Summary of Significant Accounting Policies - Fair Value Measurements (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014
Assets and liabilities carried at fair value measured on a recurring basis
Trading securities	$ 10,371	$ 13,172
Maximum Length of Time Hedged in Foreign Currency Cash Flow Hedge	6 months
Fair value measured on recurring basis \| Quoted prices in active markets (Level 1)
Assets and liabilities carried at fair value measured on a recurring basis
Money market funds		0
Time deposits	$ 0	0
Trading securities	9,514	12,428
Available-for-sale Securities	624	1,457
Derivative liabilities		0
Fair value measured on recurring basis \| Significant other observable inputs (Level 2)
Assets and liabilities carried at fair value measured on a recurring basis
Money market funds		36,828
Time deposits	18,645	16,204
Trading securities	857	744
Available-for-sale Securities	0	0
Derivative liabilities		2,411
Fair value measured on recurring basis \| Significant unobservable inputs (Level 3)
Assets and liabilities carried at fair value measured on a recurring basis
Money market funds		0
Time deposits	0	0
Trading securities	0	0
Available-for-sale Securities	0	0
Derivative liabilities		0
Fair value measured on recurring basis \| Estimated Fair Value
Assets and liabilities carried at fair value measured on a recurring basis
Money market funds		36,828
Time deposits	18,645	16,204
Trading securities	10,371	13,172
Available-for-sale Securities	$ 624	1,457
Derivative liabilities		$ 2,411

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Fair value portion of liability contracts related to the exchange of different currencies, including, but not limited to, foreign currency options, forward (delivery or nondelivery) contracts, and swaps entered into.

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Maximum period of time the entity is hedging its exposure to variability in future cash flows for forecasted transactions, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Excludes forecasted transactions related to payment of variable interest on existing financial instruments.

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Investment in short-term money-market instruments (such as commercial paper, banker's acceptances, repurchase agreements, government securities, certificates of deposit, and so forth) which are highly liquid (that is, readily convertible to known amounts of cash) and so near their maturity that they present an insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify as cash equivalents by definition. Original maturity means an original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Amount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.

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