Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

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- 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

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- Definition

Description of the payment terms of the debt instrument (for example, whether periodic payments include principal and frequency of payments) and discussion about any contingencies associated with the payment.

+ 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 210.5-02.22(a)(3))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

+ Details

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- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.16)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 20, 22
-Article 5

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.16)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 20, 22
-Article 5

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a set, unchanging rate.

+ References

+ Details

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- Definition

+ References

+ Details

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- Details

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- Details

Name:	us-gaap_DebtInstrumentAxis=nsec_PromissoryNoteMember
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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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Notes Payable and Long-Term Debt (Schedule of Long-Term Debt) (Details) - USD ($) $ in Thousands			12 Months Ended
	Jun. 21, 2007	Dec. 15, 2005	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Long-term debt			$ 17,358	$ 18,715
Unsecured Debt [Member] \| Promissory Note [Member]
Debt Instrument [Line Items]
Long-term debt			$ 4,286	5,143
Payment terms			Annual installment payments.
Unsecured Debt [Member] \| Promissory Note [Member] \| Prime Rate [Member]
Debt Instrument [Line Items]
Basis spread on variable rate			1.00%
Unsecured Debt [Member] \| Trust Preferred Security Offering, 2005 [Member]
Debt Instrument [Line Items]
Long-term debt			$ 9,279	9,279
Fixed interest rate		8.83%
Payment terms			Interest payments due quarterly.
Unsecured Debt [Member] \| Trust Preferred Security Offering, 2005 [Member] \| Three-month LIBOR [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		3.75%
Unsecured Debt [Member] \| Trust Preferred Security Offering, 2007 [Member]
Debt Instrument [Line Items]
Long-term debt			$ 3,093	3,093
Payment terms			Interest payments due quarterly.
Unsecured Debt [Member] \| Trust Preferred Security Offering, 2007 [Member] \| Three-month LIBOR [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	3.40%
Line of Credit [Member] \| Unsecured Debt [Member]
Debt Instrument [Line Items]
Amount outstanding			$ 700	700
Payment terms			Interest payment due quarterly
Line of Credit [Member] \| Unsecured Debt [Member] \| Prime Rate [Member]
Debt Instrument [Line Items]
Percentage bearing variable interest, percentage rate			5.00%
Line of Credit [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Amount outstanding			$ 0	$ 500
Payment terms			Interest payments due monthly.
Current borrowing capacity			$ 1,000
Line of Credit [Member] \| Secured Debt [Member] \| Prime Rate [Member]
Debt Instrument [Line Items]
Percentage bearing variable interest, percentage rate			4.50%