Name:	nrp_DebtCovenantRatioOfConsolidatedFundedIndebtednessToConsolidatedEarningsBeforeInterestTaxesDepreciationAmortizationsAndOtherItemsAllowedPerCreditAgreementDenominator
Namespace Prefix:	nrp_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

Debt instrument additional variable interest rate.

No definition available.

Name:	nrp_DebtInstrumentAdditionalVariableInterestRate
Namespace Prefix:	nrp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Debt Instrument Refinanced Amount

No definition available.

Name:	nrp_DebtInstrumentRefinancedAmount
Namespace Prefix:	nrp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Minimum Interest Coverage Ratio On Long Term Debt

No definition available.

Name:	nrp_MinimumInterestCoverageRatioOnLongTermDebt
Namespace Prefix:	nrp_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

Partnership leverage ratio.

No definition available.

Name:	nrp_PartnershipLeverageRatio
Namespace Prefix:	nrp_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

Partnerships leverage ratio.

No definition available.

Name:	nrp_PartnershipsLeverageRatio
Namespace Prefix:	nrp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Percentage of consolidated net tangible assets debt of subsidiaries not permitted to exceed.

No definition available.

Name:	nrp_PercentageOfConsolidatedNetTangibleAssetsDebtOfSubsidiariesNotPermittedToExceed
Namespace Prefix:	nrp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	nrp_ProformaDebtInstrumentLineItems
Namespace Prefix:	nrp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Ratio of EBITDA to consolidated fixed charges.

No definition available.

Name:	nrp_RatioOfEbitdaToConsolidatedFixedCharges
Namespace Prefix:	nrp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Ratio of indebtedness.

No definition available.

Name:	nrp_RatioOfIndebtedness
Namespace Prefix:	nrp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Short Term Credit Facilities Classified As Long Term Debt

No definition available.

Name:	nrp_ShortTermCreditFacilitiesClassifiedAsLongTermDebt
Namespace Prefix:	nrp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of the total principal payments made during the annual reporting period.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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

Weighted average interest rate of debt outstanding.

No definition available.

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

Description of the fees for amounts available, but unused under the credit facility.

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 210.5-02.19(b),22(b))

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

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

Name:	us-gaap_LineOfCreditFacilityCommitmentFeeDescription
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

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.

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

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

No definition available.

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

Amount of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates maturing in the remainder of the fiscal year following the latest fiscal year ended.

No definition available.

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

The cash inflow from the issuance of long-term debt that is not secured by collateral. Excludes proceeds from tax exempt unsecured debt.

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 14

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3255-108585

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

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

No definition available.

Name:	us-gaap_RepaymentsOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Weighted average interest rate of short-term debt outstanding.

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 210.5-02.19(b))

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

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19

-Subparagraph b

-Article 5