XML 67 R54.htm IDEA: XBRL DOCUMENT
v3.22.4

Note 5 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Loans and Allowance for Loan Losses by Evaluation Method (Details) - USD ($) $ in Thousands | Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020
--- | --- | --- | ---
Allowance for loan losses, Individually evaluated for impairment | $ 0 | $ 0 |
Allowance for loan losses, Collectively evaluated for impairment | 8,225 | 7,674 |
Allowance for loan losses | 8,225 | 7,674 | $ 8,481
Loans, Individually evaluated for impairment | 3,032 | 5,878 |
Loans, Collectively evaluated | 850,161 | 797,851 |
Loans | 853,193 | 803,729 |
Real Estate Construction Portfolio Segment[Member] |  |  |
Allowance for loan losses, Individually evaluated for impairment | 0 | 0 |
Allowance for loan losses, Collectively evaluated for impairment | 450 | 422 |
Allowance for loan losses | 450 | 422 | 503
Loans, Individually evaluated for impairment | 0 | 0 |
Loans, Collectively evaluated | 54,579 | 48,841 |
Loans | 54,579 | 48,841 |
Consumer Real Estate Portfolio Segment [Member] |  |  |
Allowance for loan losses, Individually evaluated for impairment | 0 | 0 |
Allowance for loan losses, Collectively evaluated for impairment | 2,199 | 1,930 |
Allowance for loan losses | 2,199 | 1,930 | 2,165
Loans, Individually evaluated for impairment | 186 | 191 |
Loans, Collectively evaluated | 220,866 | 208,786 |
Loans | 221,052 | 208,977 |
Commercial Real Estate Portfolio Segment [Member] |  |  |
Allowance for loan losses, Individually evaluated for impairment | 0 | 0 |
Allowance for loan losses, Collectively evaluated for impairment | 3,642 | 3,121 |
Allowance for loan losses | 3,642 | 3,121 | 3,853
Loans, Individually evaluated for impairment | 2,583 | 5,386 |
Loans, Collectively evaluated | 435,305 | 400,336 |
Loans | 437,888 | 405,722 |
Commercial Non Real Estate Segment [Member] |  |  |
Allowance for loan losses, Individually evaluated for impairment | 0 | 0 |
Allowance for loan losses, Collectively evaluated for impairment | 930 | 1,099 |
Allowance for loan losses | 930 | 1,099 | 670
Loans, Individually evaluated for impairment | 263 | 301 |
Loans, Collectively evaluated | 57,389 | 59,963 |
Loans | 57,652 | 60,264 |
Public Sector and IDA Portfolio Segment[Member] |  |  |
Allowance for loan losses, Individually evaluated for impairment | 0 | 0 |
Allowance for loan losses, Collectively evaluated for impairment | 319 | 297 |
Allowance for loan losses | 319 | 297 | 339
Loans, Individually evaluated for impairment | 0 | 0 |
Loans, Collectively evaluated | 48,074 | 47,899 |
Loans | 48,074 | 47,899 |
Consumer Non Real Estate Portfolio Segment [Member] |  |  |
Allowance for loan losses, Individually evaluated for impairment | 0 | 0 |
Allowance for loan losses, Collectively evaluated for impairment | 506 | 444 |
Allowance for loan losses | 506 | 444 | 555
Loans, Individually evaluated for impairment | 0 | 0 |
Loans, Collectively evaluated | 33,948 | 32,026 |
Loans | 33,948 | 32,026 |
Unallocated Financing Receivables [Member] |  |  |
Allowance for loan losses, Individually evaluated for impairment | 0 | 0 |
Allowance for loan losses, Collectively evaluated for impairment | 179 | 361 |
Allowance for loan losses | 179 | 361 | $ 396
Loans, Individually evaluated for impairment | 0 | 0 |
Loans, Collectively evaluated | 0 | 0 |
Loans | $ 0 | $ 0 |

X
- Definition The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (g) -URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (g) -URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The balance of financing receivables that were collectively evaluated for impairment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (h) -URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The balance of financing receivables that were individually evaluated for impairment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (h) -URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SAB Topic 6.L.1) -URI https://asc.fasb.org/extlink&oid=122038336&loc=d3e74567-122707 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (g) -URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (b)(1)(ii) -URI https://asc.fasb.org/extlink&oid=121614798&loc=d3e15032-111544 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524 + Details
Name: | us-gaap_LoansAndLeasesReceivableAllowance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI https://asc.fasb.org/extlink&oid=124259787&loc=d3e4428-111522 + Details
Name: | us-gaap_LoansAndLeasesReceivableGrossCarryingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=nksh_RealEstateConstructionPortfolioSegmentMember
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=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_FinancingReceivablePortfolioSegmentAxis=us-gaap_UnallocatedFinancingReceivablesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |