Derivatives (Derivatives Not Designated as Hedging Instruments - Foreign Exchange Contracts) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Derivative [Line Items]
Derivative assets - Fair value	$ 358,639	$ 107,816
Derivative liabilities - Fair value	263,734	118,305
Derivatives not designated as hedging instruments
Derivative [Line Items]
Notional amount	18,988,712	15,222,341
Derivative assets - Fair value	358,639	107,816
Derivative liabilities - Fair value	260,499	111,828
Derivatives not designated as hedging instruments \| Foreign exchange contracts
Derivative [Line Items]
Notional amount	4,638,136	3,407,522
Derivative assets - Fair value	59,512	21,624
Derivative liabilities - Fair value	50,397	19,329
Foreign exchange contracts \| Customer Counterparty \| Derivatives not designated as hedging instruments \| Forwards and spot
Derivative [Line Items]
Notional amount	3,205,662	2,023,425
Derivative assets - Fair value	46,233	11,719
Derivative liabilities - Fair value	34,023	13,079
Foreign exchange contracts \| Customer Counterparty \| Derivatives not designated as hedging instruments \| Swaps
Derivative [Line Items]
Notional amount	10,091	21,108
Derivative assets - Fair value	77	348
Derivative liabilities - Fair value	217	243
Foreign exchange contracts \| Customer Counterparty \| Derivatives not designated as hedging instruments \| Written options
Derivative [Line Items]
Notional amount	85,379	537
Derivative assets - Fair value	640	16
Derivative liabilities - Fair value	0	0
Foreign exchange contracts \| Customer Counterparty \| Derivatives not designated as hedging instruments \| Collars
Derivative [Line Items]
Notional amount	5,344	83,864
Derivative assets - Fair value	30	0
Derivative liabilities - Fair value	209	370
Foreign exchange contracts \| Customer Counterparty \| Derivatives not designated as hedging instruments \| Foreign exchange contracts
Derivative [Line Items]
Notional amount	3,306,476	2,128,934
Derivative assets - Fair value	46,980	12,083
Derivative liabilities - Fair value	34,449	13,692
Foreign exchange contracts \| Financial Counterparty \| Derivatives not designated as hedging instruments \| Forwards and spot
Derivative [Line Items]
Notional amount	321,044	506,342
Derivative assets - Fair value	2,538	3,407
Derivative liabilities - Fair value	5,171	2,285
Foreign exchange contracts \| Financial Counterparty \| Derivatives not designated as hedging instruments \| Swaps
Derivative [Line Items]
Notional amount	760,748	687,845
Derivative assets - Fair value	7,239	5,764
Derivative liabilities - Fair value	7,554	3,336
Foreign exchange contracts \| Financial Counterparty \| Derivatives not designated as hedging instruments \| Purchased options
Derivative [Line Items]
Notional amount	85,379	537
Derivative assets - Fair value	0	0
Derivative liabilities - Fair value	640	16
Foreign exchange contracts \| Financial Counterparty \| Derivatives not designated as hedging instruments \| Collars
Derivative [Line Items]
Notional amount	164,489	83,864
Derivative assets - Fair value	2,755	370
Derivative liabilities - Fair value	2,583	0
Foreign exchange contracts \| Financial Counterparty \| Derivatives not designated as hedging instruments \| Foreign exchange contracts
Derivative [Line Items]
Notional amount	1,331,660	1,278,588
Derivative assets - Fair value	12,532	9,541
Derivative liabilities - Fair value	$ 15,948	$ 5,637

Fair value, before 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 elected not to be offset.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

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- Definition

Fair value, before 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 elected not to be offset.

+ References

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- Definition

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.

+ References

No definition available.

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- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959

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