Investment Securities (Held-to-maturity Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity investment securities, at amortized cost (fair value of $240,000 at September 30, 2021 and $68,082 at December 31, 2020) (a)	$ 243,100	$ 66,458
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(236)	(60)
Gross Unrealized Gains	1,657	1,789
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	4,757	165
Debt Securities, Held-to-maturity, Fair Value	240,000	68,082
Amortized Cost	243,336	66,518
Debt securities, maturing 5 to 10 years, amortized cost	11,166
States and political subdivisions
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity investment securities, at amortized cost (fair value of $240,000 at September 30, 2021 and $68,082 at December 31, 2020) (a)	124,417	35,199
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(236)	(60)
Gross Unrealized Gains	675	510
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	2,421	165
Debt Securities, Held-to-maturity, Fair Value	122,435	35,484
Amortized Cost	124,417
Debt securities, maturing 5 to 10 years, amortized cost	2,511
Residential mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Gross Unrealized Gains	661	852
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	195	0
Debt Securities, Held-to-maturity, Fair Value	41,501	26,742
Amortized Cost	41,035
Debt securities, maturing 5 to 10 years, amortized cost	0
Commercial mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Gross Unrealized Gains	236	427
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	1,208	0
Debt Securities, Held-to-maturity, Fair Value	46,917	5,856
Amortized Cost	47,889
Debt securities, maturing 5 to 10 years, amortized cost	8,655
Agency Securities
Schedule of Held-to-maturity Securities [Line Items]
Gross Unrealized Gains	85
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	933
Debt Securities, Held-to-maturity, Fair Value	29,147
Amortized Cost	29,995
Debt securities, maturing 5 to 10 years, amortized cost	0
Reported Value Measurement [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity investment securities, at amortized cost (fair value of $240,000 at September 30, 2021 and $68,082 at December 31, 2020) (a)	243,100	66,458
Reported Value Measurement [Member] \| States and political subdivisions
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity investment securities, at amortized cost (fair value of $240,000 at September 30, 2021 and $68,082 at December 31, 2020) (a)	124,181	35,139
Reported Value Measurement [Member] \| Residential mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity investment securities, at amortized cost (fair value of $240,000 at September 30, 2021 and $68,082 at December 31, 2020) (a)	41,035	25,890
Reported Value Measurement [Member] \| Commercial mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity investment securities, at amortized cost (fair value of $240,000 at September 30, 2021 and $68,082 at December 31, 2020) (a)	47,889	5,429
Reported Value Measurement [Member] \| Agency Securities
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity investment securities, at amortized cost (fair value of $240,000 at September 30, 2021 and $68,082 at December 31, 2020) (a)	$ 29,995	$ 0

Amount of allowance for credit loss for debt security measured at amortized cost (held-to-maturity).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aaa)
-URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447

+ Details

Name:	us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, before allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=124255953&loc=SL82919253-210447

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7A
-URI http://asc.fasb.org/extlink&oid=123577603&loc=SL6953401-111524

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27232-111563

+ Details

Name:	us-gaap_HeldToMaturitySecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity).

+ References

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity).

+ References

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount, before other-than-temporary impairment (OTTI) accretion, of investment in debt securities measured at amortized cost (held-to-maturity).

+ References

No definition available.

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesAmortizedCostBeforeOtherThanTemporaryImpairment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value of investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27232-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(6))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5A
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123581744&loc=SL120269820-111563

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity) with single maturity date and allocated without single maturity date, maturing in sixth through tenth rolling fiscal year following current statement of financial position date. For interim and annual periods when interim period is reported on rolling approach.

+ References

No definition available.

+ Details

Name:	us-gaap_HeldtomaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_ScheduleOfHeldToMaturitySecuritiesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_ResidentialMortgageBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CommercialMortgageBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_AgencySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementBasisAxis=us-gaap_CarryingReportedAmountFairValueDisclosureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: