Investment Securities - Allowance for Credit Losses AFS (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Available-for-sale
Beginning balance	$ 5,800		$ 0
Provision for credit loss expense	0		12,800
Reduction due to sales	(2,078)		(2,078)
Net increase (decrease) in allowance on previously impaired securities	1,326	$ 0	1,326	$ 0
Securities charged-off	0		(7,000)
Ending balance	2,396		2,396
State and political subdivisions
Available-for-sale
Beginning balance	0		0
Provision for credit loss expense	0		0
Reduction due to sales	0		0
Net increase (decrease) in allowance on previously impaired securities	0	(1,183)	0	(1,183)
Securities charged-off	0		0
Ending balance	0		0
Other securities
Available-for-sale
Beginning balance	5,800		0
Provision for credit loss expense	0		12,800
Reduction due to sales	(2,078)		(2,078)
Net increase (decrease) in allowance on previously impaired securities	1,326	$ 1,183	1,326	$ 1,183
Securities charged-off	0		(7,000)
Ending balance	$ 2,396		$ 2,396

Amount of expense (reversal of expense) for allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), not intended to be sold and not more likely than not will be required to sell before recovery of amortized cost basis, with previously recorded allowance.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479106/326-30-50-9

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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- Definition

Amount of decrease in allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) from sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479106/326-30-50-9

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- Definition

Amount excluding accrued interest, of allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479130/326-30-45-1

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- Definition

Amount, excluding accrued interest, of decrease in allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) from writeoff.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479106/326-30-50-9

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- Definition

Amount, excluding accrued interest, of reversal of credit loss expense on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) transferred out of available-for-sale into investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 8B
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481830/320-10-45-8B

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