Investment Securities - Income Earned on Securities (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Non-taxable:
Total	$ 37,848	$ 27,128	$ 71,560	$ 48,701
Held-to-maturity
Taxable:
Taxable	10,578	837	12,490	1,350
Non-taxable:
Non-taxable	10,088	3,030	16,190	5,034
Available-for-sale
Taxable:
Taxable	11,217	13,757	27,453	23,364
Non-taxable:
Non-taxable	$ 5,965	$ 9,504	$ 15,427	$ 18,953

Interest income, securities, operating, by non-0taxable status [abstract]

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Amount of operating interest income, including amortization and accretion of premiums and discounts, on securities exempt from state, federal and other income tax.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.2)
-URI https://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

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-Publisher SEC
-Name Regulation S-K (SK)
-Number 229
-Section 1402
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-Publisher SEC
-Name Regulation S-K (SK)
-Number 229
-Section 1402
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Amount of operating interest income, including amortization and accretion of premiums and discounts, on securities subject to state, federal and other income tax.

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Amount before accretion (amortization) of purchase discount (premium) of interest income on nonoperating securities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.7(b))
-URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
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