD | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 506,000 669,000  
Unrealized Gain (Loss) 6,000 (10,000)  
EUR / CAD | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 0 1,283,000  
Unrealized Gain (Loss) 0 (17,000)  
EUR / CHF | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 0 1,944,000  
Unrealized Gain (Loss) 0 (17,000)  
EUR / GBP | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 14,511,000 36,567,000  
Unrealized Gain (Loss) (686,000) (424,000)  
EUR / NOK | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 2,503,000 3,375,000  
Unrealized Gain (Loss) (25,000) (55,000)  
EUR / SEK | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 0 2,464,000  
Unrealized Gain (Loss) 0 (42,000)  
EUR / NZD | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 3,777,000 3,609,000  
Unrealized Gain (Loss) 16,000 476,000  
GBP / AUD | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 503,000 830,000  
Unrealized Gain (Loss) 34,000 (46,000)  
GBP / CHF | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 215,000 463,000  
Unrealized Gain (Loss) (10,000) (7,000)  
GBP / SEK | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 1,389,000 2,067,000  
Unrealized Gain (Loss) (42,000) (1,000)  
AUD / NZD | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 0 352,000  
Unrealized Gain (Loss) 0 8,000  
CHF / DKK | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 595,000 0  
Unrealized Gain (Loss) (2,000) 0  
DKK / SEK | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 31,978,000 37,293,000  
Unrealized Gain (Loss) 49,000 46,000  
NOK / CHF | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 1,335,000 0  
Unrealized Gain (Loss) (13,000) 0  
NOK / SEK | Designated as Hedging Instrument      
Derivative [Line Items]      
Notional Amount 2,618,000 3,524,000  
Unrealized Gain (Loss) $ 21,000 $ (39,000)