XML 47 R40.htm IDEA: XBRL DOCUMENT v3.25.3

Note 3 - Loans and Allowance for Credit Losses - Past Due and Nonaccrual Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Loans, gross	$ 1,016,945	$ 988,613
Nonaccruals	2,027	2,222
Nonaccruals, no allowance	1,833	2,013
Nonaccruals, with allowance	194	209
Financial Asset, Not Past Due [Member]
Loans, gross	1,011,854	982,894
Financing Receivables 30 to 89 Days Past Due [Member]
Loans, gross	2,781	2,949
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, gross	477	757
Loans 90 or more days past due and accruing	283	548
Consumer Real Estate Portfolio Segment [Member]
Loans, gross	324,597	307,855
Real Estate Construction Portfolio Segment [Member]
Loans, gross	46,381	50,798
Commercial Real Estate Portfolio Segment [Member]
Loans, gross	490,968	478,078
Commercial Non Real Estate Segment [Member]
Loans, gross	53,532	51,844
Public Sector and IDA Portfolio Segment [Member]
Loans, gross	54,332	57,171
Nonaccruals	0	0
Public Sector and IDA Portfolio Segment [Member] | Financial Asset, Not Past Due [Member]
Loans, gross	54,332	57,171
Public Sector and IDA Portfolio Segment [Member] | Financing Receivables 30 to 89 Days Past Due [Member]
Loans, gross	0	0
Public Sector and IDA Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, gross	0	0
Loans 90 or more days past due and accruing	0	0
Consumer Non Real Estate Portfolio Segment [Member]
Loans, gross	47,135	42,867
Construction, 1-4 Family Residential [Member] | Real Estate Construction Portfolio Segment [Member]
Loans, gross	17,527	16,162
Nonaccruals	0	0
Construction, 1-4 Family Residential [Member] | Real Estate Construction Portfolio Segment [Member] | Financial Asset, Not Past Due [Member]
Loans, gross	17,527	16,162
Construction, 1-4 Family Residential [Member] | Real Estate Construction Portfolio Segment [Member] | Financing Receivables 30 to 89 Days Past Due [Member]
Loans, gross	0	0
Construction, 1-4 Family Residential [Member] | Real Estate Construction Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, gross	0	0
Loans 90 or more days past due and accruing	0	0
Construction, Other [Member] | Real Estate Construction Portfolio Segment [Member]
Loans, gross	28,854	34,636
Nonaccruals	0	0
Construction, Other [Member] | Real Estate Construction Portfolio Segment [Member] | Financial Asset, Not Past Due [Member]
Loans, gross	28,818	34,636
Construction, Other [Member] | Real Estate Construction Portfolio Segment [Member] | Financing Receivables 30 to 89 Days Past Due [Member]
Loans, gross	36	0
Construction, Other [Member] | Real Estate Construction Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, gross	0	0
Loans 90 or more days past due and accruing	0	0
Equity Lines [Member] | Consumer Real Estate Portfolio Segment [Member]
Loans, gross	26,922	22,618
Nonaccruals	0	0
Equity Lines [Member] | Consumer Real Estate Portfolio Segment [Member] | Financial Asset, Not Past Due [Member]
Loans, gross	26,922	22,551
Equity Lines [Member] | Consumer Real Estate Portfolio Segment [Member] | Financing Receivables 30 to 89 Days Past Due [Member]
Loans, gross	0	67
Equity Lines [Member] | Consumer Real Estate Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, gross	0	0
Loans 90 or more days past due and accruing	0	0
Closed End First Liens [Member] | Consumer Real Estate Portfolio Segment [Member]
Loans, gross	195,826	171,382
Nonaccruals	0	0
Closed End First Liens [Member] | Consumer Real Estate Portfolio Segment [Member] | Financial Asset, Not Past Due [Member]
Loans, gross	194,837	170,110
Closed End First Liens [Member] | Consumer Real Estate Portfolio Segment [Member] | Financing Receivables 30 to 89 Days Past Due [Member]
Loans, gross	909	949
Closed End First Liens [Member] | Consumer Real Estate Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, gross	80	323
Loans 90 or more days past due and accruing	80	323
Closed End Junior Liens [Member] | Consumer Real Estate Portfolio Segment [Member]
Loans, gross	10,483	8,574
Nonaccruals	0	0
Closed End Junior Liens [Member] | Consumer Real Estate Portfolio Segment [Member] | Financial Asset, Not Past Due [Member]
Loans, gross	10,476	8,565
Closed End Junior Liens [Member] | Consumer Real Estate Portfolio Segment [Member] | Financing Receivables 30 to 89 Days Past Due [Member]
Loans, gross	7	9
Closed End Junior Liens [Member] | Consumer Real Estate Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, gross	0	0
Loans 90 or more days past due and accruing	0	0
Investor Owned Residential Real Estate [Member] | Consumer Real Estate Portfolio Segment [Member]
Loans, gross	91,366	105,281
Nonaccruals	0	0
Investor Owned Residential Real Estate [Member] | Consumer Real Estate Portfolio Segment [Member] | Financial Asset, Not Past Due [Member]
Loans, gross	91,138	104,756
Investor Owned Residential Real Estate [Member] | Consumer Real Estate Portfolio Segment [Member] | Financing Receivables 30 to 89 Days Past Due [Member]
Loans, gross	228	347
Investor Owned Residential Real Estate [Member] | Consumer Real Estate Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, gross	0	178
Loans 90 or more days past due and accruing	0	178
Multifamily Real Estate [Member] | Consumer Real Estate Portfolio Segment [Member]
Loans, gross	162,679
Multifamily Real Estate [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans, gross	162,679	143,630
Nonaccruals	0	0
Multifamily Real Estate [Member] | Commercial Real Estate Portfolio Segment [Member] | Financial Asset, Not Past Due [Member]
Loans, gross	162,129	143,444
Multifamily Real Estate [Member] | Commercial Real Estate Portfolio Segment [Member] | Financing Receivables 30 to 89 Days Past Due [Member]
Loans, gross	356	186
Multifamily Real Estate [Member] | Commercial Real Estate Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, gross	194	0
Loans 90 or more days past due and accruing	194	0
Commercial Real Estate, Owner Occupied [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans, gross	134,093	140,653
Nonaccruals	2,027	2,222
Nonaccruals, no allowance	1,833	2,013
Nonaccruals, with allowance	194	209
Commercial Real Estate, Owner Occupied [Member] | Commercial Real Estate Portfolio Segment [Member] | Financial Asset, Not Past Due [Member]
Loans, gross	132,066	138,284
Commercial Real Estate, Owner Occupied [Member] | Commercial Real Estate Portfolio Segment [Member] | Financing Receivables 30 to 89 Days Past Due [Member]
Loans, gross	0	147
Commercial Real Estate, Owner Occupied [Member] | Commercial Real Estate Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, gross	194	209
Loans 90 or more days past due and accruing	0	0
Commercial Real Estate Other [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans, gross	194,196	193,795
Nonaccruals	0	0
Commercial Real Estate Other [Member] | Commercial Real Estate Portfolio Segment [Member] | Financial Asset, Not Past Due [Member]
Loans, gross	193,656	193,249
Commercial Real Estate Other [Member] | Commercial Real Estate Portfolio Segment [Member] | Financing Receivables 30 to 89 Days Past Due [Member]
Loans, gross	540	546
Commercial Real Estate Other [Member] | Commercial Real Estate Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, gross	0	0
Loans 90 or more days past due and accruing	0	0
Commercial and Industrial [Member] | Commercial Non Real Estate Segment [Member]
Loans, gross	53,532	51,844
Nonaccruals	0	0
Commercial and Industrial [Member] | Commercial Non Real Estate Segment [Member] | Financial Asset, Not Past Due [Member]
Loans, gross	53,420	51,547
Commercial and Industrial [Member] | Commercial Non Real Estate Segment [Member] | Financing Receivables 30 to 89 Days Past Due [Member]
Loans, gross	112	253
Commercial and Industrial [Member] | Commercial Non Real Estate Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, gross	0	44
Loans 90 or more days past due and accruing	0	44
Commercial and Industrial [Member] | Consumer Non Real Estate Portfolio Segment [Member]
Loans, gross	53,532
Credit Card Receivable [Member] | Consumer Non Real Estate Portfolio Segment [Member]
Loans, gross	4,696	4,698
Nonaccruals	0	0
Credit Card Receivable [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Financial Asset, Not Past Due [Member]
Loans, gross	4,687	4,696
Credit Card Receivable [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Financing Receivables 30 to 89 Days Past Due [Member]
Loans, gross	4	2
Credit Card Receivable [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, gross	5	0
Loans 90 or more days past due and accruing	5	0
Automobile Loan [Member] | Consumer Non Real Estate Portfolio Segment [Member]
Loans, gross	12,310	12,995
Nonaccruals	0	0
Automobile Loan [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Financial Asset, Not Past Due [Member]
Loans, gross	12,168	12,802
Automobile Loan [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Financing Receivables 30 to 89 Days Past Due [Member]
Loans, gross	142	193
Automobile Loan [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, gross	0	0
Loans 90 or more days past due and accruing	0	0
Other Consumer Loans [Member] | Consumer Non Real Estate Portfolio Segment [Member]
Loans, gross	30,129	25,174
Nonaccruals	0	0
Other Consumer Loans [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Financial Asset, Not Past Due [Member]
Loans, gross	29,678	24,921
Other Consumer Loans [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Financing Receivables 30 to 89 Days Past Due [Member]
Loans, gross	447	250
Other Consumer Loans [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Loans, gross	4	3
Loans 90 or more days past due and accruing	$ 4	$ 3

X

- Definition

Amortized cost, before allowance for credit loss, fee, and loan in process, of financing receivable. Excludes financing receivable covered under loss sharing agreement and net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481990/310-10-45-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-5

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(7))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

+ Details

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

X

- Definition

Amortized cost excluding accrued interest, of financing receivable on nonaccrual status. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-16

+ Details

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

X

- Definition

Amortized cost excluding accrued interest, of financing receivable on nonaccrual status with no allowance for credit loss. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-16

+ Details

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

X

- Definition

Amortized cost of financing receivable 90 days or more past due and still accruing. Excludes net investment in lease.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-7

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 80
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-80

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-16

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amortized cost of financing receivable on nonaccrual status. Excludes net investment in lease.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-7

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph a
-Subparagraph (3)
-Publisher SEC

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph a
-Subparagraph (2)
-Publisher SEC

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-16

+ Details

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

X

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancialAssetNotPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=nksh_FinancingReceivables30To89DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=nksh_ConsumerRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=nksh_RealEstateConstructionPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=nksh_CommercialNonRealEstateSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=nksh_PublicSectorAndIDAPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=nksh_ConsumerNonRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nksh_Construction14FamilyResidentialMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nksh_ConstructionOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nksh_EquityLinesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nksh_ClosedEndFirstLiensMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nksh_ClosedEndJuniorLiensMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nksh_InvestorOwnedResidentialRealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nksh_MultifamilyRealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nksh_CommercialRealEstateOwnerOccupiedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nksh_CommercialRealEstateOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nksh_CommercialAndIndustrialMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CreditCardReceivablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_AutomobileLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nksh_OtherConsumerLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: