Fair Value Measurement - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Available-for-sale securities:
Available-for-sale securities	$ 824,622	$ 601,035
Recurring
Available-for-sale securities:
Totals	614,280	393,433
Liabilities:
Totals	1,460	5,409
Recurring \| Time deposits
Available-for-sale securities:
Available-for-sale securities	515,000	235,000
Recurring \| Money market funds
Available-for-sale securities:
Available-for-sale securities	94,016	140,800
Recurring \| Interest rate contracts
Available-for-sale securities:
Derivative asset	4,070	2,138
Liabilities:
Derivative Liability	0	392
Recurring \| Foreign exchange forward contracts
Available-for-sale securities:
Derivative asset	1,194	15,495
Liabilities:
Derivative Liability	1,460	5,017
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Recurring
Available-for-sale securities:
Totals	94,016	140,800
Liabilities:
Totals	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Recurring \| Time deposits
Available-for-sale securities:
Available-for-sale securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Recurring \| Money market funds
Available-for-sale securities:
Available-for-sale securities	94,016	140,800
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Recurring \| Interest rate contracts
Available-for-sale securities:
Derivative asset	0	0
Liabilities:
Derivative Liability	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Recurring \| Foreign exchange forward contracts
Available-for-sale securities:
Derivative asset	0	0
Liabilities:
Derivative Liability	0	0
Significant Other Observable Inputs (Level 2) \| Recurring
Available-for-sale securities:
Totals	520,264	252,633
Liabilities:
Totals	1,460	5,409
Significant Other Observable Inputs (Level 2) \| Recurring \| Time deposits
Available-for-sale securities:
Available-for-sale securities	515,000	235,000
Significant Other Observable Inputs (Level 2) \| Recurring \| Money market funds
Available-for-sale securities:
Available-for-sale securities	0	0
Significant Other Observable Inputs (Level 2) \| Recurring \| Interest rate contracts
Available-for-sale securities:
Derivative asset	4,070	2,138
Liabilities:
Derivative Liability	0	392
Significant Other Observable Inputs (Level 2) \| Recurring \| Foreign exchange forward contracts
Available-for-sale securities:
Derivative asset	1,194	15,495
Liabilities:
Derivative Liability	$ 1,460	$ 5,017

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

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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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.

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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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