Noninterest Income - Foreign Exchange Fees (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 221,371	$ 122,459	$ 438,628	$ 233,821
Revenue not from contract with customer	112,379	70,230	175,498	114,386
Foreign exchange fees	38,506	34,077	76,554	67,904
Spot contract commissions
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	34,696	31,548	69,725	62,750
Forward contract commissions
Disaggregation of Revenue [Line Items]
Revenue not from contract with customer	3,778	2,455	6,773	4,940
Option premium fees
Disaggregation of Revenue [Line Items]
Revenue not from contract with customer	$ 32	$ 74	$ 56	$ 214

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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