Natural Resource Partners (NRP) 10-Q 6 Nov 19 2019 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Nov. 04, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Entity Current Reporting Status	Yes
Document Fiscal Year Focus	2019
Document Period End Date	Sep. 30, 2019
Document Fiscal Period Focus	Q3
Interactive Data Current	Yes
Entity Registrant Name	NATURAL RESOURCE PARTNERS LP
Entity Central Index Key	0001171486
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Shell Company	false
Entity Common Stock, Shares Outstanding		12,261,199

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 99,636	$ 101,839
Restricted cash	12,527	104,191
Accounts receivable, net	27,447	32,058
Prepaid expenses and other	3,111	3,462
Current assets of discontinued operations	988	993
Total current assets	143,709	242,543
Land	24,008	24,008
Plant and equipment, net	762	984
Mineral rights, net	733,154	743,112
Intangible assets, net	40,461	42,513
Equity in unconsolidated investment	258,063	247,051
Long-term contract receivable	37,473	38,945
Other assets	6,274	2,491
Total assets	1,243,904	1,341,647
Current liabilities:
Accounts payable	1,591	2,414
Accrued liabilities	7,290	12,347
Accrued interest	14,364	14,345
Current portion of deferred revenue	5,047	3,509
Current portion of long-term debt, net	45,789	115,184
Current liabilities of discontinued operations	174	947
Total current liabilities	74,255	148,746
Deferred revenue	43,587	49,044
Long-term debt, net	490,378	557,574
Other non-current liabilities	4,843	1,150
Total liabilities	613,063	756,514
Commitments and contingencies	0	0
Class A Convertible Preferred Units (250,000 units issued and outstanding at $1,000 par value per unit; liquidation preference of $1,500 per unit)	164,587	164,587
Partners’ capital:
Common unitholders’ interest (12,261,199 and 12,249,469 units issued and outstanding at September 30, 2019 and December 31, 2018, respectively)	400,266	355,113
General partner’s interest	5,909	5,014
Warrant holders’ interest	66,816	66,816
Accumulated other comprehensive loss	(3,802)	(3,462)
Total partners’ capital	469,189	423,481
Non-controlling interest	(2,935)	(2,935)
Total capital	466,254	420,546
Total liabilities and capital	$ 1,243,904	$ 1,341,647

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Common units outstanding (in shares)	12,261,199	12,249,469
Common units issued (in shares)	12,261,199	12,249,469
Preferred Units, Issued	250,000	250,000
Preferred units outstanding (in shares)	250,000	250,000
Preferred unit par value per unit	$ 1,000	$ 1,000
Preferred unit liquidation preference per unit	$ 1,500	$ 1,500

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues	$ 57,602	$ 58,207	$ 205,610	$ 187,136
Gain on asset sales and disposals	6,107	0	6,609	819
Total revenues and other income	63,709	58,207	212,219	187,955
Operating expenses
Operating and maintenance expenses	5,994	6,790	26,813	21,122
Depreciation, depletion and amortization	3,384	4,888	11,746	15,364
General and administrative expenses	4,253	3,183	12,799	10,782
Asset impairments	484	0	484	242
Total operating expenses	14,115	14,861	51,842	47,510
Income from operations	49,594	43,346	160,377	140,445
Other expenses, net
Interest expense, net	(10,431)	(17,493)	(37,061)	(53,177)
Loss on extinguishment of debt	0	0	(29,282)	0
Total other expenses, net	(10,431)	(17,493)	(66,343)	(53,177)
Net income from continuing operations	39,163	25,853	94,034	87,268
Income from discontinued operations	7	2,688	206	3,721
Net income	39,170	28,541	94,240	90,989
Net loss (income) attributable to non-controlling interest	0	359	0	(510)
Net income attributable to NRP	39,170	28,900	94,240	90,479
Less: income attributable to preferred unitholders	(7,500)	(7,500)	(22,500)	(22,500)
Net income attributable to common unitholders and general partner	31,670	21,400	71,740	67,979
Net income attributable to common unitholders	31,036	20,972	70,305	66,619
Net income attributable to the general partner	$ 634	$ 428	$ 1,435	$ 1,360
Income from continuing operations per common unit
Basic (in dollars per share)	$ 2.53	$ 1.50	$ 5.72	$ 5.14
Diluted (in dollars per share)	1.66	1.18	3.91	3.89
Net income per common unit
Basic (in dollars per share)	2.53	1.71	5.73	5.44
Diluted (in dollars per share)	$ 1.66	$ 1.30	$ 3.92	$ 4.06
Comprehensive income (loss) from unconsolidated investment and other	$ (520)	$ 791	$ (340)	$ (768)
Comprehensive income	38,650	29,332	93,900	90,221
Comprehensive loss (income) attributable to non-controlling interest	0	359	0	(510)
Comprehensive income attributable to NRP	38,650	29,691	93,900	89,711
Coal Royalty and Other
Revenues	39,919	42,518	154,037	134,912
Soda Ash
Revenues	13,818	8,836	36,833	34,986
Transportation and processing services revenues | Coal Royalty and Other
Revenues	$ 3,865	$ 6,853	$ 14,740	$ 17,238

Consolidated Statements of Part

Consolidated Statements of Partners' Capital - USD ($) shares in Thousands, $ in Thousands	Total	General Partner	Common Unitholders	Warrant Holders	Accumulated Other Comprehensive Loss	Partners' Capital Excluding Non-Controlling Interest		Non-Controlling Interest	Common Unitholders	Common UnitholdersCommon Unitholders	Common unitholders and general partner	Common unitholders and general partnerPartners' Capital Excluding Non-Controlling Interest	General Partner	General PartnerGeneral Partner	Preferred Partner	Preferred PartnerGeneral Partner	Preferred PartnerCommon Unitholders	Preferred PartnerPartners' Capital Excluding Non-Controlling Interest
Balance, beginning of period (in shares) at Dec. 31, 2017			12,232
Balance, beginning of period at Dec. 31, 2017	$ 261,817	$ 1,857	$ 199,851	$ 66,816	$ (3,313)	$ 265,211		$ (3,394)
Net income attributable to NRP		487	$ 23,851			24,338	[1]
Net income	24,338							0
Distributions to unitholders										$ (5,505)	$ (5,617)	$ (5,617)		$ (112)	$ (7,765)	$ (155)	$ (7,610)	$ (7,765)
Issuance of unit-based awards (units)			14
Issuance of unit-based awards	410		$ 410			410
Unit-based awards amortization and vesting	197		197			197
Comprehensive income from unconsolidated investment and other	(1,117)	8	$ 0		(1,125)	(1,117)		0
Balance, end of period (in shares) at Mar. 31, 2018			12,246
Balance, end of period at Mar. 31, 2018	342,729	3,494	$ 280,251	66,816	(4,438)	346,123		(3,394)
Income attributable to preferred unitholders	7,500								$ 7,350				$ 150
Balance, beginning of period (in shares) at Dec. 31, 2017			12,232
Balance, beginning of period at Dec. 31, 2017	261,817	1,857	$ 199,851	66,816	(3,313)	265,211		(3,394)
Net income attributable to NRP	90,479
Net income	90,989
Balance, end of period (in shares) at Sep. 30, 2018			12,246
Balance, end of period at Sep. 30, 2018	383,766	4,293	$ 319,673	66,816	(4,081)	386,701		(2,935)
Income attributable to preferred unitholders	22,500
Balance, beginning of period (in shares) at Mar. 31, 2018			12,246
Balance, beginning of period at Mar. 31, 2018	342,729	3,494	$ 280,251	66,816	(4,438)	346,123		(3,394)
Net income attributable to NRP		745	36,496			37,241	[1]
Net income	38,110							869
Distributions to unitholders										(5,510)	(5,623)	(5,623)		(113)	(7,500)	(150)	(7,350)	(7,500)
Unit-based awards amortization and vesting	136		136			136
Comprehensive income from unconsolidated investment and other	(434)	1	$ 50		(434)	(383)		(51)
Balance, end of period (in shares) at Jun. 30, 2018			12,246
Balance, end of period at Jun. 30, 2018	367,418	3,977	$ 304,073	66,816	(4,872)	369,994		(2,576)
Income attributable to preferred unitholders	7,500								7,350				150
Net income attributable to NRP	28,900	578	28,322			28,900	[1]
Net income	28,541							(359)
Distributions to unitholders										(5,511)	(5,623)	(5,623)		(112)	(7,500)	(150)	(7,350)	(7,500)
Unit-based awards amortization and vesting	139		139			139
Comprehensive income from unconsolidated investment and other	791	0	$ 0		791	791		0
Balance, end of period (in shares) at Sep. 30, 2018			12,246
Balance, end of period at Sep. 30, 2018	383,766	4,293	$ 319,673	66,816	(4,081)	386,701		(2,935)
Income attributable to preferred unitholders	7,500								7,350				150
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 attributable to NRP		714	$ 35,005			35,719	[1]
Net income	35,719							0
Distributions to unitholders										(5,513)	(5,625)	(5,625)		(112)	(7,500)	(150)	(7,350)	(7,500)
Issuance of unit-based awards (units)			12
Issuance of unit-based awards	486		$ 486			486
Unit-based awards amortization and vesting	399		399			399
Comprehensive income from unconsolidated investment and other	1,015	10	$ 0		1,005	1,015		0
Balance, end of period (in shares) at Mar. 31, 2019			12,261
Balance, end of period at Mar. 31, 2019	445,040	5,476	$ 378,140	66,816	(2,457)	447,975		(2,935)
Income attributable to preferred unitholders	7,500								7,350				150
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 attributable to NRP	94,240
Net income	94,240
Balance, end of period (in shares) at Sep. 30, 2019			12,261
Balance, end of period at Sep. 30, 2019	466,254	5,909	$ 400,266	66,816	(3,802)	469,189		(2,935)
Income attributable to preferred unitholders	22,500
Balance, beginning of period (in shares) at Mar. 31, 2019			12,261
Balance, beginning of period at Mar. 31, 2019	445,040	5,476	$ 378,140	66,816	(2,457)	447,975		(2,935)
Net income attributable to NRP		387	18,964			19,351	[1]
Net income	19,351							0
Distributions to unitholders										(15,939)	(16,265)	(16,265)		(326)	(7,500)	(150)	(7,350)	(7,500)
Unit-based awards amortization and vesting	460		460			460
Comprehensive income from unconsolidated investment and other	(825)	0	$ 0		(825)	(825)		0
Balance, end of period (in shares) at Jun. 30, 2019			12,261
Balance, end of period at Jun. 30, 2019	440,261	5,387	$ 374,275	66,816	(3,282)	443,196		(2,935)
Income attributable to preferred unitholders	7,500								7,350				150
Net income attributable to NRP	39,170	784	38,386			39,170	[1]
Net income	39,170							0
Distributions to unitholders										$ (5,518)	$ (5,630)	$ (5,630)		$ (112)	$ (7,500)	$ (150)	$ (7,350)	$ (7,500)
Unit-based awards amortization and vesting	473		473			473
Comprehensive income from unconsolidated investment and other	(520)	0	$ 0		(520)	(520)		0
Balance, end of period (in shares) at Sep. 30, 2019			12,261
Balance, end of period at Sep. 30, 2019	466,254	$ 5,909	$ 400,266	$ 66,816	$ (3,802)	$ 469,189		$ (2,935)
Income attributable to preferred unitholders	$ 7,500								$ 7,350				$ 150
[1]	Common Unitholders General Partner Warrant Holders AccumulatedOtherComprehensive Loss Partners' Capital Excluding Non-Controlling Interest Non-Controlling Interest Total Capital (In thousands)Units Amounts Balance at December 31, 201812,249 $355,113 $5,014 $66,816 $(3,462) $423,481 $(2,935) $420,546Net income (1)— 35,005 714 — — 35,719 — 35,719Distributions to common unitholders and general partner— (5,513) (112) — — (5,625) — (5,625)Distributions to preferred unitholders— (7,350) (150) — — (7,500) — (7,500)Issuance of unit-based awards12 486 — — — 486 — 486Unit-based awards amortization and vesting— 399 — — — 399 — 399Comprehensive income from unconsolidated investment and other— — 10 — 1,005 1,015 — 1,015Balance at March 31, 201912,261 $378,140 $5,476 $66,816 $(2,457) $447,975 $(2,935) $445,040Net income (1)— 18,964 387 — — 19,351 — 19,351Distributions to common unitholders and general partner— (15,939) (326) — — (16,265) — (16,265)Distributions to preferred unitholders— (7,350) (150) — — (7,500) — (7,500)Unit-based awards amortization and vesting— 460 — — — 460 — 460Comprehensive loss from unconsolidated investment and other— — — — (825) (825) — (825)Balance at June 30, 201912,261 $374,275 $5,387 $66,816 $(3,282) $443,196 $(2,935) $440,261Net income (1)— 38,386 784 — — 39,170 — 39,170Distributions to common unitholders and general partner— (5,518) (112) — — (5,630) — (5,630)Distributions to preferred unitholders— (7,350) (150) — — (7,500) — (7,500)Unit-based awards amortization and vesting— 473 — — — 473 — 473Comprehensive loss from unconsolidated investment and other— — — — (520) (520) — (520)Balance at September 30, 201912,261 $400,266 $5,909 $66,816 $(3,802) $469,189 $(2,935) $466,254 (1)Net income includes $7.5 million attributable to preferred unitholders that accumulated during the period, of which $7.35 million is allocated to the common unitholders and $0.15 million is allocated to the general partner.

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Net income	$ 94,240	$ 90,989
Adjustments to reconcile net income to net cash provided by operating activities of continuing operations:
Depreciation, depletion and amortization	11,746	15,364
Distributions from unconsolidated investment	25,480	34,653
Equity earnings from unconsolidated investment	(36,833)	(34,986)
Gain on asset sales and disposals	(6,609)	(819)
Loss on extinguishment of debt	29,282	0
Income from discontinued operations	(206)	(3,721)
Asset impairments	484	242
Unit-based compensation expense	1,842	1,144
Amortization of debt issuance costs and other	3,223	4,021
Change in operating assets and liabilities:
Accounts receivable	4,731	(6,283)
Accounts payable	(822)	90
Accrued liabilities	(5,083)	(3,193)
Accrued interest	19	(9,944)
Deferred revenue	(3,920)	9,200
Other items, net	351	1,036
Net cash provided by operating activities of continuing operations	117,925	97,793
Net cash provided by (used in) operating activities of discontinued operations	(4)	9,755
Net cash provided by operating activities	117,921	107,548
Cash flows from investing activities
Distributions from unconsolidated investment in excess of cumulative earnings	0	2,097
Proceeds from asset sales and disposals	6,611	826
Return of long-term contract receivable	1,351	2,606
Net cash provided by investing activities of continuing operations	7,962	5,529
Net cash used in investing activities of discontinued operations	(556)	(9,343)
Net cash provided by (used in) investing activities	7,406	(3,814)
Cash flows from financing activities
Debt borrowings	300,000	35,000
Debt repayments	(442,747)	(55,720)
Contributions to discontinued operations	(560)	(2,275)
Debt issuance costs and other	(26,427)	(228)
Net cash used in financing activities of continuing operations	(219,754)	(71,695)
Net cash provided by financing activities of discontinued operations	560	1,521
Net cash used in financing activities	(219,194)	(70,174)
Net increase (decrease) in cash, cash equivalents and restricted cash	(93,867)	33,560
Cash, cash equivalents and restricted cash of continuing operations at beginning of period	112,163	58,607
Cash and cash equivalents of discontinued operations at beginning of period	0	(4,780)
Cash, cash equivalents and restricted cash at beginning of period	112,163	63,387
Cash paid during the period for interest of continuing operations	36,270	58,153
General Partner
Cash flows from financing activities
Distributions to common unitholders and general partner	(27,520)	(16,863)
Preferred Partner
Cash flows from financing activities
Distributions to common unitholders and general partner	(22,500)	(22,765)
Class A Convertible Preferred Units
Cash flows from financing activities
Redemption of preferred units paid-in-kind	$ 0	$ (8,844)

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation Nature of Business Natural Resource Partners L.P. (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 Ciner Wyoming LLC ("Ciner Wyoming"), a trona ore mining and soda ash production business. The Partnership is organized into two operating segments further described in Note 6. 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. Principles of Consolidation and Reporting The accompanying unaudited consolidated financial statements of the Partnership have been prepared in accordance with generally accepted accounting principles in the United States of America ("GAAP") for interim financial information and with Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. These financial statements should be read in conjunction with the financial statements for the year ended December 31, 2018 and notes thereto included in the Partnership's Annual Report on Form 10-K, which was filed with the SEC on March 7, 2019. In management's opinion, all necessary adjustments to fairly present the Partnership's results of operations, financial position and cash flows for the periods presented have been made and all such adjustments were of a normal and recurring nature. Certain reclassifications have been made to prior period amounts on the Consolidated Balance Sheets, Consolidated Statements of Comprehensive Income and Consolidated Statements of Cash Flows to conform with current period presentation. These reclassifications had no impact on previously reported total assets, total liabilities, partners' capital, net income or cash flows from operating, investing or financing activities. Recasting of Certain Prior Period Information As described in Note 3. Discontinued Operations , the Partnership reclassified prior period information for the assets and liabilities, operating results and cash flows of its construction aggregates business as discontinued operations in its consolidated financial statements for all periods presented. Restricted Cash Restricted cash at September 30, 2019 and December 31, 2018 represents the remaining net proceeds from the sale of the Partnership's construction aggregates business and other asset sales and disposals that is required to be used to repay debt, make acquisitions or make capital expenditures per the terms of the Partnership's and Opco's debt agreements. In the first nine months of 2019, the Partnership used $97.1 million of restricted cash to repay principal amounts on Opco's private placement senior notes (the "Opco Senior Notes") and it intends to use the remaining $12.5 million of restricted cash to repay a portion of the remaining principal payments on the Opco Senior Notes in 2019. Recently Adopted Accounting Standards Leases On January 1, 2019, NRP adopted Accounting Standards Codification (ASC) 842, Leases, and all the related amendments (the “new lease standard” and "ASC 842") and recognized assets and liabilities on its Consolidated Balance Sheet for the present value of the rights and obligations created by all leases with terms of more than 12 months. This standard does not apply to leases that explore for or use minerals, oil, natural gas and similar non-regenerative resources, including the intangible right to explore for those natural resources and rights to use the land in which those natural resources are contained. The guidance also required disclosures designed to give financial statement users information on the amount, timing and uncertainty of cash flows arising from leases. The guidance was adopted by NRP on January 1, 2019 using a modified retrospective approach. The Partnership is a lessee in one lease that is accounted for as an operating lease under the new lease standard, and the adoption of the new lease standard did not have a material impact to the Partnership's consolidated financial statements. For lease agreements entered into or reassessed after the adoption of ASC 842, the Partnership elected to not combine lease and non-lease components. See Note 17. Leases for more information. Recently Issued Accounting Standards Credit Losses In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326). The new standard changes how entities will measure credit losses for most financial assets and certain other instruments that are not measured at fair value through net income. The new standard replaces today's "incurred loss" model with an "expected credit loss" model that requires entities to estimate an expected lifetime credit loss on financial assets, including trade accounts receivable. The guidance is effective for annual and interim periods beginning after December 15, 2019 and is to be adopted using a modified retrospective approach. The Partnership is continuing to evaluate the provisions of this guidance on its consolidated financial statements, but based on its analysis to date, the Partnership does not expect this standard to have a material effect on its consolidated financial statements.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	9 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	Revenues from Contracts with Customers The following table represents the Partnership's Coal Royalty and Other segment revenues by major source: Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2019 2018 2019 2018 Coal royalty revenues $ 24,727 $ 30,709 $ 87,561 $ 96,473 Production lease minimum revenues 2,752 1,769 21,331 6,310 Minimum lease straight-line revenues 3,982 567 11,152 1,739 Property tax revenues 1,606 1,263 4,416 3,968 Wheelage revenues 1,675 1,572 5,035 5,155 Coal overriding royalty revenues 2,189 3,918 10,163 10,492 Lease amendment revenues 1,535 — 6,720 — Aggregates royalty revenues 954 888 3,655 3,551 Oil and gas royalty revenues 374 1,427 2,575 5,679 Other revenues 125 405 1,429 1,545 Coal royalty and other revenues (1) $ 39,919 $ 42,518 $ 154,037 $ 134,912 Transportation and processing services revenues (2) 3,865 6,853 14,740 17,238 Total Coal Royalty and Other segment revenues $ 43,784 $ 49,371 $ 168,777 $ 152,150 (1) Coal royalty and other revenues from contracts with customers as defined under ASC 606. (2) Transportation and processing services revenues from contracts with customers as defined under ASC 606 was $1.7 million and $3.6 million for the three months ended September 30, 2019 and 2018 , respectively, and $7.3 million and $9.6 million for the nine months ended September 30, 2019 and 2018 , respectively. The remaining transportation and processing services revenues of $2.2 million and $3.3 million for the three months ended September 30, 2019 , and 2018 , respectively, and $7.5 million and $7.6 million for the nine months ended September 30, 2019 and 2018 , respectively, related to other NRP-owned infrastructure leased to and operated by third party operators accounted for under other guidance. See Note 16. Financing Transaction and Note 17. Leases for more information. The following table details the Partnership's Coal Royalty and Other segment receivables and liabilities resulting from contracts with customers: September 30, December 31, (In thousands) 2019 2018 Receivables Accounts receivable, net $ 24,758 $ 29,001 Prepaid expenses and other (1) 2,852 2,483 Contract liabilities Current portion of deferred revenue $ 5,047 $ 3,509 Deferred revenue 43,587 49,044 (1) Prepaid expenses and other includes notes receivable from contracts with customers. The following table shows the activity related to the Partnership's Coal Royalty and Other segment deferred revenue: Nine Months Ended September 30, (In thousands) 2019 2018 Balance at end of prior period (current and non-current) $ 52,553 $ 100,605 Cumulative adjustment for change in accounting principle — (65,591 ) Balance at beginning of period (current and non-current) $ 52,553 $ 35,014 Increase due to minimums and lease amendment fees 37,315 23,534 Recognition of previously deferred revenue (41,234 ) (16,260 ) Balance at end of period (current and non-current) $ 48,634 $ 42,288 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 (in thousands): Lease Term (1) Weighted Average Remaining Years as of September 30, 2019 Annual Minimum Payments (2) 0 - 5 years 2.2 $ 12,439 5 - 10 years 6.4 9,426 10+ years 12.1 46,737 Total 9.6 $ 68,602 (1) Lease term does not include renewal periods. (2) Annual minimum payments do not include $5.0 million from a coal infrastructure lease that is accounted for as a financing transaction. See Note 16. Financing Transaction for additional information.

Discontinued Operations

Discontinued Operations	9 Months Ended
	Sep. 30, 2019
Discontinued Operations [Abstract]
Discontinued Operations	Discontinued Operations In December 2018, the Partnership sold VantaCore Partners LLC, its construction aggregates business, and in July 2016, the Partnership sold its non-operated oil and gas working interest assets. The Partnership's exit from both its construction aggregates business and non-operated oil and gas working interest business represented strategic shifts to reduce debt and focus on its Coal Royalty and Other and Soda Ash business segments. As a result, the Partnership classified the assets and liabilities, operating results and cash flows of these businesses as discontinued operations in its Consolidated Balance Sheets, Consolidated Statements of Comprehensive Income and Consolidated Statements of Cash Flows for all periods presented. The following table presents the carrying amounts of the Partnership's assets and liabilities of discontinued operations in the Consolidated Balance Sheets: September 30, 2019 December 31, 2018 (In thousands) Construction Aggregates NRP Total Construction Aggregates NRP Total ASSETS Current assets Accounts receivable, net $ — $ 988 $ 988 $ 5 $ 988 $ 993 Total assets of discontinued operations $ — $ 988 $ 988 $ 5 $ 988 $ 993 LIABILITIES Current liabilities Accounts payable $ 42 $ — $ 42 $ 181 $ — $ 181 Accrued liabilities 132 — 132 766 — 766 Total liabilities of discontinued operations $ 174 $ — $ 174 $ 947 $ — $ 947 The following tables present summarized financial results of the Partnership's discontinued operations in the Consolidated Statements of Comprehensive Income: Three Months Ended September 30, 2019 2018 (In thousands) Construction Aggregates NRP Total Construction Aggregates NRP Oil and Gas Total Revenues and other income Construction aggregates $ — $ — $ — $ 30,398 $ — $ 30,398 Road construction and asphalt paving services — — — 6,250 — 6,250 Oil and gas — 2 2 — (1 ) (1 ) Gain on asset sales and disposals 5 — 5 163 — 163 Total revenues and other income $ 5 $ 2 $ 7 $ 36,811 $ (1 ) $ 36,810 Operating expenses Operating and maintenance expenses $ — $ — $ — $ 30,758 $ 23 $ 30,781 Depreciation, depletion and amortization — — — 3,333 — 3,333 Total operating expenses $ — $ — $ — $ 34,091 $ 23 $ 34,114 Interest expense — — — (8 ) — (8 ) Income (loss) from discontinued operations $ 5 $ 2 $ 7 $ 2,712 $ (24 ) $ 2,688 Nine Months Ended September 30, 2019 2018 (In thousands) Construction Aggregates NRP Total Construction Aggregates NRP Oil and Gas Total Revenues and other income Construction aggregates $ — $ — $ — $ 91,055 $ — $ 91,055 Road construction and asphalt paving services — — — 13,154 — 13,154 Oil and gas — 2 2 — (3 ) (3 ) Gain on asset sales and disposals 243 — 243 214 — 214 Total revenues and other income $ 243 $ 2 $ 245 $ 104,423 $ (3 ) $ 104,420 Operating expenses Operating and maintenance expenses $ 27 $ 12 $ 39 $ 91,225 $ 69 $ 91,294 Depreciation, depletion and amortization — — — 9,377 — 9,377 Total operating expenses $ 27 $ 12 $ 39 $ 100,602 $ 69 $ 100,671 Interest expense — — — (28 ) — (28 ) Income (loss) from discontinued operations $ 216 $ (10 ) $ 206 $ 3,793 $ (72 ) $ 3,721 Capital expenditures related to the Partnership's discontinued operations were $9.7 million during the nine months ended September 30, 2018 .

Common and Preferred Unit Distr

Common and Preferred Unit Distributions	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Common and Preferred Unit Distributions	Common and Preferred Unit Distributions The Partnership makes cash distributions to common and preferred unitholders on a quarterly basis, subject to approval by the Board of Directors of GP Natural Resource Partners LLC (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 available to common unitholders and the general partner is reduced by preferred unit distributions that accumulated during the period. NRP reduced net income attributable to common unitholders and the general partner by $7.5 million during the three months ended September 30, 2019 and 2018 and $22.5 million during the nine months ended September 30, 2019 and 2018 as a result of accumulated preferred unit distributions earned during the period. During the three months ended March 31, 2018, the Partnership redeemed all of the outstanding PIK Units, which resulted in an $8.8 million cash payment during the period. This $8.8 million cash payment is not included in the table below. The following table shows the distributions declared and paid to common and preferred unitholders during the nine months ended September 30, 2019 and 2018 , respectively: Common Units Preferred Units Date Paid Period Covered by Distribution Distribution per Unit Total Distribution (1) (In thousands) Distribution per Unit Total Distribution (In thousands) 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 (2) Special Distribution 0.85 10,635 — — August 2019 April 1 - June 30, 2019 0.45 5,630 30.00 7,500 2018 February 2018 October 1 - December 31, 2017 $ 0.45 $ 5,617 $ 30.00 $ 7,765 May 2018 January 1 - March 31, 2018 0.45 5,623 30.00 7,500 August 2018 April 1 - June 30, 2018 0.45 5,623 30.00 7,500 (1) Totals include the amount paid to NRP's general partner in accordance with the general partner's 2% general partner interest. (2) The special distribution of $0.85 per common unit was made to cover the common unitholders’ tax liability resulting from the sale of NRP’s construction aggregates business in December 2018.

Net Income Per Common Unit

Net Income Per Common Unit	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Net Income Per Common Unit	Net Income Per Common Unit Basic net income per common unit is computed by dividing net income, after considering income attributable to non-controlling interest, preferred unitholders and the general partner’s general partner interest, by the weighted average number of common units outstanding. Diluted net income 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 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 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 the dilutive effect of the warrants for the three months ended September 30, 2019 and 2018 and the nine months ended September 30, 2018 includes the net settlement of warrants to purchase 1.75 million common units with a strike price of $22.81 but did 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 income per common unit for the nine months ended September 30, 2019 includes both the net settlement of warrants to purchase 1.75 million common units at a strike price of $22.81 and the net settlement of warrants to purchase 2.25 million common units with a strike price of $34.00 . The following table reconciles the numerator and denominator of the basic and diluted net income per common unit computations and calculates basic and diluted net income per common unit: Three Months Ended Nine Months Ended (In thousands, except per unit data) 2019 2018 2019 2018 Allocation of net income Net income from continuing operations $ 39,163 $ 25,853 $ 94,034 $ 87,268 Add (less): net loss (income) attributable to non-controlling interest — 359 — (510 ) Less: income attributable to preferred unitholders (7,500 ) (7,500 ) (22,500 ) (22,500 ) Net income from continuing operations attributable to common unitholders and general partner $ 31,663 $ 18,712 $ 71,534 $ 64,258 Less: net income from continuing operations attributable to the general partner (634 ) (374 ) (1,431 ) (1,285 ) Net income from continuing operations attributable to common unitholders $ 31,029 $ 18,338 $ 70,103 $ 62,973 Net income from discontinued operations $ 7 $ 2,688 $ 206 $ 3,721 Less: net income from discontinued operations attributable to the general partner 0 (54 ) (4 ) (75 ) Net income from discontinued operations attributable to common unitholders $ 7 $ 2,634 $ 202 $ 3,646 Net income $ 39,170 $ 28,541 $ 94,240 $ 90,989 Add (less): net loss (income) attributable to non-controlling interest — 359 — (510 ) Less: income attributable to preferred unitholders (7,500 ) (7,500 ) (22,500 ) (22,500 ) Net income attributable to common unitholders and general partner $ 31,670 $ 21,400 $ 71,740 $ 67,979 Less: net income attributable to the general partner (634 ) (428 ) (1,435 ) (1,360 ) Net income attributable to common unitholders $ 31,036 $ 20,972 $ 70,305 $ 66,619 Basic net income per common unit Weighted average common units—basic 12,261 12,246 12,259 12,243 Basic net income from continuing operations per common unit $ 2.53 $ 1.50 $ 5.72 $ 5.14 Basic net income from discontinued operations per common unit $ 0.00 $ 0.22 $ 0.02 $ 0.30 Basic net income per common unit $ 2.53 $ 1.71 $ 5.73 $ 5.44 Three Months Ended Nine Months Ended (In thousands, except per unit data) 2019 2018 2019 2018 Diluted income per common unit Weighted average common units—basic 12,261 12,246 12,259 12,243 Plus: dilutive effect of Preferred Units 10,494 9,124 10,494 9,124 Plus: dilutive effect of Warrants 389 470 800 474 Plus: dilutive effect of unvested unit-based awards 13 — 31 — Weighted average common units—diluted 23,157 21,840 23,584 21,841 Net income from continuing operations $ 39,163 $ 25,853 $ 94,034 $ 87,268 Add (less): net loss (income) attributable to non-controlling interest — 359 — (510 ) Diluted net income from continuing operations attributable to common unitholders and general partner $ 39,163 $ 26,212 $ 94,034 $ 86,758 Less: diluted net income from continuing operations attributable to the general partner (784 ) (524 ) (1,881 ) (1,735 ) Diluted net income from continuing operations attributable to common unitholders $ 38,379 $ 25,688 $ 92,153 $ 85,023 Diluted net income from discontinued operations attributable to common unitholders $ 7 $ 2,634 $ 202 $ 3,646 Net income $ 39,170 $ 28,541 $ 94,240 $ 90,989 Add (less): net loss (income) attributable to non-controlling interest — 359 — (510 ) Diluted net income attributable to common unitholders and general partner $ 39,170 $ 28,900 $ 94,240 $ 90,479 Less: diluted net income attributable to the general partner (784 ) (578 ) (1,885 ) (1,810 ) Diluted net income attributable to common unitholders $ 38,386 $ 28,322 $ 92,355 $ 88,669 Diluted net income from continuing operations per common unit $ 1.66 $ 1.18 $ 3.91 $ 3.89 Diluted net income from discontinued operations per common unit $ 0.00 $ 0.12 $ 0.01 $ 0.17 Diluted net income per common unit $ 1.66 $ 1.30 $ 3.92 $ 4.06

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2019
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. that are managed accordingly. NRP has the following two operating segments: Coal Royalty and Other —consists primarily of coal royalty properties and coal-related transportation and processing assets. Other assets include industrial mineral royalty properties, aggregates royalty properties, oil and gas royalty properties and timber. The Partnership's coal reserves are primarily located in Appalachia, the Illinois Basin and the Northern Powder River Basin in the United States. The Partnership's industrial minerals and aggregates properties are located in a number of states across the United States. The Partnership's oil and gas royalty assets are primarily located in Louisiana. Soda Ash —consists of the Partnership's 49% non-controlling equity interest in Ciner Wyoming, a trona ore mining and soda ash production business located in the Green River Basin of Wyoming. Ciner Resources LP, the Partnership's operating partner, mines the trona, processes it into soda ash, and distributes the soda ash both domestically and internationally to the glass and chemicals industries. In December 2018, the Partnership sold its construction aggregates business which enabled it to further reduce debt and focus on its Coal Royalty and Other and Soda Ash business segments. See Note 3. Discontinued Operations for more information. 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. 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. The following table summarizes certain financial information for each of the Partnership's business segments: Operating Segments (In thousands) Coal Royalty and Other Soda Ash Corporate and Financing Total Three Months Ended September 30, 2019 Revenues $ 43,784 $ 13,818 $ — $ 57,602 Gain on asset sales and disposals 6,107 — — 6,107 Operating and maintenance expenses 5,771 223 — 5,994 Depreciation, depletion and amortization 3,384 — — 3,384 General and administrative expenses — — 4,253 4,253 Asset impairments 484 — — 484 Other expenses, net — — 10,431 10,431 Net income (loss) from continuing operations 40,252 13,595 (14,684 ) 39,163 Income from discontinued operations — — — 7 Three Months Ended September 30, 2018 Revenues $ 49,371 $ 8,836 $ — $ 58,207 Operating and maintenance expenses 6,790 — — 6,790 Depreciation, depletion and amortization 4,888 — — 4,888 General and administrative expenses — — 3,183 3,183 Other expenses, net — — 17,493 17,493 Net income (loss) from continuing operations 37,693 8,836 (20,676 ) 25,853 Income from discontinued operations — — — 2,688 Nine Months Ended September 30, 2019 Revenues $ 168,777 $ 36,833 $ — $ 205,610 Gain on asset sales and disposals 6,609 — — 6,609 Operating and maintenance expenses 26,590 223 — 26,813 Depreciation, depletion and amortization 11,746 — — 11,746 General and administrative expenses — — 12,799 12,799 Asset impairments 484 — — 484 Other expenses, net — — 66,343 66,343 Net income (loss) from continuing operations 136,566 36,610 (79,142 ) 94,034 Income from discontinued operations — — — 206 Operating Segments (In thousands) Coal Royalty and Other Soda Ash Corporate and Financing Total Nine Months Ended September 30, 2018 Revenues $ 152,150 $ 34,986 $ — $ 187,136 Gain on asset sales and disposals 819 — — 819 Operating and maintenance expenses 21,122 — — 21,122 Depreciation, depletion and amortization 15,364 — — 15,364 General and administrative expenses — — 10,782 10,782 Asset impairments 242 — — 242 Other expenses, net — — 53,177 53,177 Net income (loss) from continuing operations 116,241 34,986 (63,959 ) 87,268 Income from discontinued operations — — — 3,721 As of September 30, 2019 Total assets of continuing operations $ 969,425 $ 258,063 $ 15,428 $ 1,242,916 Total assets of discontinued operations — — — 988 As of December 31, 2018 Total assets of continuing operations $ 986,680 $ 247,051 $ 106,923 $ 1,340,654 Total assets of discontinued operations — — — 993

Equity Investment

Equity Investment	9 Months Ended
	Sep. 30, 2019
Equity Method Investments and Joint Ventures [Abstract]
Equity Investment	Equity Investment The Partnership accounts for its 49% investment in Ciner Wyoming using the equity method of accounting. Activity related to this investment is as follows: Three Months Ended Nine Months Ended (In thousands) 2019 2018 2019 2018 Balance at beginning of period $ 251,135 $ 245,524 $ 247,051 $ 245,433 Income allocation to NRP’s equity interests 15,068 10,036 40,511 38,525 Amortization of basis difference (1,250 ) (1,200 ) (3,678 ) (3,539 ) Comprehensive income (loss) from unconsolidated investment (520 ) 791 (341 ) (768 ) Distribution (6,370 ) (12,250 ) (25,480 ) (36,750 ) Balance at end of period $ 258,063 $ 242,901 $ 258,063 $ 242,901 The following table represents summarized financial information for Ciner Wyoming as derived from their unaudited financial statements: Three Months Ended Nine Months Ended (In thousands) 2019 2018 2019 2018 Sales $ 137,148 $ 123,366 $ 397,378 $ 354,467 Gross profit 36,747 26,253 103,382 68,497 Net income 30,750 20,481 82,675 78,623

Mineral Rights, Net

Mineral Rights, Net	9 Months Ended
	Sep. 30, 2019
Extractive Industries [Abstract]
Mineral Rights, Net	Mineral Rights, Net The Partnership’s mineral rights consist of the following: September 30, 2019 December 31, 2018 (In thousands) Cost Accumulated Depletion Net Book Value Cost Accumulated Depletion Net Book Value Coal properties $ 1,147,692 $ (459,122 ) $ 688,570 $ 1,164,845 $ (451,210 ) $ 713,635 Aggregates properties 41,589 (13,132 ) 28,457 24,920 (11,814 ) 13,106 Oil and gas royalty properties 12,395 (7,823 ) 4,572 12,395 (7,632 ) 4,763 Other 13,156 (1,601 ) 11,555 13,158 (1,550 ) 11,608 Total mineral rights, net $ 1,214,832 $ (481,678 ) $ 733,154 $ 1,215,318 $ (472,206 ) $ 743,112 Depletion expense related to the Partnership’s mineral rights is included in depreciation, depletion and amortization on its Consolidated Statements of Comprehensive Income and totaled $2.8 million and $3.9 million for the three months ended September 30, 2019 and 2018 , respectively, and $9.5 million and $12.8 million for the nine months ended September 30, 2019 and 2018 , respectively. During the three and nine months ended September 30, 2019, the Partnership recorded a gain of $6.1 million and $6.6 million , respectively, included in gain on asset sales and disposals on the Consolidated Statements of Comprehensive Income primarily related to the disposal of certain coal mineral rights with a $0 net book value.

Intangible Assets, Net

Intangible Assets, Net	9 Months Ended
	Sep. 30, 2019
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 LP ("Foresight Energy") 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: September 30, December 31, (In thousands) 2019 2018 Intangible assets at cost $ 81,109 $ 81,109 Less: accumulated amortization (40,648 ) (38,596 ) Total intangible assets, net $ 40,461 $ 42,513 Amortization expense included in depreciation, depletion and amortization on the Partnership's Consolidated Statements of Comprehensive Income was $0.5 million and $0.9 million for the three months ended September 30, 2019 and 2018 , respectively and $2.1 million and $2.3 million for the nine months ended September 30, 2019 and 2018 , respectively.

Debt, Net

Debt, Net	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Debt, Net	Debt, Net The Partnership's debt consists of the following: September 30, December 31, (In thousands) 2019 2018 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 $ — 10.500% senior notes, with semi-annual interest payments in March and September, due March 2022, $241 million issued at par and $105 million issued at 98.75% ("2022 Senior Notes") — 345,638 Opco debt: Revolving credit facility $ — $ — Senior Notes 8.38% with semi-annual interest payments in March and September, with annual principal payments in March, due March 2019 $ — $ 21,319 5.05% with semi-annual interest payments in January and July, with annual principal payments in July, due July 2020 6,780 15,290 5.55% with semi-annual interest payments in June and December, with annual principal payments in June, due June 2023 9,458 13,414 4.73% with semi-annual interest payments in June and December, with annual principal payments in December, due December 2023 30,019 37,195 5.82% with semi-annual interest payments in March and September, with annual principal payments in March, due March 2024 63,423 89,529 8.92% with semi-annual interest payments in March and September, with annual principal payments in March, due March 2024 20,059 27,185 5.03% with semi-annual interest payments in June and December, with annual principal payments in December, due December 2026 91,365 107,013 5.18% with semi-annual interest payments in June and December, with annual principal payments in December, due December 2026 23,286 30,555 Total Opco Senior Notes $ 244,390 $ 341,500 Total debt at face value $ 544,390 $ 687,138 Net unamortized debt discount — (1,266 ) Net unamortized debt issuance costs (8,223 ) (13,114 ) Total debt, net $ 536,167 $ 672,758 Less: current portion of long-term debt (45,789 ) (115,184 ) Total long-term debt, net $ 490,378 $ 557,574 NRP LP Debt 2025 Senior Notes In April 2019, NRP and NRP Finance issued the 2025 Senior Notes and used the $300 million proceeds and $76 million of cash on hand to fund the redemption of the 2022 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 beginning December 30, 2019. 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. Furthermore, before October 30, 2021, NRP may on any one or more occasions redeem up to 35% of the aggregate principal amount of the 2025 Senior Notes with the net proceeds of certain public or private equity offerings at a redemption price of 109.125% of the principal amount of 2025 Senior Notes, plus any accrued and unpaid interest, if any, to the date of redemption, if at least 65% of the aggregate principal amount of the 2025 Senior Notes issued under the 2025 Indenture remains outstanding immediately after such redemption and the redemption occurs within 180 days of the closing date of such equity offering. 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 September 30, 2019 , NRP and NRP Finance were in compliance with the terms of the Indenture relating to their 2025 Senior Notes. 2022 Senior Notes During the second quarter of 2019, the Partnership redeemed the 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. 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 NRP Trona LLC. As of September 30, 2019 and December 31, 2018 , Opco was in compliance with the terms of the financial covenants contained in its debt agreements. Opco Credit Facility In April 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 . 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 4.0 x; 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 4.0 x to 3.0 x; 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. As of September 30, 2019 , the Partnership did not have any borrowings outstanding under the Opco Credit Facility and had $100 million in available borrowing capacity. The weighted average interest rates for the borrowings outstanding under the Opco Credit Facility during the three and nine months ended September 30, 2018 were 6.34% and 6.18% , respectively. There were no borrowings outstanding under the Opco Credit Facility during the three and nine months ended September 30, 2019 . The Opco Credit Facility is collateralized and secured by liens on certain of Opco’s assets with carrying values of $541.5 million and $548.9 million classified as mineral rights, net and plant and equipment, net on the Partnership’s Consolidated Balance Sheets as of September 30, 2019 and December 31, 2018 , respectively. Opco Senior Notes As of September 30, 2019 and December 31, 2018 , the Opco Senior Notes had cumulative principal balances of $244.4 million and $341.5 million , respectively. Opco made mandatory principal payments of $97.1 million , which included a $49.3 million pre-payment as a result of the sale of the Partnership's construction aggregates business, during the nine months ended September 30, 2019 , and $55.7 million during the nine months ended September 30, 2018 . 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 September 30, 2019 .

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2019
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, restricted cash, contract receivable and debt. The carrying amounts reported on the Consolidated Balance Sheets for cash and cash equivalents and restricted cash approximate fair value due to their short-term nature. There were no transfers between Level 1, Level 2 or Level 3 of the fair value hierarchy during the three and nine months ended September 30, 2019 or 2018 . 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 amount and estimated fair value of the Partnership's debt and contract receivable: September 30, 2019 December 31, 2018 (In thousands) Fair Value Hierarchy Level Carrying Estimated Carrying Estimated Debt: NRP 2025 Senior Notes 1 $ 293,824 $ 287,250 $ — $ — NRP 2022 Senior Notes 1 — — 334,024 356,871 Opco Senior Notes 3 242,343 234,003 338,734 352,599 Opco Credit Facility 3 — — — — Assets: Contract receivable (current and long-term) 3 $ 39,416 $ 33,784 $ 40,776 $ 34,704 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 expense, net on the Partnership's Consolidated Statements of Comprehensive Income. The embedded derivatives had zero value as of September 30, 2019 and December 31, 2018 .

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2019
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. NRP also reimburses overhead costs incurred by its affiliates 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 on the Partnership's Consolidated Statements of Comprehensive Income. Direct general and administrative expenses charged to the Partnership by QMC and WPPLP are included in the Partnership's Consolidated Statement of Comprehensive Income as follows: Three Months Ended Nine Months Ended (In thousands) 2019 2018 2019 2018 Operating and maintenance expenses $ 1,598 $ 1,560 $ 4,806 $ 4,694 General and administrative expenses 855 934 2,704 2,714 The Partnership had accounts payable to QMC of $0.4 million and $0.5 million on its Consolidated Balance Sheets as of September 30, 2019 and December 31, 2018 , respectively. During the three months ended September 30, 2019 and 2018 , the Partnership recognized $0.3 million and $0.6 million in operating and maintenance expenses, respectively, on its Consolidated Statements of Comprehensive Income related to an overriding royalty agreement with WPPLP. These amounts were $3.8 million and $3.5 million during the nine months ended September 30, 2019 and 2018 , respectively. At September 30, 2019 , the Partnership had $0.1 million of other assets on its Consolidated Balance Sheets related to a prepaid royalty for this agreement and at December 31, 2018 the Partnership had $1.4 million of accounts payable to WPPLP for this agreement. Quintana Capital Group GP, Ltd. Corbin J. Robertson, Jr. is a principal in Quintana Capital Group GP, Ltd. ("Quintana Capital"), which controls several private equity funds focused on investments in the energy business. In connection with the formation of Quintana Capital, the Partnership adopted a formal conflicts policy that establishes the opportunities that will be pursued by the Partnership and those that will be pursued by Quintana Capital. The governance documents of Quintana Capital’s affiliated investment funds reflect the guidelines set forth in the Partnership's conflicts policy. At September 30, 2019 , a fund controlled by Quintana Capital owned a substantial interest in Corsa Coal Corp. ("Corsa"), a coal mining company traded on the TSX Venture Exchange that was one of the Partnership’s lessees in Tennessee. During the second quarter of 2018, Corsa assigned its lease with NRP to a third party and is no longer deemed a related party as of such date. Coal related revenues from Corsa totaled $0.4 million for the nine months ended September 30, 2018 . Industrial Minerals Group LLC Corbin J. Robertson, III, a Director of GP Natural Resource Partners LLC, owns a minority ownership interest in Industrial Minerals Group LLC (“Industrial Minerals”), which, through its subsidiaries, leases two of NRP's coal royalty properties in Central Appalachia. Coal royalty related revenues from Industrial Minerals totaled $0.4 million and $0.2 million for the three months ended September 30, 2019 and 2018 , respectively and $0.9 million and $0.6 million for the nine months ended September 30, 2019 and 2018 , respectively. The Partnership had accounts receivable from Industrial Minerals of $0.2 million and $0.1 million on its Consolidated Balance Sheets as of September 30, 2019 and December 31, 2018 , respectively.

Major Customers

Major Customers	9 Months Ended
	Sep. 30, 2019
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: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (In thousands) Revenues Percent Revenues Percent Revenues Percent Revenues Percent Foresight Energy (1) $ 12,375 21 % $ 15,035 26 % $ 44,604 22 % $ 40,456 22 % Contura Energy (1) (2) 9,190 16 % 4,709 8 % 32,915 16 % 16,091 9 % (1) Revenues from Foresight Energy and Contura Energy are included within the Partnership's Coal Royalty and Other segment. (2) In the fourth quarter of 2018, Contura Energy and Alpha Natural Resources merged. Revenues during the three and nine months ended September 30, 2019 relate to the combined company, while revenues during the three and nine months ended September 30, 2018 do not include revenues from Alpha Natural Resources.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2019
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. During the third quarter, NRP was also involved in the matters described below. Anadarko Contingent Consideration Payment Dispute In January 2013, NRP acquired a non-controlling 48.51% general partner interest in OCI Wyoming, L.P. ("OCI LP") and all of the preferred stock and a portion of the common stock of OCI Wyoming Co. ("OCI Co") (which in turn owned a 1% limited partner interest in OCI LP) from Anadarko Holding Company and its subsidiary, Big Island Trona Company (together, "Anadarko"). The remaining general partner interest in OCI LP and common stock of OCI Co were owned by subsidiaries of OCI Chemical Corporation. The acquisition agreement provided for additional contingent consideration of up to $50 million to be paid by NRP if certain performance criteria were met at OCI LP as defined in the purchase and sale agreement in any of the years 2013, 2014 or 2015. For those years, NRP paid an aggregate of $11.5 million to Anadarko in full satisfaction of these contingent consideration payment obligations. In July 2013, pursuant to a series of transactions in connection with an initial public offering by a subsidiary of OCI Chemical Corporation, the ownership structure in OCI LP was simplified. In connection with such reorganization, NRP exchanged the stock of OCI Co for a limited partner interest in OCI LP. Following the reorganization, NRP's interest in OCI LP remained at 49% , consisting of both limited and general partner interests. The restructuring did not have any impact on the operations, revenues, management or control of OCI LP. In July 2017, Anadarko filed a lawsuit against Opco and NRP Trona LLC in the District Court of Harris County, Texas, 157th judicial district. The complaint alleged that the transactions conducted in 2013 triggered an acceleration of NRP's obligation under the purchase agreement with Anadarko to pay additional contingent consideration in full and demanded immediate payment of such amount, together with interest, court costs and attorneys’ fees. NRP does not believe the reorganization transactions triggered an obligation to pay any additional contingent consideration and is vigorously defending this lawsuit. However, the ultimate outcome cannot be predicted with certainty and the Partnership estimates a possible range of loss between $0 , if it prevails, and approximately $40 million plus interest, court costs and attorneys’ fees if Anadarko prevails and is awarded the full damages it seeks. A trial in this matter was held in October 2019. The parties are currently awaiting a ruling by the trial court.

Unit-Based Compensation

Unit-Based Compensation	9 Months Ended
	Sep. 30, 2019
Unit-Based Compensation [Abstract]
Unit-Based Compensation	Unit-Based Compensation The Partnership's unit-based awards granted in 2019 and 2018 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 nine months ended September 30, 2019 and 2018 were $5.4 million and $2.2 million , respectively. Total unit-based compensation expense associated with these awards was $0.5 million and $0.2 million for the three months ended September 30, 2019 and 2018 , respectively, and $1.8 million and $0.9 million for the nine months ended September 30, 2019 and 2018 , respectively and is included in general and administrative expenses and operating and maintenance expenses on the Partnership's Consolidated Statements of Comprehensive Income. The unamortized cost associated with unvested outstanding awards as of September 30, 2019 is $4.0 million , which is to be recognized over a weighted average period of 2.2 years . The unamortized cost associated with unvested outstanding awards as of December 31, 2018 was $1.2 million . A summary of the unit activity in the outstanding grants during 2019 is as follows: (In thousands) Common Units Weighted Average Exercise Price Outstanding at January 1, 2019 55 $ 29.10 Granted 129 $ 41.41 Fully vested and issued (12 ) $ 41.47 Forfeitures (15 ) $ 37.33 Outstanding at September 30, 2019 157 $ 37.48

Financing Transaction

Financing Transaction	9 Months Ended
	Sep. 30, 2019
Financing Transaction [Abstract]
Financing Transaction	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 Energy. The infrastructure at the Sugar Camp mine is leased to a subsidiary of Foresight Energy 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 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. The following table shows certain amounts related to the Partnership's Sugar Camp lease: (In thousands) September 30, 2019 December 31, 2018 Accounts receivable $ 347 $ 661 Contract receivable (current and long-term) 39,416 40,776 Unearned income 22,667 25,058 Projected remaining payments $ 62,430 $ 66,495

Leases

Leases	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Leases	Leases Lessee Accounting As of September 30, 2019 , 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 September 30, 2019 , 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 Sheet 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 assets and other non-current liabilities, respectively, on its Consolidated Balance Sheet totaled $3.5 million at both January 1, 2019 and September 30, 2019 . During the three and nine months ended September 30, 2019 , the Partnership incurred total operating lease expenses of $0.1 million and $0.4 million , respectively, included in both operating and maintenance expenses and general and administrative expenses on its Consolidated Statement of Comprehensive Income. 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) As of September 30, 2019 2019 $ 121 2020 483 2021 483 2022 483 2023 483 After 2023 12,079 Total lease payments (1) $ 14,132 Less: present value adjustment (2) (10,623 ) Total operating lease liability $ 3,509 (1) The remaining lease term of the Partnership's operating lease is 29.25 years. (2) The present value of the operating lease liability on the Partnership's Consolidated Balance Sheet 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. Lessor Accounting The Partnership owns loadout and other transportation assets at the Partnership's Macoupin property in the Illinois Basin which is operated by Foresight Energy. The infrastructure at the Macoupin property is leased to a subsidiary of Foresight Energy and is accounted for as an operating lease under ASC 842. The lease with Macoupin expires in January 2108. From the inception of this lease in 2009 through January 2039, the lease provides that the Partnership is entitled to variable lease payments in the form of throughput fees determined based on the amount of coal transported and processed utilizing the Partnership's assets. These fees are included in transportation and processing services revenues on the Partnership's Consolidated Statements of Comprehensive Income and were $1.1 million and $1.4 million in the three months ended September 30, 2019 and 2018 , respectively, and $3.6 million and $3.5 million in the nine months ended September 30, 2019 and 2018 , respectively. After January 2039, the lease provides that the Partnership is entitled to an annual rent of $10 thousand per year in place of the variable lease payments. 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) As of September 30, 2019 2019 $ 121 2020 483 2021 483 2022 483 2023 483 After 2023 12,079 Total lease payments (1) $ 14,132 Less: present value adjustment (2) (10,623 ) Total operating lease liability $ 3,509 (1) The remaining lease term of the Partnership's operating lease is 29.25 years. (2) The present value of the operating lease liability on the Partnership's Consolidated Balance Sheet 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 Lessee Accounting As of September 30, 2019 , 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 September 30, 2019 , 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 Sheet 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 assets and other non-current liabilities, respectively, on its Consolidated Balance Sheet totaled $3.5 million at both January 1, 2019 and September 30, 2019 . During the three and nine months ended September 30, 2019 , the Partnership incurred total operating lease expenses of $0.1 million and $0.4 million , respectively, included in both operating and maintenance expenses and general and administrative expenses on its Consolidated Statement of Comprehensive Income. 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) As of September 30, 2019 2019 $ 121 2020 483 2021 483 2022 483 2023 483 After 2023 12,079 Total lease payments (1) $ 14,132 Less: present value adjustment (2) (10,623 ) Total operating lease liability $ 3,509 (1) The remaining lease term of the Partnership's operating lease is 29.25 years. (2) The present value of the operating lease liability on the Partnership's Consolidated Balance Sheet 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. Lessor Accounting The Partnership owns loadout and other transportation assets at the Partnership's Macoupin property in the Illinois Basin which is operated by Foresight Energy. The infrastructure at the Macoupin property is leased to a subsidiary of Foresight Energy and is accounted for as an operating lease under ASC 842. The lease with Macoupin expires in January 2108. From the inception of this lease in 2009 through January 2039, the lease provides that the Partnership is entitled to variable lease payments in the form of throughput fees determined based on the amount of coal transported and processed utilizing the Partnership's assets. These fees are included in transportation and processing services revenues on the Partnership's Consolidated Statements of Comprehensive Income and were $1.1 million and $1.4 million in the three months ended September 30, 2019 and 2018 , respectively, and $3.6 million and $3.5 million in the nine months ended September 30, 2019 and 2018 , respectively. After January 2039, the lease provides that the Partnership is entitled to an annual rent of $10 thousand per year in place of the variable lease payments.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events The following represents material events that have occurred subsequent to September 30, 2019 through the time of the Partnership’s filing of its Quarterly Report on Form 10-Q with the SEC: Distributions Declared In October 2019, the Board of Directors declared a distribution of $0.45 per common unit with respect to the third quarter of 2019. The Board of Directors also declared a cash distribution on NRP's Preferred Units with respect to the third quarter of 2019 totaling $7.5 million .

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Principles of Consolidation Reporting	Principles of Consolidation and Reporting The accompanying unaudited consolidated financial statements of the Partnership have been prepared in accordance with generally accepted accounting principles in the United States of America ("GAAP") for interim financial information and with Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. These financial statements should be read in conjunction with the financial statements for the year ended December 31, 2018 and notes thereto included in the Partnership's Annual Report on Form 10-K, which was filed with the SEC on March 7, 2019. In management's opinion, all necessary adjustments to fairly present the Partnership's results of operations, financial position and cash flows for the periods presented have been made and all such adjustments were of a normal and recurring nature. Certain reclassifications have been made to prior period amounts on the Consolidated Balance Sheets, Consolidated Statements of Comprehensive Income and Consolidated Statements of Cash Flows to conform with current period presentation. These reclassifications had no impact on previously reported total assets, total liabilities, partners' capital, net income or cash flows from operating, investing or financing activities.
Recasting of Certain Prior Period Information	Recasting of Certain Prior Period Information As described in Note 3. Discontinued Operations , the Partnership reclassified prior period information for the assets and liabilities, operating results and cash flows of its construction aggregates business as discontinued operations in its consolidated financial statements for all periods presented.
Recently Issued Accounting Standards	Recently Adopted Accounting Standards Leases On January 1, 2019, NRP adopted Accounting Standards Codification (ASC) 842, Leases, and all the related amendments (the “new lease standard” and "ASC 842") and recognized assets and liabilities on its Consolidated Balance Sheet for the present value of the rights and obligations created by all leases with terms of more than 12 months. This standard does not apply to leases that explore for or use minerals, oil, natural gas and similar non-regenerative resources, including the intangible right to explore for those natural resources and rights to use the land in which those natural resources are contained. The guidance also required disclosures designed to give financial statement users information on the amount, timing and uncertainty of cash flows arising from leases. The guidance was adopted by NRP on January 1, 2019 using a modified retrospective approach. The Partnership is a lessee in one lease that is accounted for as an operating lease under the new lease standard, and the adoption of the new lease standard did not have a material impact to the Partnership's consolidated financial statements. For lease agreements entered into or reassessed after the adoption of ASC 842, the Partnership elected to not combine lease and non-lease components. See Note 17. Leases for more information. Recently Issued Accounting Standards Credit Losses In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326). The new standard changes how entities will measure credit losses for most financial assets and certain other instruments that are not measured at fair value through net income. The new standard replaces today's "incurred loss" model with an "expected credit loss" model that requires entities to estimate an expected lifetime credit loss on financial assets, including trade accounts receivable. The guidance is effective for annual and interim periods beginning after December 15, 2019 and is to be adopted using a modified retrospective approach. The Partnership is continuing to evaluate the provisions of this guidance on its consolidated financial statements, but based on its analysis to date, the Partnership does not expect this standard to have a material effect on its consolidated financial statements.

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	9 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers by Source	The following table represents the Partnership's Coal Royalty and Other segment revenues by major source: Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2019 2018 2019 2018 Coal royalty revenues $ 24,727 $ 30,709 $ 87,561 $ 96,473 Production lease minimum revenues 2,752 1,769 21,331 6,310 Minimum lease straight-line revenues 3,982 567 11,152 1,739 Property tax revenues 1,606 1,263 4,416 3,968 Wheelage revenues 1,675 1,572 5,035 5,155 Coal overriding royalty revenues 2,189 3,918 10,163 10,492 Lease amendment revenues 1,535 — 6,720 — Aggregates royalty revenues 954 888 3,655 3,551 Oil and gas royalty revenues 374 1,427 2,575 5,679 Other revenues 125 405 1,429 1,545 Coal royalty and other revenues (1) $ 39,919 $ 42,518 $ 154,037 $ 134,912 Transportation and processing services revenues (2) 3,865 6,853 14,740 17,238 Total Coal Royalty and Other segment revenues $ 43,784 $ 49,371 $ 168,777 $ 152,150 (1) Coal royalty and other revenues from contracts with customers as defined under ASC 606. (2) Transportation and processing services revenues from contracts with customers as defined under ASC 606 was $1.7 million and $3.6 million for the three months ended September 30, 2019 and 2018 , respectively, and $7.3 million and $9.6 million for the nine months ended September 30, 2019 and 2018 , respectively. The remaining transportation and processing services revenues of $2.2 million and $3.3 million for the three months ended September 30, 2019 , and 2018 , respectively, and $7.5 million and $7.6 million for the nine months ended September 30, 2019 and 2018 , respectively, related to other NRP-owned infrastructure leased to and operated by third party operators accounted for under other guidance. See Note 16. Financing Transaction and Note 17. Leases for more information.
Schedule of Receivables and Liabilities from Contracts with Customers	The following table details the Partnership's Coal Royalty and Other segment receivables and liabilities resulting from contracts with customers: September 30, December 31, (In thousands) 2019 2018 Receivables Accounts receivable, net $ 24,758 $ 29,001 Prepaid expenses and other (1) 2,852 2,483 Contract liabilities Current portion of deferred revenue $ 5,047 $ 3,509 Deferred revenue 43,587 49,044 (1) Prepaid expenses and other includes notes receivable from contracts with customers.
Activity Related to Coal Royalty and Other Segment Deferred Revenue	The following table shows the activity related to the Partnership's Coal Royalty and Other segment deferred revenue: Nine Months Ended September 30, (In thousands) 2019 2018 Balance at end of prior period (current and non-current) $ 52,553 $ 100,605 Cumulative adjustment for change in accounting principle — (65,591 ) Balance at beginning of period (current and non-current) $ 52,553 $ 35,014 Increase due to minimums and lease amendment fees 37,315 23,534 Recognition of previously deferred revenue (41,234 ) (16,260 ) Balance at end of period (current and non-current) $ 48,634 $ 42,288
Schedule of Annual Minimums by Current Remaining Contract Term	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 (in thousands): Lease Term (1) Weighted Average Remaining Years as of September 30, 2019 Annual Minimum Payments (2) 0 - 5 years 2.2 $ 12,439 5 - 10 years 6.4 9,426 10+ years 12.1 46,737 Total 9.6 $ 68,602 (1) Lease term does not include renewal periods. (2) Annual minimum payments do not include $5.0 million from a coal infrastructure lease that is accounted for as a financing transaction. See Note 16. Financing Transaction for additional information.

Discontinued Operations (Tables

Discontinued Operations (Tables)	9 Months Ended
	Sep. 30, 2019
Discontinued Operations [Abstract]
Financial Results of Discontinued Operations	The following table presents the carrying amounts of the Partnership's assets and liabilities of discontinued operations in the Consolidated Balance Sheets: September 30, 2019 December 31, 2018 (In thousands) Construction Aggregates NRP Total Construction Aggregates NRP Total ASSETS Current assets Accounts receivable, net $ — $ 988 $ 988 $ 5 $ 988 $ 993 Total assets of discontinued operations $ — $ 988 $ 988 $ 5 $ 988 $ 993 LIABILITIES Current liabilities Accounts payable $ 42 $ — $ 42 $ 181 $ — $ 181 Accrued liabilities 132 — 132 766 — 766 Total liabilities of discontinued operations $ 174 $ — $ 174 $ 947 $ — $ 947 The following tables present summarized financial results of the Partnership's discontinued operations in the Consolidated Statements of Comprehensive Income: Three Months Ended September 30, 2019 2018 (In thousands) Construction Aggregates NRP Total Construction Aggregates NRP Oil and Gas Total Revenues and other income Construction aggregates $ — $ — $ — $ 30,398 $ — $ 30,398 Road construction and asphalt paving services — — — 6,250 — 6,250 Oil and gas — 2 2 — (1 ) (1 ) Gain on asset sales and disposals 5 — 5 163 — 163 Total revenues and other income $ 5 $ 2 $ 7 $ 36,811 $ (1 ) $ 36,810 Operating expenses Operating and maintenance expenses $ — $ — $ — $ 30,758 $ 23 $ 30,781 Depreciation, depletion and amortization — — — 3,333 — 3,333 Total operating expenses $ — $ — $ — $ 34,091 $ 23 $ 34,114 Interest expense — — — (8 ) — (8 ) Income (loss) from discontinued operations $ 5 $ 2 $ 7 $ 2,712 $ (24 ) $ 2,688 Nine Months Ended September 30, 2019 2018 (In thousands) Construction Aggregates NRP Total Construction Aggregates NRP Oil and Gas Total Revenues and other income Construction aggregates $ — $ — $ — $ 91,055 $ — $ 91,055 Road construction and asphalt paving services — — — 13,154 — 13,154 Oil and gas — 2 2 — (3 ) (3 ) Gain on asset sales and disposals 243 — 243 214 — 214 Total revenues and other income $ 243 $ 2 $ 245 $ 104,423 $ (3 ) $ 104,420 Operating expenses Operating and maintenance expenses $ 27 $ 12 $ 39 $ 91,225 $ 69 $ 91,294 Depreciation, depletion and amortization — — — 9,377 — 9,377 Total operating expenses $ 27 $ 12 $ 39 $ 100,602 $ 69 $ 100,671 Interest expense — — — (28 ) — (28 ) Income (loss) from discontinued operations $ 216 $ (10 ) $ 206 $ 3,793 $ (72 ) $ 3,721

Common and Preferred Unit Dis_2

Common and Preferred Unit Distributions (Tables)	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Distributions declared and paid	The following table shows the distributions declared and paid to common and preferred unitholders during the nine months ended September 30, 2019 and 2018 , respectively: Common Units Preferred Units Date Paid Period Covered by Distribution Distribution per Unit Total Distribution (1) (In thousands) Distribution per Unit Total Distribution (In thousands) 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 (2) Special Distribution 0.85 10,635 — — August 2019 April 1 - June 30, 2019 0.45 5,630 30.00 7,500 2018 February 2018 October 1 - December 31, 2017 $ 0.45 $ 5,617 $ 30.00 $ 7,765 May 2018 January 1 - March 31, 2018 0.45 5,623 30.00 7,500 August 2018 April 1 - June 30, 2018 0.45 5,623 30.00 7,500 (1) Totals include the amount paid to NRP's general partner in accordance with the general partner's 2% general partner interest. (2) The special distribution of $0.85 per common unit was made to cover the common unitholders’ tax liability resulting from the sale of NRP’s construction aggregates business in December 2018.

Net Income Per Common Unit (Tab

Net Income Per Common Unit (Tables)	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Reconciliation of Net Income to Weighted Average Units Outstanding	The following table reconciles the numerator and denominator of the basic and diluted net income per common unit computations and calculates basic and diluted net income per common unit: Three Months Ended Nine Months Ended (In thousands, except per unit data) 2019 2018 2019 2018 Allocation of net income Net income from continuing operations $ 39,163 $ 25,853 $ 94,034 $ 87,268 Add (less): net loss (income) attributable to non-controlling interest — 359 — (510 ) Less: income attributable to preferred unitholders (7,500 ) (7,500 ) (22,500 ) (22,500 ) Net income from continuing operations attributable to common unitholders and general partner $ 31,663 $ 18,712 $ 71,534 $ 64,258 Less: net income from continuing operations attributable to the general partner (634 ) (374 ) (1,431 ) (1,285 ) Net income from continuing operations attributable to common unitholders $ 31,029 $ 18,338 $ 70,103 $ 62,973 Net income from discontinued operations $ 7 $ 2,688 $ 206 $ 3,721 Less: net income from discontinued operations attributable to the general partner 0 (54 ) (4 ) (75 ) Net income from discontinued operations attributable to common unitholders $ 7 $ 2,634 $ 202 $ 3,646 Net income $ 39,170 $ 28,541 $ 94,240 $ 90,989 Add (less): net loss (income) attributable to non-controlling interest — 359 — (510 ) Less: income attributable to preferred unitholders (7,500 ) (7,500 ) (22,500 ) (22,500 ) Net income attributable to common unitholders and general partner $ 31,670 $ 21,400 $ 71,740 $ 67,979 Less: net income attributable to the general partner (634 ) (428 ) (1,435 ) (1,360 ) Net income attributable to common unitholders $ 31,036 $ 20,972 $ 70,305 $ 66,619 Basic net income per common unit Weighted average common units—basic 12,261 12,246 12,259 12,243 Basic net income from continuing operations per common unit $ 2.53 $ 1.50 $ 5.72 $ 5.14 Basic net income from discontinued operations per common unit $ 0.00 $ 0.22 $ 0.02 $ 0.30 Basic net income per common unit $ 2.53 $ 1.71 $ 5.73 $ 5.44 Three Months Ended Nine Months Ended (In thousands, except per unit data) 2019 2018 2019 2018 Diluted income per common unit Weighted average common units—basic 12,261 12,246 12,259 12,243 Plus: dilutive effect of Preferred Units 10,494 9,124 10,494 9,124 Plus: dilutive effect of Warrants 389 470 800 474 Plus: dilutive effect of unvested unit-based awards 13 — 31 — Weighted average common units—diluted 23,157 21,840 23,584 21,841 Net income from continuing operations $ 39,163 $ 25,853 $ 94,034 $ 87,268 Add (less): net loss (income) attributable to non-controlling interest — 359 — (510 ) Diluted net income from continuing operations attributable to common unitholders and general partner $ 39,163 $ 26,212 $ 94,034 $ 86,758 Less: diluted net income from continuing operations attributable to the general partner (784 ) (524 ) (1,881 ) (1,735 ) Diluted net income from continuing operations attributable to common unitholders $ 38,379 $ 25,688 $ 92,153 $ 85,023 Diluted net income from discontinued operations attributable to common unitholders $ 7 $ 2,634 $ 202 $ 3,646 Net income $ 39,170 $ 28,541 $ 94,240 $ 90,989 Add (less): net loss (income) attributable to non-controlling interest — 359 — (510 ) Diluted net income attributable to common unitholders and general partner $ 39,170 $ 28,900 $ 94,240 $ 90,479 Less: diluted net income attributable to the general partner (784 ) (578 ) (1,885 ) (1,810 ) Diluted net income attributable to common unitholders $ 38,386 $ 28,322 $ 92,355 $ 88,669 Diluted net income from continuing operations per common unit $ 1.66 $ 1.18 $ 3.91 $ 3.89 Diluted net income from discontinued operations per common unit $ 0.00 $ 0.12 $ 0.01 $ 0.17 Diluted net income per common unit $ 1.66 $ 1.30 $ 3.92 $ 4.06

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2019
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) Coal Royalty and Other Soda Ash Corporate and Financing Total Three Months Ended September 30, 2019 Revenues $ 43,784 $ 13,818 $ — $ 57,602 Gain on asset sales and disposals 6,107 — — 6,107 Operating and maintenance expenses 5,771 223 — 5,994 Depreciation, depletion and amortization 3,384 — — 3,384 General and administrative expenses — — 4,253 4,253 Asset impairments 484 — — 484 Other expenses, net — — 10,431 10,431 Net income (loss) from continuing operations 40,252 13,595 (14,684 ) 39,163 Income from discontinued operations — — — 7 Three Months Ended September 30, 2018 Revenues $ 49,371 $ 8,836 $ — $ 58,207 Operating and maintenance expenses 6,790 — — 6,790 Depreciation, depletion and amortization 4,888 — — 4,888 General and administrative expenses — — 3,183 3,183 Other expenses, net — — 17,493 17,493 Net income (loss) from continuing operations 37,693 8,836 (20,676 ) 25,853 Income from discontinued operations — — — 2,688 Nine Months Ended September 30, 2019 Revenues $ 168,777 $ 36,833 $ — $ 205,610 Gain on asset sales and disposals 6,609 — — 6,609 Operating and maintenance expenses 26,590 223 — 26,813 Depreciation, depletion and amortization 11,746 — — 11,746 General and administrative expenses — — 12,799 12,799 Asset impairments 484 — — 484 Other expenses, net — — 66,343 66,343 Net income (loss) from continuing operations 136,566 36,610 (79,142 ) 94,034 Income from discontinued operations — — — 206 Operating Segments (In thousands) Coal Royalty and Other Soda Ash Corporate and Financing Total Nine Months Ended September 30, 2018 Revenues $ 152,150 $ 34,986 $ — $ 187,136 Gain on asset sales and disposals 819 — — 819 Operating and maintenance expenses 21,122 — — 21,122 Depreciation, depletion and amortization 15,364 — — 15,364 General and administrative expenses — — 10,782 10,782 Asset impairments 242 — — 242 Other expenses, net — — 53,177 53,177 Net income (loss) from continuing operations 116,241 34,986 (63,959 ) 87,268 Income from discontinued operations — — — 3,721 As of September 30, 2019 Total assets of continuing operations $ 969,425 $ 258,063 $ 15,428 $ 1,242,916 Total assets of discontinued operations — — — 988 As of December 31, 2018 Total assets of continuing operations $ 986,680 $ 247,051 $ 106,923 $ 1,340,654 Total assets of discontinued operations — — — 993

Equity Investment (Tables)

Equity Investment (Tables)	9 Months Ended
	Sep. 30, 2019
Equity Method Investments and Joint Ventures [Abstract]
Schedule of Summarized Financial Information	Activity related to this investment is as follows: Three Months Ended Nine Months Ended (In thousands) 2019 2018 2019 2018 Balance at beginning of period $ 251,135 $ 245,524 $ 247,051 $ 245,433 Income allocation to NRP’s equity interests 15,068 10,036 40,511 38,525 Amortization of basis difference (1,250 ) (1,200 ) (3,678 ) (3,539 ) Comprehensive income (loss) from unconsolidated investment (520 ) 791 (341 ) (768 ) Distribution (6,370 ) (12,250 ) (25,480 ) (36,750 ) Balance at end of period $ 258,063 $ 242,901 $ 258,063 $ 242,901 The following table represents summarized financial information for Ciner Wyoming as derived from their unaudited financial statements: Three Months Ended Nine Months Ended (In thousands) 2019 2018 2019 2018 Sales $ 137,148 $ 123,366 $ 397,378 $ 354,467 Gross profit 36,747 26,253 103,382 68,497 Net income 30,750 20,481 82,675 78,623

Mineral Rights, Net (Tables)

Mineral Rights, Net (Tables)	9 Months Ended
	Sep. 30, 2019
Extractive Industries [Abstract]
Mineral Rights	The Partnership’s mineral rights consist of the following: September 30, 2019 December 31, 2018 (In thousands) Cost Accumulated Depletion Net Book Value Cost Accumulated Depletion Net Book Value Coal properties $ 1,147,692 $ (459,122 ) $ 688,570 $ 1,164,845 $ (451,210 ) $ 713,635 Aggregates properties 41,589 (13,132 ) 28,457 24,920 (11,814 ) 13,106 Oil and gas royalty properties 12,395 (7,823 ) 4,572 12,395 (7,632 ) 4,763 Other 13,156 (1,601 ) 11,555 13,158 (1,550 ) 11,608 Total mineral rights, net $ 1,214,832 $ (481,678 ) $ 733,154 $ 1,215,318 $ (472,206 ) $ 743,112

Intangible Assets, Net (Tables)

Intangible Assets, Net (Tables)	9 Months Ended
	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Finite-Lived Intangible Assets	The Partnership's intangible assets included on its Consolidated Balance Sheets are as follows: September 30, December 31, (In thousands) 2019 2018 Intangible assets at cost $ 81,109 $ 81,109 Less: accumulated amortization (40,648 ) (38,596 ) Total intangible assets, net $ 40,461 $ 42,513

Debt, Net (Tables)

Debt, Net (Tables)	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Total Debt	The Partnership's debt consists of the following: September 30, December 31, (In thousands) 2019 2018 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 $ — 10.500% senior notes, with semi-annual interest payments in March and September, due March 2022, $241 million issued at par and $105 million issued at 98.75% ("2022 Senior Notes") — 345,638 Opco debt: Revolving credit facility $ — $ — Senior Notes 8.38% with semi-annual interest payments in March and September, with annual principal payments in March, due March 2019 $ — $ 21,319 5.05% with semi-annual interest payments in January and July, with annual principal payments in July, due July 2020 6,780 15,290 5.55% with semi-annual interest payments in June and December, with annual principal payments in June, due June 2023 9,458 13,414 4.73% with semi-annual interest payments in June and December, with annual principal payments in December, due December 2023 30,019 37,195 5.82% with semi-annual interest payments in March and September, with annual principal payments in March, due March 2024 63,423 89,529 8.92% with semi-annual interest payments in March and September, with annual principal payments in March, due March 2024 20,059 27,185 5.03% with semi-annual interest payments in June and December, with annual principal payments in December, due December 2026 91,365 107,013 5.18% with semi-annual interest payments in June and December, with annual principal payments in December, due December 2026 23,286 30,555 Total Opco Senior Notes $ 244,390 $ 341,500 Total debt at face value $ 544,390 $ 687,138 Net unamortized debt discount — (1,266 ) Net unamortized debt issuance costs (8,223 ) (13,114 ) Total debt, net $ 536,167 $ 672,758 Less: current portion of long-term debt (45,789 ) (115,184 ) Total long-term debt, net $ 490,378 $ 557,574

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Debt and Contracts Receivable	The following table shows the carrying amount and estimated fair value of the Partnership's debt and contract receivable: September 30, 2019 December 31, 2018 (In thousands) Fair Value Hierarchy Level Carrying Estimated Carrying Estimated Debt: NRP 2025 Senior Notes 1 $ 293,824 $ 287,250 $ — $ — NRP 2022 Senior Notes 1 — — 334,024 356,871 Opco Senior Notes 3 242,343 234,003 338,734 352,599 Opco Credit Facility 3 — — — — Assets: Contract receivable (current and long-term) 3 $ 39,416 $ 33,784 $ 40,776 $ 34,704

Related Party Transactions (Tab

Related Party Transactions (Tables)	9 Months Ended
	Sep. 30, 2019
Related Party Transactions [Abstract]
Summary of Reimbursements	Direct general and administrative expenses charged to the Partnership by QMC and WPPLP are included in the Partnership's Consolidated Statement of Comprehensive Income as follows: Three Months Ended Nine Months Ended (In thousands) 2019 2018 2019 2018 Operating and maintenance expenses $ 1,598 $ 1,560 $ 4,806 $ 4,694 General and administrative expenses 855 934 2,704 2,714

Major Customers (Tables)

Major Customers (Tables)	9 Months Ended
	Sep. 30, 2019
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: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (In thousands) Revenues Percent Revenues Percent Revenues Percent Revenues Percent Foresight Energy (1) $ 12,375 21 % $ 15,035 26 % $ 44,604 22 % $ 40,456 22 % Contura Energy (1) (2) 9,190 16 % 4,709 8 % 32,915 16 % 16,091 9 % (1) Revenues from Foresight Energy and Contura Energy are included within the Partnership's Coal Royalty and Other segment. (2) In the fourth quarter of 2018, Contura Energy and Alpha Natural Resources merged. Revenues during the three and nine months ended September 30, 2019 relate to the combined company, while revenues during the three and nine months ended September 30, 2018 do not include revenues from Alpha Natural Resources.

Unit-Based Compensation (Tables

Unit-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2019
Unit-Based Compensation [Abstract]
Summary of Activity in Awards	A summary of the unit activity in the outstanding grants during 2019 is as follows: (In thousands) Common Units Weighted Average Exercise Price Outstanding at January 1, 2019 55 $ 29.10 Granted 129 $ 41.41 Fully vested and issued (12 ) $ 41.47 Forfeitures (15 ) $ 37.33 Outstanding at September 30, 2019 157 $ 37.48

Financing Transaction (Tables)

Financing Transaction (Tables)	9 Months Ended
	Sep. 30, 2019
Financing Transaction [Abstract]
Financing Receivable, after Allowance for Credit Loss	The following table shows certain amounts related to the Partnership's Sugar Camp lease: (In thousands) September 30, 2019 December 31, 2018 Accounts receivable $ 347 $ 661 Contract receivable (current and long-term) 39,416 40,776 Unearned income 22,667 25,058 Projected remaining payments $ 62,430 $ 66,495

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Lessee, Operating Lease, Liability, Maturity	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) As of September 30, 2019 2019 $ 121 2020 483 2021 483 2022 483 2023 483 After 2023 12,079 Total lease payments (1) $ 14,132 Less: present value adjustment (2) (10,623 ) Total operating lease liability $ 3,509 (1) The remaining lease term of the Partnership's operating lease is 29.25 years. (2) The present value of the operating lease liability on the Partnership's Consolidated Balance Sheet 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.

Basis of Presentation - Narrati

Basis of Presentation - Narrative (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)segment	Sep. 30, 2018USD ($)	Dec. 31, 2018USD ($)	Jul. 31, 2013
Accounting Policies [Abstract]
Number of operating segments | segment	2
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash	$ 12,527		$ 104,191
Senior Notes | Opco
Restricted Cash and Cash Equivalents Items [Line Items]
Principal payments on its senior notes	$ 97,100	$ 55,700
Ciner Wyoming
Restricted Cash and Cash Equivalents Items [Line Items]
Percentage of partnership interest owned (percent)	49.00%			49.00%

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Schedule of Partnerships' Coal Royalty and Other Segment Revenues from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Total Coal Royalty and Other segment revenues	$ 43,784	$ 49,371	$ 168,777	$ 152,150
Revenues	57,602	58,207	205,610	187,136
Coal Royalty and Other
Disaggregation of Revenue [Line Items]
Total Coal Royalty and Other segment revenues	39,919	42,518	154,037	134,912
Revenues	39,919	42,518	154,037	134,912
Coal Royalty and Other | Coal royalty revenues
Disaggregation of Revenue [Line Items]
Total Coal Royalty and Other segment revenues	24,727	30,709	87,561	96,473
Coal Royalty and Other | Production lease minimum revenues
Disaggregation of Revenue [Line Items]
Total Coal Royalty and Other segment revenues	2,752	1,769	21,331	6,310
Coal Royalty and Other | Minimum lease straight-line revenues
Disaggregation of Revenue [Line Items]
Total Coal Royalty and Other segment revenues	3,982	567	11,152	1,739
Coal Royalty and Other | Property tax revenues
Disaggregation of Revenue [Line Items]
Total Coal Royalty and Other segment revenues	1,606	1,263	4,416	3,968
Coal Royalty and Other | Wheelage revenues
Disaggregation of Revenue [Line Items]
Total Coal Royalty and Other segment revenues	1,675	1,572	5,035	5,155
Coal Royalty and Other | Coal overriding royalty revenues
Disaggregation of Revenue [Line Items]
Total Coal Royalty and Other segment revenues	2,189	3,918	10,163	10,492
Coal Royalty and Other | Lease amendment revenues
Disaggregation of Revenue [Line Items]
Total Coal Royalty and Other segment revenues	1,535	0	6,720	0
Coal Royalty and Other | Aggregates royalty revenues
Disaggregation of Revenue [Line Items]
Total Coal Royalty and Other segment revenues	954	888	3,655	3,551
Coal Royalty and Other | Oil and gas royalty revenues
Disaggregation of Revenue [Line Items]
Total Coal Royalty and Other segment revenues	374	1,427	2,575	5,679
Coal Royalty and Other | Other revenues
Disaggregation of Revenue [Line Items]
Total Coal Royalty and Other segment revenues	125	405	1,429	1,545
Coal Royalty and Other | Transportation and processing services revenues
Disaggregation of Revenue [Line Items]
Total Coal Royalty and Other segment revenues	1,700	3,600	7,300	9,600
Revenues	3,865	6,853	14,740	17,238
Coal Royalty and Other | Transportation and processing revenues
Disaggregation of Revenue [Line Items]
Lease revenue	$ 2,200	$ 3,300	$ 7,500	$ 7,600

Revenue from Contracts with C_4

Revenue from Contracts with Customers - Schedule of Receivables and Liabilities from Contracts with Customers (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Current portion of deferred revenue	$ 5,047	$ 3,509
Deferred revenue	43,587	49,044
Coal Royalty
Segment Reporting Information [Line Items]
Accounts receivable, net	24,758	29,001
Prepaid expenses and other	2,852	2,483
Current portion of deferred revenue	5,047	3,509
Deferred revenue	$ 43,587	$ 49,044

Revenue from Contracts with C_5

Revenue from Contracts with Customers Revenue Recognition Deferred Revenue Rollforward (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Jan. 01, 2019	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Deferred Revenue	$ 48,634	$ 42,288	$ 52,553	$ 52,553	$ 35,014	$ 100,605
Increase due to minimums and lease amendment fees	37,315	23,534
Recognition of previously deferred revenue	$ (41,234)	$ (16,260)
Accounting Standards Update 2014-09
Deferred Revenue					$ (65,591)

Revenue from Contracts with C_6

Revenue from Contracts with Customers - Schedule of Annual Minimums by Current Remaining Contract Term (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Payments for (Proceeds from) Loans Receivable, Annual Minimum Payment	$ 5,000
Average Remaining Contract Term	9 years 7 months
Annual minimum payments	$ 68,602
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Average Remaining Contract Term	2 years 2 months 27 days
Annual minimum payments	$ 12,439
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Average Remaining Contract Term	6 years 5 months 10 days
Annual minimum payments	$ 9,426
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Average Remaining Contract Term	12 years 1 month 2 days
Annual minimum payments	$ 46,737

Revenue from Contracts with C_7

Revenue from Contracts with Customers - Narrative (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)
Disaggregation of Revenue [Line Items]
Average Remaining Contract Term	9 years 7 months
Annual minimum payments	$ 68,602
Payments from coal lease accounted for as financing transaction	$ 5,000

Discontinued Operations (Detail

Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accounts receivable, net - Discontinued Operations	$ 988		$ 988		$ 993
Total assets of discontinued operations	988		988		993
Accounts payable - Discontinued Operations	42		42		181
Accrued liabilities - Discontinued Operations	132		132		766
Total liabilities of discontinued operations	174		174		947
Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Construction aggregates revenues	0	$ 30,398	0	$ 91,055
Road construction and asphalt paving services	0	6,250	0	13,154
Oil and gas revenues	2	(1)	2	(3)
Gain (loss) on asset sales - Discontinued Operations	5	163	243	214
Total revenues and other income - Discontinued Operations	7	36,810	245	104,420
Operating and maintenance expenses - Discontinued Operations	0	30,781	39	91,294
Depreciation, depletion and amortization - Discontinued Operations	0	3,333	0	9,377
Total operating expenses - Discontinued Operations	0	34,114	39	100,671
Interest expense - Discontinued Operations	0	(8)	0	(28)
Income (loss) from discontinued operations	7	2,688	206	3,721
Construction Aggregates
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accounts receivable, net - Discontinued Operations	0		0		5
Total assets of discontinued operations	0		0		5
Accounts payable - Discontinued Operations	42		42		181
Accrued liabilities - Discontinued Operations	132		132		766
Total liabilities of discontinued operations	174		174		947
NRP Oil and Gas
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accounts receivable, net - Discontinued Operations	988		988		988
Total assets of discontinued operations	988		988		988
Accounts payable - Discontinued Operations	0		0		0
Accrued liabilities - Discontinued Operations	0		0		0
Total liabilities of discontinued operations	0		0		$ 0
Construction Aggregates | Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Construction aggregates revenues	0	30,398	0	91,055
Road construction and asphalt paving services	0	6,250	0	13,154
Oil and gas revenues	0	0		0
Gain (loss) on asset sales - Discontinued Operations	5	163	243	214
Total revenues and other income - Discontinued Operations	5	36,811	243	104,423
Operating and maintenance expenses - Discontinued Operations	0	30,758	27	91,225
Depreciation, depletion and amortization - Discontinued Operations	0	3,333	0	9,377
Total operating expenses - Discontinued Operations	0	34,091	27	100,602
Interest expense - Discontinued Operations	0	(8)	0	(28)
Income (loss) from discontinued operations	5	2,712	216	3,793
Capital Expenditures, Discontinued Operations				9,700
NRP Oil and Gas | Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Construction aggregates revenues	0	0	0	0
Road construction and asphalt paving services	0	0	0	0
Oil and gas revenues	2	(1)	2	(3)
Gain (loss) on asset sales - Discontinued Operations	0	0	0	0
Total revenues and other income - Discontinued Operations	2	(1)	2	(3)
Operating and maintenance expenses - Discontinued Operations	0	23	12	69
Depreciation, depletion and amortization - Discontinued Operations	0	0	0	0
Total operating expenses - Discontinued Operations	0	23	12	69
Interest expense - Discontinued Operations	0	0	0	0
Income (loss) from discontinued operations	$ 2	$ (24)	$ (10)	$ (72)

Common and Preferred Unit Dis_3

Common and Preferred Unit Distributions Narrative (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Temporary Equity [Line Items]
Income attributable to preferred unitholders	$ (7,500)	$ (7,500)	$ (7,500)	$ (7,500)	$ (7,500)	$ (7,500)	$ (22,500)	$ (22,500)
Class A Convertible Preferred Units
Temporary Equity [Line Items]
Cash payment for redeemed paid-in-kind units						$ 8,800	$ 0	$ 8,844
General Partner
Temporary Equity [Line Items]
General partner's general partner distribution							2.00%

Common and Preferred Unit Dis_4

Common and Preferred Unit Distributions Distributions declared and paid (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018
Common Units
Class of Stock [Line Items]
Distribution per Unit	$ 0.45	$ 0.45	$ 0.45	$ 0.45	$ 0.45	$ 0.45
Total distributions, common units	$ 5,630	$ 16,265	$ 5,625	$ 5,623	$ 5,623	$ 5,617
Preferred Units
Class of Stock [Line Items]
Total distributions, common units	$ 7,500	$ 7,500	$ 7,500	$ 7,500	$ 7,500	$ 7,765
Preferred Units | Preferred Stock
Class of Stock [Line Items]
Distribution per Unit	$ 30	$ 30	$ 30	$ 30	$ 30	$ 30
Total distributions, preferred units	$ 7,500	$ 7,500	$ 7,500	$ 7,500	$ 7,500	$ 7,765
Cash Distribution | Common Units
Class of Stock [Line Items]
Total distributions, common units	$ 5,630	$ 5,630	$ 5,625	$ 5,623	$ 5,623	$ 5,617
Special Tax Distribution | Common Units
Class of Stock [Line Items]
Distribution per Unit		$ 0.85
Total distributions, common units		$ 10,635

Net Income Per Common Unit (Det

Net Income Per Common Unit (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Allocation of net income
Net income from continuing operations	$ 39,163			$ 25,853			$ 94,034	$ 87,268
Add (less): net loss (income) attributable to non-controlling interest	0			359			0	(510)
Less: income attributable to preferred unitholders	(7,500)	$ (7,500)	$ (7,500)	(7,500)	$ (7,500)	$ (7,500)	(22,500)	(22,500)
Net income from continuing operations attributable to common unitholders and general partner	31,663			18,712			71,534	64,258
Less: net income from continuing operations attributable to the general partner	(634)			(374)			(1,431)	(1,285)
Net income from continuing operations attributable to common unitholders	31,029			18,338			70,103	62,973
Net income from discontinued operations	7			2,688			206	3,721
Less: net income from discontinued operations attributable to the general partner	0			(54)			(4)	(75)
Net income from discontinued operations attributable to common unitholders	7			2,634			202	3,646
Net income	39,170	$ 19,351	$ 35,719	28,541	$ 38,110	$ 24,338	94,240	90,989
Net income attributable to common unitholders and general partner	31,670			21,400			71,740	67,979
Less: net income attributable to the general partner	(634)			(428)			(1,435)	(1,360)
Net income attributable to common unitholders	$ 31,036			$ 20,972			$ 70,305	$ 66,619
Basic Income (Loss) per Unit:
Weighted average common units (in shares)	12,261			12,246			12,259	12,243
Basic net income from continuing operations per common unit	$ 2.53			$ 1.50			$ 5.72	$ 5.14
Basic net income from discontinued operations per common unit	0			0.22			0.02	0.30
Basic net income per common unit	$ 2.53			$ 1.71			$ 5.73	$ 5.44
Diluted income per common unit
Dilutive effect of Preferred Units (in shares)	10,494			9,124			10,494	9,124
Dilutive effect of Warrants (in shares)	389			470			800	474
Dilutive effect of unvested common unit awards (in shares)	13			0			31	0
Weighted average common units—diluted (in shares)	23,157			21,840			23,584	21,841
Diluted net income from continuing operations attributable to common unitholders and general partner	$ 39,163			$ 26,212			$ 94,034	$ 86,758
Less: diluted net income from continuing operations attributable to the general partner	(784)			(524)			(1,881)	(1,735)
Diluted net income from continuing operations attributable to common unitholders	38,379			25,688			92,153	85,023
Diluted net income from discontinued operations attributable to common unitholders	7			2,634			202	3,646
Diluted net income attributable to common unitholders and general partner	39,170			28,900			94,240	90,479
Less: diluted net income attributable to the general partner	(784)			(578)			(1,885)	(1,810)
Diluted net income attributable to common unitholders	$ 38,386			$ 28,322			$ 92,355	$ 88,669
Diluted net income per common unit from continuing operations (in dollars per share)	$ 1.66			$ 1.18			$ 3.91	$ 3.89
Diluted net income (loss) from discontinued operations per common unit (in dollars per share)	0			0.12			0.01	0.17
Diluted net income per common unit (in dollars per share)	$ 1.66			$ 1.30			$ 3.92	$ 4.06
Warrant Holders | Warrants at $22.81 Strike
Class of Warrant or Right, Warrants Issued	1,750			1,750			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

Segment Information - Additiona

Segment Information - Additional Information (Details) - segment	9 Months Ended
	Sep. 30, 2019	Jul. 31, 2013
Segment Reporting Information [Line Items]
Number of operating segments	2
Ciner Wyoming
Segment Reporting Information [Line Items]
Percentage of partnership interest owned (percent)	49.00%	49.00%

Segment Information - Schedule

Segment Information - Schedule of Segment Reporting Information, by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Segment Reporting Information [Line Items]
Revenues	$ 57,602	$ 58,207	$ 205,610	$ 187,136
Gain on asset sales and disposals	6,107	0	6,609	819
Operating and maintenance expenses	5,994	6,790	26,813	21,122
Depreciation, depletion and amortization	3,384	4,888	11,746	15,364
General and administrative expenses	4,253	3,183	12,799	10,782
Asset impairments	484	0	484	242
Other expenses, net	10,431	17,493	66,343	53,177
Net income (loss) from continuing operations	39,163	25,853	94,034	87,268
Net income from discontinued operations	7	2,688	206	3,721
Total assets	1,243,904		1,243,904		$ 1,341,647
Corporate and Financing
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Gain on asset sales and disposals	0		0	0
Operating and maintenance expenses	0	0	0	0
Depreciation, depletion and amortization	0	0	0	0
General and administrative expenses	4,253	3,183	12,799	10,782
Asset impairments			0	0
Other expenses, net	10,431	17,493	66,343	53,177
Net income (loss) from continuing operations	(14,684)	(20,676)	(79,142)	(63,959)
Net income from discontinued operations	0	0		0
Coal Royalty and Other
Segment Reporting Information [Line Items]
Revenues	39,919	42,518	154,037	134,912
Coal Royalty and Other | Operating Segments
Segment Reporting Information [Line Items]
Revenues	43,784	49,371	168,777	152,150
Gain on asset sales and disposals	6,107		6,609	819
Operating and maintenance expenses	5,771	6,790	26,590	21,122
Depreciation, depletion and amortization	3,384	4,888	11,746	15,364
General and administrative expenses	0	0	0	0
Asset impairments			484	242
Other expenses, net	0	0	0	0
Net income (loss) from continuing operations	40,252	37,693	136,566	116,241
Net income from discontinued operations	0	0		0
Soda Ash
Segment Reporting Information [Line Items]
Revenues	13,818	8,836	36,833	34,986
Soda Ash | Operating Segments
Segment Reporting Information [Line Items]
Revenues	13,818	8,836	36,833	34,986
Gain on asset sales and disposals	0		0	0
Operating and maintenance expenses	223	0	223	0
Depreciation, depletion and amortization	0	0	0	0
General and administrative expenses	0	0	0	0
Asset impairments			0	0
Other expenses, net	0	0	0	0
Net income (loss) from continuing operations	13,595	8,836	36,610	34,986
Net income from discontinued operations	0	$ 0		$ 0
Continuing Operations
Segment Reporting Information [Line Items]
Total assets	1,242,916		1,242,916		1,340,654
Continuing Operations | Corporate and Financing
Segment Reporting Information [Line Items]
Total assets	15,428		15,428		106,923
Continuing Operations | Coal Royalty and Other | Operating Segments
Segment Reporting Information [Line Items]
Total assets	969,425		969,425		986,680
Continuing Operations | Soda Ash | Operating Segments
Segment Reporting Information [Line Items]
Total assets	258,063		258,063		247,051
Discontinued Operations
Segment Reporting Information [Line Items]
Total assets	988		988		993
Discontinued Operations | Corporate and Financing
Segment Reporting Information [Line Items]
Total assets	0		0		0
Discontinued Operations | Coal Royalty and Other | Operating Segments
Segment Reporting Information [Line Items]
Total assets	0		0		0
Discontinued Operations | Soda Ash | Operating Segments
Segment Reporting Information [Line Items]
Total assets	$ 0		$ 0		$ 0

Equity Investment - Additional

Equity Investment - Additional Information (Detail)	Sep. 30, 2019	Jul. 31, 2013
Ciner Wyoming
Schedule of Equity Method Investments [Line Items]
Percentage of partnership interest owned (percent)	49.00%	49.00%

Equity Investment - Schedule o

Equity Investment - Schedule of Summarized Financial Information of Unaudited Financial Statements (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Equity Method Investments [Roll Forward]
Balance at beginning of period			$ 247,051
Comprehensive income (loss) from unconsolidated investment	$ 38,650	$ 29,332	93,900	$ 90,221
Balance at end of period	258,063		258,063
Sales			36,833	34,986
Ciner Wyoming
Equity Method Investments [Roll Forward]
Balance at beginning of period	251,135	245,524	247,051	245,433
Income allocation to NRP’s equity interests	15,068	10,036	40,511	38,525
Amortization of basis difference	(1,250)	(1,200)	(3,678)	(3,539)
Comprehensive income (loss) from unconsolidated investment	(520)	791	(341)	(768)
Distribution	(6,370)	(12,250)	(25,480)	(36,750)
Balance at end of period	258,063	242,901	258,063	242,901
Sales	137,148	123,366	397,378	354,467
Gross profit	36,747	26,253	103,382	68,497
Net income	$ 30,750	$ 20,481	$ 82,675	$ 78,623

Mineral Rights, Net - Mineral R

Mineral Rights, Net - Mineral Rights (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Cost	$ 1,214,832	$ 1,215,318
Accumulated Depletion	(481,678)	(472,206)
Net Book Value	733,154	743,112
Coal Mineral Rights
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Cost	1,147,692	1,164,845
Accumulated Depletion	(459,122)	(451,210)
Net Book Value	688,570	713,635
Aggregates Mineral Rights
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Cost	41,589	24,920
Accumulated Depletion	(13,132)	(11,814)
Net Book Value	28,457	13,106
Oil And Gas Mineral Rights
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Cost	12,395	12,395
Accumulated Depletion	(7,823)	(7,632)
Net Book Value	4,572	4,763
Other Mineral Rights
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Cost	13,156	13,158
Accumulated Depletion	(1,601)	(1,550)
Net Book Value	$ 11,555	$ 11,608

Mineral Rights, Net - Additiona

Mineral Rights, Net - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Gain on asset sales and disposals	$ 6,107	$ 0	$ 6,609	$ 819
Net Book Value	733,154		733,154		$ 743,112
Depletion and amortization expense on coal and other mineral rights	2,800	$ 3,900	9,500	$ 12,800
Coal Mineral Rights
Property, Plant and Equipment [Line Items]
Net Book Value	688,570		688,570		$ 713,635
Mineral rights disposed of | Coal Mineral Rights
Property, Plant and Equipment [Line Items]
Net Book Value	$ 0		$ 0

Intangible Assets, Net - Intang

Intangible Assets, Net - Intangible Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible assets at cost	$ 81,109	$ 81,109
Less accumulated amortization	(40,648)	(38,596)
Total intangible assets, net	$ 40,461	$ 42,513

Intangible Assets, Net - Additi

Intangible Assets, Net - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense	$ 0.5	$ 0.9	$ 2.1	$ 2.3

Debt, Net - Debt (Detail)

Debt, Net - Debt (Detail) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Principal balance	$ 544,390,000	$ 687,138,000
Net unamortized debt discount	0	(1,266,000)
Net unamortized debt issuance costs	(8,223,000)	(13,114,000)
Total debt, net	536,167,000	672,758,000
Less - current portion of long term debt	(45,789,000)	(115,184,000)
Total long-term debt, net	490,378,000	557,574,000
NRP LP | 9.125% senior notes, with semi-annual interest payments in June and December, maturing June 2025
Debt Instrument [Line Items]
Principal balance	$ 300,000,000	0
Rate of senior notes	9.125%
NRP LP | 10.5% senior notes, with semi-annual interest payments in March and September, maturing March 2022
Debt Instrument [Line Items]
Principal balance	$ 0	$ 345,638,000
Rate of senior notes		10.50%
Opco | Floating Rate Revolving Credit Facility Due April Two Thousand Twenty Three
Debt Instrument [Line Items]
Principal balance	0
Floating rate revolving credit facility	100,000,000
Opco | Floating Rate Revolving Credit Facility Due April Two Thousand Twenty
Debt Instrument [Line Items]
Principal balance		$ 0
Opco | Senior Notes
Debt Instrument [Line Items]
Principal balance	244,390,000	341,500,000
Opco | 8.38% senior notes, with semi-annual interest payments in March and September, with annual principal payments in March, maturing in March 2019
Debt Instrument [Line Items]
Principal balance	$ 0	21,319,000
Rate of senior notes	8.38%
Opco | 5.05% senior notes, with semi-annual interest payments in January and July, with annual principal payments in July, maturing in July 2020
Debt Instrument [Line Items]
Principal balance	$ 6,780,000	15,290,000
Rate of senior notes	5.05%
Opco | 5.55% senior notes, with semi-annual interest payments in June and December, with annual principal payments in June, maturing in June 2023
Debt Instrument [Line Items]
Principal balance	$ 9,458,000	13,414,000
Rate of senior notes	5.55%
Opco | 4.73% senior notes, with semi-annual interest payments in June and December, with scheduled principal payments beginning December 2014, maturing in December 2023
Debt Instrument [Line Items]
Principal balance	$ 30,019,000	37,195,000
Rate of senior notes	4.73%
Opco | 5.82% senior notes, with semi-annual interest payments in March and September, with annual principal payments in March, maturing in March 2024
Debt Instrument [Line Items]
Principal balance	$ 63,423,000	89,529,000
Rate of senior notes	5.82%
Opco | 8.92% senior notes, with semi-annual interest payments in March and September, with scheduled principal payments beginning March 2014, maturing in March 2024
Debt Instrument [Line Items]
Principal balance	$ 20,059,000	27,185,000
Rate of senior notes	8.92%
Opco | 5.03% senior notes, with semi-annual interest payments in June and December, with scheduled principal payments beginning December 2014, maturing in December 2026
Debt Instrument [Line Items]
Principal balance	$ 91,365,000	107,013,000
Rate of senior notes	5.03%
Opco | 5.18% senior notes, with semi-annual interest payments in June and December, with scheduled principal payments beginning December 2014, maturing in December 2026
Debt Instrument [Line Items]
Principal balance	$ 23,286,000	30,555,000
Rate of senior notes	5.18%
Senior Notes Offering Price Two | NRP LP | 10.5% senior notes, with semi-annual interest payments in March and September, maturing March 2022
Debt Instrument [Line Items]
Principal balance		$ 105,000,000
Senior Note issue percentage		98.75%
Senior Notes Offering Price One | NRP LP | 10.5% senior notes, with semi-annual interest payments in March and September, maturing March 2022
Debt Instrument [Line Items]
Principal balance		$ 240,638,000
Senior Note issue percentage		100.00%

Debt, Net - Additional Informat

Debt, Net - Additional Information (Detail)	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2019USD ($)$ / shares	Sep. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Debt Instrument [Line Items]
Principal balance		$ 544,390,000		$ 687,138,000
Redemption premium		18,100,000
Write off of Deferred Debt Issuance Cost		$ 10,400,000
9.125% senior notes, with semi-annual interest payments in June and December, maturing June 2025 | Senior Notes
Debt Instrument [Line Items]
Rate of senior notes		9.125%
Percentage of principal eligible for redemption		35.00%
Redemption price percentage of principal remaining after redemption		65.00%
Redemption price at change of control event as percentage of principal amount		101.00%
10.5% senior notes, with semi-annual interest payments in March and September, maturing March 2022 | Senior Notes
Debt Instrument [Line Items]
Redemption percentage of principal		105.25%
Principal payments on its senior notes		$ 76,100,000
NRP LP | 9.125% senior notes, with semi-annual interest payments in June and December, maturing June 2025
Debt Instrument [Line Items]
Principal balance		$ 300,000,000		0
Rate of senior notes		9.125%
Opco | Floating Rate Revolving Credit Facility Due April Two Thousand Twenty Three
Debt Instrument [Line Items]
Principal balance		$ 0
Lender commitments under Opco credit facility		$ 100,000,000
Distribution per share (in dollars per share) | $ / shares		$ 0.45
Ratio Of Ebitda to consolidated fixed charges		3.5
Weighted average interest rate	6.34%		6.18%
Collateral carrying amount		$ 541,500,000		548,900,000
Floating rate revolving credit facility		100,000,000
Opco | 8.92% senior notes, with semi-annual interest payments in March and September, with scheduled principal payments beginning March 2014, maturing in March 2024
Debt Instrument [Line Items]
Principal balance		$ 20,059,000		27,185,000
Rate of senior notes		8.92%
Opco | Senior Notes
Debt Instrument [Line Items]
Principal balance		$ 244,390,000		$ 341,500,000
Principal payments on its senior notes		97,100,000	$ 55,700,000
Pre-payment of Senior Notes		$ 49,300,000
Partnership leverage ratio		3.75
Additional interest accrue		2.00%
Dividend at or Below $0.45 per Share | Opco | Floating Rate Revolving Credit Facility Due April Two Thousand Twenty Three
Debt Instrument [Line Items]
Maximum leverage ratio		4
Dividend Above $0.45 per Share | Opco | Floating Rate Revolving Credit Facility Due April Two Thousand Twenty Three
Debt Instrument [Line Items]
Maximum leverage ratio		3
Debt Instrument, Redemption, Period Two | 9.125% senior notes, with semi-annual interest payments in June and December, maturing June 2025 | Senior Notes
Debt Instrument [Line Items]
Redemption percentage of principal		104.563%
Debt Instrument, Redemption, Period Three | 9.125% senior notes, with semi-annual interest payments in June and December, maturing June 2025 | Senior Notes
Debt Instrument [Line Items]
Redemption percentage of principal		102.281%
Debt Instrument, Redemption, Period Four | 9.125% senior notes, with semi-annual interest payments in June and December, maturing June 2025 | Senior Notes
Debt Instrument [Line Items]
Redemption percentage of principal		100.00%
Debt Instrument, Redemption, Period One | 9.125% senior notes, with semi-annual interest payments in June and December, maturing June 2025 | Senior Notes
Debt Instrument [Line Items]
Redemption percentage of principal		109.125%

Fair Value Measurements - Contr

Fair Value Measurements - Contracts Receivable and Debt (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Transfers between Levels 1, 2, 3	$ 0	$ 0	$ 0	$ 0
Carrying Value	536,167,000		536,167,000		$ 672,758,000
Contracts receivable (current and long-term)	39,416,000		39,416,000		40,776,000
Fair Value, Inputs, Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Contracts receivable (current and long-term)	33,784,000		33,784,000		34,704,000
Senior Notes due 2025
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying Value	293,824,000		293,824,000		0
Senior Notes due 2025 | Fair Value, Inputs, Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	287,250,000		287,250,000		0
Senior Notes due 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying Value	0		0		334,024,000
Senior Notes due 2022 | Fair Value, Inputs, Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	0		0		356,871,000
Opco Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying Value	242,343,000		242,343,000		338,734,000
Opco Senior Notes | Fair Value, Inputs, Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	234,003,000		234,003,000		352,599,000
Opco Revolving Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying Value	0		0		0
Opco Revolving Credit Facility | Fair Value, Inputs, Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	$ 0		$ 0		$ 0

Fair Value Measurements - Embed

Fair Value Measurements - Embedded Derivatives (Detail) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Equity [Abstract]
Fair value of embedded derivatives	$ 0	$ 0

Related Party Transactions - Na

Related Party Transactions - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Quintana Minerals | Affiliated Entity
Related Party Transaction [Line Items]
Accounts payable to related parties	$ 0.4		$ 0.4		$ 0.5
Western Pocahontas Properties Limited Partnership | Affiliated Entity
Related Party Transaction [Line Items]
Accounts payable to related parties					1.4
Operating and maintenance expenses	0.3	$ 0.6	3.8	$ 3.5
Other related party assets	0.1		0.1
Corsa
Related Party Transaction [Line Items]
Revenue from related parties				0.4
Industrial Minerals Group
Related Party Transaction [Line Items]
Revenue from related parties	0.4	$ 0.2	0.9	$ 0.6
Accounts receivable from related parties	$ 0.2		$ 0.2		$ 0.1

Related Party Transactions - Su

Related Party Transactions - Summary of Reimbursements (Details) - Affiliated Entity - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Western Pocahontas Properties Limited Partnership
Related Party Transaction [Line Items]
Operating and maintenance expenses	$ 300	$ 600	$ 3,800	$ 3,500
Western Pocahontas Properties and Quintana Minerals Corporation
Related Party Transaction [Line Items]
Operating and maintenance expenses	1,598	1,560	4,806	4,694
General and administrative expenses	$ 855	$ 934	$ 2,704	$ 2,714

Major Customers (Detail)

Major Customers (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Concentration Risk [Line Items]
Revenues	$ 57,602	$ 58,207	$ 205,610	$ 187,136
Foresight Energy Lp
Concentration Risk [Line Items]
Revenues	12,375	15,035	44,604	40,456
Contura Energy
Concentration Risk [Line Items]
Revenues	$ 9,190	$ 4,709	$ 32,915	$ 16,091
Sales Revenue | Customer Concentration Risk | Foresight Energy Lp
Concentration Risk [Line Items]
Percent	21.00%	26.00%	22.00%	22.00%
Sales Revenue | Customer Concentration Risk | Contura Energy
Concentration Risk [Line Items]
Percent	16.00%	8.00%	16.00%	9.00%

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Thousands	36 Months Ended
	Dec. 31, 2015	Sep. 30, 2019	Jul. 31, 2013	Jan. 31, 2013
Anadarko Holding Company
Commitments And Contingencies [Line Items]
Contingent consideration to be paid by NRP				$ 50,000
Ciner Wyoming | Anadarko Holding Company
Commitments And Contingencies [Line Items]
Contingent consideration paid	$ 11,500
OCI LP
Commitments And Contingencies [Line Items]
Percentage of partnership interest owned (percent)				48.51%
Ciner Wyoming
Commitments And Contingencies [Line Items]
Percentage of partnership interest owned (percent)		49.00%	49.00%
OCI CO
Commitments And Contingencies [Line Items]
Percentage of partnership interest owned (percent)				1.00%
Pending Litigation | Minimum | Anadarko Holding Company
Commitments And Contingencies [Line Items]
Minimum deficiency payments		$ 0
Pending Litigation | Maximum | Anadarko Holding Company
Commitments And Contingencies [Line Items]
Minimum deficiency payments		$ 40,000

Unit-Based Compensation (Detail

Unit-Based Compensation (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of awards granted			$ 5.4	$ 2.2
Weighted average remaining term vesting recognized			2 years 2 months 20 days
Unamortized cost associated with unvested outstanding awards	$ 4		$ 4		$ 1.2
General and administrative expense and operating and maintenance expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit based compensation expense	$ 0.5	$ 0.2	$ 1.8	$ 0.9

Unit-Based Compensation Summary

Unit-Based Compensation Summary of unit based activity (Details) shares in Thousands	9 Months Ended
	Sep. 30, 2019$ / sharesshares
Common Units
Outstanding at beginning of period | shares	55
Granted | shares	129
Fully vested and issued | shares	(12)
Forfeitures | shares	(15)
Outstanding at the end of period | shares	157
Weighted Average Exercise Price
Outstanding at beginning of period | $ / shares	$ 37.48
Granted | $ / shares	41.41
Fully vested and issued | $ / shares	41.47
Forfeitures | $ / shares	37.33
Outstanding at the end of period | $ / shares	$ 29.10

Financing Transaction (Details)

Financing Transaction (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2039	Dec. 31, 2032
Accounts, Notes, Loans and Financing Receivable [Line Items]
Option to extend operating lease, term	P80Y
Payments from coal lease accounted for as financing transaction	$ 5,000
Forecast
Accounts, Notes, Loans and Financing Receivable [Line Items]
Annual rent amount after lease completion		$ 10	$ 10

Financing Transaction Financing

Financing Transaction Financing Receivable, after Allowance for Credit Loss (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	$ 27,447	$ 32,058
Foresight Energy Lp
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	347	661
Contract receivable (current and long-term)	39,416	40,776
Unearned income	(22,667)	(25,058)
Projected remaining payments	$ 62,430	$ 66,495

Leases Lessee accounting under

Leases Lessee accounting under ASC 842 - narrative (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Jan. 01, 2019
Lessor, Lease, Description [Line Items]
Number of options to extend		5
Length of renewal term	5 years	5 years
Operating lease, right-of-use asset	$ 3,500	$ 3,500	$ 3,500
Operating lease liability	3,509	3,509	$ 3,500
Operating lease expenses	$ 100	$ 400
Operating Lease, Weighted Average Remaining Lease Term	29 years 3 months	29 years 3 months
Minimum
Lessor, Lease, Description [Line Items]
Base term on lease (in years)	5 years	5 years

Leases Operating lease maturity

Leases Operating lease maturity schedule (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019
Lessee, Lease, Description [Line Items]
Operating Lease, Weighted Average Remaining Lease Term	29 years 3 months
Lessee, Operating Lease, Discount Rate	13.50%
Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract]
2019	$ 121
2020	483
2021	483
2022	483
2023	483
After 2023	12,079
Total lease payments	14,132
Less: present value adjustment	(10,623)
Total operating lease liability	$ 3,509	$ 3,500
Maximum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	30 years

Leases Lessor accounting under

Leases Lessor accounting under 842 - narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2039	Dec. 31, 2032
Throughput fees	$ 1,100	$ 1,400	$ 3,600	$ 3,500
Forecast
Annual rent amount after lease completion					$ 10	$ 10

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - Subsequent Event $ / shares in Units, $ in Millions	Nov. 14, 2019USD ($)$ / shares
Subsequent Event [Line Items]
Distribution per Unit | $ / shares	$ 0.45
Preferred unit dividends | $	$ 7.5

Uncategorized Items - nrp-20190

Label	Element	Value
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	$ 26,980,000
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	206,030,000
Disposal Group, Including Discontinued Operation, Cash and Cash Equivalents	us-gaap_DisposalGroupIncludingDiscontinuedOperationCashAndCashEquivalents	2,847,000
Disposal Group, Including Discontinued Operation, Cash and Cash Equivalents	us-gaap_DisposalGroupIncludingDiscontinuedOperationCashAndCashEquivalents	0
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	70,466,000
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Including Disposal Group and Discontinued Operations	us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	29,827,000
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Including Disposal Group and Discontinued Operations	us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	206,030,000
General Partner [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	1,409,000
Common Stock [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	69,057,000
Partners Capital Excluding Noncontrolling Interest [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 70,466,000