XML 62 R41.htm IDEA: XBRL DOCUMENT
v3.2.0.727

Note 5 - Securities (Details) - Securities Available-for-sale - USD ($) $ in Thousands | Jun. 30, 2015 | Dec. 31, 2014
--- | --- | ---
Available for Sale: |  |
Securities available-for-sale, amortized costs | $ 225,903 | $ 225,279
Securities available-for-sale, gross unrealized gains | 1,291 | 2,148
Securities available-for-sale, gross unrealized losses | 8,670 | 4,583
Securities available-for-sale, fair value | 218,524 | 222,844
US Government Agencies Debt Securities [Member] |  |
Available for Sale: |  |
Securities available-for-sale, amortized costs | 200,713 | 197,740
Securities available-for-sale, gross unrealized gains | 464 | 973
Securities available-for-sale, gross unrealized losses | 8,231 | 4,494
Securities available-for-sale, fair value | 192,946 | 194,219
US States and Political Subdivisions Debt Securities [Member] |  |
Available for Sale: |  |
Securities available-for-sale, amortized costs | 16,481 | 18,529
Securities available-for-sale, gross unrealized gains | 649 | 851
Securities available-for-sale, fair value | 17,130 | 19,380
Collateralized Mortgage Backed Securities [Member] |  |
Available for Sale: |  |
Securities available-for-sale, amortized costs | 1,530 | 1,830
Securities available-for-sale, gross unrealized gains | 160 | 184
Securities available-for-sale, fair value | 1,690 | 2,014
Corporate Debt Securities [Member] |  |
Available for Sale: |  |
Securities available-for-sale, amortized costs | 6,991 | 6,991
Securities available-for-sale, gross unrealized gains | 18 | 140
Securities available-for-sale, gross unrealized losses | 386 | 27
Securities available-for-sale, fair value | 6,623 | 7,104
Other Securities [Member] |  |
Available for Sale: |  |
Securities available-for-sale, amortized costs | 188 | 189
Securities available-for-sale, gross unrealized losses | 53 | 62
Securities available-for-sale, fair value | $ 135 | $ 127

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

X
- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=51813488&loc=d3e22054-111558 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=49167202&loc=d3e26610-111562 + Details
Name: | us-gaap_AvailableForSaleSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.2) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_AvailableForSaleSecuritiesAmortizedCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_MortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=nksh_OtherSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |