Financial Instruments (Details) $ in Thousands, € in Millions	3 Months Ended
	Mar. 31, 2016 USD ($)	Mar. 31, 2015 USD ($)	Mar. 31, 2016 EUR (€)	Dec. 31, 2015 USD ($)	Dec. 31, 2015 EUR (€)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
swiss franc per euro floor	1.2		1.2
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	$ 1,000	$ (9,300)
Not Designated as Hedging Instrument [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	295,800			$ 318,700
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	3,400
Foreign Exchange Forward [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Unrealized Gain (Loss) on Foreign Currency Derivatives, Net, before Tax	(500)	22,800
Gain (Loss) on Interest Rate Cash Flow Hedge Ineffectiveness	0	0
2.52% $50 Million Interest Rate Swap [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Line Of Credit Facility Forecasted Borrowing Amount	$ 50,000
Derivative, Fixed Interest Rate	2.52%		2.52%
Gain (Loss) on Interest Rate Cash Flow Hedge Ineffectiveness	$ 0	$ 0
2.25% $100 Million Interest Rate Swap [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Line Of Credit Facility Forecasted Borrowing Amount	$ 100,000
Derivative, Fixed Interest Rate	2.25%		2.25%
Derivative Maturing in 2015 [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Value Local Currency	$ 86,000
Derivative, Forward Exchange Rate	1.21		1.21
Derivative Maturing in 2016 [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Value Local Currency	$ 67,000
Derivative, Forward Exchange Rate	1.19		1.19
Derivative Maturing in 2016 [Member] | Foreign Exchange Forward [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	$ 57,900			$ 73,000
Notional Value Local Currency | €			€ 51.6		€ 67.0