XML 29 R30.htm IDEA: XBRL DOCUMENT
v3.2.0.727

Note 4 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans (Details) - Allowance for Loan Losses - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended | 12 Months Ended
--- | --- | --- | ---
Jun. 30, 2015 | Jun. 30, 2014 | Jun. 30, 2015 | Jun. 30, 2014 | Dec. 31, 2014
Financing Receivable, Allowance for Credit Losses [Line Items] |  |  |  |  |
Balance | $ 8,227 |  | $ 8,263 | $ 8,227 | $ 8,227
Charge-offs |  |  | (776) | (1,244) | (1,860)
Recoveries |  |  | 88 | 184 | 255
Provision for loan losses | 355 | $ 701 | 556 | 804 | 1,641
Balance, end | 8,131 | 7,971 | 8,131 | 7,971 | 8,263
Real Estate Construction Portfolio Segment[Member] |  |  |  |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |  |  |  |
Balance | 863 |  | 612 | 863 | 863
Charge-offs |  |  | 0 | (2) | (2)
Recoveries |  |  | 0 | 0 | 0
Provision for loan losses |  |  | (136) | (198) | (249)
Balance, end | 476 | 663 | 476 | 663 | 612
Consumer Real Estate Portfolio Segment [Member] |  |  |  |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |  |  |  |
Balance | 1,697 |  | 1,662 | 1,697 | 1,697
Charge-offs |  |  | (201) | (70) | (222)
Recoveries |  |  | 1 | 0 | 0
Provision for loan losses |  |  | 375 | (73) | 187
Balance, end | 1,837 | 1,554 | 1,837 | 1,554 | 1,662
Commercial Real Estate Portfolio Segment [Member] |  |  |  |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |  |  |  |
Balance | 3,685 |  | 3,537 | 3,685 | 3,685
Charge-offs |  |  | (116) | (943) | (1,201)
Recoveries |  |  | 24 | 25 | 50
Provision for loan losses |  |  | 373 | 1,023 | 1,003
Balance, end | 3,818 | 3,790 | 3,818 | 3,790 | 3,537
Commercial Portfolio Segment [Member] |  |  |  |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |  |  |  |
Balance | 989 |  | 1,475 | 989 | 989
Charge-offs |  |  | (330) | (79) | (89)
Recoveries |  |  | 0 | 131 | 132
Provision for loan losses |  |  | (204) | 15 | 443
Balance, end | 941 | 1,056 | 941 | 1,056 | 1,475
Public Sector and IDA Portfolio Segment[Member] |  |  |  |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |  |  |  |
Balance | 132 |  | 327 | 132 | 132
Charge-offs |  |  | 0 | 0 | 0
Recoveries |  |  | 0 | 0 | 0
Provision for loan losses |  |  | 159 | 146 | 195
Balance, end | 486 | 278 | 486 | 278 | 327
Consumer Portfolio Segment [Member] |  |  |  |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |  |  |  |
Balance | 576 |  | 602 | 576 | 576
Charge-offs |  |  | (129) | (150) | (346)
Recoveries |  |  | 63 | 28 | 73
Provision for loan losses |  |  | (22) | 98 | 299
Balance, end | 514 | 552 | 514 | 552 | 602
Unallocated Financing Receivables [Member] |  |  |  |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |  |  |  |
Balance | 285 |  | 48 | 285 | 285
Charge-offs |  |  | 0 | 0 | 0
Recoveries |  |  | 0 | 0 | 0
Provision for loan losses |  |  | 11 | (207) | (237)
Balance, end | $ 59 | $ 78 | $ 59 | $ 78 | $ 48

X
- 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_FinancingReceivableAllowanceForCreditLossesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of recovery of financing receivables doubtful of collection that were previously charged off. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(4) -URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of direct write-downs of financing receivables charged against the allowance. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953423-111524 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953423-111524 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.7(d)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (b)(1)(ii) -URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 6 -Section L -Subsection 1 + Details
Name: | us-gaap_LoansAndLeasesReceivableAllowance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of expense related to estimated loss from loan and lease transactions. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.11) -URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953423-111524 + Details
Name: | us-gaap_ProvisionForLoanAndLeaseLosses
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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=us-gaap_CommercialPortfolioSegmentMember
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=us-gaap_ConsumerPortfolioSegmentMember
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: |