| Cover | Mar. 15, 2021 | Aug. 07, 2020 |
| Cover [Abstract] | ||
| Document Type | 8-K | |
| Document Period End Date | Mar. 15, 2021 | |
| Entity Registrant Name | NATURAL RESOURCE PARTNERS LP | |
| Entity Incorporation, State or Country Code | DE | |
| Entity File Number | 001-31465 | |
| Entity Tax Identification Number | 35-2164875 | |
| Entity Address, Address Line One | 1201 Louisiana St., Suite 3400 | |
| Entity Address, City or Town | Houston, | |
| Entity Address, State or Province | TX | |
| Entity Address, Postal Zip Code | 77002 | |
| City Area Code | (713) | |
| Local Phone Number | 751-7507 | |
| Title of 12(b) Security | Common Units representing limited partner interests | |
| Trading Symbol | NRP | |
| Security Exchange Name | NYSE | |
| Written Communications | false | |
| Soliciting Material | false | |
| Pre-commencement Tender Offer | false | |
| Pre-commencement Issuer Tender Offer | false | |
| Entity Emerging Growth Company | false | |
| Amendment Flag | false | |
| Entity Central Index Key | 0001171486 |
