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AFS Securities (Amortized cost and fair value of AFS securities by contractual maturity) (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale, Maturity, Amortized Cost, Rolling Maturity [Abstract]
Maturing, Due in One Year or Less	$ 15,866
Maturing, After One Year But Within Five Years	284,859
Maturing, After Five Years But Within Ten Years	26,622
Maturing, After Ten Years	26,840
Securities With Variable Monthly Payments or Noncontractual Maturities	208,769
Amortized Cost	562,956	$ 485,710
Debt Securities, Available-for-sale, Maturity, Fair Value, Rolling Maturity [Abstract]
Maturing, Due in One Year or Less, Fair value	15,917
Maturing, After One Year But Within Five Years, Fair value	271,929
Maturing, After Five Years But Within Ten Years, Fair value	26,157
Maturing, After Ten Years, Fair value	26,030
Securities With Variable Monthly Payments or Noncontractual Maturities, Fair value	204,886
Total, Fair value	544,919	490,601
States and political subdivisions [Member]
Debt Securities, Available-for-sale, Maturity, Amortized Cost, Rolling Maturity [Abstract]
Maturing, Due in One Year or Less	15,866
Maturing, After One Year But Within Five Years	52,934
Maturing, After Five Years But Within Ten Years	18,472
Maturing, After Ten Years	26,840
Securities With Variable Monthly Payments or Noncontractual Maturities	0
Amortized Cost	114,112	116,836
Debt Securities, Available-for-sale, Maturity, Fair Value, Rolling Maturity [Abstract]
Total, Fair value	114,015	121,205
Auction rate money market preferred [Member]
Debt Securities, Available-for-sale, Maturity, Amortized Cost, Rolling Maturity [Abstract]
Maturing, Due in One Year or Less	0
Maturing, After One Year But Within Five Years	0
Maturing, After Five Years But Within Ten Years	0
Maturing, After Ten Years	0
Securities With Variable Monthly Payments or Noncontractual Maturities	3,200
Amortized Cost	3,200	3,200
Debt Securities, Available-for-sale, Maturity, Fair Value, Rolling Maturity [Abstract]
Total, Fair value	2,867	3,242
Mortgage-backed securities [Member]
Debt Securities, Available-for-sale, Maturity, Amortized Cost, Rolling Maturity [Abstract]
Maturing, Due in One Year or Less	0
Maturing, After One Year But Within Five Years	0
Maturing, After Five Years But Within Ten Years	0
Maturing, After Ten Years	0
Securities With Variable Monthly Payments or Noncontractual Maturities	50,775
Amortized Cost	50,775	54,710
Debt Securities, Available-for-sale, Maturity, Fair Value, Rolling Maturity [Abstract]
Total, Fair value	49,578	56,148
Collateralized mortgage obligations [Member]
Debt Securities, Available-for-sale, Maturity, Amortized Cost, Rolling Maturity [Abstract]
Maturing, Due in One Year or Less	0
Maturing, After One Year But Within Five Years	0
Maturing, After Five Years But Within Ten Years	0
Maturing, After Ten Years	0
Securities With Variable Monthly Payments or Noncontractual Maturities	154,794
Amortized Cost	154,794	90,435
Debt Securities, Available-for-sale, Maturity, Fair Value, Rolling Maturity [Abstract]
Total, Fair value	152,441	92,301
Corporate Debt Securities
Debt Securities, Available-for-sale, Maturity, Amortized Cost, Rolling Maturity [Abstract]
Maturing, Due in One Year or Less	0
Maturing, After One Year But Within Five Years	0
Maturing, After Five Years But Within Ten Years	8,150
Maturing, After Ten Years	0
Securities With Variable Monthly Payments or Noncontractual Maturities	0
Amortized Cost	8,150	8,150
Debt Securities, Available-for-sale, Maturity, Fair Value, Rolling Maturity [Abstract]
Total, Fair value	7,750	8,002
US Treasury Securities
Debt Securities, Available-for-sale, Maturity, Amortized Cost, Rolling Maturity [Abstract]
Maturing, Due in One Year or Less	0
Maturing, After One Year But Within Five Years	231,925
Maturing, After Five Years But Within Ten Years	0
Maturing, After Ten Years	0
Securities With Variable Monthly Payments or Noncontractual Maturities	0
Amortized Cost	231,925	212,379
Debt Securities, Available-for-sale, Maturity, Fair Value, Rolling Maturity [Abstract]
Total, Fair value	$ 218,268	$ 209,703

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Available-for-sale Securities, Debt Maturities, With Variable Monthly Payments Or Without Single Maturity Date, Amortized Cost Basis

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Amortized cost of 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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27161-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
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Amount of 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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
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