Derivatives Notional Amounts (Details) (USD $)	3 Months Ended																											12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended
	Mar. 31, 2014 Foreign Exchange Forward [Member]	Mar. 31, 2013 Foreign Exchange Forward [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member]	Mar. 31, 2013 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member]	Mar. 31, 2013 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member] EUR / AUD [Member]	Mar. 31, 2013 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member] EUR / AUD [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member] EUR / DKK [Member]	Mar. 31, 2013 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member] EUR / DKK [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member] AUD / EUR [Member]	Mar. 31, 2013 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member] AUD / EUR [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member] AUD / GBP [Member]	Mar. 31, 2013 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member] AUD / GBP [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member]	Mar. 31, 2013 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member]	Mar. 31, 2013 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member]	Mar. 31, 2013 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member]	Mar. 31, 2013 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member]	Mar. 31, 2013 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member]	Mar. 31, 2013 Foreign Exchange Forward [Member] Not Designated as Hedging Instrument [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member]	Dec. 31, 2013 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] EUR / AUD [Member]	Dec. 31, 2013 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] EUR / AUD [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] EUR / DKK [Member]	Dec. 31, 2013 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] EUR / DKK [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] DKK / SEK [Member]	Dec. 31, 2013 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] DKK / SEK [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member]	Dec. 31, 2013 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member]	Dec. 31, 2013 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member]	Dec. 31, 2013 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member]	Dec. 31, 2013 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member]	Dec. 31, 2013 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member]	Dec. 31, 2013 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member]	Dec. 31, 2013 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member]	Dec. 31, 2013 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] EUR / CAD [Member]	Dec. 31, 2013 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] EUR / CAD [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] EUR / CHF [Member]	Dec. 31, 2013 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] EUR / CHF [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] EUR / GBP [Member]	Dec. 31, 2013 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] EUR / GBP [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] EUR / SEK [Member]	Dec. 31, 2013 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] EUR / SEK [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] AUD / CAD [Member]	Dec. 31, 2013 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] AUD / CAD [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] EUR / NZD [Member]	Dec. 31, 2013 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] EUR / NZD [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] GBP / CHF [Member]	Dec. 31, 2013 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] GBP / CHF [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] GBP / SEK [Member]	Dec. 31, 2013 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] GBP / SEK [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] NOK / CHF [Member]	Dec. 31, 2013 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] NOK / CHF [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] AUD / NZD [Member]	Dec. 31, 2013 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] AUD / NZD [Member]	Mar. 31, 2014 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] EUR / NOK [Member]	Dec. 31, 2013 Foreign Exchange Forward [Member] Designated as Hedging Instrument [Member] EUR / NOK [Member]	Mar. 31, 2014 Minimum [Member]	Mar. 31, 2014 Maximum [Member]
Derivative [Line Items]
Derivative, Percentage of Forcasted Transactions With Currency Rate Exposure																																																																									60.00%	90.00%
Notional Amount			$ 44,300,000	$ 51,556,000	$ 2,100,000	$ 0	$ 0	$ 1,500,000	$ 5,548,000	$ 0	$ 2,106,000	$ 0	$ 0	$ 2,966,000	$ 5,612,000	$ 24,120,000	$ 1,482,000	$ 0	$ 15,138,000	$ 0	$ 5,000,000	$ 0	$ 678,000	$ 0	$ 6,636,000	$ 22,970,000	$ 116,359,000	$ 135,009,000	$ 500,000	$ 0	$ 1,096,000	$ 1,382,000	$ 3,981,000	$ 5,337,000	$ 1,650,000	$ 0	$ 10,600,000	$ 11,730,000	$ 339,000	$ 486,000	$ 39,317,000	$ 51,106,000	$ 2,132,000	$ 2,686,000	$ 1,204,000	$ 0	$ 1,734,000	$ 2,485,000	$ 8,683,000	$ 5,960,000	$ 1,326,000	$ 1,710,000	$ 2,322,000	$ 2,654,000	$ 23,440,000	$ 29,614,000	$ 2,790,000	$ 3,432,000	$ 1,323,000	$ 0	$ 5,679,000	$ 6,959,000	$ 661,000	$ 837,000	$ 1,644,000	$ 2,078,000	$ 2,575,000	$ 3,418,000	$ 883,000	$ 0	$ 2,480,000	$ 3,135,000
Unrealized Gain (Loss)																											(1,373,000)	(781,000)	(16,000)	0	(3,000)	(5,000)	(29,000)	(94,000)	(54,000)	0	(207,000)	(66,000)	(8,000)	4,000	(767,000)	(168,000)	(85,000)	(45,000)	(47,000)	0	(5,000)	58,000	174,000	102,000	71,000	(1,000)	32,000	1,000	(601,000)	(501,000)	11,000	75,000	(18,000)	0	224,000	(111,000)	(16,000)	(26,000)	(78,000)	(101,000)	24,000	31,000	(6,000)	0	31,000	66,000
Amount of Gain (Loss) Recognized in Income on Derivatives	$ (345,000)	$ (1,171,000)	$ (345,000)	$ (1,171,000)	$ (52,000)	$ 0	$ 0	$ (35,000)	$ (9,000)	$ 0	$ (6,000)	$ 0	$ 0	$ 6,000	$ (184,000)	$ (544,000)	$ (40,000)	$ 0	$ 18,000	$ 0	$ (86,000)	$ 0	$ 1,000	$ 0	$ 13,000	$ (598,000)