Note 15 - Credit Losses - Allowance for Credit Losses (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Receivables, gross	$ 36,438	$ 37,270
Receivables, allowance	(4,171)	(4,425)
Receivables, net	32,267	32,845
Long-term contract receivable, gross	23,550	24,323
Long-term contract receivable, allowance	(816)	(843)
Long-term contract receivable, net	22,734	23,480
Total, gross	59,988	61,593
Total, allowance	(4,987)	(5,268)
Total, net	$ 55,001	$ 56,325

The total amount of current expected credit loss (CECL) allowance at the reporting date.

No definition available.

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

- Definition

The amount of gross short-term receivables at the reporting date.

+ References

No definition available.

+ Details

Name:	nrp_ShorttermReceivablesGross
Namespace Prefix:	nrp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of short-term receivables, net of CECL allowance, at the reporting date.

+ References

No definition available.

+ Details

Name:	nrp_ShorttermReceivablesNetOfCeclAllowance
Namespace Prefix:	nrp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of total gross receivables at the reporting date.

+ References

No definition available.

+ Details

Name:	nrp_TotalReceivablesGross
Namespace Prefix:	nrp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of total receivables, net of CECL allowance, at the reporting date.

+ References

No definition available.

+ Details

Name:	nrp_TotalReceivablesNetOfCeclAllowance
Namespace Prefix:	nrp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of allowance for credit loss on accounts receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(5))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(4))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479344/326-20-45-1

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-4

+ Details

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

- Definition

Amount of allowance for credit loss for right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time.

+ References

+ Details

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

- Definition

Amount, before allowance for credit loss, of right to consideration in exchange for good or service transferred to customer, when right is conditioned on something other than passage of time.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-7A

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-14

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479837/606-10-45-1

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479837/606-10-45-3

+ Details

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

- Definition

The total amount of investments that are intended to be held for an extended period of time (longer than one operating cycle) and amount due to the Entity from outside sources, including trade accounts receivable, notes and loans receivable, as well as any other types of receivables, net of allowances established for the purpose of reducing such investments and receivables to an amount that approximates their net realizable value.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(18))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

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