XML 44 R34.htm IDEA: XBRL DOCUMENT
v3.22.2.2

Note 3 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Loans Past Due 90 Days or More and Impaired Loans (Details) - USD ($) $ in Thousands | 9 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2022 | Sep. 30, 2021 | Dec. 31, 2021
Loans past due 90 days or more and still accruing |  | $ 48 |  | $ 62 | $ 90 |
Ratio of loans past due 90 days or more and still accruing to loans, net of unearned income and deferred fees and costs |  | 0.01% |  | 0.01% | 0.01% |
Accruing restructured loans |  | $ 279 |  | $ 3,009 | $ 3,005 |
Impaired loans: |  |  |  |  |  |
Impaired loans with no valuation allowance |  | 3,049 | [1] | 6,084 | 5,878 | [1]
Impaired loans with a valuation allowance |  | 0 |  | 0 | 0 | [1]
Total impaired loans |  | 3,049 | [1] | 6,084 | 5,878 | [1]
Valuation allowance |  | 0 |  | 0 | 0 |
Impaired loans, net of allowance |  | 3,049 |  | 6,084 | 5,878 |
Average recorded investment in impaired loans(1) | [1] | 3,067 |  | 6,108 | 5,901 |
Interest income recognized on impaired loans, after designation as impaired |  | 13 |  | 175 | 137 |
Amount of income recognized on a cash basis |  | $ 0 |  | $ 0 | $ 0 |
[1] | Recorded investment is net of charge-offs and interest paid while a loan is in nonaccrual status.

X
- Definition Reflects the carrying amount of loans modified in a troubled debt restructuring that are accruing interest. + References No definition available. + Details
Name: | nksh_AccruingRestructuredLoans
Namespace Prefix: | nksh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses, net of allowance. + References No definition available. + Details
Name: | nksh_ImpairedLoansNetOfAllowance
Namespace Prefix: | nksh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Represents ratio of loans past due 90 days or more and still accruing to loans, net of unearned income and deferred fees. + References No definition available. + Details
Name: | nksh_RatioOfLoansPastDue90DaysOrMoreAndStillAccruingToLoans
Namespace Prefix: | nksh_
Data Type: | dtr-types:percentItemType
Balance Type: | na
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://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 16 -Subparagraph (c) -URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919258-210447 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 7 -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5111-111524 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 55 -Paragraph 80 -URI https://asc.fasb.org/extlink&oid=124267575&loc=SL82922355-210448 + Details
Name: | us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 17 -URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5258-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(2) -URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of interest income recognized on a cash-basis method of accounting that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(3) -URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableInterestIncomeCashBasisMethod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 14A -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953550-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_ImpairedFinancingReceivableRecordedInvestmentAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of allowance for credit losses related to recorded investment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(3) -URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableRelatedAllowance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of investment in impaired financing receivables for which there is no related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 14A -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953550-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in impaired financing receivables for which there is a related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 14A -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953550-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant