The maximum cash flow leverage ratio the borrower is allowable to maintain under a debt instrument agreement.

No definition available.

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- Definition

The minimum fixed charge coverage ratio the borrower is required to maintain under a debt instrument agreement.

+ References

No definition available.

+ Details

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- Definition

The interest rate applicable to the portion of the carrying amount of debt instrument borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a rate subject to change from time to time.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
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Period Type:	instant

- Definition

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

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of the required periodic payments including both interest and principal payments.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of unused borrowing capacity under the long-term financing arrangement that is available to the entity as of the balance sheet date.

+ References

+ Details

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Balance Type:	credit
Period Type:	instant

- 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://fasb.org/us-gaap/role/ref/legacyRef
-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 2: http://fasb.org/us-gaap/role/ref/legacyRef
-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 3: http://fasb.org/us-gaap/role/ref/legacyRef
-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=119400593&loc=d3e572229-122910

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3255-108585

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash inflow from a borrowing supported by a written promise to pay an obligation.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Weighted average interest rate of short-term debt outstanding calculated over time.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

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Namespace Prefix:
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Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=nrc_FirstNationalBankOfOmahaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Data Type:	na
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Period Type:

- Details

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Data Type:	na
Balance Type:
Period Type:

- Details

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- Details

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- Details

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Note 5 - Notes Payable (Details Textual)		1 Months Ended	3 Months Ended	9 Months Ended
Note 5 - Notes Payable (Details Textual)	Apr. 18, 2018 USD ($)	May 31, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Proceeds from Notes Payable, Total					$ 40,000,000
Credit Agreement [Member] \| First National Bank of Omaha [Member]
Debt Instrument, Covenant, Minimum Fixed Charge Coverage Ratio				1.1
Debt Instrument, Covenant, Maximum Cash Flow Leverage Ratio				3
Credit Agreement [Member] \| First National Bank of Omaha [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate	2.25%
Debt Instrument, Percentage Bearing Variable Interest, Percentage Rate			4.33%	4.33%
Credit Agreement [Member] \| First National Bank of Omaha [Member] \| Term Loan [Member]
Proceeds from Notes Payable, Total	$ 40,000,000
Debt Instrument, Periodic Payment, Total	$ 462,988
Debt Instrument, Interest Rate, Stated Percentage	5.00%
Credit Agreement [Member] \| First National Bank of Omaha [Member] \| Term Loan [Member] \| Forecast [Member]
Debt Instrument, Periodic Payment, Total		$ 526,362
Credit Agreement [Member] \| First National Bank of Omaha [Member] \| Delayed Draw Term Loan [Member]
Debt Instrument, Unused Borrowing Capacity, Amount	$ 15,000,000
Proceeds from Issuance of Long-term Debt, Total				$ 0
Credit Agreement [Member] \| First National Bank of Omaha [Member] \| Revolving Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 15,000,000
Debt Instrument, Unused Borrowing Capacity, Amount			$ 15,000,000	15,000,000
Long-term Line of Credit, Total			$ 0	$ 0		$ 0
Short-term Debt, Weighted Average Interest Rate, over Time			4.62%	4.72%