Fair Value Measurement - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Available-for-sale securities:
Available-for-sale securities	$ 452,615	$ 425,963
Time deposits
Available-for-sale securities:
Available-for-sale securities	220,000	210,000
Money market funds
Available-for-sale securities:
Available-for-sale securities	110,461
Recurring \| Total Estimated Fair Value
Available-for-sale securities:
Totals	342,786	210,000
Liabilities:
Totals	1,613	0
Recurring \| Total Estimated Fair Value \| Interest rate contracts
Available-for-sale securities:
Derivative asset	201	0
Liabilities:
Interest rate contracts	1,322	0
Recurring \| Total Estimated Fair Value \| Foreign exchange forward contracts
Available-for-sale securities:
Derivative asset	12,124	0
Liabilities:
Interest rate contracts	291	0
Recurring \| Total Estimated Fair Value \| Time deposits
Available-for-sale securities:
Available-for-sale securities	220,000	210,000
Recurring \| Total Estimated Fair Value \| Money market funds
Available-for-sale securities:
Available-for-sale securities	110,461	0
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Available-for-sale securities:
Totals	110,461
Liabilities:
Totals	0
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Interest rate contracts
Available-for-sale securities:
Derivative asset	0
Liabilities:
Interest rate contracts	0
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Foreign exchange forward contracts
Available-for-sale securities:
Derivative asset	0
Liabilities:
Interest rate contracts	0
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Time deposits
Available-for-sale securities:
Available-for-sale securities	0
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Money market funds
Available-for-sale securities:
Available-for-sale securities	110,461
Recurring \| Significant Other Observable Inputs (Level 2)
Available-for-sale securities:
Totals	232,325	210,000
Liabilities:
Totals	1,613	0
Recurring \| Significant Other Observable Inputs (Level 2) \| Interest rate contracts
Available-for-sale securities:
Derivative asset	201	0
Liabilities:
Interest rate contracts	1,322	0
Recurring \| Significant Other Observable Inputs (Level 2) \| Foreign exchange forward contracts
Available-for-sale securities:
Derivative asset	12,124	0
Liabilities:
Interest rate contracts	291	0
Recurring \| Significant Other Observable Inputs (Level 2) \| Time deposits
Available-for-sale securities:
Available-for-sale securities	220,000	210,000
Recurring \| Significant Other Observable Inputs (Level 2) \| Money market funds
Available-for-sale securities:
Available-for-sale securities	$ 0	$ 0

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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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.

+ References

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Fair value of financial obligations, including, but not limited to, debt instruments, derivative liabilities, federal funds purchased and sold under agreements to repurchase, securities loaned or sold under agreements to repurchase, financial instruments sold not yet purchased, guarantees, line of credit, loans and notes payable, servicing liability, and trading liabilities.

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