Natural Resource Partners (NRP) 10-K 15 Mar 22 2021 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Mar. 01, 2022	Jun. 30, 2021
Document And Entity Information [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Document Transition Report	false
Entity File Number	001-31465
Entity Registrant Name	NATURAL RESOURCE PARTNERS LP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	35-2164875
Entity Address, Address Line One	1201 Louisiana Street, 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
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 190
Documents Incorporated by Reference	None.
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Entity Central Index Key	0001171486
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Entity Common Stock, Shares Outstanding		12,505,996

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2021
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Auditor Name	Ernst & Young LLP
Auditor Location	Houston, Texas
Auditor Firm ID	42
Subsidiaries
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Auditor Name	Deloitte & Touche LLP
Auditor Location	Atlanta, Georgia
Auditor Firm ID	34

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 135,520	$ 99,790
Accounts receivable, net	24,538	12,322
Other current assets, net	2,723	5,080
Total current assets	162,781	117,192
Land	24,008	24,008
Mineral rights, net	437,697	460,373
Intangible assets, net	16,130	17,459
Equity in unconsolidated investment	276,004	262,514
Long-term contract receivable, net	31,371	33,264
Other long-term assets, net	5,832	7,067
Total assets	953,823	921,877
Current liabilities
Accounts payable	1,956	1,385
Accrued liabilities	10,297	7,733
Accrued interest	1,213	1,714
Current portion of deferred revenue	11,817	11,485
Current portion of long-term debt, net	39,102	39,055
Total current liabilities	64,385	61,372
Deferred revenue	50,045	50,069
Long-term debt, net	394,443	432,444
Other non-current liabilities	5,018	5,131
Total liabilities	513,891	549,016
Class A Convertible Preferred Units (269,321 and 253,750 units issued and outstanding at December 31, 2021 and 2020, respectively, at $1,000 par value per unit; liquidation preference of $1,850 per unit at December 31, 2021 and $1,700 per unit per unit at December 31, 2020)	183,908	168,337
Partners’ capital
Common unitholders’ interest (12,351,306 and 12,261,199 units issued and outstanding at December 31, 2021 and 2020, respectively)	203,062	136,927
General partner’s interest	1,787	459
Warrant holders’ interest	47,964	66,816
Accumulated other comprehensive income	3,211	322
Total partners' capital	256,024	204,524
Total liabilities and partners' capital	$ 953,823	$ 921,877

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Class A convertible preferred units (in units)	269,321	253,750
Class A preferred units, outstanding (in units)	269,321	253,750
Class A convertible preferred units (in units)	$ 1,000	$ 1,000
Class A convertible preferred units, liquidation preference (in USD per unit)	$ 1,850	$ 1,700
Common unitholders', units issued (in units)	12,351,306	12,261,199
Common unitholders', units outstanding (in units)	12,351,306	12,261,199

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019
Revenues		$ 216,119		$ 139,739		$ 257,437
Gain on asset sales and disposals		245		581		6,498
Total revenues and other income		216,364		140,320		263,935
Operating expenses
Operating and maintenance expenses		27,049		24,795		32,738
Depreciation, depletion and amortization		19,075		9,198		14,932
General and administrative expenses		17,360		14,293		16,730
Asset impairments		5,102		135,885		148,214
Total operating expenses		68,586		184,171		212,614
Income (loss) from operations		147,778		(43,851)		51,321
Other expenses, net
Interest expense, net		(38,876)		(40,968)		(47,453)
Loss on extinguishment of debt		0		0		(29,282)
Other expenses, net		(38,876)		(40,968)		(76,735)
Net income (loss) from continuing operations		108,902		(84,819)		(25,414)
Income from discontinued operations		0		0		956
Net income (loss)		108,902	[1]	(84,819)	[2]	(24,458)	[2]
Net income attributable to non-controlling interest	[2]					0
Less: income attributable to preferred unitholders		(31,609)		(30,225)		(30,000)
Net income (loss) attributable to common unitholders and the general partner		77,293		(115,044)		(54,458)
Net income (loss) attributable to common unitholders		75,747		(112,743)		(53,369)
Net income (loss) attributable to the general partner		$ 1,546		$ (2,301)		$ (1,089)
Income from continuing operations per common unit
Income (loss) from continuing operations per common unit (basic)		$ 6.14		$ (9.20)		$ (4.43)
Income (loss) from continuing operations per common unit (diluted)		4.81		(9.20)		(4.43)
Basic and diluted net income per common unit (in dollars per share):
Net income per common unit (basic)		6.14		(9.20)		(4.35)
Net income per common unit (diluted)		$ 4.81		$ (9.20)		$ (4.35)
Comprehensive income from unconsolidated investment and other		$ 2,889		$ 2,916		$ 868
Comprehensive income (loss)		111,791		(81,903)		(23,590)
Transportation and processing services | Mineral Rights
Revenues		9,052		8,845		19,279
Royalty and other mineral rights | Mineral Rights
Revenues		185,196		120,166		191,069
Soda Ash | Soda Ash
Revenues		$ 21,871		$ 10,728		$ 47,089
[1]	Net loss includes $30.2 million of income attributable to preferred unitholders that accumulated during the period, of which $29.6 million is allocated to the common unitholders and $0.6 million is allocated to the general partner. (3) Net income includes $31.6 million of income attributable to preferred unitholders that accumulated during the period, of which $31.0 million is allocated to the common unitholders and $0.6 million is allocated to the general partner.
[2]	Net loss includes $30.0 million of income attributable to preferred unitholders that accumulated during the period, of which $29.4 million is allocated to the common unitholders and $0.6 million is allocated to the general partner.

Consolidated Statements of Part

Consolidated Statements of Partners' Capital - USD ($) shares in Thousands, $ in Thousands		Total	Cumulative Effect, Period of Adoption, Adjustment	General Partner	General PartnerCumulative Effect, Period of Adoption, Adjustment	Common Unitholders	Warrant Holders	Accumulated Other Comprehensive Income (Loss)	Partners Capital Excluding Noncontrolling Interest	Partners Capital Excluding Noncontrolling InterestCumulative Effect, Period of Adoption, Adjustment	Non-Controlling Interest	Common unitholders	Common unitholdersCommon Unitholders	Common unitholdersCommon UnitholdersCumulative Effect, Period of Adoption, Adjustment	General Partner	General PartnerGeneral Partner	Common unitholders and general partner	Common unitholders and general partnerPartners Capital Excluding Noncontrolling Interest	Preferred Partner	Preferred PartnerGeneral Partner	Preferred PartnerCommon Unitholders	Preferred PartnerPartners Capital Excluding Noncontrolling Interest
Balance, beginning of period (in shares) at Dec. 31, 2018						12,249
Balance, beginning of period at Dec. 31, 2018		$ 420,546		$ 5,014		$ 355,113	$ 66,816	$ (3,462)	$ 423,481		$ (2,935)
Net income (loss)	[1]			(489)		$ (23,969)			(24,458)
Net income (loss)	[1]	(24,458)
Distributions to unitholders													$ (32,487)			$ (663)	$ (33,150)	$ (33,150)	$ (30,000)	$ (600)	$ (29,400)	$ (30,000)
Partners' Capital Account, Unit-based Payment Arrangement, Number of Units						12
Partners' Capital Account, Unit-based Payment Arrangement, Amount		486				$ 486			486
Partners' Capital Account, Unit-based Compensation, Amortization		1,804				1,804			1,804
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent, Excluding General Partner Distributions		800		8		$ (76)		868	800		0
Unit-based awards amortization and vesting							0
Comprehensive income (loss) from unconsolidated investment and other		868
Balance, end of period (in shares) at Dec. 31, 2019						12,261
Balance, end of period at Dec. 31, 2019		336,028	$ (3,911)	3,270	$ (78)	$ 271,471	66,816	(2,594)	338,963	$ (3,911)	(2,935)			$ (3,833)
Net Income (Loss) Attributable to Noncontrolling Interest	[1]	0
Income attributable to preferred unitholders		(30,000)										$ 29,400			$ 600
Net income (loss)	[1]			(1,696)		(83,123)			(84,819)
Net income (loss)	[1]	(84,819)									0
Distributions to unitholders													(16,552)			(338)	(16,890)	(16,890)	(30,113)	(602)	(29,511)	(30,113)
Partners' Capital Account, Unit-based Compensation, Amortization						3,222
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent, Excluding General Partner Distributions		2,916		0		$ 0		2,916	2,916		0
Unit-based awards amortization and vesting		3,222					0		3,222
Comprehensive income (loss) from unconsolidated investment and other		2,916
Balance, end of period (in shares) at Dec. 31, 2020						12,261
Balance, end of period at Dec. 31, 2020		204,524		459		$ 136,927	66,816	322	204,524		0
Income attributable to preferred unitholders		(30,225)										29,600			600
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests		(1,909)		(97)		(4,747)			(4,844)		2,935
Net income (loss)	[2]			2,178		$ 106,724			108,902
Net income (loss)	[2]	108,902									0
Distributions to unitholders													$ (22,192)			$ (453)	$ (22,645)	$ (22,645)	$ (31,142)	(623)	$ (30,519)	$ (31,142)
Partners' Capital Account, Unit-based Payment Arrangement, Number of Units						90
Partners' Capital Account, Unit-based Payment Arrangement, Amount		0				$ 0			0
Partners' Capital Account, Unit-based Compensation, Amortization		2,647				2,647			2,647
Partners' Capital Account, Contributions		32							32											32
Partners' Capital Account, Warrant Settlement		(9,183)				$ 9,475	(18,852)		(9,183)											$ 194
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent, Excluding General Partner Distributions		2,889						2,889	2,889
Comprehensive income (loss) from unconsolidated investment and other		2,889
Balance, end of period (in shares) at Dec. 31, 2021						12,351
Balance, end of period at Dec. 31, 2021		256,024		$ 1,787		$ 203,062	$ 47,964	$ 3,211	$ 256,024		$ 0
Income attributable to preferred unitholders		$ (31,609)										$ (31,000)			$ (600)
[1]	Net loss includes $30.0 million of income attributable to preferred unitholders that accumulated during the period, of which $29.4 million is allocated to the common unitholders and $0.6 million is allocated to the general partner.
[2]	Net loss includes $30.2 million of income attributable to preferred unitholders that accumulated during the period, of which $29.6 million is allocated to the common unitholders and $0.6 million is allocated to the general partner. (3) Net income includes $31.6 million of income attributable to preferred unitholders that accumulated during the period, of which $31.0 million is allocated to the common unitholders and $0.6 million is allocated to the general partner.

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019
Net income (loss)	$ 108,902,000	[1]	$ (84,819,000)	[2]	$ (24,458,000)	[2]
Adjustments to reconcile net income (loss) to net cash provided by operating activities of continuing operations:
Depreciation, depletion and amortization	19,075,000		9,198,000		14,932,000
Distributions from unconsolidated investment	11,270,000		14,210,000		31,850,000
Equity earnings from unconsolidated investment	(21,871,000)		(10,728,000)		(47,089,000)
Gain on asset sales and disposals	(245,000)		(581,000)		(6,498,000)
Loss on extinguishment of debt	0		0		29,282,000
Income from discontinued operations	0		0		(956,000)
Asset impairments	5,102,000		135,885,000		148,214,000
Bad debt expense	2,572,000		4,001,000		7,462,000
Unit-based compensation expense	4,039,000		3,570,000		2,361,000
Amortization of debt issuance costs and other	2,265,000		1,323,000		3,687,000
Change in operating assets and liabilities:
Accounts receivable	(14,415,000)		12,853,000		(6,035,000)
Accounts payable	570,000		207,000		(1,234,000)
Accrued liabilities	3,020,000		(2,205,000)		(3,656,000)
Accrued interest	(501,000)		(602,000)		(12,029,000)
Deferred revenue	307,000		9,733,000		(732,000)
Other items, net	1,714,000		(4,477,000)		2,218,000
Net cash provided by operating activities of continuing operations	121,804,000		87,568,000		137,319,000
Net cash provided by (used in) operating activities of discontinued operations	0		1,706,000		(8,000)
Net cash provided by operating activities	121,804,000		89,274,000		137,311,000
Cash flows from investing activities
Proceeds from asset sales and disposals	249,000		623,000		6,500,000
Acquisition of non-controlling interest in BRP	0		(1,000,000)		0
Acquisition of mineral rights	0		0		(22,000)
Return of long-term contract receivable	2,163,000		2,122,000		1,743,000
Net cash provided by investing activities of continuing operations	2,412,000		1,745,000		8,221,000
Net cash used in investing activities of discontinued operations	0		(65,000)		(629,000)
Cash flows from financing activities
Debt borrowings	0		0		300,000,000
Debt repayments	(39,396,000)		(46,176,000)		(463,082,000)
Cash Settlement, Warrant Redemption	(9,183,000)		0		0
Payments to Acquire Equity Method Investments, Financing Activities	(1,000,000)		0		0
Contributions from (to) discontinued operations	0		1,641,000		(637,000)
Other items	(691,000)		0		(26,436,000)
Net cash used in financing activities of continuing operations	(88,486,000)		(87,788,000)		(253,305,000)
Net cash provided by investing activities	2,412,000		1,680,000		7,592,000
Net cash provided by (used in) financing activities of discontinued operations	0		(1,641,000)		637,000
Net cash used in financing activities	(88,486,000)		(89,429,000)		(252,668,000)
Net increase (decrease) in cash and cash equivalents	35,730,000		1,525,000		(107,765,000)
Cash and cash equivalents at end of period	135,520,000		99,790,000		98,265,000
Cash, cash equivalents and restricted cash of continuing operations at end of period	99,790,000		98,265,000		206,030,000
Supplemental Cash Flow Elements [Abstract]
Cash paid for interest	37,378,000		39,830,000		58,597,000
Plant, equipment and mineral rights funded with accounts payable or accrued liabilities	0		970,000		0
Dividends, Paid-in-kind	15,571,000		3,750,000		0
Preferred Partner
Cash flows from financing activities
Distributions to common unitholders and the general partner	(15,571,000)		(26,363,000)		(30,000,000)
General Partner
Cash flows from financing activities
Distributions to common unitholders and the general partner	$ (22,645,000)		$ (16,890,000)		$ (33,150,000)
[1]	Net loss includes $30.2 million of income attributable to preferred unitholders that accumulated during the period, of which $29.6 million is allocated to the common unitholders and $0.6 million is allocated to the general partner. (3) Net income includes $31.6 million of income attributable to preferred unitholders that accumulated during the period, of which $31.0 million is allocated to the common unitholders and $0.6 million is allocated to the general partner.
[2]	Net loss includes $30.0 million of income attributable to preferred unitholders that accumulated during the period, of which $29.4 million is allocated to the common unitholders and $0.6 million is allocated to the general partner.

Organization and Nature of Oper

Organization and Nature of Operations	12 Months Ended
	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Nature of Operations	Organization and Nature of Operations Natural Resource Partners L.P. (the "Partnership"), a Delaware limited partnership, was formed in April 2002. The general partner of the Partnership is NRP (GP) LP ("NRP GP"), a Delaware limited partnership, whose general partner is GP Natural Resource Partners LLC, a Delaware limited liability company. The Partnership engages principally in the business of owning, managing and leasing a diversified portfolio of mineral properties in the United States, including interests in coal and other natural resources and owns a non-controlling 49% interest in Sisecam Wyoming LLC ("Sisecam Wyoming"), formerly known as Ciner Wyoming, a trona ore mining and soda ash production business. The Partnership is organized into two operating segments further described in Note 7. Segment Information . As used in these Notes to Consolidated Financial Statements, the terms "NRP," "we," "us" and "our" refer to Natural Resource Partners L.P. and its subsidiaries, unless otherwise stated or indicated by context. The Partnership’s operations are conducted through, and its operating assets are owned by, its subsidiaries. The Partnership owns its subsidiaries through one wholly owned operating company, NRP (Operating) LLC ("Opco"). NRP GP has sole responsibility for conducting the Partnership's business and for managing its operations. Because NRP GP is a limited partnership, its general partner, GP Natural Resource Partners LLC, conducts its business and operations, and the board of directors and officers of GP Natural Resource Partners LLC makes decisions on its behalf. Robertson Coal Management LLC ("RCM"), a limited liability company wholly owned by Corbin J. Robertson, Jr., owns all of the membership interest in GP Natural Resource Partners LLC. Subject to the Board Representation and Observation Rights Agreement with certain entities controlled by funds affiliated with Blackstone Inc. (collectively referred to as "Blackstone") and affiliates of GoldenTree Asset Management LP (collectively referred to as "GoldenTree"), RCM is entitled to appoint the directors of the Board of Directors of GP Natural Resource Partners LLC (the "Board of Directors"). RCM has delegated the right to appoint one director to Blackstone.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The accompanying Consolidated Financial Statements of the Partnership have been prepared in accordance with generally accepted accounting principles in the United States of America ("GAAP"). The Consolidated Financial Statements include the accounts of Natural Resource Partners L.P. and its wholly owned subsidiaries. The Partnership has an equity investment in Sisecam Wyoming through which it is able to exercise significant influence over but does not control the investee and is not the primary beneficiary of the investee’s activities and is accounted for using the equity method. Intercompany transactions and balances have been eliminated. Certain reclassifications have been made to prior year amounts in the Notes to Consolidated Financial Statements to conform with current year presentation. These reclassifications had no impact on previously reported total assets, total liabilities, partners' capital, net income (loss) or cash flows from operating, investing or financing activities. Use of Estimates Preparation of the accompanying financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities on the accompanying Consolidated Balance Sheets, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses on the accompanying Consolidated Statements of Comprehensive Income (Loss) during the reporting period. Actual results could differ from those estimates. The most significant estimates pertain to coal and aggregates mineral rights and related cash flow estimates which are used to compute depreciation, depletion and amortization and impairments of coal and aggregates properties and related intangible assets and commitments and contingencies. Fair Value The Partnership discloses certain assets and liabilities using fair value as defined by authoritative guidance. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. See Note 12. Fair Value Measurements for further details. There are three levels of inputs that may be used to measure fair value: • Level 1—Quoted prices in active markets for identical assets or liabilities. • Level 2—Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. • Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Level 3 assets and liabilities include financial assets and liabilities whose value is determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation. Cash and Cash Equivalents The Partnership considers all highly liquid short-term investments with an original maturity of three months or less to be cash equivalents Allowance for Doubtful Accounts The Partnership records an allowance for doubtful accounts for its accounts receivable and notes receivable comprised of estimated credit risk and non-credit risk (e.g., legal disputes) losses. Receivables are written off when collection efforts are exhausted and future recovery is doubtful. The Partnership includes an allowance for current expected credit losses ("CECL") on its financial assets based on the loss-rate method. NRP assesses the likelihood of collection of its receivables utilizing historical loss rates, current market conditions that include the estimated impact of the global COVID-19 pandemic, industry and macroeconomic factors, reasonable and supportable forecasts and facts or circumstances of individual customers and properties. See Note 18. Credit Losses for more information. The total allowance related to accounts receivables included in accounts receivables, net on the Partnership's Consolidated Balance Sheets was $3.2 million and $1.7 million at December 31, 2021 and 2020, respectively. The total allowance related to short-term notes receivables included in other current assets, net on the Partnership's Consolidated Balance Sheets was $0.1 million and $0.6 million at December 31, 2021 and 2020, respectively. The total allowance related to the Partnership's long-term financing receivable included in long-term contract receivable, net on the Consolidated Balance Sheets was $1.1 million and $1.6 million at December 31, 2021 and 2020, respectively. The Partnership recorded bad debt expense of $2.6 million, $4.0 million and $7.5 million included in operating and maintenance expenses on its Consolidated Statements of Comprehensive Income (Loss) for the year ended December 31, 2021, 2020 and 2019, respectively. Mineral Rights Mineral rights owned and leased are recorded at its original cost of construction or, upon acquisition, at fair value of the assets acquired. Coal and aggregates mineral rights are depleted on a unit-of-production basis by lease, based upon minerals mined in relation to the net cost of the mineral properties and estimated economic tonnage therein. Intangible Assets The Partnership’s intangible assets consist of mineral royalty and transportation contracts that at acquisition were more favorable for the Partnership than prevailing market rates, known as above-market contracts. The estimated fair value of the above-market rate contracts are determined based on the present value of future cash flow projections related to the underlying assets acquired. Intangible assets are amortized on a unit-of-production basis by asset based upon minerals mined or transported in relation to the net book value of the intangible asset and estimated economic tonnage expected to be mined or transported during the above-market contract term. Asset Impairment The Partnership has developed procedures to evaluate its long-lived assets, including intangible assets, for possible impairment periodically or whenever events or changes in circumstances indicate an asset's net book value may not be recoverable. Potential events or circumstances include, but are not limited to, specific events such as a reduction in economically recoverable tons or production ceasing on a property for an extended period. This analysis is based on historic, current and future performance and considers both quantitative and qualitative information. A long-lived asset is deemed impaired when the future expected undiscounted cash flows from its use and disposition is less than the asset's net book value. Impairment is measured based on the estimated fair value, which is usually determined based upon the present value of the projected future cash flows compared to the asset's net book value. The Partnership believes its estimates of cash flows and discount rates are consistent with those of principal market participants. The Partnership evaluates its equity investment for impairment when events or changes in circumstances indicate, in management’s judgment, that the carrying value of such investment may have experienced an other-than-temporary decline in value. When evidence of loss in value has occurred, management compares the estimated fair value of the investment to the carrying value of the investment to determine whether potential impairment has occurred. If the estimated fair value is less than the carrying value and management considers the decline in value to be other than temporary, the excess of the carrying value over the estimated fair value is recognized in the financial statements as an impairment loss. The fair value of the impaired investment is based on quoted market prices (Level 1), or upon the present value of expected cash flows using discount rates believed to be consistent with those used by principal market participants (Level 3), plus market analysis of comparable assets owned by the investee, if appropriate (Level 3). Accrued Liabilities Included in accrued liabilities on the Partnership's Consolidated Balance Sheets at December 31, 2021 were $7.7 million of accrued employee costs and $2.6 million of other accrued liabilities, which includes property taxes. These amounts were $3.7 million and $4.0 million of accrued employee costs and other accrued liabilities, respectively, at December 31, 2020. Other accrued liabilities at December 31, 2020 primarily included property taxes. Revenue Recognition Mineral Rights Segment Revenues Royalty-based leases. Approximately two-thirds of the Partnership's royalty-based leases have initial terms of five three The Partnership has defined its coal and aggregates royalty lease performance obligation as providing the lessee the right to mine and sell its coal or aggregates over the lease term. NRP then evaluated the likelihood that consideration it expected to receive from its lessees resulting from production would exceed consideration expected to be received from minimum payments over the lease term. As a result of this evaluation, revenue recognition from the Partnership's royalty-based leases is based on either production or minimum payments as follows: • Production Leases : Leases for which the Partnership expects that consideration from production will be greater than consideration from minimums over the lease term. Revenue for these leases is recognized over time based on production as royalty revenues, as applicable. Deferred revenue from minimums is recognized as royalty revenues when recoupment occurs or as production lease minimum revenues when the recoupment period expires. In addition, NRP recognizes breakage revenue from minimums when NRP determines that recoupment is remote. This breakage revenue is included in production lease minimum revenues. • Minimum Leases : Leases for which the Partnership expects that consideration from minimums will be greater than consideration from production over the lease term. Revenue for these leases is recognized straight-line over the lease term based on the minimum consideration amount as minimum lease straight-line revenues. This evaluation is performed at the inception of the lease and only reassessed upon modification or renewal of the lease. Oil and gas related revenues consist of revenues from royalties and overriding royalties and are recognized on the basis of volume of hydrocarbons sold by lessees and the corresponding revenues from those sales. Also, included within oil and gas royalty revenues are lease bonus payments, which are generally paid upon the execution of a lease. The Partnership also has overriding royalty revenue interests in certain coal mineral rights. Revenue from these interests is recognized over time based on when the coal is sold. Forest CO 2 sequestration revenues. Revenues related to the sale of NRP's carbon offset credits that are recognized at a point in time upon execution of the transaction. Wheelage revenues. Revenues related to fees collected per ton to transport foreign coal across property owned by the Partnership that is recognized over time as transportation across the property occurs. Other revenues. Other revenues consists primarily of rental payments and surface damage fees related to certain land owned by the Partnership and are recognized straight-line over time as it is earned. Other revenues also include property tax revenues. The majority of property taxes paid on the Partnership's properties are reimbursable by the lessee and are recognized on a gross basis over time which reflects the reimbursement of property taxes by the lessee. Property taxes paid by NRP are included in operating and maintenance expenses on the Partnership's Consolidated Statements of Comprehensive Income (Loss). Transportation and processing services revenues. The Partnership owns transportation and processing infrastructure that is leased to third parties for throughput fees. Revenue is recognized over time based on the coal tons transported over the beltlines or processed through the facilities. Contract Modifications Contract modifications that impact goods or services or the transaction price are evaluated in accordance with ASC 606. A majority of the Partnership's contract modifications pertain to its coal and aggregates royalty contracts and include, but are not limited to, extending the lease term, changes to royalty rates, floor prices or minimum consideration, assignment of the contract or forfeiture of recoupment rights. Consideration received in conjunction with a modification of an ongoing lease will be deferred and recognized straight-line over the remaining term of the contract. Consideration received to assign a lease to another party and related forfeited minimums will be recognized immediately upon the termination of the contract. Fees from contract modifications are recognized in lease amendment revenues within royalty and other mineral rights revenues on the Consolidated Statements of Comprehensive Income (Loss) while modifications in royalty rates and minimums will be recognized prospectively in accordance with the above lease classification. Contract Assets and Liabilities from Contracts with Customers Contract assets include receivables from contracts with customers and are recorded when the right to consideration becomes unconditional. Receivables are recognized when the minimums are contractually owed, production occurs or minimums accrued for based on the passage of time. Contract liabilities represent minimum consideration received, contractually owed or earned based on the passage of time. The current portion of deferred revenue relates to deferred revenue on minimum leases and lease amendment fees that are to be recognized as revenue on a straight-line basis over the next twelve months. The long-term portion of deferred revenue relates to deferred revenue on production leases and lease amendment fees that are to be recognized as revenue on a straight-line basis beyond the next twelve months. Due to uncertainty in the amount of deferred revenue that will be recouped and recognized as coal royalty revenues from its production leases over the next twelve months, the Partnership is unable to estimate the current portion of deferred revenue. Equity in Earnings of Sisecam Wyoming The Partnership accounts for non-marketable equity investments using the equity method of accounting if the investment gives it the ability to exercise significant influence over, but not control of, an investee. The Partnership's 49% investment in Sisecam Wyoming is accounted for using this method. Under the equity method of accounting, investments are stated at initial cost and are adjusted for subsequent additional investments and the proportionate share of earnings or losses and distributions. The basis difference between the investment and the proportional share of investee's net assets is attributed to net tangible assets and is amortized over its estimated useful life. The carrying value in Sisecam Wyoming is recognized in equity in unconsolidated investment on the Partnership's Consolidated Balance Sheets. The Partnership's adjusted share of the earnings or losses of Sisecam Wyoming and amortization of the basis difference is recognized in equity in earnings of Sisecam Wyoming on the Consolidated Statements of Comprehensive Income (Loss). The Partnership decreases its investment for its proportional share of distributions received from Sisecam Wyoming. These cash flows are reported utilizing the cumulative earnings approach. Under this approach, distributions received are considered returns on investment and classified as operating cash inflows unless the cumulative distributions received exceed the Partnership's cumulative equity in earnings. The excess of cumulative distributions received over the Partnership's cumulative equity in earnings are considered returns of investment and classified as investing cash inflows. Property Taxes The Partnership is responsible for paying property taxes on the properties it owns. Typically, the lessees are contractually responsible for reimbursing the Partnership for property taxes on the leased properties. The payment of and reimbursement of property taxes is included in operating and maintenance expenses and in royalty and other mineral rights revenues, respectively, on the Consolidated Statements of Comprehensive Income (Loss). Unit-Based Compensation The Partnership has awarded unit-based compensation in the form of equity-based awards and phantom units. Compensation cost is measured at the grant date for equity-classified awards and remeasured each reporting period for liability-classified awards based on the fair value of an award and is recognized over the service period, which is generally the vesting period. Forfeitures are recognized as they occur. Unit-based compensation expense for all awards is recognized in general and administrative expenses and operating and maintenance expenses on the Consolidated Statements of Comprehensive Income (Loss). See Note 16. Unit-Based Compensation for more information. Deferred Financing Costs Deferred financing costs consist of legal and other costs related to the issuance of the Partnership’s debt. These costs are amortized over the term of the respective line-of-credit or debt arrangements. Deferred financing costs related to the Partnership's revolving credit facility are included in other long-term assets, net on the Partnership's Consolidated Balance Sheets. Deferred financing costs related to the Partnership's note agreements are included as a direct deduction from the carrying amount of the debt liability in current portion of long-term debt, net or long-term debt, net on the Partnership's Consolidated Balance Sheets. Income Taxes The Partnership is not subject to federal or material state income taxes as the unitholders are taxed individually on their allocable share of taxable income. Net income (loss) for financial statement purposes may differ significantly from taxable income reportable to unitholders as a result of differences between the tax basis and financial reporting basis of assets and liabilities. In the event of an examination of the Partnership’s tax return, the tax liability of the unitholders could be changed if an adjustment in the Partnership’s income is ultimately sustained by the taxing authorities.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	12 Months Ended
	Dec. 31, 2021
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	3. Revenues from Contracts with Customers The following table represents the Partnership's Mineral Rights segment revenues by major source: For the Year Ended December 31, (In thousands) 2021 2020 2019 Coal royalty revenues $ 104,089 $ 51,868 $ 109,612 Production lease minimum revenues 14,269 21,749 24,068 Minimum lease straight-line revenues 20,564 16,796 14,910 Forest CO 2 sequestration revenues 13,790 — — Property tax revenues 6,028 5,786 6,287 Wheelage revenues 10,065 7,025 5,880 Coal overriding royalty revenues 4,367 4,977 13,496 Lease amendment revenues 4,696 3,450 7,991 Aggregates royalty revenues 1,889 1,717 4,265 Oil and gas royalty revenues 4,506 5,816 3,031 Other revenues 933 982 1,529 Royalty and other mineral rights revenues $ 185,196 $ 120,166 $ 191,069 Transportation and processing services revenues (1) 9,052 8,845 19,279 Total Mineral Rights segment revenues $ 194,248 $ 129,011 $ 210,348 (1) Transportation and processing services revenues from contracts with customers as defined under ASC 606 was $5.4 million, $5.0 million and $9.6 million for the year ended December 31, 2021, 2020 and 2019, respectively. The remaining transportation and processing services revenues of $3.6 million, $3.8 million and $9.7 million for the year ended December 31, 2021, 2020 and 2019, respectively, related to other NRP-owned infrastructure leased to and operated by third-party operators accounted for under other guidance. See Note 17. Financing Transaction for more information. The following table details the Partnership's Mineral Rights segment receivables and liabilities resulting from contracts with customers: December 31, (In thousands) 2021 2020 Receivables Accounts receivable, net $ 22,277 $ 10,193 Other current assets, net (1) 769 3,307 Other long-term assets, net (2) 250 525 Contract liabilities Current portion of deferred revenue $ 11,817 $ 11,485 Deferred revenue 50,045 50,069 (1) Other current assets, net includes short-term notes receivables from contracts with customers. (2) Other long-term assets, net includes long-term lease amendment fee receivables from contracts with customers. The following table shows the activity related to the Partnership's Mineral Rights segment deferred revenue: For the Year Ended December 31, (In thousands) 2021 2020 2019 Balance at beginning of period (current and non-current) $ 61,554 $ 51,821 $ 52,553 Increase due to minimums and lease amendment fees 19,842 41,557 47,038 Recognition of previously deferred revenue (19,534) (31,824) (47,770) Balance at end of period (current and non-current) $ 61,862 $ 61,554 $ 51,821 The Partnership's non-cancelable annual minimum payments due under the lease terms of its coal and aggregates royalty and overriding royalty leases are as follows as of December 31, 2021 (in thousands): Lease Term (1) Weighted Average Remaining Years Annual Minimum Payments 0 - 5 years 2.6 $ 18,341 5 - 10 years 4.1 6,823 10+ years 13.5 28,069 Total 8.6 $ 53,233 (1) Lease term does not include renewal periods.

Class A Convertible Preferred U

Class A Convertible Preferred Units and Warrants	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Class A Convertible Preferred Units and Warrants	Class A Convertible Preferred Units and Warrants On March 2, 2017, NRP issued $250 million of Class A Convertible Preferred Units representing limited partner interests in NRP (the "preferred units") to certain entities controlled by funds affiliated with The Blackstone Group Inc. (collectively referred to as "Blackstone") and certain affiliates of GoldenTree Asset Management LP (collectively referred to as "GoldenTree") (together the "preferred purchasers") pursuant to a Preferred Unit and Warrant Purchase Agreement. NRP issued 250,000 preferred units to the preferred purchasers at a price of $1,000 per preferred unit (the "per unit purchase price"), less a 2.5% structuring and origination fee. The preferred units entitle the preferred purchasers to receive cumulative distributions at a rate of 12% of the purchase price per year, up to one half of which NRP may pay in additional preferred units (such additional preferred units, the "PIK units"). The preferred units have a perpetual term, unless converted or redeemed as described below. NRP also issued two tranches of warrants (the "warrants") to purchase common units to the preferred purchasers (warrants to purchase 1.75 million common units with a strike price of $22.81 and warrants to purchase 2.25 million common units with a strike price of $34.00). The warrants may be exercised by the holders thereof at any time before the eighth anniversary of the closing date. Upon exercise of the warrants, NRP may, at its option, elect to settle the warrants in common units or cash, each on a net basis. After March 2, 2022 and prior to March 2, 2025, the holders of the preferred units may elect to convert up to 33% of the outstanding preferred units in any 12-month period into common units if the volume weighted average trading price of our common units (the "VWAP") for the 30 trading days immediately prior to date notice is provided is greater than $51.00. In such case, the number of common units to be issued upon conversion would be equal to the per unit purchase price plus the value of any accrued and unpaid distributions divided by an amount equal to a 7.5% discount to the VWAP for the 30 trading days immediately prior to the notice of conversion. Rather than have the preferred units convert to common units in accordance with the provisions of this paragraph, NRP would have the option to elect to redeem the preferred units proposed to be converted for cash at a price equal to the per unit purchase price plus the value of any accrued and unpaid distributions. On or after March 2, 2025, the holders of the preferred units may elect to convert the preferred units to common units at a conversion rate equal to the Liquidation Value divided by an amount equal to a 10% discount to the VWAP for the 30 trading days immediately prior to the notice of conversion. The “liquidation value” will be an amount equal to the greater of: (1) (a) the per unit purchase price multiplied by (i) prior to March 2, 2020, 1.50, (ii) on or after March 2, 2020 and prior to March 2, 2021, 1.70 and (iii) on or after March 2, 2021, 1.85, less (b)(i) all preferred unit distributions previously made by NRP and (ii) all cash payments previously made in respect of redemption of any PIK units; and (2) the per unit purchase price plus the value of all accrued and unpaid distributions. To the extent the holders of the preferred units have not elected to convert their preferred units before March 2, 2029, NRP has the right to force conversion of the preferred units at a price equal to the liquidation value divided by an amount equal to a 10% discount to the VWAP for the 30 trading days immediately prior to the notice of conversion. In addition, NRP has the ability to redeem at any time (subject to compliance with its debt agreements) all or any portion of the preferred units and any outstanding PIK units for cash. The redemption price for each outstanding PIK unit is $1,000 plus the value of any accrued and unpaid distributions per PIK unit. The redemption price for each preferred unit is the liquidation value divided by the number of outstanding preferred units. The preferred units are redeemable at the option of the preferred purchasers only upon a change in control. The terms of the preferred units contain certain restrictions on NRP's ability to pay distributions on its common units. To the extent that either (i) NRP's consolidated Leverage Ratio, as defined in the Partnership's Fifth Amended and Restated Partnership Agreement dated March 2, 2017 (the "restated partnership agreement"), is greater than 3.25x, or (ii) the ratio of NRP's Distributable Cash Flow (as defined in the Restated Partnership Agreement) to cash distributions made or proposed to be made is less than 1.2x (in each case, with respect to the most recently completed four-quarter period), NRP may not increase the quarterly distribution above $0.45 per quarter without the approval of the holders of a majority of the outstanding preferred units. In addition, if at any time after January 1, 2022, any PIK units are outstanding, NRP may not make distributions on its common units until it has redeemed all PIK units for cash. The holders of the preferred units have the right to vote with holders of NRP’s common units on an as-converted basis and have other customary approval rights with respect to changes of the terms of the preferred units. In addition, Blackstone has certain approval rights over certain matters as identified in the restated partnership agreement. GoldenTree also has more limited approval rights that will expand once Blackstone's ownership goes below the minimum preferred unit threshold (as defined below). These approval rights are not transferrable without NRP's consent. In addition, the approval rights held by Blackstone and GoldenTree will terminate at such time that Blackstone (together with their affiliates) or GoldenTree (together with their affiliates), as applicable, no longer own at least 20% of the total number of preferred units issued on the closing date, together with all PIK units that have been issued but not redeemed (the "minimum preferred unit threshold"). At the closing, pursuant to the Board Representation and Observation Rights Agreement, the Preferred Purchasers received certain board appointment and observation rights, and Blackstone appointed one director and one observer to the Board of Directors. NRP also entered into a registration rights agreement (the "preferred unit and warrant registration rights agreement") with the preferred purchasers, pursuant to which NRP is required to file (i) a shelf registration statement to register the common units issuable upon exercise of the warrants and to cause such registration statement to become effective not later than 90 days following the closing date and (ii) a shelf registration statement to register the common units issuable upon conversion of the preferred units and to cause such registration statement to become effective not later than the earlier of the fifth anniversary of the closing date or 90 days following the first issuance of any common units upon conversion of preferred units (the "registration deadlines"). In addition, the preferred unit and warrant registration rights agreement gives the preferred purchasers piggyback registration and demand underwritten offering rights under certain circumstances. The shelf registration statement to register the common units issuable upon exercise of the warrants became effective on April 20, 2017. If the shelf registration statement to register the common units issuable upon conversion of the preferred units is not effective by the applicable registration deadline, NRP will be required to pay the preferred purchasers liquidated damages in the amounts and upon the term set forth in the preferred unit and warrant registration rights agreement. Accounting for the Preferred Units and Warrants Classification The preferred units are accounted for as temporary equity on NRP's Consolidated Balance Sheets due to certain contingent redemption rights that may be exercised at the election of preferred purchasers. The warrants are accounted for as equity on NRP's Consolidated Balance Sheets. Initial Measurement The net transaction price was allocated to the preferred units and warrants based on their relative fair values at inception date. NRP allocated the transaction issuance costs to the preferred units and warrants primarily on a pro-rata basis based on their relative inception date allocated values. Subsequent Measurement Subsequent adjustment of the preferred units will not occur until NRP has determined that the conversion or redemption of all or a portion of the preferred units is probable of occurring. Once conversion or redemption becomes probable of occurring, the carrying amount of the preferred units will be accreted to their redemption value over the period from the date the feature is probable of occurring to the date the preferred units can first be converted or redeemed. Activity related to the preferred units is as follows: (In thousands, except unit data) Units Outstanding Financial Balance at December 31, 2018 and 2019 250,000 $ 164,587 Distribution paid-in-kind 3,750 3,750 Balance at December 31, 2020 253,750 $ 168,337 Distributions paid-in-kind 15,571 15,571 Balance at December 31, 2021 269,321 $ 183,908 Subsequent adjustment of the warrants will not occur until the warrants are exercised, at which time, NRP may, at its option, elect to settle the warrants in common units or cash, each on a net basis. The net basis will be equal to the difference between the Partnership's common unit price and the strike price of the warrant. Once warrant exercise occurs, the difference between the carrying amount of the warrants and the net settlement amount will be allocated on a pro-rata basis to the common unitholders and general part ner. On November 10, 2021 (the "exercise date"), Blackstone exercised all of its 997,500 warrants with a strike price of $22.81 and NRP settled the warrants in cash on a net basis. NRP delivered the net cash settlement amount of $9.2 million. The 15-day VWAP ending on the business day prior to the exercise date was $32.02. Activity related to the warrants is as follows: (In thousands, except warrant data) Warrants Outstanding Financial Balance at December 31, 2018, 2019 and 2020 4,000,000 $ 66,816 Warrant settlement (997,500) (18,852) Balance at December 31, 2021 3,002,500 $ 47,964 Certain embedded features within the preferred unit and warrant purchase agreement are accounted for at fair value and are remeasured each quarter. See Note 12. Fair Value Measurements

Common and Preferred Unit Distr

Common and Preferred Unit Distributions	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Common and Preferred Unit Distributions	Common and Preferred Unit Distributions The Partnership makes distributions to common and preferred unitholders on a quarterly basis, subject to approval by the Board of Directors. NRP recognizes both common unit and preferred unit distributions on the date the distribution is declared. Distributions made on the common units and the general partner's general partner ("GP") interest are made on a pro-rata basis in accordance with their relative percentage interests in the Partnership. The general partner is entitled to receive 2% of such distributions. Income (loss) available to common unitholders and the general partner is reduced by preferred unit distributions that accumulated during the period. NRP reduced net income (loss) available to common unitholders and the general partner by $31.6 million, $30.2 million and $30.0 million during the year ended December 31, 2021, 2020 and 2019, respectively as a result of accumulated preferred unit distributions earned during the period. The following table shows the distributions declared and paid to common and preferred unitholders during the year ended December 31, 2021, 2020 and 2019, respectively: Cash Distributions Paid-in-kind Distributions Common Units Preferred Units Date Paid Period Covered by Distribution Distribution Total Distribution (1) (In thousands) Distribution per Unit Total Distribution Total Distribution 2021 February 2021 October 1 - December 31, 2020 $ 0.45 $ 5,630 $ 15.00 $ 3,806 3,806 May 2021 January 1 - March 31, 2021 0.45 5,672 15.00 3,864 3,864 August 2021 April 1 - June 30, 2021 0.45 5,671 15.00 3,921 3,921 November 2021 July 1 - September 30, 2021 0.45 5,672 15.00 3,980 3,980 2020 February 2020 October 1 - December 31, 2019 $ 0.45 $ 5,630 $ 30.00 $ 7,500 — May 2020 January 1 - March 31, 2020 — — 15.00 3,750 3,750 June 2020 (2) January 1 - March 31, 2020 — — 15.45 3,863 — August 2020 April 1 - June 30, 2020 0.45 5,630 30.00 7,500 — November 2020 July 1 - September 30, 2020 0.45 5,630 15.00 3,750 3,750 2019 February 2019 October 1 - December 31, 2018 $ 0.45 $ 5,625 $ 30.00 $ 7,500 — May 2019 January 1 - March 31, 2019 0.45 5,630 30.00 7,500 — May 2019 (3) Special Distribution 0.85 10,635 — — — August 2019 April 1 - June 30, 2019 0.45 5,630 30.00 7,500 — November 2019 July 1 - September 30, 2019 0.45 5,630 30.00 7,500 — (1) Total common unit distribution includes the amount paid to NRP's general partner in accordance with the general partner's 2% general partner interest. (2) Redemption of preferred units paid in kind plus accrued interest. (3) Special distribution was made to cover the common unitholders' tax liability resulting from the sale of NRP's construction aggregates business in December 2018.

Net Income (Loss) Per Common Un

Net Income (Loss) Per Common Unit	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Net Income (Loss) Per Common Unit	Net Income (Loss) Per Common Unit Basic net income (loss) per common unit is computed by dividing net income (loss), after considering income attributable to preferred unitholders and the general partner’s general partner interest, by the weighted average number of common units outstanding. Diluted net income (loss) per common unit includes the effect of NRP's preferred units, warrants, and unvested unit-based awards if the inclusion of these items is dilutive. The dilutive effect of the preferred units is calculated using the if-converted method. Under the if-converted method, the preferred units are assumed to be converted at the beginning of the period, and the resulting common units are included in the denominator of the diluted net income (loss) per unit calculation for the period being presented. Distributions declared in the period and undeclared distributions on the preferred units that accumulated during the period are added back to the numerator for purposes of the if-converted calculation. The calculation of diluted net income per common unit for the year ended December 31, 2021 includes the assumed conversion of the preferred units. The calculation of diluted net loss per common unit for the years ended December 31, 2020 and 2019 does not include the assumed conversion of the preferred units because the impact would have been anti-dilutive. The dilutive effect of the warrants is calculated using the treasury stock method, which assumes that the proceeds from the exercise of these instruments are used to purchase common units at the average market price for the period. The calculation of diluted net income per common unit for the year ended December 31, 2021 includes the net settlement of warrants to purchase 0.75 million common units with a strike price of $22.81 but does not include the net settlement of warrants to purchase 2.25 million common units with a strike price of $34.00 because the impact would have been anti-dilutive. The calculation of diluted net loss per common unit for the years ended December 31, 2020 and 2019 does not include the net settlement of warrants to purchase 1.75 million common units with a strike price of $22.81 or the net settlement of warrants to purchase 2.25 million common units with a strike price of $34.00 because the impact would have been anti-dilutive. The following tables reconcile the numerators and denominators of the basic and diluted net income (loss) per common unit computations and calculates basic and diluted net income (loss) per common unit: For the Year Ended December 31, (In thousands, except per unit data) 2021 2020 2019 Allocation of net income (loss) Net income (loss) from continuing operations $ 108,902 $ (84,819) $ (25,414) Less: income attributable to preferred unitholders (31,609) (30,225) (30,000) Net income (loss) from continuing operations attributable to common unitholders and the general partner $ 77,293 $ (115,044) $ (55,414) Add (less): net loss (income) from continuing operations attributable to the general partner (1,546) 2,301 1,108 Net income (loss) from continuing operations attributable to common unitholders $ 75,747 $ (112,743) $ (54,306) Net income from discontinued operations $ — $ — $ 956 Less: net income from discontinued operations attributable to the general partner — — (19) Net income from discontinued operations attributable to common unitholders $ — $ — $ 937 Net income (loss) $ 108,902 $ (84,819) $ (24,458) Less: income attributable to preferred unitholders (31,609) (30,225) (30,000) Net income (loss) attributable to common unitholders and the general partner $ 77,293 $ (115,044) $ (54,458) Add (less): net loss (income) attributable to the general partner (1,546) 2,301 1,089 Net income (loss) attributable to common unitholders $ 75,747 $ (112,743) $ (53,369) Basic income (loss) per common unit Weighted average common units—basic 12,337 12,261 12,260 Basic net income (loss) from continuing operations per common unit $ 6.14 $ (9.20) $ (4.43) Basic net income from discontinued operations per common unit $ — $ — $ 0.08 Basic net income (loss) per common unit $ 6.14 $ (9.20) $ (4.35) For the Year Ended December 31, (In thousands, except per unit data) 2021 2020 2019 Diluted income (loss) per common unit Weighted average common units—basic 12,337 12,261 12,260 Plus: dilutive effect of preferred units 9,604 — — Plus: dilutive effect of warrants 74 — — Plus: dilutive effect of unvested unit-based awards 178 — — Weighted average common units—diluted 22,193 12,261 12,260 Net income (loss) from continuing operations $ 108,902 $ (84,819) $ (25,414) Less: income attributable to preferred unitholders — (30,225) (30,000) Diluted net income (loss) from continuing operations attributable to common unitholders and the general partner $ 108,902 $ (115,044) $ (55,414) Add (less): net loss (income) from continuing operations attributable to the general partner (2,178) 2,301 1,108 Diluted net income (loss) from continuing operations attributable to common unitholders $ 106,724 $ (112,743) $ (54,306) Diluted net income from discontinued operations attributable to common unitholders $ — $ — $ 937 Net income (loss) $ 108,902 $ (84,819) $ (24,458) Less: income attributable to preferred unitholders — (30,225) (30,000) Diluted net income (loss) attributable to common unitholders and the general partner $ 108,902 $ (115,044) $ (54,458) Add (less): diluted net loss (income) attributable to the general partner (2,178) 2,301 1,089 Diluted net income (loss) attributable to common unitholders $ 106,724 $ (112,743) $ (53,369) Diluted net income (loss) from continuing operations per common unit $ 4.81 $ (9.20) $ (4.43) Diluted net income from discontinued operations per common unit $ — $ — $ 0.08 Diluted net income (loss) per common unit $ 4.81 $ (9.20) $ (4.35)

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2021
Segment Reporting [Abstract]
Segment Information	Segment Information The Partnership's segments are strategic business units that offer distinct products and services to different customers in different geographies within the U.S. and that are managed accordingly. NRP has the following two operating segments: Mineral Rights (formerly named Coal Royalty and Other segment) —c onsists of mineral interests and other subsurface rights across the United States. NRP's ownership provides critical inputs for the manufacturing of steel, electricity and basic building materials, as well as opportunities for carbon sequestration and renewable energy. The Partnership is working to strategically redefine its business as a key player in the transitional energy economy in the years to come. Soda Ash —consists of the Partnership's 49% non-controlling equity interest in Sisecam Wyoming, a trona ore mining operation and soda ash refinery in the Green River Basin of Wyoming. Sisecam Wyoming mines trona and processes it into soda ash that is sold both domestically and internationally into the glass and chemicals industries. Direct segment costs and certain other costs incurred at the corporate level that are identifiable and that benefit the Partnership's segments are allocated to the operating segments accordingly. These allocated costs generally include salaries and benefits, insurance, property taxes, legal, royalty, information technology and shared facilities services and are included in operating and maintenance expenses on the Partnership's Consolidated Statements of Comprehensive Income (Loss). Corporate and Financing includes functional corporate departments that do not earn revenues. Costs incurred by these departments include interest and financing, corporate headquarters and overhead, centralized treasury, legal and accounting and other corporate-level activity not specifically allocated to a segment and are included in general and administrative expenses on the Partnership's Consolidated Statements of Comprehensive Income (Loss). The following table summarizes certain financial information for each of the Partnership's business segments: Operating Segments (In thousands) Mineral Rights Soda Ash Corporate and Financing Total For the Year Ended December 31, 2021 Revenues $ 194,248 $ 21,871 $ — $ 216,119 Gain on asset sales and disposals 245 — — 245 Operating and maintenance expenses 26,880 169 — 27,049 Depreciation, depletion and amortization 19,075 — — 19,075 General and administrative expenses — — 17,360 17,360 Asset impairments 5,102 — — 5,102 Other expenses, net 24 — 38,852 38,876 Net income (loss) from continuing operations 143,412 21,702 (56,212) 108,902 As of December 31, 2021 Total assets $ 675,579 $ 276,004 $ 2,240 $ 953,823 For the Year Ended December 31, 2020 Revenues $ 129,011 $ 10,728 $ — $ 139,739 Gain on asset sales and disposals 581 — — 581 Operating and maintenance expenses 24,610 185 — 24,795 Depreciation, depletion and amortization 9,198 — — 9,198 General and administrative expenses — — 14,293 14,293 Asset impairments 135,885 — — 135,885 Other expenses, net 79 — 40,889 40,968 Net income (loss) from continuing operations (40,180) 10,543 (55,182) (84,819) As of December 31, 2020 Total assets $ 656,505 $ 262,514 $ 2,858 $ 921,877 For the Year Ended December 31, 2019 Revenues $ 210,348 $ 47,089 $ — $ 257,437 Gain on asset sales and disposals 6,498 — — 6,498 Operating and maintenance expenses 32,489 249 — 32,738 Depreciation, depletion and amortization 14,932 — — 14,932 General and administrative expenses — — 16,730 16,730 Asset impairments 148,214 — — 148,214 Other expenses, net — — 76,735 76,735 Net income (loss) from continuing operations 21,211 46,840 (93,465) (25,414) Income from discontinued operations — — — 956

Equity Investment

Equity Investment	12 Months Ended
	Dec. 31, 2021
Equity Method Investments and Joint Ventures [Abstract]
Equity Investment	Equity Investment The Partnership accounts for its 49% investment in Sisecam Wyoming using the equity method of accounting. Activity related to this investment is as follows: For the Year Ended December 31, (In thousands) 2021 2020 2019 Balance at beginning of period $ 262,514 $ 263,080 $ 247,051 Income allocation to NRP’s equity interests (1) 26,979 15,205 52,016 Amortization of basis difference (5,108) (4,477) (4,927) Other comprehensive income 2,889 2,916 790 Distribution (11,270) (14,210) (31,850) Balance at end of period $ 276,004 $ 262,514 $ 263,080 (1) Includes reclassifications of accumulated other comprehensive income (loss) to income allocation to NRP equity interest of $0.0 million, $1.7 million and $0.6 million for the year ended December 31, 2021, 2020 and 2019, respectively. The difference between the amount at which the investment in Sisecam Wyoming is carried and the amount of underly ing equity in Sisecam Wyoming's net assets was $126.3 million and $131.4 million as of December 31, 2021 and 2020, respectively. This excess basis relates to property, plant and equipment and right to mine assets. The excess basis difference that relates to property, plant and equipment is being amortized into income using the straight-line method over 27 years. The excess basis difference that relates to right to mine assets is being amortized into income using the units of production method. The following table represents summarized financial information for Sisecam Wyoming as derived from their respective financial statements for the years ended December 31, 2021, 2020, and 2019: For the Year Ended December 31, (In thousands) 2021 2020 2019 Net sales $ 540,139 $ 392,231 $ 522,843 Gross profit 80,550 54,838 131,712 Net income 55,059 31,030 106,155 The financial position of Sisecam Wyoming is summarized as follows: December 31, (In thousands) 2021 2020 Current assets $ 206,315 $ 164,720 Noncurrent assets 297,210 294,008 Current liabilities 73,181 55,313 Noncurrent liabilities 124,749 135,776

Mineral Rights, Net

Mineral Rights, Net	12 Months Ended
	Dec. 31, 2021
Extractive Industries [Abstract]
Mineral Rights, Net	Mineral Rights, Net The Partnership’s mineral rights consist of the following: December 31, 2021 2020 (In thousands) Carrying Value Accumulated Depletion Net Book Value Carrying Value Accumulated Depletion Net Book Value Coal properties $ 670,650 $ (253,503) $ 417,147 $ 785,623 $ (346,773) $ 438,850 Aggregates properties 8,747 (2,975) 5,772 9,039 (2,819) 6,220 Oil and gas royalty properties 12,354 (9,115) 3,239 12,354 (8,593) 3,761 Other 13,151 (1,612) 11,539 13,154 (1,612) 11,542 Total mineral rights, net $ 704,902 $ (267,205) $ 437,697 $ 820,170 $ (359,797) $ 460,373 Depletion expense related to the Partnership’s mineral rights is included in depreciation, depletion and amortization on its Consolidated Statements of Comprehensive Income (Loss) and totaled $17.6 million, $8.8 million and $12.1 million for the year ended December 31, 2021, 2020 and 2019, respectively. Sales of Mineral Rights During the year ended December 31, 2021 and 2020, the Partnership recorded a cumulative gain of $0.2 million and $0.6 million, respectively, included in gain on asset sales and disposals on the Consolidated Statements of Comprehensive Income (Loss) related to sales of certain mineral rights. During the year ended December 31, 2019, the Partnership recorded a cumulative gain of $6.5 million included in gain on asset sales and disposals on the Consolidated Statements of Comprehensive Income (Loss) primarily related to the disposal of certain coal mineral rights with a $0 net book value. Impairment of Mineral Rights During the years ended December 31, 2021, 2020 and 2019, the Partnership identified facts and circumstances that indicated that the carrying value of certain of its mineral rights exceed future cash flows from those assets and recorded non-cash impairment expense included in asset impairments on the Consolidated Statements of Comprehensive Income (Loss) as follows: For the Year Ended December 31, (In thousands) 2021 2020 2019 Coal properties (1) $ 5,015 $ 114,302 $ 125,806 Aggregates properties (2) 87 21,583 103 Total $ 5,102 $ 135,885 $ 125,909 (1) The Partnership recorded $5.0 million of impairment expense during the year ended December 31, 2021 primarily related to a lease termination. T he Partners hip recorded $114.3 million of impairment expense to impair certain assets during the year ended December 31, 2020 primarily related to weakened coal markets that resulted in termination of certain coal leases and changes to lessee mine plans resulting in permanent moves off certain of our coal properties. The partnership recorded $125.8 million of impairment expense during the year ended December 31, 2019 primarily due to deterioration in thermal coal markets, lessee capital constraints, thermal coal lease terminations, and expectations of further reductions in global and domestic thermal coal demand due to low natural gas prices and continued pressure on the electric power generation industry over emissions and climate change, resulting in reductions in expected cash flows (combination of lower expected coal sales volumes, sales prices, minimums and/or life of mine assumptions) on certain of our coal properties. During the year ended December 31, 2019, the Partnership recorded $36.0 million to fully impair certain coal properties. In addition, NRP recorded $89.8 million of impairment expense on coal royalty properties with $97 million of net book value, resulting in a fair value of $7.2 million at December 31, 2019. The fair value of the impaired assets at December 31, 2019 was calculated using a discount rate of 15%. NRP compared the net book value of its coal properties to estimated undiscounted future net cash flows. If the net book value exceeded the undiscounted future cash flows, the Partnership recorded an impairment for the excess of the net book value over fair value. A discounted cash flow model was used to estimate fair value. Significant inputs used to determine fair value include estimates of future cash flows from coal sales and minimum payments, discount rate and useful economic life. Estimated cash flows are the product of a process that began with current realized pricing as of the measurement date and included an adjustment for risk related to the future realization of cash flows. (2) The Partnership recorded $0.1 million of aggregates royalty property impairments during the year ended December 31, 2021. Th e Partnership recorded $21.6 million of aggregates royalty property impairments during the year ended December 31, 2020 primarily related to decreased oil and gas drilling activity which negatively impacted the outlook for NRP's frac sand properties. The Partnership recorded $0.1 million of aggregates royalty property impairments during the year ended December 31, 2019. NRP compared the net book value of its aggregates and timber properties to estimated undiscounted future net cash flows. If the net book value exceeded the undiscounted cash flows, the Partnership recorded an impairment for the excess of the net book value over fair value. A discounted cash flow model was used to estimate fair value. Significant inputs used to determine fair value include estimates of future cash flows from aggregates sales and minimum payments, discount rate and useful economic life. Estimated cash flows are the product of a process that began with current realized pricing as of the measurement date and included an adjustment for risk related to the future realization of cash flows. While the Partnership's impairment evaluation as of December 31, 2021 incorporated an estimated impact of the global COVID-19 pandemic, there is significant uncertainty as to the severity and duration of this disruption. If the impact is worse than we currently estimate, an additional impairment charge may be recognized in future periods.

Intangible Assets, Net

Intangible Assets, Net	12 Months Ended
	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets, Net	Intangible Assets, Net The Partnership's intangible assets consist of above-market coal royalty and related transportation contracts with subsidiaries of Foresight Energy Resources LLC ("Foresight") pursuant to which the Partnership receives royalty payments for coal sales and throughput fees for the transportation and processing of coal. The Partnership's intangible assets included on its Consolidated Balance Sheets are as follows: December 31, (In thousands) 2021 2020 Intangible assets at cost $ 51,353 $ 53,878 Less: accumulated amortization (35,223) (36,419) Total intangible assets, net $ 16,130 $ 17,459 Amortization expense included in depreciation, depletion and amortization on the Partnership's Consolidated Statements of Comprehensive Income (Loss) was $1.3 million, $0.2 million and $2.5 million for the year ended December 31, 2021, 2020 and 2019, respectively. The estimates of amortization expense for the years ended December 31, as indicated below, are based on current mining plans and are subject to revision as those plans change in future periods. (In thousands) Estimated Amortization Expense 2022 $ 1,127 2023 1,041 2024 1,238 2025 1,202 2026 1,202

Debt, Net

Debt, Net	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Debt, Net	Debt, Net The Partnership's debt consists of the following: December 31, (In thousands) 2021 2020 NRP LP debt: 9.125% senior notes, with semi-annual interest payments in June and December, due June 2025 issued at par ("2025 Senior Notes") $ 300,000 $ 300,000 Opco debt: Revolving credit facility $ — $ — Senior Notes 5.55% with semi-annual interest payments in June and December, with annual principal payments in June, due June 2023 $ 4,730 $ 7,094 4.73% with semi-annual interest payments in June and December, with annual principal payments in December, due December 2023 12,008 18,013 5.82% with semi-annual interest payments in March and September, with annual principal payments in March, due March 2024 38,053 50,738 8.92% with semi-annual interest payments in March and September, with annual principal payments in March, due March 2024 12,035 16,047 5.03% with semi-annual interest payments in June and December, with annual principal payments in December, due December 2026 57,104 68,524 5.18% with semi-annual interest payments in June and December, with annual principal payments in December, due December 2026 14,554 17,464 Total Opco Senior Notes $ 138,484 $ 177,880 Total debt at face value $ 438,484 $ 477,880 Net unamortized debt issuance costs (4,939) (6,381) Total debt, net $ 433,545 $ 471,499 Less: current portion of long-term debt (39,102) (39,055) Total long-term debt, net $ 394,443 $ 432,444 NRP LP Debt 2025 Senior Notes The 2025 Senior Notes were issued under an Indenture dated as of April 29, 2019 (the "2025 Indenture"), bear interest at 9.125% per year and mature on June 30, 2025. Interest is payable semi-annually on June 30 and December 30. NRP and NRP Finance have the option to redeem the 2025 Senior Notes, in whole or in part, at any time on or after October 30, 2021, at the redemption prices (expressed as percentages of principal amount) of 104.563% for the 12-month period beginning October 30, 2021, 102.281% for the 12-month period beginning October 30, 2022, and thereafter at 100.000%, together, in each case, with any accrued and unpaid interest to the date of redemption. In the event of a change of control, as defined in the 2025 Indenture, the holders of the 2025 Senior Notes may require us to purchase their 2025 Senior Notes at a purchase price equal to 101% of the principal amount of the 2025 Senior Notes, plus accrued and unpaid interest, if any. The 2025 Senior Notes were issued at par. The 2025 Senior Notes are the senior unsecured obligations of NRP and NRP Finance. The 2025 Senior Notes rank equal in right of payment to all existing and future senior unsecured debt of NRP and NRP Finance and senior in right of payment to any of NRP's subordinated debt. The 2025 Senior Notes are effectively subordinated in right of payment to all future secured debt of NRP and NRP Finance to the extent of the value of the collateral securing such indebtedness and are structurally subordinated in right of payment to all existing and future debt and other liabilities of our subsidiaries, including the Opco Credit Facility and each series of Opco’s existing senior notes. None of NRP's subsidiaries guarantee the 2025 Senior Notes. As of December 31, 2021 and 2020, NRP and NRP Finance were in compliance with the terms of the Indenture relating to their 2025 Senior Notes. 2022 Senior Notes In 2019, the Partnership redeemed its 2022 Senior Notes at a redemption price equal to 105.250% of the principal amount of the 2022 Senior Notes, plus accrued and unpaid interest. In connection with the early redemption, the Partnership paid an $18.1 million call premium and also wrote off $10.4 million of unamortized debt issuance costs and debt discount. These expenses are included in loss on extinguishment of debt on the Partnership's Consolidated Statements of Comprehensive Income (Loss). Opco Debt All of Opco’s debt is guaranteed by its wholly owned subsidiaries and is secured by certain of the assets of Opco and its wholly owned subsidiaries, other than BRP LLC and NRP Trona LLC. As of December 31, 2021 and 2020, Opco was in compliance with the terms of the financial covenants contained in its debt agreements. Opco Credit Facility In 2019, the Partnership entered into the Fourth Amendment (the “Fourth Amendment”) to the Opco Credit Facility (the "Opco Credit Facility"). The Fourth Amendment extends the term of the Opco Credit Facility until April 2023. Lender commitments under the Opco Credit Facility remain at $100.0 million. Indebtedness under the Opco Credit Facility bears interest, at Opco's option, at: • the higher of (i) the prime rate as announced by the agent bank; (ii) the federal funds rate plus 0.50%; or (iii) LIBOR plus 1%, in each case plus an applicable margin ranging from 2.50% to 3.50%; or • a rate equal to LIBOR plus an applicable margin ranging from 3.50% to 4.50%. During the years ended December 31, 2021 and 2020, the Partnership did not have any borrowings outstanding under the Opco Credit Facility and had $100.0 million in available borrowing capacity at both December 31, 2021 and 2020. Opco will incur a commitment fee on the unused portion of the revolving credit facility at a rate of 0.50% per annum. Opco may prepay all amounts outstanding under the Opco Credit Facility at any time without penalty. The Opco Credit Facility contains financial covenants requiring Opco to maintain: • A leverage ratio of consolidated indebtedness to EBITDDA (as defined in the Opco Credit Facility) not to exceed 4.0x; provided, however, that if the Partnership increases its quarterly distribution to its common unitholders above $0.45 per common unit, the maximum leverage ratio under the Opco Credit Facility will permanently decrease from 4.0x to 3.0x; and • a fixed charge coverage ratio of consolidated EBITDDA to consolidated fixed charges (consisting of consolidated interest expense and consolidated lease expense) of not less than 3.5 to 1.0. The Opco Credit Facility contains certain additional customary negative covenants that, among other items, restrict Opco’s ability to incur additional debt, grant liens on its assets, make investments, sell assets and engage in business combinations. Included in the investment covenant are restrictions upon Opco’s ability to acquire assets where Opco does not maintain certain levels of liquidity. In addition, Opco is required to use 75% of the net cash proceeds of certain non-ordinary course asset sales to repay the Opco Credit Facility (without any corresponding commitment reduction) and use the remaining 25% of the net cash proceeds to offer to repay its Senior Notes on a pro-rata basis, as described below under “—Opco Senior Notes.” The Opco Credit Facility also contains customary events of default, including cross-defaults under Opco’s Senior Notes. The Opco Credit Facility is collateralized and secured by liens on certain of Opco’s assets with carrying values o f $345.0 million and $364.5 million classified as mineral rights, net and other long-term assets, net on the Partnership’s Consolidated Balance Sheets as of December 31, 2021 and 2020, respectively. The collateral includes (1) the equity interests in all of Opco’s wholly owned subsidiaries, other than BRP LLC and NRP Trona LLC (which owns a 49% non-controlling equity interest in Sisecam Wyoming), (2) the personal property and fixtures owned by Opco’s wholly owned subsidiaries, other than BRP LLC and NRP Trona LLC, (3) Opco’s material coal royalty revenue producing properties, and (4) certain of Opco’s coal-related infrastructure assets. Opco Senior Notes Opco has issued several series of private placement senior notes (the "Opco Senior Notes") with various interest rates and principal due dates. As of December 31, 2021 and 2020, the Opco Senior Notes had cumulative principal balances of $138.5 million and $177.9 million, respectively. Opco made mandatory principal payments on the Opco Senior Notes of $39.4 million, $46.2 million and $117.4 million during the year ended December 31, 2021, 2020 and 2019, respectively. The payments made during the year ended December 31, 2019 included a $49.3 million pre-payment as a result of the sale of the Partnership's construction aggregates business. The Note Purchase Agreements relating to the Opco Senior Notes contain covenants requiring Opco to: • maintain a ratio of consolidated indebtedness to consolidated EBITDDA (as defined in the note purchase agreement) of no more than 4.0 to 1.0 for the four most recent quarters; • not permit debt secured by certain liens and debt of subsidiaries to exceed 10% of consolidated net tangible assets (as defined in the note purchase agreement); and • maintain the ratio of consolidated EBITDDA (as defined in the note purchase agreement) to consolidated fixed charges (consisting of consolidated interest expense and consolidated operating lease expense) at not less than 3.5 to 1.0. In addition, the Note Purchase Agreements include a covenant that provides that, in the event NRP Operating or any of its subsidiaries is subject to any additional or more restrictive covenants under the agreements governing its material indebtedness (including the Opco Credit Facility and all renewals, amendments or restatements thereof), such covenants shall be deemed to be incorporated by reference in the Note Purchase Agreements and the holders of the Notes shall receive the benefit of such additional or more restrictive covenants to the same extent as the lenders under such material indebtedness agreement. The 8.92% Opco Senior Notes also provides that in the event that Opco’s leverage ratio of consolidated indebtedness to consolidated EBITDDA (as defined in the Note Purchase Agreements) exceeds 3.75 to 1.00 at the end of any fiscal quarter, then in addition to all other interest accruing on these notes, additional interest in the amount of 2.00% per annum shall accrue on the notes for the two succeeding quarters and for as long thereafter as the leverage ratio remains above 3.75 to 1.00. Opco has not exceeded the 3.75 to 1.00 ratio at the end of any fiscal quarter through December 31, 2021. In September 2016, Opco amended the Opco Senior Notes. Under this amendment, Opco agreed to use certain asset sale proceeds to make mandatory prepayment offers to the holders of the Opco Senior Notes using an amount of net cash proceeds from certain asset sales that will be calculated pro-rata based on the amount of Opco Senior Notes then outstanding compared to the other total Opco senior debt outstanding that is being prepaid. The mandatory prepayment offers described above will be made pro-rata across each series of outstanding Opco Senior Notes and will not require any make-whole payment by Opco. In addition, the remaining principal and interest payments on the Opco Senior Notes will be adjusted accordingly based on the amount of Opco Senior Notes actually prepaid. The prepayments do not affect the maturity dates of any series of the Opco Senior Notes. Consolidated Principal Payments The consolidated principal payments due are set forth below: NRP LP Opco (In thousands) Senior Notes Senior Notes Credit Facility Total 2022 $ — $ 39,396 $ — $ 39,396 2023 — 39,396 — 39,396 2024 — 31,028 — 31,028 2025 300,000 14,332 — 314,332 2026 — 14,332 — 14,332 Thereafter — — — — $ 300,000 $ 138,484 $ — $ 438,484

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Fair Value of Financial Assets and Liabilities The Partnership’s financial assets and liabilities consist of cash and cash equivalents, a contract receivable and debt. The carrying amounts reported on the Consolidated Balance Sheets for cash and cash equivalents approximate fair value due to their short-term nature. The Partnership uses available market data and valuation methodologies to estimate the fair value of its debt and contract receivable. The following table shows the carrying value and estimated fair value of the Partnership's debt and contract receivable: December 31, 2021 2020 (In thousands) Fair Value Hierarchy Level Carrying Estimated Carrying Estimated Debt: NRP 2025 Senior Notes 1 $ 296,236 $ 300,000 $ 295,160 $ 274,500 Opco Senior Notes (1) 3 137,309 138,484 176,339 162,760 Opco Credit Facility 3 — — — — Assets: Contract receivable, net (current and long-term) (2) 3 $ 33,612 $ 26,010 $ 35,313 $ 27,025 (1) The fair value of the Opco Senior Notes are estimated by management using quotations obtained for the NRP 2025 Senior Notes on the closing trading prices near period end, which were at 100% and 92% of par value at December 31, 2021 and 2020, respectively. (2) The fair value of the Partnership's contract receivable is determined based on the present value of future cash flow projections related to the underlying asset at a discount rate of 15% at December 31, 2021 and 2020. NRP has embedded derivatives in the preferred units related to certain conversion options, redemption features and the change of control provision that are accounted for separately from the preferred units as assets and liabilities at fair value on the Partnership's Consolidated Balance Sheets. Level 3 valuation of the embedded derivatives are based on numerous factors including the likelihood of the event occurring. The embedded derivatives are revalued quarterly and changes in their fair value would be recorded in other expenses, net on the Partnership's Consolidated Statements of Comprehensive Income (Loss). The embedded derivatives had zero value as of December 31, 2021 and 2020. Fair Value of Non-Financial Assets The Partnership discloses or recognizes its non-financial assets, such as impairments of coal and aggregates properties at fair value on a nonrecurring basis. Refer to Note 9. Mineral Rights, Net for additional disclosures related to the fair value associated with the impaired assets.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2021
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Affiliates of our General Partner The Partnership’s general partner does not receive any management fee or other compensation for its management of NRP. However, in accordance with the partnership agreement, the general partner and its affiliates are reimbursed for services provided to the Partnership and for expenses incurred on the Partnership’s behalf. Employees of Quintana Minerals Corporation ("QMC") and Western Pocahontas Properties Limited Partnership ("WPPLP"), affiliates of the Partnership, provide their services to manage the Partnership's business. QMC and WPPLP charge the Partnership the portion of their employee salary and benefits costs related to their employee services provided to NRP. These QMC and WPPLP employee management service costs are presented as operating and maintenance expenses and general and administrative expenses on the Partnership's Consolidated Statements of Comprehensive Income (Loss). NRP also reimburses overhead costs incurred by its affiliates, including Quintana Infrastructure Development ("QID"), to manage the Partnership's business. These overhead costs include certain rent, information technology, administration of employee benefits and other corporate services incurred by or on behalf of the Partnership’s general partner and its affiliates and are presented as operating and maintenance expenses and general and administrative expenses on the Partnership's Consolidated Statements of Comprehensive Income (Loss). Direct general and administrative expenses charged to the Partnership by QMC, WPPLP and QID are included on the Partnership's Consolidated Statement of Comprehensive Income (Loss) as follows: For the Year Ended December 31, (In thousands) 2021 2020 2019 Operating and maintenance expenses $ 6,543 $ 6,559 $ 6,656 General and administrative expenses 4,611 4,611 4,946 The Partnership had accounts payable to QMC of $0.4 million on its Consolidated Balance Sheets as of December 31, 2021 and 2020 and $0.9 million and $0.3 million of accounts payable to WPPLP as of December 31, 2021 and 2020, respectively. During the years ended December 31, 2021, 2020 and 2019, the Partnership recognized $3.3 million, $0.4 million and $4.0 million in operating and maintenance expenses, respectively, on its Consolidated Statements of Comprehensive Income (Loss) related to an overriding royalty agreement with WPPLP. At December 31, 2021 and 2020, the Partnership ha d $0.0 million and $0.3 million, respectively, of other long-term assets, net on its Consolidated Balance Sheets related to a p repaid royalty for this agreement. Corbin J. Robertson, Jr. owns 85% of the general partner of Great Northern Properties Limited Partnership ("GNP"), a privately held company primarily engaged in owning and managing mineral properties and surface leases. As of December 31, 2021 the Partnership had $0.1 million of accounts receivable from GNP included in accounts receivable, net on its Consolidated Balance Sheets related to amounts collected for surface leases that belong to NRP. Industrial Minerals Group LLC Prior to December 31, 2019, Corbin J. Robertson, III, a Director of GP Natural Resource Partners LLC, held a minority ownership interest in Industrial Minerals Group LLC (“Industrial Minerals”), which, through its subsidiaries, leases one of NRP’s coal royalty properties in Central Appalachia. Coal royalty related revenues from Industrial Minerals totaled $1.7 million for the year ended December 31, 2019. Quinwood Coal Company Royalty Quinwood Coal Partners LP (“Quinwood”), an entity controlled by Corbin J. Robertson, III, leases two coal properties from NRP in Central Appalachia. Coal related revenues from Quinwood totaled $0.0 million, $0.0 million and $0.2 million for the year ended December 31, 2021, 2020 and 2019, respectively.

Major Customers

Major Customers	12 Months Ended
	Dec. 31, 2021
Risks and Uncertainties [Abstract]
Major Customers	Major Customers Revenues from customers that exceeded 10 percent of total revenues for any of the periods presented below are as follows: For the Year Ended December 31, 2021 2020 2019 (In thousands) Revenues Percent Revenues Percent Revenues Percent Foresight (1) (2) $ 37,366 17 % $ 35,704 26 % $ 58,923 23 % Alpha Metallurgical Resources, Inc. (1) 49,440 23 % 33,227 24 % 40,743 16 % (1) Revenues from Foresight and Alpha Metallurgical Resources, Inc. are included within the Partnership's Mineral Rights segment. (2) In June 2020, the Partnership entered into lease amendments with Foresight pursuant to which Foresight agreed to pay NRP fixed cash payments to satisfy all obligations arising out of the existing various coal mining leases and transportation infrastructure fee agreements between the Partnership and Foresight for calendar years 2020 and 2021.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal NRP is involved, from time to time, in various legal proceedings arising in the ordinary course of business. While the ultimate results of these proceedings cannot be predicted with certainty, Partnership management believes these ordinary course matters will not have a material effect on the Partnership’s financial position, liquidity or operations. Environmental Compliance The operations the Partnership’s lessees conduct on its properties, as well as the industrial minerals, aggregates and oil and gas operations in which the Partnership has interests, are subject to federal and state environmental laws and regulations. See " Items 1. and 2. Business and Properties—Regulation and Environmental Matters ." As an owner of surface interests in some properties, the Partnership may be liable for certain environmental conditions occurring on the surface properties. The terms of substantially all of the Partnership’s coal leases require the lessee to comply with all applicable laws and regulations, including environmental laws and regulations. Lessees post reclamation bonds assuring that reclamation will be completed as required by the relevant permit, and substantially all of the leases require the lessee to indemnify the Partnership against, among other things, environmental liabilities. Some of these indemnifications survive the termination of the lease. The Partnership makes regular visits to the mines to ensure compliance with lease terms, but the duty to comply with all regulations rests with the lessees. The Partnership believes that its lessees will be able to comply with existing regulations and does not expect that any lessee’s failure to comply with environmental laws and regulations will have a material impact on the Partnership’s financial condition or results of operations. The Partnership has neither incurred, nor is aware of, any material environmental charges imposed on the Partnership related to its properties for the period ended December 31, 2021. The Partnership is not associated with any material environmental contamination that may require remediation costs. However, the Partnership’s lessees are required to conduct reclamation work on the properties under lease to them. Because the Partnership is not the permittee of the mines being reclaimed, the Partnership is not responsible for the costs associated with these reclamation operations.

Unit-Based Compensation

Unit-Based Compensation	12 Months Ended
	Dec. 31, 2021
Share-based Payment Arrangement [Abstract]
Unit-Based Compensation	Unit-Based Compensation 2017 Long-Term Incentive Plan In December 2017, the 2017 Long-Term Incentive Plan (the “2017 LTIP”) was approved and it became effective in January 2018. The 2017 LTIP authorizes 800,000 common units that are available for delivery by the Partnership pursuant to awards under the plan. The term is 10 years from the date of approval of the Board of Directors or, if earlier, the date the 2017 LTIP is terminated by the Board of Directors or the committee appointed by the Board of Directors to administer the 2017 LTIP, or the date all available common units available have been delivered. Common units delivered pursuant to the 2017 LTIP will consist, in whole or part, of (i) common units acquired in the open market, (ii) common units acquired from the Partnership (including newly issued units), any of our affiliates or any other person or (iii) any combination of the foregoing. Employees, consultants and non-employee directors of the Partnership, the General Partner, GP LLC and their affiliates are generally eligible to receive awards under the 2017 LTIP. The 2017 LTIP provides for the issuance of a variety of equity-based grants, including grants of (i) options, (ii) unit appreciation rights, (iii) restricted units, (iv) phantom units, (v) cash awards, (vi) performance awards, (vii) distribution equivalent rights, and (viii) other unit-based awards. The plan is administered by the Compensation, Nominating and Governance Committee ("CNG Committee") of the Board of Directors, which determines the terms and conditions of awards granted under the 2017 LTIP. The Partnership recognizes forfeitures for any awards issued under this plan as they occur. Unit-Based Awards Unit-based awards under the 2017 LTIP are generally issued to certain employees and non-employee directors of the Partnership. Awards granted to employees either vest 3 years following the grant date or vest ratably over the 3 year period following the grant date. Awards granted to non-employee directors vest over a 1 year period. Directors are given the option to take immediate issuance of the vested awards or defer such issuance until a later date. Upon deferral of issuance, such units will continue to accumulate distribution equivalent rights ("DERs") until issuance. In connection with the phantom unit awards, the CNG Committee also granted tandem DERs, which entitle the holders to receive distributions equal to the distributions paid on the Partnership’s common units between the date the units are granted and the settlement date. The DERs are payable in cash upon vesting but may be subject to forfeiture if the grantee ceases employment prior to vesting. The awards granted in 2021, 2020 and 2019 were valued using the closing price of NRP's units as of the grant date. The grant date fair value of these awards granted during the year ended December 31, 2021, 2020 and 2019 were $3.8 million, $3.5 million and $5.4 million, respectively. Total unit-based compensation expense associated with these awards was $4.0 million,$3.6 million and $2.4 million for the year ended December 31, 2021, 2020 and 2019, respectively, and is included in general and administrative expenses and operating and maintenance expenses on the Partnership's Consolidated Statements of Comprehensive Income (Loss). The unamortized cost associated with unvested outstanding awards as of December 31, 2021 is $3.3 million, which is to be recognized over a weighted average period of 1.7 years. The unamortized cost associated with unvested outstanding awards as of December 31, 2020 was $3.7 million. A summary of the unit activity in the outstanding grants during 2021 is as follows: (In thousands) Common Units Weighted Average Grant Date Fair value per Common Unit Outstanding grants at January 1, 2021 355 $ 26.20 Granted 219 $ 17.31 Fully vested and issued (129) $ 21.38 Forfeitures (34) $ 26.00 Outstanding at December 31, 2021 411 $ 23.00

Financing Transaction

Financing Transaction	12 Months Ended
	Dec. 31, 2021
Financing Receivable [Abstract]
Financing Transaction	17. Financing Transaction The Partnership owns rail loadout and associated infrastructure at the Sugar Camp mine in the Illinois Basin operated by a subsidiary of Foresight. The infrastructure at the Sugar Camp mine is leased to a subsidiary of Foresight and is accounted for as a financing transaction (the "Sugar Camp lease"). The Sugar Camp lease expires in 2032 with renewal options for up to 80 additional years. Minimum payments are $5.0 million per year through the end of the lease term. The $5.0 million due to the Partnership in 2020 and 2021 is included in the fixed cash payments from Foresight resulting from contract modifications entered into during the second quarter of 2020 as discussed in Note 14. Major Customers . The Partnership is also entitled to variable payments in the form of throughput fees determined based on the amount of coal transported and processed utilizing the Partnership's assets. In the event the Sugar Camp lease is renewed beyond 2032, payments become a fixed $10 thousand per year for the remainder of the renewed term.

Credit Losses

Credit Losses	12 Months Ended
	Dec. 31, 2021
Credit Loss [Abstract]
Credit Losses	Credit Losses The Partnership is exposed to credit losses through collection of its trade receivables resulting from contracts with customers and a long-term receivable resulting from a financing transaction with a customer. The Partnership records an allowance for current expected credit losses on these receivables based on the loss-rate method. NRP assessed the likelihood of collection of its receivables utilizing historical loss rates, current market conditions that included the estimated impact of the global COVID-19 pandemic, industry and macroeconomic factors, reasonable and supportable forecasts and facts or circumstances of individual customers and properties. Examples of these facts or circumstances include, but are not limited to, contract disputes or renegotiations with the customer and evaluation of short and long-term economic viability of the contracted property. For its long-term contract receivable, management reverts to the historical loss experience immediately after the reasonable and supportable forecast period ends. As of December 31, 2021 and 2020, NRP recorded the following current expected credit loss (“CECL”) related to its receivables and long-term contract receivable: December 31, 2021 2020 (In thousands) Gross CECL Allowance Net Gross CECL Allowance Net Receivables $ 28,869 $ (3,312) $ 25,557 $ 18,512 $ (2,358) $ 16,154 Long-term contract receivable 32,497 (1,126) 31,371 34,818 (1,554) 33,264 Total $ 61,366 $ (4,438) $ 56,928 $ 53,330 $ (3,912) $ 49,418 NRP recorded $0.5 million and $0.0 million in operating and maintenance expenses on its Consolidated Statements of Comprehensive Income (Loss) related to the change in the CECL allowance during the year ended December 31, 2021 and 2020, respectively. NRP has procedures in place to monitor its ongoing credit exposure through timely review of counterparty balances against contract terms and due dates, account and financing receivable reconciliations, bankruptcy monitoring, lessee audits and dispute resolution. The Partnership may employ legal counsel or collection specialists to pursue recovery of defaulted receivables.

Leases

Leases	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Leases	Leases As of December 31, 2021, the Partnership had one operating lease for an office building that is owned by WPPLP. On January 1, 2019, the Partnership entered into a new lease of the building with a five-year base term and five additional five-year renewal options. Upon lease commencement and as of December 31, 2021 and 2020, the Partnership was reasonably certain to exercise all renewal options included in the lease and capitalized the right-of-use asset and corresponding lease liability on its Consolidated Balance Sheets using the present value of the future lease payments over 30 years. The Partnership's right-of-use asset and lease liability included within other long-term assets other non-current liabilities The following table details the maturity analysis of the Partnership's operating lease liability and reconciles the undiscounted cash flows to the operating lease liability included on its Consolidated Balance Sheet: Remaining Annual Lease Payments (In thousands) December 31, 2021 2022 $ 483 2023 483 2024 483 2025 483 2026 483 After 2026 10,631 Total lease payments (1) $ 13,046 Less: present value adjustment (2) (9,562) Total operating lease liability $ 3,484 (1) The remaining lease term of the Partnership's operating lease is 27 years. (2) The present value of the operating lease liability on the Partnership's Consolidated Balance Sheets was calculated using a 13.5% discount rate which represents the Partnership's estimated incremental borrowing rate under the lease. As the Partnership's lease does not provide an implicit rate, the Partnership estimated the incremental borrowing rate at the time the lease was entered into by utilizing the rate of the Partnership's secured debt and adjusting it for factors that reflect the profile of borrowing over the 30-year expected lease term.
Leases	Leases As of December 31, 2021, the Partnership had one operating lease for an office building that is owned by WPPLP. On January 1, 2019, the Partnership entered into a new lease of the building with a five-year base term and five additional five-year renewal options. Upon lease commencement and as of December 31, 2021 and 2020, the Partnership was reasonably certain to exercise all renewal options included in the lease and capitalized the right-of-use asset and corresponding lease liability on its Consolidated Balance Sheets using the present value of the future lease payments over 30 years. The Partnership's right-of-use asset and lease liability included within other long-term assets other non-current liabilities The following table details the maturity analysis of the Partnership's operating lease liability and reconciles the undiscounted cash flows to the operating lease liability included on its Consolidated Balance Sheet: Remaining Annual Lease Payments (In thousands) December 31, 2021 2022 $ 483 2023 483 2024 483 2025 483 2026 483 After 2026 10,631 Total lease payments (1) $ 13,046 Less: present value adjustment (2) (9,562) Total operating lease liability $ 3,484 (1) The remaining lease term of the Partnership's operating lease is 27 years. (2) The present value of the operating lease liability on the Partnership's Consolidated Balance Sheets was calculated using a 13.5% discount rate which represents the Partnership's estimated incremental borrowing rate under the lease. As the Partnership's lease does not provide an implicit rate, the Partnership estimated the incremental borrowing rate at the time the lease was entered into by utilizing the rate of the Partnership's secured debt and adjusting it for factors that reflect the profile of borrowing over the 30-year expected lease term.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying Consolidated Financial Statements of the Partnership have been prepared in accordance with generally accepted accounting principles in the United States of America ("GAAP"). The Consolidated Financial Statements include the accounts of Natural Resource Partners L.P. and its wholly owned subsidiaries. The Partnership has an equity investment in Sisecam Wyoming through which it is able to exercise significant influence over but does not control the investee and is not the primary beneficiary of the investee’s activities and is accounted for using the equity method. Intercompany transactions and balances have been eliminated. Certain reclassifications have been made to prior year amounts in the Notes to Consolidated Financial Statements to conform with current year presentation. These reclassifications had no impact on previously reported total assets, total liabilities, partners' capital, net income (loss) or cash flows from operating, investing or financing activities.
Use of Estimates	Use of EstimatesPreparation of the accompanying financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities on the accompanying Consolidated Balance Sheets, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses on the accompanying Consolidated Statements of Comprehensive Income (Loss) during the reporting period. Actual results could differ from those estimates. The most significant estimates pertain to coal and aggregates mineral rights and related cash flow estimates which are used to compute depreciation, depletion and amortization and impairments of coal and aggregates properties and related intangible assets and commitments and contingencies.
Fair Value	Fair Value The Partnership discloses certain assets and liabilities using fair value as defined by authoritative guidance. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. See Note 12. Fair Value Measurements for further details. There are three levels of inputs that may be used to measure fair value: • Level 1—Quoted prices in active markets for identical assets or liabilities. • Level 2—Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. • Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Level 3 assets and liabilities include financial assets and liabilities whose value is determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation.
Cash and Cash Equivalents	Cash and Cash Equivalents The Partnership considers all highly liquid short-term investments with an original maturity of three months or less to be cash equivalents
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts The Partnership records an allowance for doubtful accounts for its accounts receivable and notes receivable comprised of estimated credit risk and non-credit risk (e.g., legal disputes) losses. Receivables are written off when collection efforts are exhausted and future recovery is doubtful. The Partnership includes an allowance for current expected credit losses ("CECL") on its financial assets based on the loss-rate method. NRP assesses the likelihood of collection of its receivables utilizing historical loss rates, current market conditions that include the estimated impact of the global COVID-19 pandemic, industry and macroeconomic factors, reasonable and supportable forecasts and facts or circumstances of individual customers and properties. See Note 18. Credit Losses
Mineral Rights	Mineral RightsMineral rights owned and leased are recorded at its original cost of construction or, upon acquisition, at fair value of the assets acquired. Coal and aggregates mineral rights are depleted on a unit-of-production basis by lease, based upon minerals mined in relation to the net cost of the mineral properties and estimated economic tonnage therein.
Intangible Assets	Intangible Assets The Partnership’s intangible assets consist of mineral royalty and transportation contracts that at acquisition were more favorable for the Partnership than prevailing market rates, known as above-market contracts. The estimated fair value of the above-market rate contracts are determined based on the present value of future cash flow projections related to the underlying assets acquired. Intangible assets are amortized on a unit-of-production basis by asset based upon minerals mined or transported in relation to the net book value of the intangible asset and estimated economic tonnage expected to be mined or transported during the above-market contract term.
Asset Impairment	Asset Impairment The Partnership has developed procedures to evaluate its long-lived assets, including intangible assets, for possible impairment periodically or whenever events or changes in circumstances indicate an asset's net book value may not be recoverable. Potential events or circumstances include, but are not limited to, specific events such as a reduction in economically recoverable tons or production ceasing on a property for an extended period. This analysis is based on historic, current and future performance and considers both quantitative and qualitative information. A long-lived asset is deemed impaired when the future expected undiscounted cash flows from its use and disposition is less than the asset's net book value. Impairment is measured based on the estimated fair value, which is usually determined based upon the present value of the projected future cash flows compared to the asset's net book value. The Partnership believes its estimates of cash flows and discount rates are consistent with those of principal market participants. The Partnership evaluates its equity investment for impairment when events or changes in circumstances indicate, in management’s judgment, that the carrying value of such investment may have experienced an other-than-temporary decline in value. When evidence of loss in value has occurred, management compares the estimated fair value of the investment to the carrying value of the investment to determine whether potential impairment has occurred. If the estimated fair value is less than the carrying value and management considers the decline in value to be other than temporary, the excess of the carrying value over the estimated fair value is recognized in the financial statements as an impairment loss. The fair value of the impaired investment is based on quoted market prices (Level 1), or upon the present value of expected cash flows using discount rates believed to be consistent with those used by principal market participants (Level 3), plus market analysis of comparable assets owned by the investee, if appropriate (Level 3).
Accrued Liabilities	Accrued Liabilities Included in accrued liabilities on the Partnership's Consolidated Balance Sheets at December 31, 2021 were $7.7 million of accrued employee costs and $2.6 million of other accrued liabilities, which includes property taxes. These amounts were $3.7 million and $4.0 million of accrued employee costs and other accrued liabilities, respectively, at December 31, 2020. Other accrued liabilities at December 31, 2020 primarily included property taxes.
Revenue Recognition	Revenue Recognition Mineral Rights Segment Revenues Royalty-based leases. Approximately two-thirds of the Partnership's royalty-based leases have initial terms of five three The Partnership has defined its coal and aggregates royalty lease performance obligation as providing the lessee the right to mine and sell its coal or aggregates over the lease term. NRP then evaluated the likelihood that consideration it expected to receive from its lessees resulting from production would exceed consideration expected to be received from minimum payments over the lease term. As a result of this evaluation, revenue recognition from the Partnership's royalty-based leases is based on either production or minimum payments as follows: • Production Leases : Leases for which the Partnership expects that consideration from production will be greater than consideration from minimums over the lease term. Revenue for these leases is recognized over time based on production as royalty revenues, as applicable. Deferred revenue from minimums is recognized as royalty revenues when recoupment occurs or as production lease minimum revenues when the recoupment period expires. In addition, NRP recognizes breakage revenue from minimums when NRP determines that recoupment is remote. This breakage revenue is included in production lease minimum revenues. • Minimum Leases : Leases for which the Partnership expects that consideration from minimums will be greater than consideration from production over the lease term. Revenue for these leases is recognized straight-line over the lease term based on the minimum consideration amount as minimum lease straight-line revenues. This evaluation is performed at the inception of the lease and only reassessed upon modification or renewal of the lease. Oil and gas related revenues consist of revenues from royalties and overriding royalties and are recognized on the basis of volume of hydrocarbons sold by lessees and the corresponding revenues from those sales. Also, included within oil and gas royalty revenues are lease bonus payments, which are generally paid upon the execution of a lease. The Partnership also has overriding royalty revenue interests in certain coal mineral rights. Revenue from these interests is recognized over time based on when the coal is sold. Forest CO 2 sequestration revenues. Revenues related to the sale of NRP's carbon offset credits that are recognized at a point in time upon execution of the transaction. Wheelage revenues. Revenues related to fees collected per ton to transport foreign coal across property owned by the Partnership that is recognized over time as transportation across the property occurs. Other revenues. Other revenues consists primarily of rental payments and surface damage fees related to certain land owned by the Partnership and are recognized straight-line over time as it is earned. Other revenues also include property tax revenues. The majority of property taxes paid on the Partnership's properties are reimbursable by the lessee and are recognized on a gross basis over time which reflects the reimbursement of property taxes by the lessee. Property taxes paid by NRP are included in operating and maintenance expenses on the Partnership's Consolidated Statements of Comprehensive Income (Loss). Transportation and processing services revenues. The Partnership owns transportation and processing infrastructure that is leased to third parties for throughput fees. Revenue is recognized over time based on the coal tons transported over the beltlines or processed through the facilities. Contract Modifications Contract modifications that impact goods or services or the transaction price are evaluated in accordance with ASC 606. A majority of the Partnership's contract modifications pertain to its coal and aggregates royalty contracts and include, but are not limited to, extending the lease term, changes to royalty rates, floor prices or minimum consideration, assignment of the contract or forfeiture of recoupment rights. Consideration received in conjunction with a modification of an ongoing lease will be deferred and recognized straight-line over the remaining term of the contract. Consideration received to assign a lease to another party and related forfeited minimums will be recognized immediately upon the termination of the contract. Fees from contract modifications are recognized in lease amendment revenues within royalty and other mineral rights revenues on the Consolidated Statements of Comprehensive Income (Loss) while modifications in royalty rates and minimums will be recognized prospectively in accordance with the above lease classification. Contract Assets and Liabilities from Contracts with Customers Contract assets include receivables from contracts with customers and are recorded when the right to consideration becomes unconditional. Receivables are recognized when the minimums are contractually owed, production occurs or minimums accrued for based on the passage of time. Contract liabilities represent minimum consideration received, contractually owed or earned based on the passage of time. The current portion of deferred revenue relates to deferred revenue on minimum leases and lease amendment fees that are to be recognized as revenue on a straight-line basis over the next twelve months. The long-term portion of deferred revenue relates to deferred revenue on production leases and lease amendment fees that are to be recognized as revenue on a straight-line basis beyond the next twelve months. Due to uncertainty in the amount of deferred revenue that will be recouped and recognized as coal royalty revenues from its production leases over the next twelve months, the Partnership is unable to estimate the current portion of deferred revenue.
Property Taxes	Property Taxes The Partnership is responsible for paying property taxes on the properties it owns. Typically, the lessees are contractually responsible for reimbursing the Partnership for property taxes on the leased properties. The payment of and reimbursement of property taxes is included in operating and maintenance expenses and in royalty and other mineral rights revenues, respectively, on the Consolidated Statements of Comprehensive Income (Loss).
Unit-Based Compensation	Unit-Based Compensation The Partnership has awarded unit-based compensation in the form of equity-based awards and phantom units. Compensation cost is measured at the grant date for equity-classified awards and remeasured each reporting period for liability-classified awards based on the fair value of an award and is recognized over the service period, which is generally the vesting period. Forfeitures are recognized as they occur. Unit-based compensation expense for all awards is recognized in general and administrative expenses and operating and maintenance expenses on the Consolidated Statements of Comprehensive Income (Loss). See Note 16. Unit-Based Compensation
Deferred Financing Costs	Deferred Financing CostsDeferred financing costs consist of legal and other costs related to the issuance of the Partnership’s debt. These costs are amortized over the term of the respective line-of-credit or debt arrangements. Deferred financing costs related to the Partnership's revolving credit facility are included in other long-term assets, net on the Partnership's Consolidated Balance Sheets. Deferred financing costs related to the Partnership's note agreements are included as a direct deduction from the carrying amount of the debt liability in current portion of long-term debt, net or long-term debt, net on the Partnership's Consolidated Balance Sheets.
Income Taxes	Income Taxes The Partnership is not subject to federal or material state income taxes as the unitholders are taxed individually on their allocable share of taxable income. Net income (loss) for financial statement purposes may differ significantly from taxable income reportable to unitholders as a result of differences between the tax basis and financial reporting basis of assets and liabilities. In the event of an examination of the Partnership’s tax return, the tax liability of the unitholders could be changed if an adjustment in the Partnership’s income is ultimately sustained by the taxing authorities.

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	12 Months Ended
	Dec. 31, 2021
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following table represents the Partnership's Mineral Rights segment revenues by major source: For the Year Ended December 31, (In thousands) 2021 2020 2019 Coal royalty revenues $ 104,089 $ 51,868 $ 109,612 Production lease minimum revenues 14,269 21,749 24,068 Minimum lease straight-line revenues 20,564 16,796 14,910 Forest CO 2 sequestration revenues 13,790 — — Property tax revenues 6,028 5,786 6,287 Wheelage revenues 10,065 7,025 5,880 Coal overriding royalty revenues 4,367 4,977 13,496 Lease amendment revenues 4,696 3,450 7,991 Aggregates royalty revenues 1,889 1,717 4,265 Oil and gas royalty revenues 4,506 5,816 3,031 Other revenues 933 982 1,529 Royalty and other mineral rights revenues $ 185,196 $ 120,166 $ 191,069 Transportation and processing services revenues (1) 9,052 8,845 19,279 Total Mineral Rights segment revenues $ 194,248 $ 129,011 $ 210,348 (1) Transportation and processing services revenues from contracts with customers as defined under ASC 606 was $5.4 million, $5.0 million and $9.6 million for the year ended December 31, 2021, 2020 and 2019, respectively. The remaining transportation and processing services revenues of $3.6 million, $3.8 million and $9.7 million for the year ended December 31, 2021, 2020 and 2019, respectively, related to other NRP-owned infrastructure leased to and operated by third-party operators accounted for under other guidance. See Note 17. Financing Transaction for more information.
Contract with Customer, Asset and Liability	The following table details the Partnership's Mineral Rights segment receivables and liabilities resulting from contracts with customers: December 31, (In thousands) 2021 2020 Receivables Accounts receivable, net $ 22,277 $ 10,193 Other current assets, net (1) 769 3,307 Other long-term assets, net (2) 250 525 Contract liabilities Current portion of deferred revenue $ 11,817 $ 11,485 Deferred revenue 50,045 50,069 (1) Other current assets, net includes short-term notes receivables from contracts with customers. (2) Other long-term assets, net includes long-term lease amendment fee receivables from contracts with customers.
Revenue Recognition Deferred Revenue Rollforward	The following table shows the activity related to the Partnership's Mineral Rights segment deferred revenue: For the Year Ended December 31, (In thousands) 2021 2020 2019 Balance at beginning of period (current and non-current) $ 61,554 $ 51,821 $ 52,553 Increase due to minimums and lease amendment fees 19,842 41,557 47,038 Recognition of previously deferred revenue (19,534) (31,824) (47,770) Balance at end of period (current and non-current) $ 61,862 $ 61,554 $ 51,821
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction	The Partnership's non-cancelable annual minimum payments due under the lease terms of its coal and aggregates royalty and overriding royalty leases are as follows as of December 31, 2021 (in thousands): Lease Term (1) Weighted Average Remaining Years Annual Minimum Payments 0 - 5 years 2.6 $ 18,341 5 - 10 years 4.1 6,823 10+ years 13.5 28,069 Total 8.6 $ 53,233 (1) Lease term does not include renewal periods.

Class A Convertible Preferred_2

Class A Convertible Preferred Units and Warrants (Tables)	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Financial Position of Preferred Units	Activity related to the preferred units is as follows: (In thousands, except unit data) Units Outstanding Financial Balance at December 31, 2018 and 2019 250,000 $ 164,587 Distribution paid-in-kind 3,750 3,750 Balance at December 31, 2020 253,750 $ 168,337 Distributions paid-in-kind 15,571 15,571 Balance at December 31, 2021 269,321 $ 183,908

Common and Preferred Unit Dis_2

Common and Preferred Unit Distributions (Tables)	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Schedule of distributions paid	The following table shows the distributions declared and paid to common and preferred unitholders during the year ended December 31, 2021, 2020 and 2019, respectively: Cash Distributions Paid-in-kind Distributions Common Units Preferred Units Date Paid Period Covered by Distribution Distribution Total Distribution (1) (In thousands) Distribution per Unit Total Distribution Total Distribution 2021 February 2021 October 1 - December 31, 2020 $ 0.45 $ 5,630 $ 15.00 $ 3,806 3,806 May 2021 January 1 - March 31, 2021 0.45 5,672 15.00 3,864 3,864 August 2021 April 1 - June 30, 2021 0.45 5,671 15.00 3,921 3,921 November 2021 July 1 - September 30, 2021 0.45 5,672 15.00 3,980 3,980 2020 February 2020 October 1 - December 31, 2019 $ 0.45 $ 5,630 $ 30.00 $ 7,500 — May 2020 January 1 - March 31, 2020 — — 15.00 3,750 3,750 June 2020 (2) January 1 - March 31, 2020 — — 15.45 3,863 — August 2020 April 1 - June 30, 2020 0.45 5,630 30.00 7,500 — November 2020 July 1 - September 30, 2020 0.45 5,630 15.00 3,750 3,750 2019 February 2019 October 1 - December 31, 2018 $ 0.45 $ 5,625 $ 30.00 $ 7,500 — May 2019 January 1 - March 31, 2019 0.45 5,630 30.00 7,500 — May 2019 (3) Special Distribution 0.85 10,635 — — — August 2019 April 1 - June 30, 2019 0.45 5,630 30.00 7,500 — November 2019 July 1 - September 30, 2019 0.45 5,630 30.00 7,500 — (1) Total common unit distribution includes the amount paid to NRP's general partner in accordance with the general partner's 2% general partner interest. (2) Redemption of preferred units paid in kind plus accrued interest. (3) Special distribution was made to cover the common unitholders' tax liability resulting from the sale of NRP's construction aggregates business in December 2018.

Net Income (Loss) Per Common _2

Net Income (Loss) Per Common Unit (Tables)	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Reconciliation of Net Income to Weighted Average Units Outstanding	The following tables reconcile the numerators and denominators of the basic and diluted net income (loss) per common unit computations and calculates basic and diluted net income (loss) per common unit: For the Year Ended December 31, (In thousands, except per unit data) 2021 2020 2019 Allocation of net income (loss) Net income (loss) from continuing operations $ 108,902 $ (84,819) $ (25,414) Less: income attributable to preferred unitholders (31,609) (30,225) (30,000) Net income (loss) from continuing operations attributable to common unitholders and the general partner $ 77,293 $ (115,044) $ (55,414) Add (less): net loss (income) from continuing operations attributable to the general partner (1,546) 2,301 1,108 Net income (loss) from continuing operations attributable to common unitholders $ 75,747 $ (112,743) $ (54,306) Net income from discontinued operations $ — $ — $ 956 Less: net income from discontinued operations attributable to the general partner — — (19) Net income from discontinued operations attributable to common unitholders $ — $ — $ 937 Net income (loss) $ 108,902 $ (84,819) $ (24,458) Less: income attributable to preferred unitholders (31,609) (30,225) (30,000) Net income (loss) attributable to common unitholders and the general partner $ 77,293 $ (115,044) $ (54,458) Add (less): net loss (income) attributable to the general partner (1,546) 2,301 1,089 Net income (loss) attributable to common unitholders $ 75,747 $ (112,743) $ (53,369) Basic income (loss) per common unit Weighted average common units—basic 12,337 12,261 12,260 Basic net income (loss) from continuing operations per common unit $ 6.14 $ (9.20) $ (4.43) Basic net income from discontinued operations per common unit $ — $ — $ 0.08 Basic net income (loss) per common unit $ 6.14 $ (9.20) $ (4.35) For the Year Ended December 31, (In thousands, except per unit data) 2021 2020 2019 Diluted income (loss) per common unit Weighted average common units—basic 12,337 12,261 12,260 Plus: dilutive effect of preferred units 9,604 — — Plus: dilutive effect of warrants 74 — — Plus: dilutive effect of unvested unit-based awards 178 — — Weighted average common units—diluted 22,193 12,261 12,260 Net income (loss) from continuing operations $ 108,902 $ (84,819) $ (25,414) Less: income attributable to preferred unitholders — (30,225) (30,000) Diluted net income (loss) from continuing operations attributable to common unitholders and the general partner $ 108,902 $ (115,044) $ (55,414) Add (less): net loss (income) from continuing operations attributable to the general partner (2,178) 2,301 1,108 Diluted net income (loss) from continuing operations attributable to common unitholders $ 106,724 $ (112,743) $ (54,306) Diluted net income from discontinued operations attributable to common unitholders $ — $ — $ 937 Net income (loss) $ 108,902 $ (84,819) $ (24,458) Less: income attributable to preferred unitholders — (30,225) (30,000) Diluted net income (loss) attributable to common unitholders and the general partner $ 108,902 $ (115,044) $ (54,458) Add (less): diluted net loss (income) attributable to the general partner (2,178) 2,301 1,089 Diluted net income (loss) attributable to common unitholders $ 106,724 $ (112,743) $ (53,369) Diluted net income (loss) from continuing operations per common unit $ 4.81 $ (9.20) $ (4.43) Diluted net income from discontinued operations per common unit $ — $ — $ 0.08 Diluted net income (loss) per common unit $ 4.81 $ (9.20) $ (4.35)

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2021
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	The following table summarizes certain financial information for each of the Partnership's business segments: Operating Segments (In thousands) Mineral Rights Soda Ash Corporate and Financing Total For the Year Ended December 31, 2021 Revenues $ 194,248 $ 21,871 $ — $ 216,119 Gain on asset sales and disposals 245 — — 245 Operating and maintenance expenses 26,880 169 — 27,049 Depreciation, depletion and amortization 19,075 — — 19,075 General and administrative expenses — — 17,360 17,360 Asset impairments 5,102 — — 5,102 Other expenses, net 24 — 38,852 38,876 Net income (loss) from continuing operations 143,412 21,702 (56,212) 108,902 As of December 31, 2021 Total assets $ 675,579 $ 276,004 $ 2,240 $ 953,823 For the Year Ended December 31, 2020 Revenues $ 129,011 $ 10,728 $ — $ 139,739 Gain on asset sales and disposals 581 — — 581 Operating and maintenance expenses 24,610 185 — 24,795 Depreciation, depletion and amortization 9,198 — — 9,198 General and administrative expenses — — 14,293 14,293 Asset impairments 135,885 — — 135,885 Other expenses, net 79 — 40,889 40,968 Net income (loss) from continuing operations (40,180) 10,543 (55,182) (84,819) As of December 31, 2020 Total assets $ 656,505 $ 262,514 $ 2,858 $ 921,877 For the Year Ended December 31, 2019 Revenues $ 210,348 $ 47,089 $ — $ 257,437 Gain on asset sales and disposals 6,498 — — 6,498 Operating and maintenance expenses 32,489 249 — 32,738 Depreciation, depletion and amortization 14,932 — — 14,932 General and administrative expenses — — 16,730 16,730 Asset impairments 148,214 — — 148,214 Other expenses, net — — 76,735 76,735 Net income (loss) from continuing operations 21,211 46,840 (93,465) (25,414) Income from discontinued operations — — — 956

Equity Investment (Tables)

Equity Investment (Tables)	12 Months Ended
	Dec. 31, 2021
Equity Method Investments and Joint Ventures [Abstract]
Schedule of Summarized Financial Information	The Partnership accounts for its 49% investment in Sisecam Wyoming using the equity method of accounting. Activity related to this investment is as follows: For the Year Ended December 31, (In thousands) 2021 2020 2019 Balance at beginning of period $ 262,514 $ 263,080 $ 247,051 Income allocation to NRP’s equity interests (1) 26,979 15,205 52,016 Amortization of basis difference (5,108) (4,477) (4,927) Other comprehensive income 2,889 2,916 790 Distribution (11,270) (14,210) (31,850) Balance at end of period $ 276,004 $ 262,514 $ 263,080 (1) Includes reclassifications of accumulated other comprehensive income (loss) to income allocation to NRP equity interest of $0.0 million, $1.7 million and $0.6 million for the year ended December 31, 2021, 2020 and 2019, respectively. The following table represents summarized financial information for Sisecam Wyoming as derived from their respective financial statements for the years ended December 31, 2021, 2020, and 2019: For the Year Ended December 31, (In thousands) 2021 2020 2019 Net sales $ 540,139 $ 392,231 $ 522,843 Gross profit 80,550 54,838 131,712 Net income 55,059 31,030 106,155 The financial position of Sisecam Wyoming is summarized as follows: December 31, (In thousands) 2021 2020 Current assets $ 206,315 $ 164,720 Noncurrent assets 297,210 294,008 Current liabilities 73,181 55,313 Noncurrent liabilities 124,749 135,776

Mineral Rights, Net (Tables)

Mineral Rights, Net (Tables)	12 Months Ended
	Dec. 31, 2021
Extractive Industries [Abstract]
Mineral Rights	The Partnership’s mineral rights consist of the following: December 31, 2021 2020 (In thousands) Carrying Value Accumulated Depletion Net Book Value Carrying Value Accumulated Depletion Net Book Value Coal properties $ 670,650 $ (253,503) $ 417,147 $ 785,623 $ (346,773) $ 438,850 Aggregates properties 8,747 (2,975) 5,772 9,039 (2,819) 6,220 Oil and gas royalty properties 12,354 (9,115) 3,239 12,354 (8,593) 3,761 Other 13,151 (1,612) 11,539 13,154 (1,612) 11,542 Total mineral rights, net $ 704,902 $ (267,205) $ 437,697 $ 820,170 $ (359,797) $ 460,373
Schedule of Impairment Expense	During the years ended December 31, 2021, 2020 and 2019, the Partnership identified facts and circumstances that indicated that the carrying value of certain of its mineral rights exceed future cash flows from those assets and recorded non-cash impairment expense included in asset impairments on the Consolidated Statements of Comprehensive Income (Loss) as follows: For the Year Ended December 31, (In thousands) 2021 2020 2019 Coal properties (1) $ 5,015 $ 114,302 $ 125,806 Aggregates properties (2) 87 21,583 103 Total $ 5,102 $ 135,885 $ 125,909 (1) The Partnership recorded $5.0 million of impairment expense during the year ended December 31, 2021 primarily related to a lease termination. T he Partners hip recorded $114.3 million of impairment expense to impair certain assets during the year ended December 31, 2020 primarily related to weakened coal markets that resulted in termination of certain coal leases and changes to lessee mine plans resulting in permanent moves off certain of our coal properties. The partnership recorded $125.8 million of impairment expense during the year ended December 31, 2019 primarily due to deterioration in thermal coal markets, lessee capital constraints, thermal coal lease terminations, and expectations of further reductions in global and domestic thermal coal demand due to low natural gas prices and continued pressure on the electric power generation industry over emissions and climate change, resulting in reductions in expected cash flows (combination of lower expected coal sales volumes, sales prices, minimums and/or life of mine assumptions) on certain of our coal properties. During the year ended December 31, 2019, the Partnership recorded $36.0 million to fully impair certain coal properties. In addition, NRP recorded $89.8 million of impairment expense on coal royalty properties with $97 million of net book value, resulting in a fair value of $7.2 million at December 31, 2019. The fair value of the impaired assets at December 31, 2019 was calculated using a discount rate of 15%. NRP compared the net book value of its coal properties to estimated undiscounted future net cash flows. If the net book value exceeded the undiscounted future cash flows, the Partnership recorded an impairment for the excess of the net book value over fair value. A discounted cash flow model was used to estimate fair value. Significant inputs used to determine fair value include estimates of future cash flows from coal sales and minimum payments, discount rate and useful economic life. Estimated cash flows are the product of a process that began with current realized pricing as of the measurement date and included an adjustment for risk related to the future realization of cash flows. (2) The Partnership recorded $0.1 million of aggregates royalty property impairments during the year ended December 31, 2021. Th e Partnership recorded $21.6 million of aggregates royalty property impairments during the year ended December 31, 2020 primarily related to decreased oil and gas drilling activity which negatively impacted the outlook for NRP's frac sand properties. The Partnership recorded $0.1 million of aggregates royalty property impairments during the year ended December 31, 2019. NRP compared the net book value of its aggregates and timber properties to estimated undiscounted future net cash flows. If the net book value exceeded the undiscounted cash flows, the Partnership recorded an impairment for the excess of the net book value over fair value. A discounted cash flow model was used to estimate fair value. Significant inputs used to determine fair value include estimates of future cash flows from aggregates sales and minimum payments, discount rate and useful economic life. Estimated cash flows are the product of a process that began with current realized pricing as of the measurement date and included an adjustment for risk related to the future realization of cash flows. While the Partnership's impairment evaluation as of December 31, 2021 incorporated an estimated impact of the global COVID-19 pandemic, there is significant uncertainty as to the severity and duration of this disruption. If the impact is worse than we currently estimate, an additional impairment charge may be recognized in future periods.

Intangible Assets, Net (Tables)

Intangible Assets, Net (Tables)	12 Months Ended
	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Schedule of Finite-Lived Intangible Assets	The Partnership's intangible assets included on its Consolidated Balance Sheets are as follows: December 31, (In thousands) 2021 2020 Intangible assets at cost $ 51,353 $ 53,878 Less: accumulated amortization (35,223) (36,419) Total intangible assets, net $ 16,130 $ 17,459
Estimated Amortization Expense	The estimates of amortization expense for the years ended December 31, as indicated below, are based on current mining plans and are subject to revision as those plans change in future periods. (In thousands) Estimated Amortization Expense 2022 $ 1,127 2023 1,041 2024 1,238 2025 1,202 2026 1,202

Debt, Net (Tables)

Debt, Net (Tables)	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Long-Term Debt	The Partnership's debt consists of the following: December 31, (In thousands) 2021 2020 NRP LP debt: 9.125% senior notes, with semi-annual interest payments in June and December, due June 2025 issued at par ("2025 Senior Notes") $ 300,000 $ 300,000 Opco debt: Revolving credit facility $ — $ — Senior Notes 5.55% with semi-annual interest payments in June and December, with annual principal payments in June, due June 2023 $ 4,730 $ 7,094 4.73% with semi-annual interest payments in June and December, with annual principal payments in December, due December 2023 12,008 18,013 5.82% with semi-annual interest payments in March and September, with annual principal payments in March, due March 2024 38,053 50,738 8.92% with semi-annual interest payments in March and September, with annual principal payments in March, due March 2024 12,035 16,047 5.03% with semi-annual interest payments in June and December, with annual principal payments in December, due December 2026 57,104 68,524 5.18% with semi-annual interest payments in June and December, with annual principal payments in December, due December 2026 14,554 17,464 Total Opco Senior Notes $ 138,484 $ 177,880 Total debt at face value $ 438,484 $ 477,880 Net unamortized debt issuance costs (4,939) (6,381) Total debt, net $ 433,545 $ 471,499 Less: current portion of long-term debt (39,102) (39,055) Total long-term debt, net $ 394,443 $ 432,444
Principal Payments Due	The consolidated principal payments due are set forth below: NRP LP Opco (In thousands) Senior Notes Senior Notes Credit Facility Total 2022 $ — $ 39,396 $ — $ 39,396 2023 — 39,396 — 39,396 2024 — 31,028 — 31,028 2025 300,000 14,332 — 314,332 2026 — 14,332 — 14,332 Thereafter — — — — $ 300,000 $ 138,484 $ — $ 438,484

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Contractual Override, Note Receivable and Long-Term Debt	The following table shows the carrying value and estimated fair value of the Partnership's debt and contract receivable: December 31, 2021 2020 (In thousands) Fair Value Hierarchy Level Carrying Estimated Carrying Estimated Debt: NRP 2025 Senior Notes 1 $ 296,236 $ 300,000 $ 295,160 $ 274,500 Opco Senior Notes (1) 3 137,309 138,484 176,339 162,760 Opco Credit Facility 3 — — — — Assets: Contract receivable, net (current and long-term) (2) 3 $ 33,612 $ 26,010 $ 35,313 $ 27,025

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2021
Related Party Transactions [Abstract]
Summary of Reimbursements	Direct general and administrative expenses charged to the Partnership by QMC, WPPLP and QID are included on the Partnership's Consolidated Statement of Comprehensive Income (Loss) as follows: For the Year Ended December 31, (In thousands) 2021 2020 2019 Operating and maintenance expenses $ 6,543 $ 6,559 $ 6,656 General and administrative expenses 4,611 4,611 4,946

Major Customers (Tables)

Major Customers (Tables)	12 Months Ended
	Dec. 31, 2021
Risks and Uncertainties [Abstract]
Major customers	Revenues from customers that exceeded 10 percent of total revenues for any of the periods presented below are as follows: For the Year Ended December 31, 2021 2020 2019 (In thousands) Revenues Percent Revenues Percent Revenues Percent Foresight (1) (2) $ 37,366 17 % $ 35,704 26 % $ 58,923 23 % Alpha Metallurgical Resources, Inc. (1) 49,440 23 % 33,227 24 % 40,743 16 % (1) Revenues from Foresight and Alpha Metallurgical Resources, Inc. are included within the Partnership's Mineral Rights segment. (2) In June 2020, the Partnership entered into lease amendments with Foresight pursuant to which Foresight agreed to pay NRP fixed cash payments to satisfy all obligations arising out of the existing various coal mining leases and transportation infrastructure fee agreements between the Partnership and Foresight for calendar years 2020 and 2021.

Unit-Based Compensation (Tables

Unit-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2021
Share-based Payment Arrangement [Abstract]
Summary of Activity in Outstanding Grants	A summary of the unit activity in the outstanding grants during 2021 is as follows: (In thousands) Common Units Weighted Average Grant Date Fair value per Common Unit Outstanding grants at January 1, 2021 355 $ 26.20 Granted 219 $ 17.31 Fully vested and issued (129) $ 21.38 Forfeitures (34) $ 26.00 Outstanding at December 31, 2021 411 $ 23.00

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Schedule of operating lease maturities	The following table details the maturity analysis of the Partnership's operating lease liability and reconciles the undiscounted cash flows to the operating lease liability included on its Consolidated Balance Sheet: Remaining Annual Lease Payments (In thousands) December 31, 2021 2022 $ 483 2023 483 2024 483 2025 483 2026 483 After 2026 10,631 Total lease payments (1) $ 13,046 Less: present value adjustment (2) (9,562) Total operating lease liability $ 3,484 (1) The remaining lease term of the Partnership's operating lease is 27 years. (2) The present value of the operating lease liability on the Partnership's Consolidated Balance Sheets was calculated using a 13.5% discount rate which represents the Partnership's estimated incremental borrowing rate under the lease. As the Partnership's lease does not provide an implicit rate, the Partnership estimated the incremental borrowing rate at the time the lease was entered into by utilizing the rate of the Partnership's secured debt and adjusting it for factors that reflect the profile of borrowing over the 30-year expected lease term.

Organization and Nature of Op_2

Organization and Nature of Operations - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2021companysegment
Schedule of Equity Method Investments [Line Items]
Number of operating segments | segment	2
Number of operating companies owned | company	1
Ciner Wyoming
Schedule of Equity Method Investments [Line Items]
Percentage of partnership interest owned (percent)	49.00%

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Schedule Of Significant Accounting Policies [Line Items]
Accounts Receivable, Allowance for Credit Loss	$ (3,312)	$ (2,358)
Bad debt expense	2,600	4,000	$ 7,500
Adjustment for accounting standard change	(256,024)	(204,524)	(336,028)	$ (420,546)
Allowance for credit loss in long-term contract receivable	$ (1,126)	(1,554)
Cumulative Effect, Period of Adoption, Adjustment
Schedule Of Significant Accounting Policies [Line Items]
Adjustment for accounting standard change			$ 3,911
Ciner Wyoming
Schedule Of Significant Accounting Policies [Line Items]
Percentage of partnership interest owned (percent)	49.00%
Minimum
Schedule Of Significant Accounting Policies [Line Items]
Term of operating lease	5 years
Operating lease, late payment recovery period	3 years
Maximum
Schedule Of Significant Accounting Policies [Line Items]
Term of operating lease	40 years
Operating lease, late payment recovery period	5 years
Accrued Liabilities
Schedule Of Significant Accounting Policies [Line Items]
Accrued employee cost	$ (7,700)	(3,700)
Other current accrued liabilities	(2,600)	(4,000)
Other Current Assets
Schedule Of Significant Accounting Policies [Line Items]
Accounts Receivable, Allowance for Credit Loss	(100)	(600)
Accounts Receivable
Schedule Of Significant Accounting Policies [Line Items]
Accounts Receivable, Allowance for Credit Loss	$ (3,200)	$ (1,700)

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 194,248	$ 129,011	$ 210,348
Revenue, Remaining Performance Obligation, Amount	53,233
Payments for (Proceeds from) Loans Receivable, Annual Minimum Payment	5,000
Transportation and processing services | Mineral Rights
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	5,400	5,000	9,600
Transportation and processing services revenues accounted for under other guidance | Mineral Rights
Disaggregation of Revenue [Line Items]
Sales-type Lease, Revenue	$ 3,600	$ 3,800	$ 9,700

Revenue from Contracts with C_4

Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 194,248	$ 129,011	$ 210,348
Revenues	216,119	139,739	257,437
Mineral Rights
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	185,196	120,166	191,069
Coal royalty revenues | Mineral Rights
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	104,089	51,868	109,612
Production lease minimum revenues | Mineral Rights
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	14,269	21,749	24,068
Minimum lease straight-line revenues | Mineral Rights
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	20,564	16,796	14,910
Property tax revenues | Mineral Rights
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	6,028	5,786	6,287
Wheelage revenues | Mineral Rights
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	10,065	7,025	5,880
Coal overriding royalty revenues | Mineral Rights
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	4,367	4,977	13,496
Lease amendment revenues | Mineral Rights
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	4,696	3,450	7,991
Aggregates royalty revenues | Mineral Rights
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	1,889	1,717	4,265
Oil and gas royalty revenues | Mineral Rights
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	4,506	5,816	3,031
Other revenues | Mineral Rights
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	933	982	1,529
Transportation and processing services | Mineral Rights
Disaggregation of Revenue [Line Items]
Revenues	9,052	8,845	19,279
Forest C02 Sequestration Revenues | Mineral Rights
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 13,790	$ 0	$ 0

Revenue from Contracts with C_5

Revenue from Contracts with Customers - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Revenue from External Customer [Line Items]
Current portion of deferred revenue	$ 11,817	$ 11,485
Deferred revenue	50,045	50,069
Other long-term assets, net	5,832	7,067
Mineral Rights
Revenue from External Customer [Line Items]
Accounts receivable, net	22,277	10,193
Prepaid expenses and other	769	3,307
Current portion of deferred revenue	11,817	11,485
Deferred revenue	50,045	50,069
Other long-term assets, net	$ 250	$ 525

Revenue from Contracts with C_6

Revenue from Contracts with Customers - Revenue Recognition Deferred Revenue Rollforward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Deferred Revenue	$ 61,862	$ 61,554	$ 51,821	$ 52,553
Increase due to minimums and lease amendment fees	19,842	41,557	47,038
Recognition of previously deferred revenue	$ (19,534)	$ (31,824)	$ (47,770)

Revenue from Contracts with C_7

Revenue from Contracts with Customers - Revenue Remaining Performance Obligation (Details) $ in Thousands	Dec. 31, 2021USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 53,233
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-12-31
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	8 years 7 months 6 days
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 18,341
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	2 years 7 months 6 days
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 6,823
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	4 years 1 month 6 days
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2032-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 28,069
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	13 years 6 months

Class A Convertible Preferred_3

Class A Convertible Preferred Units and Warrants - Narrative (Details) - USD ($)	Mar. 02, 2017	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Preferred units issued (in shares)		269,321				253,750		269,321	253,750
Class A convertible preferred units (in units)		$ 1,000				$ 1,000		$ 1,000	$ 1,000
Class A Convertible Preferred Units (269,321 and 253,750 units issued and outstanding at December 31, 2021 and 2020, respectively, at $1,000 par value per unit; liquidation preference of $1,850 per unit at December 31, 2021 and $1,700 per unit per unit at December 31, 2020)		$ 183,908,000				$ 168,337,000		$ 183,908,000	$ 168,337,000
Dividends, Preferred Stock, Paid-in-kind		$ 3,980	$ 3,921	$ 3,864	$ 3,806			15,571	3,750
Dividends, Paid-in-kind						$ 3,750	$ 3,750	$ 15,571,000	$ 3,750,000	$ 0
Class A Convertible Preferred Units
Class of Stock [Line Items]
Preferred units issued (in shares)	250,000
Class A convertible preferred units (in units)	$ 1,000
Preferred Units, Origination Fee, Percent	2.50%
Dividend rate (as a percent)	12.00%
Convertible Preferred Units, Redemption Price, Minimum	$ 51
Convertible Preferred Units, Maximum Redeemed Units, Percent	33.00%
Debt Instrument, Covenants, Consolidated Leverage Ratio, Minimum	3.25
Debt Instrument, Covenants, Distributable Cash Flow Ratio, Maximum	1.2
Distribution amount (in dollars per share)	$ 0.45
Purchaser approval rights threshold (as a percent)	20.00%
Warrants at $22.81 Strike | Warrant Holders
Class of Stock [Line Items]
Class of Warrant or Right, Warrants Issued	1,750,000							750,000	1,750,000	1,750,000
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 22.81	$ 22.81				$ 22.81		$ 22.81	$ 22.81	$ 22.81
Warrants at $34.00 Strike | Warrant Holders
Class of Stock [Line Items]
Class of Warrant or Right, Warrants Issued	2,250,000							2,250,000	2,250,000	2,250,000
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 34	$ 34				$ 34		$ 34	$ 34	$ 34
Debt Instrument, Redemption, Period One | Class A Convertible Preferred Units
Class of Stock [Line Items]
Convertible Preferred Units, Conversion to Common Units, Discount Percentage	7.50%
Convertible Preferred Units, Purchase Price Multiplier	1.50
Debt Instrument, Redemption, Period Two | Class A Convertible Preferred Units
Class of Stock [Line Items]
Convertible Preferred Units, Purchase Price Multiplier	1.70
Debt Instrument, Redemption, Period Three | Class A Convertible Preferred Units
Class of Stock [Line Items]
Convertible Preferred Units, Conversion to Common Units, Discount Percentage	10.00%
Convertible Preferred Units, Purchase Price Multiplier	1.85
Preferred Stock
Class of Stock [Line Items]
Transaction price, gross	$ 250,000,000
Preferred Partner | Preferred Stock
Class of Stock [Line Items]
Temporary Equity, Shares Outstanding		269,321				253,750		269,321	253,750	250,000	250,000
Class A Convertible Preferred Units (269,321 and 253,750 units issued and outstanding at December 31, 2021 and 2020, respectively, at $1,000 par value per unit; liquidation preference of $1,850 per unit at December 31, 2021 and $1,700 per unit per unit at December 31, 2020)		$ 183,908,000				$ 168,337,000		$ 183,908,000	$ 168,337,000	$ 164,587,000	$ 164,587,000

Class A Convertible Preferred_4

Class A Convertible Preferred Units and Warrants - Preferred Units and Warrants Issued (Details) - USD ($)	Mar. 02, 2017	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Nov. 09, 2021	Dec. 31, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Dividends, Preferred Stock, Paid-in-kind		$ 3,980	$ 3,921	$ 3,864	$ 3,806	$ 15,571	$ 3,750
Class A Convertible Preferred Units (269,321 and 253,750 units issued and outstanding at December 31, 2021 and 2020, respectively, at $1,000 par value per unit; liquidation preference of $1,850 per unit at December 31, 2021 and $1,700 per unit per unit at December 31, 2020)		$ 183,908,000				$ 183,908,000	$ 168,337,000
Class of Warrant or Right, Outstanding		3,002,500				3,002,500	4,000,000		4,000,000	4,000,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights						(997,500)
Fully vested and issued		$ 21.38				$ 21.38		$ 32.02
Payment For Warrant Exercies						$ 9,200,000
Adjustment for accounting standard change		$ 256,024,000				256,024,000	$ 204,524,000		$ 336,028,000	$ 420,546,000
Warrants Exercised in Period, Financial Position						(18,852,000)
Warrant Holders
Class of Stock [Line Items]
Adjustment for accounting standard change		$ 47,964,000				$ 47,964,000	$ 66,816,000		$ 66,816,000	$ 66,816,000
Warrants at $22.81 Strike | Warrant Holders
Class of Stock [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 22.81	$ 22.81				$ 22.81	$ 22.81		$ 22.81
Preferred Stock
Class of Stock [Line Items]
Transaction price, gross	$ 250,000,000
Preferred Partner | Preferred Stock
Class of Stock [Line Items]
Temporary Equity, Shares Outstanding		269,321				269,321	253,750		250,000	250,000
Class A Convertible Preferred Units (269,321 and 253,750 units issued and outstanding at December 31, 2021 and 2020, respectively, at $1,000 par value per unit; liquidation preference of $1,850 per unit at December 31, 2021 and $1,700 per unit per unit at December 31, 2020)		$ 183,908,000				$ 183,908,000	$ 168,337,000		$ 164,587,000	$ 164,587,000

Common and Preferred Unit Dis_3

Common and Preferred Unit Distributions Narrative (Details) - USD ($)	3 Months Ended		12 Months Ended
	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Temporary Equity [Line Items]
Income attributable to preferred unitholders			$ (31,609,000)	$ (30,225,000)	$ (30,000,000)
Dividends, Paid-in-kind	$ 3,750	$ 3,750	$ 15,571,000	$ 3,750,000	$ 0
General Partner | Natural Resource Partners Limited, General Partner
Temporary Equity [Line Items]
Limited Liability Company or Limited Partnership, Members or Limited Partners, Ownership Interest			2.00%

Common and Preferred Unit Dis_4

Common and Preferred Unit Distributions Schedule of Distributions Paid (Details) - USD ($)	1 Months Ended		3 Months Ended												12 Months Ended
	Jun. 30, 2020	May 31, 2019	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Dividends, Paid-in-kind							$ 3,750		$ 3,750						$ 15,571,000	$ 3,750,000	$ 0
Dividends, Preferred Stock, Paid-in-kind			$ 3,980	$ 3,921	$ 3,864	$ 3,806									15,571	3,750
Common unitholders and general partner
Class of Stock [Line Items]
Distributions per common unit (in dollars per share)			$ 0.45	$ 0.45	$ 0.45	$ 0.45	$ 0.45	$ 0.45	$ 0	$ 0.45	$ 0.45	$ 0.45	$ 0.45	$ 0.45
Total distributions paid															22,645,000	16,890,000	33,150,000
Special Distribution Made to Limited Partner, Distributions Paid, Per Unit		$ 0.85
Common unitholders and general partner | Cash Distribution
Class of Stock [Line Items]
Total distributions paid			$ 5,672,000	$ 5,671,000	$ 5,672,000	$ 5,630,000	$ 5,630,000	$ 5,630,000	$ 0	$ 5,630,000	$ 5,630,000	$ 5,630,000	$ 5,630,000	$ 5,625,000
Partners Capital Account, Special Distribution		$ 10,635,000
Common unitholders and general partner | Special Tax Distribution
Class of Stock [Line Items]
Distributions per common unit (in dollars per share)									$ 0
Total distributions paid									$ 0
Preferred Partner
Class of Stock [Line Items]
Distributions to common unitholders and general partner															15,571,000	26,363,000	30,000,000
Total distributions paid															31,142,000	30,113,000	30,000,000
Preferred Partner | Preferred Stock
Class of Stock [Line Items]
Distributions per common unit (in dollars per share)	$ 15.45	$ 0	$ 15	$ 15	$ 15	$ 15	$ 15	$ 30	$ 15	$ 30	$ 30	$ 30	$ 30	$ 30
Dividends, Preferred Stock, Cash		$ 0	$ 3,980,000	$ 3,921,000	$ 3,864,000	$ 3,806,000	$ 3,750,000	$ 7,500,000	$ 3,750,000	$ 7,500,000	$ 7,500,000	$ 7,500,000	$ 7,500,000	$ 7,500,000
PIK Redemption Payment	$ 3,863,000
General Partner
Class of Stock [Line Items]
Distributions to common unitholders and general partner															22,645,000	16,890,000	33,150,000
General Partner | Preferred Partner
Class of Stock [Line Items]
Total distributions paid															623,000	602,000	600,000
General Partner | General Partner
Class of Stock [Line Items]
Total distributions paid															$ 453,000	$ 338,000	$ 663,000

Net Income (Loss) Per Common _3

Net Income (Loss) Per Common Unit (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		Mar. 02, 2017	Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019
Net income (loss) attributable to common unitholders and the general partner			$ 77,293		$ (115,044)		$ (54,458)
Allocation of net income:
Net income (loss) from continuing operations			108,902		(84,819)		(25,414)
Net income attributable to non-controlling interest	[1]						0
Less: income attributable to preferred unitholders			(31,609)		(30,225)		(30,000)
Income (Loss) from Continuing Operations and Income Attributable to Preferred Unitholders, Including Portion Attributable to Noncontrolling Interest, Allocated to General Partner and Limited Partners			77,293		(115,044)		(55,414)
Add (less): net loss (income) from continuing operations attributable to the general partner			(1,546)		2,301		1,108
Net income (loss) from continuing operations attributable to common unitholders			75,747		(112,743)		(54,306)
Income from discontinued operations			0		0		956
Less: net income from discontinued operations attributable to the general partner			0		0		(19)
Net income from discontinued operations attributable to common unitholders			0		0		937
Net income (loss)			108,902	[2]	(84,819)	[1]	(24,458)	[1]
Net income attributable to the general partner			(1,546)		2,301		1,089
Net income (loss) attributable to common unitholders			$ 75,747		$ (112,743)		$ (53,369)
Weighted average common units—basic (in shares)			12,337		12,261		12,260
Basic net income (loss) from continuing operations per common unit			$ 6.14		$ (9.20)		$ (4.43)
Basic net income from discontinued operations per common unit			0		0		0.08
Basic net income (loss) per common unit			$ 6.14		$ (9.20)		$ (4.35)
Dilutive effect of Preferred Units (in shares)			9,604		0		0
Dilutive effect of Warrants (in shares)			74		0		0
Dilutive effect of unvested unit-based awards (in shares)			178		0		0
Weighted average common units—diluted (in shares)			22,193		12,261		12,260
Less: net income attributable to preferred unitholders			$ 0		$ (30,225)		$ (30,000)
Diluted net income (loss) from continuing operations attributable to common unitholders and general partner			108,902		(115,044)		(55,414)
Add (less): net loss (income) from continuing operations attributable to the general partner			(2,178)		2,301		1,108
Diluted net income (loss) from continuing operations attributable to common unitholders			106,724		(112,743)		(54,306)
Diluted net income from discontinued operations attributable to common unitholders			0		0		937
Diluted net income (loss) attributable to common unitholders and general partner			108,902		(115,044)		(54,458)
Add (less): diluted net loss (income) attributable to the general partner			2,178		2,301		1,089
Diluted net income (loss) attributable to common unitholders			$ 106,724		$ (112,743)		$ (53,369)
Diluted net income (loss) from continuing operations per common unit			$ 4.81		$ (9.20)		$ (4.43)
Diluted net income from discontinued operations per common unit			0		0		0.08
Diluted net income (loss) per common unit			$ 4.81		$ (9.20)		$ (4.35)
Warrant Holders | Warrants at $22.81 Strike
Class of Warrant or Right, Warrants Issued		1,750	750		1,750		1,750
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 22.81	$ 22.81		$ 22.81		$ 22.81
Warrant Holders | Warrants at $34.00 Strike
Class of Warrant or Right, Warrants Issued		2,250	2,250		2,250		2,250
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 34	$ 34		$ 34		$ 34
[1]	Net loss includes $30.0 million of income attributable to preferred unitholders that accumulated during the period, of which $29.4 million is allocated to the common unitholders and $0.6 million is allocated to the general partner.
[2]	Net loss includes $30.2 million of income attributable to preferred unitholders that accumulated during the period, of which $29.6 million is allocated to the common unitholders and $0.6 million is allocated to the general partner. (3) Net income includes $31.6 million of income attributable to preferred unitholders that accumulated during the period, of which $31.0 million is allocated to the common unitholders and $0.6 million is allocated to the general partner.

Segment Information - Additiona

Segment Information - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)segment	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | segment	2
Gain on asset sales and disposals | $	$ 245	$ 581	$ 6,498
Ciner Wyoming
Segment Reporting Information [Line Items]
Percentage of partnership interest owned (percent)	49.00%

Segment Information - Schedule

Segment Information - Schedule of Segment Reporting Information, by Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Revenues	$ 216,119	$ 139,739	$ 257,437
Gain on asset sales and disposals	245	581	6,498
Operating and maintenance expenses	27,049	24,795	32,738
Depreciation, depletion and amortization	19,075	9,198	14,932
General and administrative expenses	17,360	14,293	16,730
Asset impairments	5,102	135,885	148,214
Other expenses, net	38,876	40,968	76,735
Net income (loss) from continuing operations	108,902	(84,819)	(25,414)
Income from discontinued operations	0	0	956
Total assets	953,823	921,877
Corporate and Financing
Segment Reporting Information [Line Items]
Revenues	0	0	0
Gain on asset sales and disposals	0	0	0
Operating and maintenance expenses	0	0	0
Depreciation, depletion and amortization	0	0	0
General and administrative expenses	17,360	14,293	16,730
Asset impairments	0	0	0
Other expenses, net	38,852	40,889	76,735
Net income (loss) from continuing operations	(56,212)	(55,182)	(93,465)
Income from discontinued operations			0
Soda Ash | Operating Segments
Segment Reporting Information [Line Items]
Revenues	21,871	10,728	47,089
Gain on asset sales and disposals	0	0	0
Operating and maintenance expenses	169	185	249
Depreciation, depletion and amortization	0	0	0
General and administrative expenses	0	0	0
Asset impairments	0	0	0
Other expenses, net	0	0	0
Net income (loss) from continuing operations	21,702	10,543	46,840
Income from discontinued operations			0
Mineral Rights | Operating Segments
Segment Reporting Information [Line Items]
Revenues	194,248	129,011	210,348
Gain on asset sales and disposals	245	581	6,498
Operating and maintenance expenses	26,880	24,610	32,489
Depreciation, depletion and amortization	19,075	9,198	14,932
General and administrative expenses	0	0	0
Asset impairments	5,102	135,885	148,214
Other expenses, net	24	79	0
Net income (loss) from continuing operations	143,412	(40,180)	21,211
Income from discontinued operations			$ 0
Continuing Operations
Segment Reporting Information [Line Items]
Total assets	953,823	921,877
Continuing Operations | Corporate and Financing
Segment Reporting Information [Line Items]
Total assets	2,240	2,858
Continuing Operations | Soda Ash | Operating Segments
Segment Reporting Information [Line Items]
Total assets	276,004	262,514
Continuing Operations | Mineral Rights | Operating Segments
Segment Reporting Information [Line Items]
Total assets	$ 675,579	$ 656,505

Equity Investment - Additional

Equity Investment - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	$ 276,004	$ 262,514
Comprehensive income from unconsolidated investment and other	$ 2,889	2,916	$ 868
Weighted average useful life of assets (in years)	27 years
Ciner Wyoming
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	$ 276,004	262,514	263,080	$ 247,051
Income allocation to NRP’s equity interests	26,979	15,205	52,016
Amortization of basis difference	(5,108)	(4,477)	(4,927)
Comprehensive income from unconsolidated investment and other	2,889	2,916	790
Distribution	$ (11,270)	(14,210)	(31,850)
Ciner Wyoming
Schedule of Equity Method Investments [Line Items]
Percentage of partnership interest owned (percent)	49.00%
Reclassification of accumulated other comprehensive loss to income allocation	$ 0	1,700	$ 600
Increase in fair value of property, plant and equipment	$ 126,300	$ 131,400

Equity Investment - Schedule of

Equity Investment - Schedule of Summarized Financial Information of Unaudited Financial Statements (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Current assets	$ 162,781		$ 117,192
Current liabilities	64,385		61,372
Revenues	216,119		139,739		$ 257,437
Net income (loss)	108,902	[1]	(84,819)	[2]	(24,458)	[2]
Ciner Wyoming
Schedule of Equity Method Investments [Line Items]
Current assets	206,315		164,720
Noncurrent assets	297,210		294,008
Current liabilities	73,181		55,313
Noncurrent liabilities	124,749		135,776
Revenues	540,139		392,231		522,843
Gross Profit	80,550		54,838		131,712
Net income (loss)	$ 55,059		$ 31,030		$ 106,155
[1]	Net loss includes $30.2 million of income attributable to preferred unitholders that accumulated during the period, of which $29.6 million is allocated to the common unitholders and $0.6 million is allocated to the general partner. (3) Net income includes $31.6 million of income attributable to preferred unitholders that accumulated during the period, of which $31.0 million is allocated to the common unitholders and $0.6 million is allocated to the general partner.
[2]	Net loss includes $30.0 million of income attributable to preferred unitholders that accumulated during the period, of which $29.4 million is allocated to the common unitholders and $0.6 million is allocated to the general partner.

Mineral Rights, Net (Detail)

Mineral Rights, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Carrying Value	$ 704,902	$ 820,170
Accumulated Depletion	(267,205)	(359,797)
Net Book Value	437,697	460,373
Coal properties
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Carrying Value	670,650	785,623
Accumulated Depletion	(253,503)	(346,773)
Net Book Value	417,147	438,850
Aggregates properties
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Carrying Value	8,747	9,039
Accumulated Depletion	(2,975)	(2,819)
Net Book Value	5,772	6,220
Oil and gas royalty properties
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Carrying Value	12,354	12,354
Accumulated Depletion	(9,115)	(8,593)
Net Book Value	3,239	3,761
Other
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Carrying Value	13,151	13,154
Accumulated Depletion	(1,612)	(1,612)
Net Book Value	$ 11,539	$ 11,542

Mineral Rights, Net - Additiona

Mineral Rights, Net - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Total depletion and amortization expense on mineral interests	$ 17,600	$ 8,800	$ 12,100
Gain on asset sales and disposals	245	581	6,498
Mineral rights, net	437,697	460,373
Coal properties
Mineral rights, net	417,147	438,850
Oil and gas royalty properties
Mineral rights, net	3,239	3,761
Aggregates properties
Mineral rights, net	$ 5,772	$ 6,220
Mineral Rights | Reported Value Measurement
Mineral rights, net			$ 0

Mineral Rights, Net Schedule of

Mineral Rights, Net Schedule of Impairment Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Asset impairments	$ 5,102	$ 135,885	$ 148,214
Carrying Value	$ 704,902	$ 820,170
Discount Rate	15.00%	15.00%
Coal Mineral Rights
Property, Plant and Equipment [Line Items]
Asset impairments	$ 5,015	$ 114,302	125,806
Carrying Value	670,650	785,623
Fair value of impaired assets		7,200
Aggregates properties
Property, Plant and Equipment [Line Items]
Asset impairments	87	21,583	103
Carrying Value	8,747	9,039
Mining Properties and Mineral Rights
Property, Plant and Equipment [Line Items]
Asset impairments	$ 5,102	135,885	$ 125,909
Fully Impaired | Coal Mineral Rights
Property, Plant and Equipment [Line Items]
Asset impairments		36,000
Partially Impaired | Coal Mineral Rights
Property, Plant and Equipment [Line Items]
Asset impairments		89,800
Coal Mineral Rights | Coal Mineral Rights
Property, Plant and Equipment [Line Items]
Carrying Value		$ 97,000

Intangible Assets, Net - Intang

Intangible Assets, Net - Intangible Assets, Net (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	$ 1,300	$ 200	$ 2,500
Finite-Lived Intangible Assets, Gross	51,353	53,878
Less accumulated amortization	(35,223)	(36,419)
Total intangible assets, net	$ 16,130	$ 17,459

Intangible Assets, Net - Estima

Intangible Assets, Net - Estimated Amortization Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
2020		$ 1,127
2021		1,041
2022		1,238
2023		1,202
2026		$ 1,202
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests	$ 1,909

Intangible Assets, Net - Additi

Intangible Assets, Net - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Intangible Assets [Line Items]
Amortization expense	$ 1,300	$ 200	$ 2,500
Asset impairments	5,102	135,885	148,214
Coal properties
Intangible Assets [Line Items]
Asset impairments	$ 5,015	114,302	$ 125,806
Fair value of impaired assets		$ 7,200

Debt, Net - Debt (Detail)

Debt, Net - Debt (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Carrying Value	$ 438,484	$ 477,880
Net unamortized debt issuance costs	(4,939)	(6,381)
Total debt	433,545	471,499
Less - current portion of long term debt	(39,102)	(39,055)
Long-term debt, net	394,443	432,444
NRP LP | 9.125% senior notes, with semi-annual interest payments in June and December, due June 2025 issued at par ("2025 Senior Notes")
Debt Instrument [Line Items]
Carrying Value	$ 300,000	300,000
Interest rate	9.125%
Opco | Revolving credit facility
Debt Instrument [Line Items]
Carrying Value	$ 0	0
Line of Credit Facility, Remaining Borrowing Capacity	100,000	100,000
Opco | 5.55% with semi-annual interest payments in June and December, with annual principal payments in June, due June 2023
Debt Instrument [Line Items]
Carrying Value	$ 4,730	7,094
Interest rate	5.55%
Opco | 4.73% with semi-annual interest payments in June and December, with annual principal payments in December, due December 2023
Debt Instrument [Line Items]
Carrying Value	$ 12,008	18,013
Interest rate	4.73%
Opco | 5.82% with semi-annual interest payments in March and September, with annual principal payments in March, due March 2024
Debt Instrument [Line Items]
Carrying Value	$ 38,053	50,738
Interest rate	5.82%
Opco | 8.92% with semi-annual interest payments in March and September, with annual principal payments in March, due March 2024
Debt Instrument [Line Items]
Carrying Value	$ 12,035	16,047
Interest rate	8.92%
Opco | 5.03% with semi-annual interest payments in June and December, with annual principal payments in December, due December 2026
Debt Instrument [Line Items]
Carrying Value	$ 57,104	68,524
Interest rate	5.03%
Opco | 5.18% with semi-annual interest payments in June and December, with annual principal payments in December, due December 2026
Debt Instrument [Line Items]
Carrying Value	$ 14,554	17,464
Interest rate	5.18%
Opco | Total Opco Senior Notes
Debt Instrument [Line Items]
Carrying Value	$ 138,484	$ 177,880

Debt, Net - Additional Informat

Debt, Net - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Redemption Premium			$ 18,100
Write off of Deferred Debt Issuance Cost			10,400
Principal balance	$ 438,484	$ 477,880
Long-term Debt	433,545	471,499
Debt issuance cost capitalized	$ 4,939	6,381
9.125% senior notes, with semi-annual interest payments in June and December, due June 2025 issued at par ("2025 Senior Notes") | Total Opco Senior Notes
Debt Instrument [Line Items]
Rate of senior notes	9.125%
Debt Instrument Redemption Price At Change Of Control Event As Percentage Of Principal Amount	101.00%
Ciner Wyoming
Debt Instrument [Line Items]
Percentage of partnership interest owned (percent)	49.00%
Ciner Wyoming | Revolving credit facility
Debt Instrument [Line Items]
Percentage of partnership interest owned (percent)	49.00%
NRP LP | 9.125% senior notes, with semi-annual interest payments in June and December, due June 2025 issued at par ("2025 Senior Notes")
Debt Instrument [Line Items]
Rate of senior notes	9.125%
Principal balance	$ 300,000	300,000
Opco
Debt Instrument [Line Items]
Ratio of consolidated EBITDDA to consolidated fixed charges	3.5
Percentage of consolidated net tangible assets debt of subsidiaries not permitted to exceed	10.00%
Opco | 8.92% with semi-annual interest payments in March and September, with annual principal payments in March, due March 2024
Debt Instrument [Line Items]
Rate of senior notes	8.92%
Principal balance	$ 12,035	16,047
Opco | Total Opco Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Asset Sales Proceeds, Required to Repay Outstanding Debt, Percent	25.00%
Principal balance	$ 138,484	177,880
Principal payments on its senior notes	$ 39,400	46,200	117,400
Proceeds from (Repayments of) Short-term Debt			$ 49,300
Partnership leverage ratio	3.75
Additional interest accrue	2.00%
Opco | Revolving credit facility
Debt Instrument [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity	$ 100,000	100,000
Commitment fee (as a percent)	0.50%
Distribution amount (in dollars per share)	$ 0.45
Ratio of consolidated EBITDDA to consolidated fixed charges	3.5
Debt Instrument, Asset Sales Proceeds, Required to Repay Outstanding Debt, Percent	75.00%
Debt Instrument, Collateral Amount	$ 345,000	364,500
Principal balance	$ 0	$ 0
Opco | Maximum
Debt Instrument [Line Items]
Ratio of consolidated indebtedness to consolidated EBITDDA	4
Opco | Federal Funds Rate [Member] | Revolving credit facility
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	0.50%
Opco | London Interbank Offered Rate (LIBOR) [Member] | Revolving credit facility
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	1.00%
Opco | London Interbank Offered Rate (LIBOR) [Member] | Maximum | Revolving Credit Facility Basis Spread Condition One [Member] | Revolving credit facility
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	3.50%
Opco | London Interbank Offered Rate (LIBOR) [Member] | Maximum | Revolving Credit Facility Basis Spread Condition Two [Member] | Revolving credit facility
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	4.50%
Opco | London Interbank Offered Rate (LIBOR) [Member] | Minimum | Revolving Credit Facility Basis Spread Condition One [Member] | Revolving credit facility
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	2.50%
Opco | London Interbank Offered Rate (LIBOR) [Member] | Minimum | Revolving Credit Facility Basis Spread Condition Two [Member] | Revolving credit facility
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	3.50%
Debt Instrument, Redemption, Period Two | 9.125% senior notes, with semi-annual interest payments in June and December, due June 2025 issued at par ("2025 Senior Notes") | Total Opco Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Redemption Price, Percentage	104.563%
Debt Instrument, Redemption, Period Two | 10.5% senior notes, with semi-annual interest payments in March and September, maturing March 2022 | Total Opco Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Redemption Price, Percentage			105.25%
Debt Instrument, Redemption, Period Three | 9.125% senior notes, with semi-annual interest payments in June and December, due June 2025 issued at par ("2025 Senior Notes") | Total Opco Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Redemption Price, Percentage	102.281%
Debt Instrument, Redemption, Period Four [Member] | 9.125% senior notes, with semi-annual interest payments in June and December, due June 2025 issued at par ("2025 Senior Notes") | Total Opco Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Redemption Price, Percentage	100.00%
Dividend at or Below $0.45 per Share [Member] | Opco | Revolving credit facility
Debt Instrument [Line Items]
Debt Instrument, Covenant, Maximum Leverage Ratio	4
Dividend Above $0.45 per Share [Member] | Opco | Revolving credit facility
Debt Instrument [Line Items]
Debt Instrument, Covenant, Maximum Leverage Ratio	3

Debt, Net - Principal Payments

Debt, Net - Principal Payments Due (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
2020	$ 39,396
2021	39,396
2022	31,028
2023	314,332
2024	14,332
Thereafter	0
Principal Payments	438,484
Long-term Debt	433,545	$ 471,499
NRP LP | Total Opco Senior Notes
Debt Instrument [Line Items]
2020	0
2021	0
2022	0
2023	300,000
2024	0
Thereafter	0
Principal Payments	300,000
Opco | Total Opco Senior Notes
Debt Instrument [Line Items]
2020	39,396
2021	39,396
2022	31,028
2023	14,332
2024	14,332
Thereafter	0
Principal Payments	138,484
Opco | Revolving Credit Facility
Debt Instrument [Line Items]
2020	0
2021	0
2022	0
2023	0
2024	0
Thereafter	0
Principal Payments	$ 0

Fair Value Measurements - Debt

Fair Value Measurements - Debt and Contracts Receivable (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 433,545,000	$ 471,499,000
Carrying Value	438,484,000	477,880,000
Receivables, Fair Value Disclosure	$ 33,612,000	$ 35,313,000
Fair value, percentage of par	100.00%	92.00%
Embedded Derivative, Fair Value of Embedded Derivative Liability	$ 0	$ 0
Discount Rate	15.00%	15.00%
Embedded Derivative, Fair Value of Embedded Derivative Liability	$ 0	$ 0
Fair Value, Inputs, Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Receivables, Fair Value Disclosure	26,010,000	27,025,000
Senior Notes due 2025
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	296,236,000	295,160,000
Senior Notes due 2025 | Fair Value, Inputs, Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	300,000,000	274,500,000
Opco Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	137,309,000	176,339,000
Opco Senior Notes | Fair Value, Inputs, Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	138,484,000	162,760,000
Opco Revolving Credit Facility And Term Loan Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	0	0
Opco Revolving Credit Facility And Term Loan Facility | Fair Value, Inputs, Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	$ 0	$ 0

Related Party Transactions - Su

Related Party Transactions - Summary of Reimbursements (Detail) - USD ($)	3 Months Ended						12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
Revenues							$ 216,119,000	$ 139,739,000	$ 257,437,000
Operating Expenses							68,586,000	184,171,000	212,614,000
Class A Convertible Preferred Units (269,321 and 253,750 units issued and outstanding at December 31, 2021 and 2020, respectively, at $1,000 par value per unit; liquidation preference of $1,850 per unit at December 31, 2021 and $1,700 per unit per unit at December 31, 2020)	$ 183,908,000				$ 168,337,000		183,908,000	168,337,000
Dividends, Preferred Stock, Paid-in-kind	$ 3,980	$ 3,921	$ 3,864	$ 3,806			15,571	3,750
Dividends, Paid-in-kind					$ 3,750	$ 3,750	$ 15,571,000	$ 3,750,000	$ 0
Preferred Partner | Preferred Stock
Related Party Transaction [Line Items]
Temporary Equity, Shares Outstanding	269,321				253,750		269,321	253,750	250,000	250,000
Class A Convertible Preferred Units (269,321 and 253,750 units issued and outstanding at December 31, 2021 and 2020, respectively, at $1,000 par value per unit; liquidation preference of $1,850 per unit at December 31, 2021 and $1,700 per unit per unit at December 31, 2020)	$ 183,908,000				$ 168,337,000		$ 183,908,000	$ 168,337,000	$ 164,587,000	$ 164,587,000
Industrial Minerals Group
Related Party Transaction [Line Items]
Revenue from Related Parties									1,700,000
Quinwood Coal Company
Related Party Transaction [Line Items]
Revenue from Related Parties							0	0	200,000
Affiliated Entity | Quintana Minerals
Related Party Transaction [Line Items]
Accounts Payable, Related Parties	400,000				400,000		400,000	400,000
Affiliated Entity | Western Pocahontas Properties and Quintana Minerals Corporation
Related Party Transaction [Line Items]
Operating and maintenance expenses—affiliates							6,543,000	6,559,000	6,656,000
General and administrative—affiliates							4,611,000	4,611,000	4,946,000
Affiliated Entity | Western Pocahontas Properties Limited Partnership
Related Party Transaction [Line Items]
Accounts Payable, Related Parties, Current	900,000				$ 300,000		900,000	300,000
Operating and maintenance expenses—affiliates							3,300,000	$ 400,000	$ 4,000,000
Accounts Receivable, Related Parties, Noncurrent	0						0
Affiliated Entity | Great Northern Properties Limited Partnership
Related Party Transaction [Line Items]
Accounts Receivable, Related Parties, Noncurrent	$ 100,000						$ 100,000

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Related Party Transaction [Line Items]
Revenues	$ 216,119	$ 139,739	$ 257,437
Operating and maintenance expense	68,586	184,171	212,614
Deferred Revenue, Revenue Recognized	$ 19,534	31,824	47,770
Director | Great Northern Properties Limited Partnership | Corbin J. Robertson, Jr.
Related Party Transaction [Line Items]
Percentage of partnership interest owned (percent)	85.00%
Western Pocahontas Properties and Quintana Minerals Corporation | Affiliated Entity
Related Party Transaction [Line Items]
Operating and maintenance expenses—affiliates	$ 6,543	6,559	6,656
General and administrative—affiliates	4,611	4,611	4,946
Western Pocahontas Properties Limited Partnership | Affiliated Entity
Related Party Transaction [Line Items]
Operating and maintenance expenses—affiliates	3,300	400	4,000
Amount payable to related parties	900	300
Accounts Receivable, Related Parties, Noncurrent	0
Quinwood Coal Company
Related Party Transaction [Line Items]
Revenue from Related Parties	$ 0	$ 0	$ 200

Major Customers (Detail)

Major Customers (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Concentration Risk [Line Items]
Revenues	$ 216,119	$ 139,739	$ 257,437
Foresight Energy Lp
Concentration Risk [Line Items]
Revenues	37,366	35,704	58,923
Contura Energy
Concentration Risk [Line Items]
Revenues	$ 49,440	$ 33,227	$ 40,743
Sales Revenue | Customer Concentration Risk | Foresight Energy Lp
Concentration Risk [Line Items]
Concentration risk, percentage	17.00%	26.00%	23.00%
Sales Revenue | Customer Concentration Risk | Contura Energy
Concentration Risk [Line Items]
Concentration risk, percentage	23.00%	24.00%	16.00%

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details)	Dec. 31, 2021
Ciner Wyoming
Commitments And Contingencies [Line Items]
Percentage of partnership interest owned (percent)	49.00%

Unit-Based Compensation Additio

Unit-Based Compensation Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units available for delivery (in shares)	800,000
Term of approved plan (in years)	10 years
Vesting period of Grants (in years)	3 years
Grant date fair value	$ 3.8	$ 3.5	$ 5.4
Unaccrued Cost Associated With Outstanding Grants And Related Distribution Equivalent Rights	$ 3.3	3.7
Weighted average recognition period (in years)	1 year 8 months 12 days
Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of Grants (in years)	1 year
General and Administrative expenses and Operating and Maintenance expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 4	$ 3.6	$ 2.4

Unit-Based Compensation Summary

Unit-Based Compensation Summary of Activity in Outstanding Grants (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2021	Nov. 09, 2021
Common Units
Outstanding grants at beginning of period (in shares)	355
Grants during the period (in shares)	219
Grants vested and paid during the period (in shares)	(129)
Forfeitures during the period (in shares)	(34)
Outstanding grants at the end of the period (in shares)	411
Weighted Average Grant Date Fair value per Common Unit
Outstanding grants, beginning of period	$ 26.20
Granted	17.31
Fully vested and issued	21.38	$ 32.02
Forfeitures	26
Outstanding grants, end of period	$ 23

Financing Transaction (Details)

Financing Transaction (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2032	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Term of option to extend lease (in years)		80 years
Minimum required lease payments		$ 5,000
Forecast
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lease payments due per year after initial lease term	$ 10

Credit Losses (Details)

Credit Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Credit Loss [Abstract]
Short-term Receivables, Gross	$ 28,869	$ 18,512
Contract with Customer, Asset, before Allowance for Credit Loss	32,497	34,818
Accounts Receivable, Allowance for Credit Loss	(3,312)	(2,358)
Allowance for credit loss in long-term contract receivable	1,126	1,554
Long-term Investments and Receivables, Net	31,371	33,264
Short-term receivables, net of CECL	25,557	16,154
Total receivables, Gross	61,366	53,330
CECL Allowance - total	(4,438)	(3,912)
Total receivables, net of CECL	56,928	49,418
Financing Receivable, Credit Loss, Expense (Reversal)	(500)	0
Bad debt expense	$ 2,572	$ 4,001	$ 7,462

Leases - Additional Information

Leases - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Renewal term	5 years
Right-of-use asset	$ 3,500	$ 3,500
Lease expense	$ 500	500	$ 500
Number of options to extend	five
Total operating lease liability	$ 3,484	$ 3,500
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Other Liabilities	Other Liabilities
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other long-term assets, net	Other long-term assets, net
Minimum
Lessee, Lease, Description [Line Items]
Operating lease, term of contract (in years)	5 years
Maximum
Lessee, Lease, Description [Line Items]
Operating lease, term of contract (in years)	30 years

Leases - Lessee Accounting Unde

Leases - Lessee Accounting Under ASC 842 (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Leases [Abstract]
2020	$ 483
2021	483
2022	483
2023	483
2024	483
After 2026	10,631
Total lease payments	13,046
Less: present value adjustment	(9,562)
Total operating lease liability	$ 3,484	$ 3,500
Remaining lease term of operating leases	27 years
Discount rate	13.50%
Renewal term	5 years