Summary of Fair Value Measurements on a Recurring Basis (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	$ 79,837	$ 14,800
Derivative Assets
Foreign currency contracts assets	14,879	5,548
Derivative Liabilities
Foreign currency contracts liabilities	295	295
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	79,837	14,800
Level 2 [Member]
Derivative Assets
Foreign currency contracts assets	14,879	5,548
Derivative Liabilities
Foreign currency contracts liabilities	295	295
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents
Derivative Assets
Foreign currency contracts assets
Derivative Liabilities
Foreign currency contracts liabilities