Note 4 - Share-Based Compensation (Detail) (USD $)	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in Shares)	29,448	31,630
Options Vesting One To Five Years [Member] \| The 2001 Equity Incentive Plan [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	1 year
Options Vesting One To Five Years [Member] \| The 2001 Equity Incentive Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	5 years
Options Vesting Five Years [Member] \| The 2006 Equity Incentive Plan [Member] \| Minimum [Member]
Share-based Compensation Arrangement By Share-based Payment Award Option Term	5 years
Options Vesting Five Years [Member] \| The 2006 Equity Incentive Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement By Share-based Payment Award Option Term	10 years
Nonvested [Member]
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized (in Dollars)	445,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	3 years 94 days
Normal Term [Member] \| 2004 Director Plan [Member]
Share-based Goods and Nonemployee Services Transaction Option Terms	10 years
Termination of Service [Member] \| 2004 Director Plan [Member]
Share-based Goods and Nonemployee Services Transaction Option Terms	3 years
The 2001 Equity Incentive Plan [Member] \| Minimum [Member]
Share-based Compensation Arrangement By Share-based Payment Award Option Term	5 years
The 2001 Equity Incentive Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement By Share-based Payment Award Option Term	10 years
The 2001 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in Shares)	600,000
2004 Director Plan [Member]
Share-based Goods and Nonemployee Services Transaction, Shares Approved for Issuance (in Shares)	550,000
Common Stock Options Granted To Directors (in Shares)	12,000
Share-based Goods and Nonemployee Services Transaction Vesting Period	1 year
The 2006 Equity Incentive Plan [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	5 years
Share-based Compensation Arrangement By Share-based Payment Award Option Term	5 years
The 2006 Equity Incentive Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement By Share-based Payment Award Option Term	10 years
The 2006 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in Shares)	600,000

Gross number of share options (or share units) expected to be granted to Directors after each year's annual meeting.

No definition available.

Name:	nrci_CommonStockOptionsGrantedToDirectors
Namespace Prefix:	nrci_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Reflects the number of years from grant to when the share-based award expires as specified in the award agreement

+ References

No definition available.

+ Details

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Namespace Prefix:	nrci_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Reflects the number of years from grant to when the share-based award expires as specified in the award agreement

+ References

No definition available.

+ Details

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Namespace Prefix:	nrci_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of the period of time over which an employee's or nonemployee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, which may be expressed in a variety of ways (for example, in years, month and year).

+ References

No definition available.

+ Details

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Namespace Prefix:	nrci_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

As of the balance sheet date, the aggregate unrecognized cost of equity-based awards made to employees under equity-based compensation awards that have yet to vest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (i)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph h

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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

- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

+ Details

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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

+ Details

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

- Definition

The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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

- Definition

Gross number of share options (or share units) granted during the period.

+ References

No definition available.

+ Details

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

- Definition

The maximum number of shares (or other type of equity) that have been approved for issuance in the equity-based payment transaction.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 50

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6406099&loc=d3e25284-112666

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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