Summary of Significant Accounting Policies - Fair Value Measurements (Details) - Fair value measured on recurring basis - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Quoted prices in active markets (Level 1)
Assets and Liabilities Carried at Fair Value Measured on a Recurring Basis [Line Items]
Money Market Funds	$ 0
Time Deposits		$ 0
Trading securities	9,540	10,248
Derivative Assets	0	0
Derivative Liabilities	0	0
Significant other observable inputs (Level 2)
Assets and Liabilities Carried at Fair Value Measured on a Recurring Basis [Line Items]
Money Market Funds	30,123
Time Deposits		956
Trading securities	456	505
Derivative Assets	1,972	93
Derivative Liabilities	12,046	973
Significant unobservable inputs (Level 3)
Assets and Liabilities Carried at Fair Value Measured on a Recurring Basis [Line Items]
Money Market Funds	0
Time Deposits		0
Trading securities	0	0
Derivative Assets	0	0
Derivative Liabilities	0	0
Estimate of Fair Value Measurement
Assets and Liabilities Carried at Fair Value Measured on a Recurring Basis [Line Items]
Money Market Funds	30,123
Time Deposits		956
Trading securities	9,996	10,753
Derivative Assets	1,972	93
Derivative Liabilities	$ 12,046	$ 973

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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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.

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Any certificate of deposit or savings account held by a bank or other financial institution for a short-term specified period of time. Because of their short-term, time deposits are considered highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means 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.

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Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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