Noninterest Income - Foreign Exchange Fees (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 205,905	$ 130,437	$ 644,533	$ 364,258
Revenue not from contract with customer	88,104	79,633	263,602	194,019
Foreign exchange fees	40,309	32,656	116,863	100,560
Spot contract commissions
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	36,836	30,041	106,561	92,791
Forward contract commissions
Disaggregation of Revenue [Line Items]
Revenue not from contract with customer	3,371	2,534	10,144	7,474
Option premium fees
Disaggregation of Revenue [Line Items]
Revenue not from contract with customer	$ 102	$ 81	$ 158	$ 295

Foreign exchange fees earned from the income differential between purchases and sales of foreign currency on behalf of clients.

No definition available.

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+ References

No definition available.

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Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045

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- Definition

Amount of revenue that is not accounted for under Topic 606.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(1))
-URI http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227

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