Fair Value Measurements - Schedule of Fair Value of Marketable Securities and Foreign Currency Contracts (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed income available-for-sale securities	$ 251,969	[1]	$ 211,151	[1]
Foreign currency forward contracts, Assets	10,454	[2]	6,748	[2]
Foreign currency forward contracts, Liabilities	5,262	[3]	6,780	[3]
Quoted Prices in Active Markets for Identical Assets, Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed income available-for-sale securities	6,052	[1]	17,596	[1]
Significant Other Observable Inputs, Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed income available-for-sale securities	245,917	[1]	193,555	[1]
Foreign currency forward contracts, Assets	10,454	[2]	6,748	[2]
Foreign currency forward contracts, Liabilities	$ 5,262	[3]	$ 6,780	[3]

[1] Included in cash and cash equivalents, and short and long-term investments in the Company’s condensed consolidated balance sheets.

[2] Included in short-term derivative assets as prepaid expenses and other current assets in the Company’s condensed consolidated balance sheets.

[3] Included in short-term derivative liabilities as other accrued liabilities in the Company’s condensed consolidated balance sheets.