Summary of Gain/Loss on Derivative Instruments (Details) (USD $)	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
Derivative Financial Instruments [Abstract]
Foreign currency exchange forwards	$ (710,000)	[1]	$ 4,287,000	[1]	$ (10,651,000)	[1]	$ 2,184,000	[1]
Foreign currency transaction gains/losses, gross	1,500,000		5,900,000		14,100,000		400,000
Foreign currency transaction losses, net	$ 814,000		$ (1,627,000)		$ 3,414,000		$ 2,649,000

[1] For the three and six months ended June 30, 2013, the net gains of $0.7 million and $10.7 million, respectively, associated with our foreign currency exchange forwards were offset by net unrealized and realized losses resulting from foreign currency transactions of $1.5 million and $14.1 million, respectively, resulting in net foreign currency transaction losses of $0.8 million and $3.4 million, respectively. For the three months ended June 30, 2012, the net loss of $4.3 million associated with our foreign currency exchange forwards was offset by net unrealized and realized gains resulting from foreign currency transactions of $5.9 million resulting in a net foreign currency transaction gain of $1.6 million. For the six months ended June 30, 2012, the net loss of $2.2 million associated with our foreign currency exchange forwards and net loss of $0.4 million associated with net unrealized and realized gains resulting from foreign currency transactions resulting in a net foreign currency transaction loss of $2.6 million.