Represents the amount of cash paid to shareholders per share of stock converted in a stock conversion transaction.

No definition available.

Name:	nrc_ConversionOfStockCashPaidPerShareConverted
Namespace Prefix:	nrc_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of shares of one class of stock exchanged for each share of another class of stock in a stock conversion transaction.

+ References

No definition available.

+ Details

Name:	nrc_ConversionOfStockNumberOfSharesExchangedForEachShare
Namespace Prefix:	nrc_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the amount of payment made during the period related to recapitalization.

+ References

No definition available.

+ Details

Name:	nrc_PaymentsRelatedToRecapitalization
Namespace Prefix:	nrc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Face amount or stated value per share of common stock.

+ 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(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_CommonStockParOrStatedValuePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of new shares issued in the conversion of stock in a noncash (or part noncash) transaction. Noncash is defined as transactions during a period that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4332-108586

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4313-108586

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_ConversionOfStockByUniqueDescriptionAxis=nrc_ConversionOfClassBCommonStockIntoClassACommonStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Note 2 - Recapitalization (Details Textual) - USD ($) $ / shares in Units, $ in Thousands			9 Months Ended
	Apr. 17, 2018	Apr. 16, 2018	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Common Stock, Par or Stated Value Per Share	$ 0.001		$ 0.001		$ 0.001
Payments Related to Recapitalization			$ 72,370
Conversion of Class B Common Stock Into Class A Common Stock [Member]
Conversion of Stock, Number of Shares Exchanged for Each Share		1
Conversion of Stock, Cash Paid Per Share Converted		$ 19.59
Conversion of Stock, Shares Issued	3,617,615
Payments Related to Recapitalization	$ 72,400