Commitments and Contingencies (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Standby Letters of Credit
Guarantor Obligations [Line Items]
Standby letters of credit	$ 116,302	$ 129,819
Qualified Affordable Housing Project investments	162,300	163,900
Commitments to Extend Credit
Guarantor Obligations [Line Items]
Unused Commitments to Extend Credit	12,775,929	12,098,417
Qualified Affordable Housing Project, Unfunded Commitments	$ 49,800	$ 53,700

Amount of investment in qualified affordable housing projects.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 740
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=116633289&loc=SL49122993-202985

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The current carrying amount of the liability for the freestanding or embedded guarantor's obligations under the guarantee or each group of similar guarantees.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121555522&loc=d3e12069-110248

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+ References

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Amount of commitment or contingent commitments to qualified affordable housing project investments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 740
-Section 50
-Paragraph 2
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=116633289&loc=SL49122993-202985

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Unused amount of commitments to extend credit to customers.

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