Derivatives Notional Amounts - Not Designated as Hedges (Details) (Not Designated as Hedging Instrument [Member], USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended	3 Months Ended		9 Months Ended			12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Forward Exchange Contracts—net	Sep. 30, 2013 Forward Exchange Contracts—net	Sep. 30, 2014 Forward Exchange Contracts—net	Sep. 30, 2013 Forward Exchange Contracts—net	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 EUR / AUD [Member]	Dec. 31, 2013 EUR / AUD [Member]	Sep. 30, 2014 EUR / CAD [Member]	Dec. 31, 2013 EUR / CAD [Member]	Sep. 30, 2014 EUR / DKK [Member]	Dec. 31, 2013 EUR / DKK [Member]	Sep. 30, 2014 AUD / CAD [Member]	Dec. 31, 2013 AUD / CAD [Member]	Sep. 30, 2014 EUR / NOK [Member]	Dec. 31, 2013 EUR / NOK [Member]
Derivative [Line Items]
Notional Amount	$ 142,156	$ 34,059					$ 4,200	$ 225	$ 4,565	$ 0	$ 3,247	$ 0	$ 98,628	$ 14,867	$ 328	$ 1,645	$ 11,344	$ 0	$ 8,653	$ 0	$ 3,774	$ 0	$ 4,500	$ 3,824	$ 719	$ 0	$ 2,142	$ 2,039	$ 19	$ 0	$ 33	$ 5,470	$ 0	$ 5,989	$ 4	$ 0
Gain (Loss)	$ (2,384)	$ 370	$ (2,240)	$ 361	$ (2,384)	$ 617	$ 110	$ (1)	$ (103)	$ 0	$ (29)	$ 0	$ (1,617)	$ 250	$ (14)	$ 35	$ (580)	$ 0	$ (49)	$ 0	$ (52)	$ 0	$ 68	$ (1)	$ (32)	$ 0	$ (85)	$ 80	$ (1)	$ 0	$ 0	$ (3)	$ 0	$ 10	$ 0	$ 0