Natural Resource Partners (NRP) 10-Q 7 Nov 16 2016 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2016	Nov. 04, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q3
Trading Symbol	NRP
Entity Registrant Name	NATURAL RESOURCE PARTNERS LP
Entity Central Index Key	1,171,486
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		12,232,006

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 92,391	$ 41,204
Accounts receivable, net	44,139	43,633
Accounts receivable—affiliates, net	7,057	6,345
Inventory	7,160	7,835
Prepaid expenses and other	3,707	4,268
Current assets held for sale (see Note 6)	5,520	0
Current assets of discontinued operations (see Note 2)	991	17,844
Total current assets	160,965	121,129
Land	25,020	25,022
Plant and equipment, net	52,516	60,675
Mineral rights, net	924,181	984,522
Intangible assets, net	3,239	3,930
Intangible assets, net—affiliate	50,668	52,997
Equity in unconsolidated investment	257,661	261,942
Long-term contracts receivable—affiliate	44,224	47,359
Other assets	1,898	1,173
Other assets—affiliate	1,034	1,124
Non-current assets of discontinued operations	0	110,162
Total assets	1,521,406	1,670,035
Current liabilities:
Accounts payable	6,223	5,022
Accounts payable—affiliates	829	801
Accrued liabilities	44,816	44,997
Accrued liabilities—affiliates	0	456
Current portion of long-term debt, net	158,597	80,745
Current liabilities of discontinued operations	835	4,388
Total current liabilities	211,300	136,409
Deferred revenue	40,050	80,812
Deferred revenue—affiliates	74,663	82,853
Long-term debt, net	1,041,984	1,186,681
Long-term debt, net—affiliate	0	19,930
Other non-current liabilities	4,404	5,171
Non-current liabilities of discontinued operations	0	85,237
Commitments and contingencies
Partners’ capital:
Common unitholders’ interest (12,232,006 units outstanding)	154,315	79,094
General partner’s interest	928	(606)
Accumulated other comprehensive loss	(2,844)	(2,152)
Total partners’ capital	152,399	76,336
Non-controlling interest	(3,394)	(3,394)
Total capital	149,005	72,942
Total liabilities and capital	$ 1,521,406	$ 1,670,035

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - shares	Sep. 30, 2016	Feb. 18, 2016	Feb. 17, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Common units outstanding (in shares)	12,232,006	12,200,000	122,300,000	12,232,006

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Revenues and other income:
Revenues and other income	$ 91,448	$ 112,199	$ 284,667	$ 326,874
Gain on asset sales, net	6,426	1,833	27,280	6,903
Total revenues and other income	97,874	114,032	311,947	333,777
Operating expenses:
Operating and maintenance expenses	31,242	37,746	87,824	106,338
Operating and maintenance expenses—affiliates, net	4,062	1,744	9,948	8,090
Depreciation, depletion and amortization	11,929	15,666	32,181	44,512
Amortization expense—affiliates	902	771	2,328	2,516
General and administrative	4,268	1,809	10,676	6,014
General and administrative—affiliates	867	2,424	2,670	3,809
Asset impairments	5,697	361,703	7,681	365,506
Total operating expenses	58,967	421,863	153,308	536,785
Income (loss) from operations	38,907	(307,831)	158,639	(203,008)
Other income (expense)
Interest expense	(22,491)	(22,441)	(66,742)	(65,588)
Interest expense—affiliate	0	(464)	(523)	(1,388)
Interest income	3	0	29	16
Other expense, net	(22,488)	(22,905)	(67,236)	(66,960)
Net income (loss) from continuing operations	16,419	(330,736)	91,403	(269,968)
Income (loss) from discontinued operations (see Note 2)	7,112	(269,265)	2,001	(279,966)
Net income (loss)	23,531	(600,001)	93,404	(549,934)
Less: net loss attributable to non-controlling interest	0	1,244	0	0
Net income (loss) attributable to NRP	23,531	(598,757)	93,404	(549,934)
Net income (loss) attributable to partners:
Net income (loss) from continuing operations attributable to limited partners	16,155	(322,133)	89,771	(263,799)
Net income (loss) from discontinued operations attributable to limited partners	6,970	(263,880)	1,961	(274,367)
Net income (loss) attributable to limited partners	23,125	(586,013)	91,732	(538,166)
Net income (loss) from continuing operations attributable to the general partner	264	(7,359)	1,632	(6,169)
Net income (loss) from discontinued operations attributable to the general partner	142	(5,385)	40	(5,599)
Net income (loss) attributable to the general partner	$ 406	$ (12,744)	$ 1,672	$ (11,768)
Basic and diluted net income (loss) per common unit (in dollars per share):
Basic and diluted net income (loss) from continuing operations per common unit (in dollars per share)	$ 1.32	$ (26.34)	$ 7.34	$ (21.57)
Basic and diluted net income (loss) from discontinued operations per common unit (in dollars per share)	0.57	(21.57)	0.16	(22.43)
Basic and diluted net income (loss) per common unit (in dollars per share)	$ 1.89	$ (47.91)	$ 7.50	$ (44)
Weighted average number of common units outstanding (in shares)	12,232	12,232	12,232	12,232
Add: comprehensive loss from unconsolidated investment and other	$ (609)	$ (1,136)	$ (692)	$ (1,891)
Less: comprehensive loss attributable to non-controlling interest	0	1,244	0	0
Comprehensive income (loss) attributable to NRP	22,922	(599,893)	92,712	(551,825)
Coal Royalty and Other
Revenues and other income:
Revenues and other income	27,504	40,431	116,336	112,139
Coal royalty and other—affiliates	21,434	19,535	49,508	70,938
VantaCore
Revenues and other income:
Revenues and other income	31,757	39,616	88,081	107,058
Soda Ash
Revenues and other income:
Revenues and other income	$ 10,753	$ 12,617	$ 30,742	$ 36,739

Consolidated Statements of Part

Consolidated Statements of Partners' Capital - 9 months ended Sep. 30, 2016 - USD ($) shares in Thousands, $ in Thousands	Total	General Partner	Common Unitholders	Accumulated Other Comprehensive Loss	Partners' Capital Excluding Non-Controlling Interest	Non-Controlling Interest
Balance, beginning of period at Dec. 31, 2015	$ 72,942	$ (606)	$ 79,094	$ (2,152)	$ 76,336	$ (3,394)
Balance, beginning of period (in shares) at Dec. 31, 2015			12,232
Increase (Decrease) in Partners' Capital [Roll Forward]
Distributions to unitholders	(16,849)	(338)	$ (16,511)		(16,849)
Net income	93,404	1,672	91,732		93,404
Non-cash contributions	200	200			200
Comprehensive loss from unconsolidated investment and other	(692)			(692)	(692)
Balance, end of period at Sep. 30, 2016	$ 149,005	$ 928	$ 154,315	$ (2,844)	$ 152,399	$ (3,394)
Balance, end of period (in shares) at Sep. 30, 2016			12,232

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities:
Net income (loss)	$ 93,404	$ (549,934)
Adjustments to reconcile net income (loss) to net cash provided by operating activities of continuing operations:
Depreciation, depletion and amortization	32,181	44,512
Amortization expense—affiliates	2,328	2,516
Distributions from equity earnings from unconsolidated investment	34,300	34,545
Equity earnings from unconsolidated investment	(30,742)	(36,739)
Gain on asset sales, net	(27,280)	(6,903)
(Income) loss from discontinued operations	(2,001)	279,966
Asset impairments	7,681	365,506
Gain on reserve swap	0	(9,290)
Other, net	6,694	(7,774)
Other, net—affiliates	848	(2,139)
Change in assets and liabilities:
Accounts receivable	(341)	3,503
Accounts receivable—affiliates	(712)	2,044
Accounts payable	635	(2,163)
Accounts payable—affiliates	29	1,563
Accrued liabilities	7,287	8,485
Accrued liabilities—affiliates	(456)	457
Deferred revenue	(40,762)	6,035
Deferred revenue—affiliates	(8,190)	(3,399)
Other items, net	(356)	1,400
Net cash provided by operating activities of continuing operations	74,547	132,191
Net cash provided by operating activities of discontinued operations	8,173	29,159
Net cash provided by operating activities	82,720	161,350
Cash flows from investing activities:
Proceeds from sale of oil and gas royalty properties	35,964	0
Proceeds from sale of coal and hard mineral royalty properties	18,214	3,505
Return of long-term contract receivables—affiliate	2,577	2,121
Proceeds from sale of plant and equipment and other	1,186	11,484
Acquisition of plant and equipment and other	(4,431)	(8,581)
Acquisition of mineral rights	0	(400)
Net cash provided by investing activities of continuing operations	53,510	8,129
Net cash provided by (used in) investing activities of discontinued operations	106,821	(32,581)
Net cash provided by (used in) investing activities	160,331	(24,452)
Cash flows from financing activities:
Proceeds from loans	20,000	100,000
Repayments of loans	(106,174)	(141,175)
Distributions to partners	(16,849)	(66,142)
Distributions to non-controlling interest	0	(2,744)
Proceeds from (contributions to) discontinued operations	(40,226)	23,725
Debt issue costs and other	(14,072)	(5,840)
Net cash used in financing activities of continuing operations	(76,869)	(139,626)
Net cash provided by (used in) financing activities of discontinued operations	(125,564)	13,808
Net cash used in financing activities	(202,433)	(125,818)
Net increase in cash and cash equivalents	40,618	11,080
Cash and cash equivalents of continuing operations at beginning of period	41,204	48,971
Cash and cash equivalents of discontinued operations at beginning of period	10,569	1,105
Cash and cash equivalents at beginning of period	51,773	50,076
Cash and cash equivalents at end of period	92,391	61,156
Less: cash and cash equivalents of discontinued operations at end of period	0	11,491
Cash and cash equivalents of continuing operations at end of period	$ 92,391	$ 49,665

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2016
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, operating, managing and leasing a diversified portfolio of mineral properties in the United States, including interests in coal, trona and soda ash, construction aggregates and other natural resources. 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. Certain reclassifications have been made to prior period amounts to conform to the current period financial statement presentation. As described in Note 2. Discontinued Operations , the Partnership has classified the assets and liabilities, operating results and cash flows of its non-operated oil and gas working interest assets as discontinued operations in its consolidated financial statements for all periods presented. As described in Note 3. Segment Information , the Partnership has reclassified certain prior period amounts to conform to the way it internally manages and monitors segment performance. In particular, prior year general and administrative charges that were allocated to operating segments have been reclassified to Operating and maintenance expenses and Operating and maintenance expenses—affiliates on the Consolidated Statements of Comprehensive Income. The prior period reclassifications for new segments had no impact on the Partnership's consolidated financial position, net income (loss) or cash flows. On January 1, 2016, the Partnership adopted a new accounting standard using a retrospective approach that required the presentation of the Partnership's debt issuance costs as a direct deduction from the related debt liability, rather than recorded as an asset. The adoption resulted in a reclassification that reduced other current assets and short-term debt by $0.2 million and reduced other assets and long-term debt (including affiliate) by $13.8 million on the Partnership’s Consolidated Balance Sheet at December 31, 2015. On January 26, 2016, the board of directors of the Partnership's general partner approved a 1-for-10 reverse split on its common units, effective following market close on February 17, 2016. Pursuant to the authorization provided, the Partnership completed the 1-for-10 reverse unit split and its common units began trading on a reverse unit split-adjusted basis on the New York Stock Exchange on February 18, 2016. As a result of the reverse unit split, every 10 outstanding common units were combined into one common unit. The reverse unit split reduced the number of common units outstanding from 122.3 million units to 12.2 million units. All unit and per unit data included in these consolidated financial statements has been retroactively restated to reflect the reverse unit split. In the second quarter of 2016, the Partnership determined its net cash provided by operating activities and net cash used by financing activities were understated by $8.0 million for the three months ended March 31, 2016. The Consolidated Statement of Cash Flows for the nine months ended September 30, 2016 has been corrected for this error. In the Partnership's opinion, all adjustments considered necessary for a fair presentation have been included. The interim financial statements should be read in conjunction with the audited financial statements and related notes included in the Partnership’s Annual Report on Form 10-K for the year ended December 31, 2015. Interim results are not necessarily indicative of the results for a full year. Management’s Forecast, Strategic Plan and Going Concern Analysis While NRP has a diversified portfolio of assets and a history and continued forecast of profitable operations with positive operating cash flows, its operating results and credit metrics have been impacted by challenges in coal and other commodity markets. The following going concern analysis includes an evaluation of relevant conditions and events, including the Partnership's business performance and forecast, and its ability to meet its obligations and remain in compliance with its debt covenants over the next twelve months. As described in Note 8. Debt and Debt—Affiliate , NRP Operating LLC ("Opco"), a wholly owned subsidiary of the Partnership, has debt agreements that contain customary financial covenants, including maintenance covenants, and other covenants. In addition, the Partnership has issued $425 million of 9.125% Senior Notes due October 2018 (the "NRP Senior Notes") that are governed by an indenture (the "Indenture") containing customary incurrence-based financial covenants and other covenants, but not maintenance covenants. As of September 30, 2016 , Opco had $260.0 million of indebtedness outstanding under its revolving credit facility (the "Opco Credit Facility") with scheduled commitment reductions of $50.0 million on December 31, 2016, $30.0 million on June 30, 2017, $30.0 million on December 31, 2017, with the remaining balance of $150 million maturing on June 30, 2018. In addition, as of September 30, 2016 Opco had $529.9 million outstanding under several series of Private Placement Notes with scheduled principal payments of $80.8 million through September 30, 2017 (the "Opco Private Placement Notes") (collectively referred to as the "Opco Debt agreements"). The maximum leverage ratio under the Opco Debt agreements is required not to exceed 4.0 x. In addition, the Opco Debt agreements contain certain additional customary negative covenants that, among other items, restrict Opco’s ability to incur additional debt, grant liens on its assets, make investments, sell assets and engage in business combinations. Opco's leverage ratio was 2.95 x at September 30, 2016 . The Partnership currently forecasts that it will meet its obligations, including scheduled principal and interest payments, that it will remain in compliance with its debt covenants, and that it will continue as a going concern. However, the forecast is sensitive to commodity demand, pricing and counterparty credit and operating risk. In addition, the scheduled debt principal payments in 2017 under Opco's Debt agreements will strain the Partnership's liquidity. Inability to make these payments would result in an event of default and could result in Opco’s lenders accelerating Opco’s debt. Breaches of the Opco debt covenants that are not waived or cured would have a similar effect. Any such acceleration by the Opco lenders would result in a cross-default under the NRP Indenture. The Partnership has been and is currently pursuing or considering a number of actions in order to manage its liquidity and mitigate the effects of adverse market developments that could affect its ability to repay debt and remain in compliance with the covenants under its debt agreements. On a cumulative basis since January 1, 2015, the Partnership has reduced debt by $262.2 million and completed asset sales for $192 million in gross sales proceeds. In addition, the Partnership is continuing to take proactive steps with a long-term view to address its 2018 debt maturities and has engaged Greenhill & Co., LLC to advise in connection with these efforts. The Partnership is currently in active discussions with several institutional investors that may provide new equity capital to it. In addition, the Partnership has begun discussions with representatives of several holders of the NRP Senior Notes, and it may determine to pursue a refinancing or an exchange of some or all those notes. As the Partnership pursues these capital markets transactions, it will continue to manage its business with a focus on debt reduction, cost management, and maximizing opportunities within its current asset base, including additional asset sales. The coal markets have shown improvement during the third quarter of 2016, particularly with respect to metallurgical coal, and the Partnership expects its coal royalty business to benefit from the higher pricing environment. However, to the extent that the Partnership is unable to execute on opportunistic capital raising and/or debt refinancing efforts on favorable terms and the coal markets do not show a sustained improvement, the Partnership’s liquidity may be adversely affected. Accordingly, the Partnership may consider other alternatives over the next several months to manage its liquidity and address its debt maturities. Recently Issued Accounting Standards Not Yet Adopted The Financial Accounting Standards Board ("FASB") amended its guidance on revenue recognition. The core principle of this amendment is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance will also require enhanced disclosures, provide more comprehensive guidance for transactions such as service revenue and contract modifications, and enhance guidance for multiple-element arrangements. The Partnership is required to adopt this guidance in the first quarter of 2018 using one of two retrospective application methods. The Partnership is currently evaluating the provisions of this guidance and has not determined the impact this guidance may have on its consolidated financial statements and related disclosure or decided upon the method of adoption. The FASB issued guidance on management’s responsibility to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern and to provide related footnote disclosures. The new guidance will require a formal assessment of going concern by management based on criteria prescribed in the new guidance, but will not impact the Partnership's financial position or results of operations. This guidance is effective for annual periods ending after December 15, 2016, and interim periods thereafter. Early adoption is permitted for annual or interim reporting periods for which the financial statements have not previously been issued. The Partnership is evaluating the impact this guidance will have on its consolidated financial statements and related disclosure and reviewing its policies and processes to ensure compliance with this new guidance upon adoption. The FASB issued authoritative guidance which intended to simplify the measurement of inventory. This guidance requires an entity to measure inventory at the lower of cost or net realizable value, and defines net realizable value as the estimated selling price in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. This guidance is effective for annual and interim periods ending after December 15, 2016. The Partnership is currently evaluating the impact of this guidance on its consolidated financial statements. The FASB issued authoritative lease guidance that requires lessees to recognize assets and liabilities on the balance sheet for the present value of the rights and obligations created by all leases with terms of more than 12 months. The guidance also requires disclosures designed to give financial statement users information on the amount, timing, and uncertainty of cash flows arising from leases. The guidance is effective for annual and interim periods ending after December 31, 2018. The Partnership is currently evaluating the impact of the provisions of this guidance on its consolidated financial statements. The FASB issued authoritative guidance that replaces the incurred loss impairment methodology in the current standard with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The guidance is effective for annual and interim periods ending after December 31, 2019. The Partnership is currently evaluating the impact of the provisions of this guidance on its consolidated financial statements. The FASB issued authoritative guidance to clarify how certain cash receipts and cash payments are presented and classified in the statement of cash flows in order to reduce current and potential future diversity in practice. The guidance is effective for annual and interim periods ending after December 31, 2017. The Partnership is currently evaluating the impact of the provisions of this guidance on its consolidated financial statements.

Discontinued Operations

Discontinued Operations	9 Months Ended
	Sep. 30, 2016
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	Discontinued Operations In June 2016, the Partnership determined it met held for sale criteria for its non-operated oil and gas working interest assets. In June 2016, NRP Oil and Gas signed a definitive agreement to sell these assets for $116.1 million , subject to customary closing conditions and purchase price adjustments. In July 2016, NRP Oil and Gas closed this transaction, which had an effective date of April 1, 2016. The Partnership's exit from its non-operated oil and gas working interest business represents a strategic shift to reduce debt and focus on its aggregates, soda ash and coal royalty and other business segments. As a result, the Partnership has classified the operating results and cash flows of its non-operated oil and gas working interest assets as discontinued operations in its consolidated statements of comprehensive income and consolidated statements of cash flows for all periods presented. Prior to this exit, the Partnership's non-operated oil and gas working interest assets were included along with its oil and gas royalty assets as a separate reportable segment. During the third quarter of 2016, the Partnership transitioned management responsibilities and reporting of its oil and gas royalty assets into its Coal Royalty and Other operating segment and eliminated its Oil and Gas segment. See Note 3. Segment Information for further segment information. The following table (in thousands) presents summarized financial results of the Partnership's discontinued operations in the Consolidated Statements of Comprehensive Income: Three Months Ended Nine Months Ended September 30, September 30, 2016 2015 2016 2015 (Unaudited) (Unaudited) Revenues and other income: Oil and gas $ 41 $ 11,447 $ 16,476 $ 38,558 Gain on asset sales 8,468 — 8,284 451 Total revenues and other income 8,509 11,447 24,760 39,009 Operating expenses: Operating and maintenance expenses (including affiliates) 928 4,584 11,180 15,171 Depreciation, depletion and amortization — 10,187 7,527 35,648 Asset impairments — 265,135 564 265,135 Total operating expenses 928 279,906 19,271 315,954 Interest expense (469 ) (806 ) (3,488 ) (3,021 ) Income (loss) from discontinued operations $ 7,112 $ (269,265 ) $ 2,001 $ (279,966 ) The following table (in thousands) presents the carrying amounts of the Partnership's assets and liabilities of discontinued operations in the Consolidated Balance Sheets: September 30, December 31, (Unaudited) ASSETS Current assets: Cash and cash equivalents $ — $ 10,569 Accounts receivable, net 991 7,053 Other — 222 Total current assets 991 17,844 Mineral rights, net — 109,505 Other non-current assets — 657 Total assets of discontinued operations $ 991 $ 128,006 LIABILITIES Current liabilities: Other (including affiliates) (1) $ 835 $ 4,388 Total current liabilities 835 4,388 Long-term debt, net (2) — 83,600 Other non-current liabilities — 1,637 Total liabilities of discontinued operations $ 835 $ 89,625 (1) See Note 10. Related Party Transactions for additional information on the Partnership's related party assets and liabilities. (2) The Partnership identified the NRP Oil and Gas reserve based lending facility (the "RBL Facility") as specifically attributed to its non-operated oil and gas working interest assets and included the interest from this debt in discontinued operations. See Note 8. Debt and Debt—Affiliate for additional information on the Partnership's debt related to discontinued operations. The following table (in thousands) presents supplemental cash flow information of the Partnership's discontinued operations: Nine Months Ended September 30, 2016 2015 (Unaudited) Cash paid for interest $ 1,906 $ 2,156 Plant, equipment and mineral rights funded with accounts payable or accrued liabilities — 3,336 Capital expenditures related to the Partnership's discontinued operations were $3.1 million and $36.0 million during the nine months ended September 30, 2016 and 2015, respectively.

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2016
Segment Reporting [Abstract]
Segment Information	Segment Information The Partnership's segments are strategic business units that offer products and services to different customer segments in different geographies within the U.S. and that are managed accordingly. NRP has the following three operating segments: Coal Royalty and Other —consists primarily of coal royalty and coal related transportation and processing assets. Other assets include aggregate royalty, industrial mineral royalty, oil and gas royalty and timber. The Partnership's coal reserves are primarily located in Appalachia, the Illinois Basin and the Western United States. Its aggregates and industrial minerals are located in a number of states across the United States. As a result of the sale of its non-operated oil and gas working interest assets and exit from this oil and gas business in the third quarter of 2016, the Partnership transitioned management responsibilities and reporting of its oil and gas royalty assets into the Coal Royalty and Other operating segment. The Partnership has adjusted the corresponding items of segment information for prior periods to reflect this change. In February 2016, the Partnership sold reserves and related royalty rights at three aggregates operations located in Texas, Georgia and Tennessee. In February 2016, the Partnership also sold royalty and overriding royalty interests in several oil and gas producing properties located in the Appalachian Basin. Soda Ash —consists of the Partnership's 49% non-controlling equity interest in a trona ore mining operation and soda ash refinery in the Green River Basin, 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 into the glass and chemicals industries. The Partnership receive regular quarterly distributions from this business. VantaCore —consists of the Partnership's construction materials business that operates hard rock quarries, an underground limestone mine, sand and gravel plants, asphalt plants and marine terminals. VantaCore operates in Pennsylvania, West Virginia, Tennessee, Kentucky and Louisiana. Direct segment costs and certain costs incurred at a corporate level that are identifiable and that benefit the Partnership's segments are allocated to the operating segments. These allocated costs include costs of: taxes, legal, information technology and shared facilities services and are included in Operating and maintenance expenses and Operating and maintenance expenses—affiliates on the Consolidated Statements of Comprehensive Income. Prior year general and administrative charges of $4.8 million and $15.1 million for the three and nine months ended September 30, 2015, respectively, were allocated to the operating segments and have been reclassified to operating and maintenance expenses. Intersegment sales are at prices that approximate market. Corporate and Financing includes functional corporate departments that do not earn revenues. Costs incurred by these departments include corporate headquarters and overhead, financing, centralized treasury and accounting and other corporate-level activity not specifically allocated to a segment. The following table summarizes certain financial information for each of the Partnership's operating segments (in thousands): Operating Segments Coal Royalty and Other Soda Ash VantaCore Corporate and Financing Total For the Three Months Ended September 30, 2016 Revenues (including affiliates) $ 48,938 $ 10,753 $ 31,757 $ — $ 91,448 Intersegment revenues (expenses) 45 — (45 ) — — Gain on asset sales 6,425 — 1 — 6,426 Operating and maintenance expenses (including affiliates) 8,391 — 26,913 — 35,304 Depreciation, depletion and amortization (including affiliates) 9,070 — 3,761 — 12,831 Asset impairment 5,697 — — — 5,697 Other expense, net — — — 22,488 22,488 Net income (loss) from continuing operations 32,250 10,753 1,039 (27,623 ) 16,419 Net income (loss) from discontinued operations — — — — 7,112 For the Three Months Ended September 30, 2015 Revenues (including affiliates) $ 59,966 $ 12,617 $ 39,616 $ — $ 112,199 Gain (loss) on asset sales 2,256 — (423 ) — 1,833 Operating and maintenance expenses (including affiliates) 6,832 — 32,658 — 39,490 Depreciation, depletion and amortization (including affiliates) 12,659 — 3,778 — 16,437 Asset impairment 361,703 — — — 361,703 Other expense, net — — — 22,905 22,905 Net income (loss) from continuing operations (318,972 ) 12,617 2,757 (27,138 ) (330,736 ) Net loss from discontinued operations — — — — (269,265 ) For the Nine Months Ended September 30, 2016 Revenues (including affiliates) $ 165,844 30,742 88,081 — 284,667 Intersegment revenues (expenses) 97 — (97 ) — — Gain on asset sales 27,270 — 10 — 27,280 Operating and maintenance expenses (including affiliates) 24,232 — 73,540 — 97,772 Depreciation, depletion and amortization (including affiliates) 23,496 — 11,013 — 34,509 Asset impairment 7,681 — — — 7,681 Other expense, net — — — 67,236 67,236 Net income (loss) from continuing operations 137,802 30,742 3,441 (80,582 ) 91,403 Net income (loss) from discontinued operations — — — — 2,001 For the Nine Months Ended September 30, 2015 Revenues (including affiliates) 183,077 36,739 107,058 — 326,874 Gain (loss) on asset sales 6,927 — (24 ) — 6,903 Operating and maintenance expenses (including affiliates) 23,772 — 90,656 — 114,428 Depreciation, depletion and amortization (including affiliates) 34,529 — 12,499 — 47,028 Asset impairment 365,506 — — — 365,506 Other expense, net — — — 66,960 66,960 Net income (loss) from continuing operations (233,803 ) 36,739 3,879 (76,783 ) (269,968 ) Net loss from discontinued operations — — — — (279,996 ) Total Assets of Continuing Operations September 30, 2016 1,007,034 257,661 195,617 60,103 1,520,415 December 31, 2015 1,078,778 261,942 200,348 961 1,542,029

Equity Investment

Equity Investment	9 Months Ended
	Sep. 30, 2016
Equity Method Investments and Joint Ventures [Abstract]
Equity Investment	Equity Investment The Partnership accounts for its 49% investment in Ciner Wyoming LLC ("Ciner Wyoming") using the equity method of accounting. Ciner Wyoming distributed $34.3 million and $34.5 million to us in the nine months ended September 30, 2016 and 2015 , respectively. The difference between the amount at which the investment in Ciner Wyoming is carried and the amount of underlying equity in Ciner Wyoming's net assets was $150.9 million and $154.8 million as of September 30, 2016 and December 31, 2015 , respectively. This excess basis relates to plant, property and equipment and right to mine assets. The excess basis difference that relates to property, plant and equipment is being amortized into income using the straight-line method over a weighted average of 28 years . The excess basis difference that relates to right to mine assets is being amortized into income using the units of production method. The Partnership's equity in the earnings of Ciner Wyoming is summarized as follows (in thousands): Three Months Ended Nine Months Ended 2016 2015 2016 2015 (Unaudited) (Unaudited) Income allocation to NRP’s equity interests $ 11,973 $ 13,806 $ 34,357 $ 40,319 Amortization of basis difference (1,220 ) (1,189 ) (3,615 ) (3,580 ) Equity in earnings of unconsolidated investment $ 10,753 $ 12,617 $ 30,742 $ 36,739 The results of Ciner Wyoming’s operations are summarized as follows (in thousands): Three Months Ended Nine Months Ended 2016 2015 2016 2015 (Unaudited) (Unaudited) Sales $ 121,003 $ 117,340 $ 352,085 $ 359,970 Gross profit 30,673 32,750 87,656 96,565 Net Income 24,436 28,175 70,118 82,283 The financial position of Ciner Wyoming is summarized as follows (in thousands): September 30, December 31, (Unaudited) Current assets $ 142,549 $ 144,695 Noncurrent assets 232,462 233,845 Current liabilities 57,071 43,018 Noncurrent liabilities 100,000 116,808 The purchase agreement for the acquisition of the Partnership’s interest in Ciner Wyoming required the Partnership to pay additional contingent consideration to Anadarko to the extent certain performance criteria described in the purchase agreement were met by Ciner Wyoming in any of the years 2013, 2014 or 2015. During the first quarters of 2014, 2015 and 2016, the Partnership paid contingent consideration of $0.5 million , $3.8 million and $7.2 million , respectively, in contingent consideration to Anadarko for performance criteria met by Ciner Wyoming in 2013, 2014 and 2015, respectively. The Partnership has no further contingent consideration payments due to Anadarko under the purchase agreement.

Plant and Equipment

Plant and Equipment	9 Months Ended
	Sep. 30, 2016
Property, Plant and Equipment [Abstract]
Plant and Equipment	Plant and Equipment The Partnership’s plant and equipment consist of the following (in thousands): September 30, December 31, (Unaudited) Plant and equipment at cost $ 77,377 $ 92,049 Construction in process 1,717 646 Less accumulated depreciation (26,578 ) (32,020 ) Total plant and equipment, net $ 52,516 $ 60,675 Depreciation expense related to the Partnership's plant and equipment totaled $3.1 million and $3.9 million for the three months ended September 30, 2016 and 2015 , respectively. Depreciation expense related to the Partnership's plant and equipment totaled $9.5 million and $12.9 million for the nine months ended September 30, 2016 and 2015 , respectively.

Mineral Rights

Mineral Rights	9 Months Ended
	Sep. 30, 2016
Extractive Industries [Abstract]
Mineral Rights	Mineral Rights The Partnership’s mineral rights consist of the following (in thousands): September 30, 2016 (Unaudited) Carrying Value Accumulated Depletion Net Book Value Coal Royalty and Other $ 1,270,295 $ (454,261 ) $ 816,034 VantaCore 112,700 (4,553 ) 108,147 Total $ 1,382,995 $ (458,814 ) $ 924,181 December 31, 2015 Carrying Value Accumulated Depletion Net Book Value Coal Royalty and Other $ 1,317,158 $ (442,254 ) $ 874,904 VantaCore 112,700 (3,082 ) 109,618 Total $ 1,429,858 $ (445,336 ) $ 984,522 Depletion expense related to the Partnership’s mineral rights totaled $8.6 million and $11.6 million for the three months ended September 30, 2016 and 2015 , respectively. Depletion expense related to the Partnership's mineral rights totaled $21.9 million and $30.9 million for the nine months ended September 30, 2016 and 2015 , respectively. Sales of Royalty Properties As discussed in Note 1. "Basis of Presentation," the Partnership is currently pursuing or considering a number of actions, including dispositions of assets, in order to mitigate the effects of adverse market developments which could otherwise cause the Partnership to breach financial covenants under its debt agreements. As part of this plan, the Partnership executed a definitive agreement to sell all its mineral fee interests in Grant County, Oklahoma. As a result, approximately $5.5 million in the Partnership's oil and gas royalty mineral rights are classified as Current assets held for sale on the Consolidated Balance Sheets at September 30, 2016. In addition, the Partnership completed the sale of the following assets during the nine months ended September 30, 2016 : 1) Oil and gas royalty and overriding royalty interests in several producing properties located in the Appalachian Basin for $36.4 million . The effective date of the sale was January 1, 2016, and the Partnership recorded an $18.6 million gain from this sale included in Gain on asset sales, net on its Consolidated Statement of Comprehensive Income. 2) Hard mineral reserves and related royalty rights at three aggregates operations located in Texas, Georgia and Tennessee for $10.0 million . The effective date of the sale was February 1, 2016, and the Partnership recorded a $1.5 million gain from this sale included in Gain on asset sales, net on its Consolidated Statement of Comprehensive Income. In addition to the two asset sales described above, during the nine months ended September 30, 2016, the Partnership sold mineral reserves in multiple sale transactions for cumulative $9.8 million of gross sales proceeds and recorded $6.8 million of cumulative gain from these sale transactions that are included in Gain on asset sales, net on its Consolidated Statement of Comprehensive Income. The substantial majority of these amounts relate to eminent domain transactions with governmental agencies. During the nine months ended September 30, 2015, the Partnership sold mineral reserves for $3.7 million in gross sales proceeds and recorded a $3.3 million gain on asset sales included in Gain on asset sales, net on its Consolidated Statement of Comprehensive Income. Impairment of Mineral Rights The Partnership has developed procedures to periodically evaluate its long-lived assets for possible impairment. These procedures are performed throughout the year and consider both quantitative and qualitative information based on historic, current and future performance and are designed to identify impairment indicators. If an impairment indicator is identified, additional evaluation is performed for that asset that considers both quantitative and qualitative information. A long-lived asset is deemed impaired when the future expected undiscounted cash flows from its use and disposition are less than the assets’ carrying value. Impairment is measured based on the estimated fair value, which is primarily determined based upon the present value of the projected future cash flow compared to the assets’ carrying value. The inputs used by management for fair value measurements include significant inputs that are not observable in the market and thus represent a Level 3 fair value measurement for these types of assets. In addition to the evaluations discussed above, specific events such as a reduction in economically recoverable reserves or production ceasing on a property for an extended period may require that a separate impairment evaluation be completed on a significant property. The Partnership believes the discount rates used in estimating fair value were representative of what market participants would use in valuing the impacted assets. During the three and nine months ended September 30, 2016 and 2015, the Partnership identified facts and circumstances that indicated that the carrying value of certain of its mineral rights exceed future cash flows from those assets and recorded non-cash impairment expense as follows (in thousands): Three Months Ended Nine Months Ended Impaired Asset Description 2016 2015 2016 2015 (Unaudited) Coal properties (1) $ 3,817 $ 247,815 $ 3,908 $ 249,362 Oil and gas royalty properties (2) 36 70,527 36 70,527 Aggregates royalty properties (3) 1,411 43,361 1,677 43,361 Total $ 5,264 $ 361,703 $ 5,621 $ 363,250 (1) The Partnership recorded $3.8 million and $3.9 million of coal property impairments during the three and nine months ended September 30, 2016, respectively. Total coal property impairment expense for the nine months ended September 30, 2015 was $249.4 million . The Partnership recorded $1.5 million of coal property impairment during the three months ended June 30, 2015 and the fair value measurement of these impaired assets recorded at fair value was $0.0 million at June 30, 2015. The Partnership recorded the remaining $247.8 million of coal property impairment during the three months ended September 30, 2015 and the fair value measurement of these impaired assets recorded at fair value was $28.4 million at September 30, 2015. These impairments primarily resulted from the continued deterioration and expectations of further reductions in global and domestic coal demand due to reduced global steel demand, sustained low natural gas prices, and continued regulatory pressure on the electric power generation industry. NRP compared net capitalized costs of its coal properties to estimated undiscounted future net cash flows. If the net capitalized cost exceeded the undiscounted future cash flows, the Partnership recorded an impairment for the excess of net capitalized cost over fair value. Significant inputs used to determine fair value include estimates of future cash flow, discount rate and useful economic life. Estimated cash flows are the product of a process that began with current realized pricing as of the measurement date and included an adjustment for risk related to the future realization of cash flows. (2) The Partnership recorded $70.5 million of oil and gas royalty property impairment during the three and nine months ended September 30, 2015. The fair value measurement of these impaired assets recorded at fair value were $13.0 million at September 30, 2015. This impairment primarily resulted from declines in future expected realized commodity prices and reduced expected drilling activity on its acreage. NRP compared net capitalized costs of its oil and gas royalty properties to estimated undiscounted future net cash flows. If the net capitalized cost exceeded the undiscounted future net cash flows, the Partnership recorded an impairment for the excess of net capitalized cost over fair value. A discounted cash flow method was used to estimate fair value. Significant inputs used to determine the fair value include estimates of: (i) oil and gas reserves and risk-adjusted probable and possible reserves; (ii) future commodity prices; (iii) production costs, (iv) capital expenditures, (v) production and (vi) discount rates. The underlying commodity prices embedded in the Partnership's estimated cash flows are the product of a process that begins with NYMEX forward curve pricing as of the measurement date, adjusted for estimated location and quality differentials. (3) The Partnership recorded $1.4 million and $1.7 million of aggregates royalty property impairments during the three and nine months ended September 30, 2016, respectively. The Partnership recorded $43.4 million of aggregates royalty property impairments during the three and nine months ended September 30, 2015. The fair value measurement of these impaired assets recorded at fair value was $13.1 million at September 30, 2015. This impairment primarily resulted from greenfield development projects that have not performed as projected, leading to recent lease concessions on minimums and royalties combined with the continued regional market decline for certain properties. NRP compared net capitalized costs of its aggregates properties to estimated undiscounted future net cash flows. If the net capitalized cost exceeded the undiscounted cash flows, the Partnership recorded an impairment for the excess of net capitalized cost over fair value. A discounted cash flow model was used to estimate fair value. Significant inputs used to determine fair value include estimates of future cash flow, discount rate and useful economic life. Estimated cash flows are the product of a process that began with current realized pricing as of the measurement date and included an adjustment for risk related to the future realization of cash flows.

Intangible Assets (Including Af

Intangible Assets (Including Affiliate)	9 Months Ended
	Sep. 30, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets (Including Affiliate)	Intangible Assets (Including Affiliate) The Partnership's intangible assets—affiliate relate to above market coal transportation contracts with subsidiaries of Foresight Energy LP ("Foresight Energy"), pursuant to which it receives throughput fees for the handling and transportation of coal. September 30, December 31, (Unaudited) Intangible assets—affiliate $ 81,109 $ 81,109 Less accumulated amortization—affiliate (30,441 ) (28,112 ) Total intangible assets, net—affiliate $ 50,668 $ 52,997 Amortization expense related to the Partnership's intangible assets—affiliate totaled $0.9 million and $0.7 million for the three months ended September 30, 2016 and 2015 , respectively. Amortization expense related to the Partnership's intangible assets—affiliate totaled $2.3 million and $2.5 million for the nine months ended September 30, 2016 and 2015 , respectively. The Partnership's intangible assets consist of permits, aggregate-related trade names and other agreements as follows (in thousands): September 30, December 31, (Unaudited) Intangible assets $ 5,077 $ 5,076 Less accumulated amortization (1,838 ) (1,146 ) Total intangible assets, net $ 3,239 $ 3,930 Amortization expense related to the Partnership's intangible assets totaled $0.2 million and $0.7 million for both the three and nine months ended September 30, 2016 and 2015 , respectively.

Debt and Debt - Affiliate

Debt and Debt - Affiliate	9 Months Ended
	Sep. 30, 2016
Debt Disclosure [Abstract]
Debt and Debt—Affiliate	Debt and Debt—Affiliate As of September 30, 2016 and December 31, 2015, debt and debt—affiliate consisted of the following (in thousands): September 30, December 31, (Unaudited) NRP LP debt: 9.125% senior notes, with semi-annual interest payments in April and October, due October 2018, $300 million issued at 99.007% and $125 million issued at 99.5% $ 425,000 $ 425,000 Opco debt (1): Revolving credit facility, due June 2018 260,000 290,000 Senior notes 4.91% with semi-annual interest payments in June and December, with annual principal payments in June, due June 2018 9,233 13,850 8.38% with semi-annual interest payments in March and September, with annual principal payments in March, due March 2019 64,286 85,714 5.05% with semi-annual interest payments in January and July, with annual principal payments in July, due July 2020 30,769 38,462 5.55% with semi-annual interest payments in June and December, with annual principal payments in June, due June 2023 18,900 21,600 4.73% with semi-annual interest payments in June and December, with annual principal payments in December, due December 2023 60,000 60,000 5.82% with semi-annual interest payments in March and September, with annual principal payments in March, due March 2024 120,000 135,000 8.92% with semi-annual interest payments in March and September, with annual principal payments in March, due March 2024 36,364 40,909 5.03% with semi-annual interest payments in June and December, with annual principal payments in December, due December 2026 148,077 148,077 5.18% with semi-annual interest payments in June and December, with annual principal payments in December, due December 2026 42,308 42,308 5.31% utility local improvement obligation, with annual principal and interest payments in February, due March 2021 $ 961 $ 1,153 NRP Oil and Gas debt: Revolving credit facility — 85,000 Total debt at face value $ 1,215,898 $ 1,387,073 Net unamortized debt discount (1,511 ) (2,077 ) Net unamortized debt issuance costs (1) (13,806 ) (14,040 ) Total debt, net $ 1,200,581 $ 1,370,956 Less: current portion of long-term debt 158,597 80,745 Less: debt classified as non-current liabilities of discontinued operations — 83,600 Total long-term debt $ 1,041,984 $ 1,206,611 (1) See Note 1. Basis of Presentation for discussion of debt issuance costs reclassification upon adoption of new accounting standard on January 1, 2016. NRP LP Debt NRP Senior Notes In September 2013, the Partnership, together with NRP Finance Corporation ("NRP Finance"), a wholly owned subsidiary of the Partnership, as co-issuer, issued $300.0 million of 9.125% Senior Notes at an offering price of 99.007% of par (the "NRP Senior Notes"). Net proceeds after expenses from the issuance of NRP Senior Notes were approximately $289.0 million . The NRP Senior Notes call for semi-annual interest payments on April 1 and October 1 of each year, and will mature on October 1, 2018. In October 2014, the Partnership, together with NRP Finance as co-issuer, issued an additional $125.0 million of the NRP Senior Notes at an offering price of 99.5% of par. The additional issuance constituted the same series of securities as the existing NRP Senior Notes. Net proceeds of $122.6 million from the additional issuance of the NRP Senior Notes were used to fund a portion of the purchase price of NRP’s acquisition of non-operated working interests in oil and gas assets located in the Williston Basin in North Dakota. The Partnership and NRP Finance have the option to redeem the NRP Senior Notes, in whole or in part, at any time on or after April 1, 2016, at fixed redemption prices specified in the indenture governing the NRP Senior Notes (the "Indenture"). The Indenture contains covenants that, among other things, limit the ability of the Partnership and certain of its subsidiaries to incur or guarantee additional indebtedness. Under the Indenture, the Partnership and certain of its subsidiaries generally are not permitted to incur additional indebtedness unless, on a consolidated basis, the fixed charge coverage ratio (as defined in the indenture) is at least 2.0 to 1.0 for the four preceding full fiscal quarters. The ability of the Partnership and certain of its subsidiaries to incur additional indebtedness is further limited in the event the amount of indebtedness of the Partnership and certain of its subsidiaries that is senior to the Partnership's unsecured indebtedness exceeds certain thresholds. 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 further described below. As of September 30, 2016 and December 31, 2015, Opco was in compliance with the terms of the financial covenants contained in its debt agreements. Opco Credit Facility In June 2016, Opco entered into an amendment (the "First Amendment") to its Amended and Restated Credit Agreement (the "Opco Credit Facility") that is guaranteed by all of Opco’s wholly owned subsidiaries, and is secured by liens on certain of the assets of Opco and its subsidiaries, as further described below. Under the First Amendment: • The maturity date of the Opco Credit Facility was extended from October 1, 2017 to June 30, 2018; • The maximum leverage ratio of consolidated indebtedness to consolidated EBITDDA (as defined in the Opco Credit Facility) has been amended to remain at 4.0 x for the remaining term of the Opco Credit Facility, including for the period ending June 30, 2016; and • The asset sale covenant was amended to allow asset sales of up to $300.0 million from and after the effective date of the First Amendment; provided, however, that 75% of the net cash proceeds of any such asset sales must be used to repay the Opco Credit Facility (without any corresponding commitment reduction) and/or NRP Opco’s Senior Notes described below. On the effective date of the First Amendment, the total commitment under the Opco Credit Facility was reduced from $300.0 million to $260.0 million . In addition, Opco and the lenders agreed to further reduce commitments under the Opco Credit Facility to (a) $210.0 million on December 31, 2016, (b) $180.0 million on June 30, 2017 and (c) $150.0 million on December 31, 2017. Opco will have the right to delay any of these commitment reductions by up to 90 days each upon the agreement of the lenders holding 66.7% of the then-existing commitments. To the extent any such commitment reduction is extended under the terms of the A&R Revolving Credit Facility, Opco's ability to make distributions to the Partnership will be limited to amounts necessary for the Partnership to pay taxes and other general partnership expenses and make interest payments on its 9.125% Senior Notes due 2018. In addition to the 4.0x leverage ratio described above, the Opco Credit Facility requires Opco to maintain a 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, 2016 , Opco's leverage ratio was 2.95 x, and fixed charge coverage ratio was 5.46 x. Effective on the date of the First Amendment, indebtedness under the Opco Credit Facility bears interest, at Opco's option, at: • the higher of (i) the prime rate as announced by the agent bank; (ii) the federal funds rate plus 0.50% ; or (iii) LIBOR plus 1% , in each case plus an applicable margin ranging from 2.50% to 3.50% ; or • a rate equal to LIBOR plus an applicable margin ranging from 3.50% to 4.50% . The weighted average interest rates for the borrowings outstanding under the Opco Credit Facility for the three months ended September 30, 2016 and 2015 were 4.87% and 3.05% , respectively. The weighted average interest rates for the borrowings outstanding under the Opco Credit Facility for the nine months ended September 30, 2016 and 2015 were 4.24% and 2.41% , respectively. Opco will incur a commitment fee on the unused portion of the revolving credit facility at a rate of 0.50% per annum. Opco may prepay all amounts outstanding under the Opco Credit Facility at any time without penalty. The Opco Credit Facility contains certain additional customary negative covenants that, among other items, restrict Opco’s ability to incur additional debt, grant liens on its assets, make investments, sell assets and engage in business combinations. Included in the investment covenant are restrictions upon Opco’s ability to acquire assets where Opco does not maintain certain levels of liquidity. The Opco Credit Facility also contains customary events of default, including cross-defaults under Opco’s senior notes (as described below). The Opco Credit Facility is collateralized and secured by liens on certain of Opco’s assets with carrying values of $680.5 million and $709.9 million classified as Land, Plant and equipment and Mineral rights on the Partnership’s Consolidated Balance Sheet as of September 30, 2016 and December 31, 2015, respectively. The collateral includes (1) the equity interests in all of Opco’s wholly owned subsidiaries, other than NRP Trona LLC (which owns a 49% non-controlling equity interest in Ciner Wyoming), (2) the personal property and fixtures owned by Opco’s wholly owned subsidiaries, other than NRP Trona LLC, (3) Opco’s material coal royalty revenue producing properties, (4) real property associated with certain of VantaCore’s construction aggregates mining operations, and (5) certain of Opco’s coal-related infrastructure assets. Opco Senior Notes Opco has issued several series of private placement senior notes (the "Opco Senior Notes") with various interest rates and principal due dates. As of September 30, 2016 , and December 31, 2015, the Opco Senior Notes had cumulative principal balances of $529.9 million and $585.9 million , respectively. Opco made principal payments of $56.0 million on the Opco Senior Notes during both the nine months ended September 30, 2016 and 2015. The Note Purchase Agreements relating to the Opco Senior Notes contain covenants requiring Opco to: • maintain a ratio of consolidated indebtedness to consolidated EBITDDA (as defined in the note purchase agreement) of no more than 4.0 to 1.0 for the four most recent quarters; • not permit debt secured by certain liens and debt of subsidiaries to exceed 10% of consolidated net tangible assets (as defined in the note purchase agreement); and • maintain the ratio of consolidated EBITDDA (as defined in the note purchase agreement) to consolidated fixed charges (consisting of consolidated interest expense and consolidated operating lease expense) at not less than 3.5 to 1.0. The 8.38% and 8.92% Opco Senior Notes also provide 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, 2016 . In September 2016, Opco amended the Opco Senior Notes. Under this amendment, Opco agreed to use certain asset sale proceeds to make mandatory prepayment offers on the Opco Senior Notes as follows: • Until the earlier of the time that (1) Opco has sold $300 million of assets and (2) June 30, 2020, Opco will be required to make prepayment offers to the holders of the Opco Senior Notes using 25% of the net cash proceeds from certain asset sales; and • After the earlier to occur of the dates above, Opco will be required to make prepayment offers to the holders of the Opco Senior Notes using an amount of net cash proceeds from certain asset sales that will be calculated pro-rata based on the amount of Opco Senior Notes then outstanding compared to the other total Opco senior debt outstanding that is being prepaid. The mandatory prepayment offers described above will be made pro-rata across each series of outstanding Opco Senior Notes and will not require any make-whole payment by Opco. In addition, the remaining principal and interest payments on the Opco Senior Notes will be adjusted accordingly based on the amount of Opco Senior Notes actually prepaid. The prepayments do not affect the maturity dates of any series of the Opco Senior Notes. NRP Oil and Gas Debt Classified as Liabilities of Discontinued Operations RBL Facility In August 2013, NRP Oil and Gas entered into the RBL Facility, a senior secured, reserve-based revolving credit facility, in order to fund capital expenditure requirements related to the development of the oil and gas assets in which it owned non-operated working interests. The RBL Facility was secured by a first priority lien and security interest in substantially all of the assets of NRP Oil and Gas. NRP Oil and Gas was the sole obligor under the RBL Facility, and neither the Partnership nor any of its other subsidiaries was a guarantor of the RBL Facility. At December 31, 2015, there was $85.0 million respectively, outstanding under the RBL Facility. As described in Note 2. Discontinued Operations , the Partnership included this debt and its related interest expense in discontinued operations. In July 2016, NRP Oil and Gas LLC closed the sale of its non-operated oil and gas working interest assets and used a portion of the proceeds to repay the RBL Facility in full.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The Partnership’s financial instruments consist of cash and cash equivalents, accounts receivable, contracts receivable—affiliate, accounts payable and debt. The carrying amounts reported on the Partnership's Consolidated Balance Sheets for cash and cash equivalents, accounts receivable and accounts payable approximate fair value due to their short-term nature. The following table (in thousands) shows the carrying value and estimated fair value of the Partnership's debt, debt—affiliate and contracts receivable—affiliate: September 30, 2016 December 31, 2015 Carrying Estimated Carrying Estimated (Unaudited) Debt and debt—affiliate: NRP Senior Notes (1) $ 419,397 $ 391,531 $ 417,296 $ 277,313 Opco Senior Notes and utility local improvement obligation (2) 527,016 489,090 584,890 383,065 Opco Revolving Credit Facility (3) 254,168 260,000 285,170 290,000 NRP Oil and Gas RBL Facility (3) — — 83,600 85,000 Assets: Contracts receivable—affiliate, current and long-term (2) $ 47,542 $ 32,861 $ 49,948 $ 34,498 (1) The Level 1 fair value is based upon quotations obtained for identical instruments on the closing trading prices near period end. (2) The Level 3 fair value is estimated by management using quotations obtained for comparable instruments on the closing trading prices near period end. (3) The Level 3 fair value approximates the outstanding borrowing amount because the interest rates are variable and reflective of market rates and the terms of the credit facility allow the Partnership to repay this debt at any time without penalty.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2016
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Reimbursements to Affiliates of NRP's General Partner The Partnership’s general partner does not receive any management fee or other compensation for its management of Natural Resource Partners L.P. 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. In addition, the Partnership receives non-cash equity contributions from its general partner related to compensation paid directly by the general partner and not reimbursed by the Partnership. These amounts are presented as non-cash equity contributions on the Partnership's Consolidated Statements of Partners' Capital and were $0.2 million during the nine months ended September 30, 2016. These QMC and WPPLP employee management service costs and non-cash equity compensation expenses are presented as Operating and maintenance expenses—affiliates, net and General and administrative—affiliates on the 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 legal, accounting, treasury, information technology, insurance, administration of employee benefits and other corporate services incurred by the Partnership’s general partner and its affiliates and are presented as Operating and maintenance expenses—affiliates, net and General and administrative—affiliates on the Consolidated Statements of Comprehensive Income. The Partnership had Accounts payable—affiliates to Quintana Minerals Corporation of $0.5 million and $1.1 million , including $0.1 million and $0.7 million related to discontinued operations at September 30, 2016 and December 31, 2015, respectively, for services provided by Quintana Minerals Corporation to the Partnership. The Partnership had Accounts payable—affiliates to WPPLP of $0.5 million and $0.3 million at September 30, 2016 and December 31, 2015, respectively. Direct general and administrative expenses charged to the Partnership by WPPLP and Quintana Minerals Corporation are as follows (in thousands): Three Months Ended Nine Months Ended 2016 2015 2016 2015 (Unaudited) (Unaudited) Operating and maintenance expenses—affiliates, net $ 1,980 $ 1,540 $ 6,591 $ 7,068 General and administrative—affiliates 867 2,424 2,670 3,809 Included in income (loss) from discontinued operations are $0.4 million and $1.2 million and $0.2 million and $0.6 million of operating and maintenance expenses charged by Quintana Minerals Corporation for the three and nine months ended September 30, 2016 and 2015, respectively. Cline Affiliates Various companies controlled by Chris Cline, including Foresight Energy LP ("Foresight Energy"), lease coal reserves from the Partnership, and NRP also leases coal transportation assets to these companies for a fee. Mr. Cline owns a 31% interest in the Partnership's general partner through his affiliate Adena Minerals, LLC, as well as approximately 0.5 million of the Partnership's common units at September 30, 2016 . Coal related revenues from Foresight Energy totaled $20.6 million and $18.7 million for the three months ended September 30, 2016 and 2015, respectively. Coal related revenues from Foresight Energy totaled $47.6 million and $68.6 million for the nine months ended September 30, 2016 and 2015, respectively. As of September 30, 2016 and December 31, 2015, the Partnership had Accounts receivable—affiliates from Foresight Energy of $6.9 million and $6.4 million , respectively. The Partnership had recorded $74.7 million and $82.6 million in minimum royalty payments as Deferred revenue—affiliates at September 30, 2016 and December 31, 2015, respectively. NRP owns and leases rail load out and associated facilities to a subsidiary of Foresight Energy at Foresight Energy's Sugar Camp mine. The lease agreement is accounted for as a direct financing lease. Total projected remaining payments under the lease at September 30, 2016 were $77.7 million , with unearned income of $32.7 million , and the net amount receivable was $45.0 million , of which $2.1 million is included in Accounts receivable—affiliates while the remaining is included in Long-term contracts receivable—affiliate on the accompanying Consolidated Balance Sheets. Total projected remaining payments under the lease at December 31, 2015 were $81.2 million , with unearned income of $35.3 million and the net amount receivable was $45.9 million , of which $2.0 million is included in Accounts receivable—affiliates while the remaining is included in Long-term contracts receivable—affiliates on the accompanying Consolidated Balance Sheets. NRP holds a contractual overriding royalty interest from a subsidiary of Foresight Energy that provides for payments based upon production from specific tons at Foresight Energy's Sugar Camp operations. This overriding royalty was accounted for as a financing arrangement and is reflected as an affiliate receivable. The net amount receivable under the agreement as of September 30, 2016 was $2.7 million , of which $1.4 million is included in Accounts receivable—affiliates, while the remaining is included in Long-term contracts receivable—affiliate. The net amount receivable under the agreement as of December 31, 2015 was $4.9 million , of which $1.5 million is included in Accounts receivable—affiliates while the remaining is included in Long-term contracts receivable—affiliate on the accompanying Consolidated Balance Sheets. NRP owns rail load out transportation assets and subcontracts out the operating responsibilities to an affiliate of Foresight Energy at Foresight's Williamson mine. During the three and nine months ended September 30, 2016, the Partnership recorded operating and maintenance expenses—affiliates of $0.4 million and $1.0 million , respectively, to operate these assets. During the three and nine months ended September 30, 2015, the Partnership recorded operating and maintenance expenses—affiliates of $0.3 million and $1.0 million , respectively, to the operate these assets. Long-Term Debt—Affiliate Donald R. Holcomb, one of the Partnership’s former directors, was a manager of Cline Trust Company, LLC (the "Cline Trust Company") as of December 31, 2015, that owned approximately 0.5 million of the Partnership’s common units and $20.0 million in principal amount of the Partnership’s 9.125% Senior Notes due 2018. As of December 31, 2015, the members of the Cline Trust Company were four trusts for the benefit of the children of Chris Cline, each of which owned an approximately equal membership interest in the Cline Trust Company. As of December 31, 2015, Mr. Holcomb also served as trustee of each of the four trusts. The balance on this portion of the Partnership’s 9.125% Senior Notes due 2018 was $19.9 million as of December 31, 2015 and was included in Long-term debt, net—affiliate on the accompanying Consolidated Balance Sheet. In April 2016, Mr. Holcomb resigned from the Partnership's board of directors and as a result the $19.9 million debt balance held by Cline Trust Company was subsequently reclassified as Long-term debt, net on the Partnership's accompanying Consolidated Balance Sheet. 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, 2016 , a fund controlled by Quintana Capital owned a majority interest in Corsa Coal Corp. ("Corsa"), a coal mining company traded on the TSX Venture Exchange that is one of the Partnership’s lessees in Tennessee. Corbin J. Robertson III, one of the Partnership’s directors, is Chairman of the Board of Corsa. Coal related revenues from Corsa totaled $0.8 million and $0.9 million for the three months ended September 30, 2016 and 2015, respectively and $1.9 million and $2.4 million for the nine months ended September 30, 2016 and 2015, respectively. The Partnership had recorded $0.3 million in minimum royalty payments as Deferred revenue—affiliates at both September 30, 2016 and December 31, 2015. The Partnership also had Accounts receivable—affiliates totaling $0.2 million from Corsa at both September 30, 2016 and December 31, 2015. WPPLP Production Royalty and Overriding Royalty The Partnership recorded $0.0 million and $0.7 million in operating and maintenance expenses—affiliates related to a non-participating production royalty payable to WPPLP pursuant to a conveyance agreement entered into in 2007 for the three and nine months ended September 30, 2016 , respectively. The Partnership recorded ( $0.1 million ) and $0.0 million in operating and maintenance expenses—affiliates related to this non-participating production royalty payable to WPPLP for the three and nine months ended September 30, 2015. The Partnership had Other assets—affiliate from WPPLP of $1.0 million and $1.1 million at September 30, 2016 and December 31, 2015, respectively related to a non-production royalty receivable from WPPLP for overriding royalty interest on a mine.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2016
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 claims will not have a material effect on the Partnership’s financial position, liquidity or operations. Since 2013, several citizen group lawsuits have been filed against landowners alleging ongoing discharges of pollutants, including selenium and conductivity, from valley fills located at reclaimed mountaintop removal mining sites in West Virginia. In each case, the mine on the subject property had been closed, the property had been reclaimed, and the state reclamation bond had been released. Any determination that a landowner or lessee has liability for discharges from a previously reclaimed mine site could result in substantial compliance costs or fines and would result in uncertainty as to continuing liability for completed and reclaimed coal mine operations. A subsidiary of the Partnership has been named as a defendant in one of these lawsuits. The Partnership currently cannot reasonably estimate a range of potential loss, if any, related to this matter. Foresight Energy Disputes In November 2015, a subsidiary of the Partnership filed a lawsuit against Foresight Energy’s subsidiary, Hillsboro Energy LLC ("Hillsboro"), in the Circuit Court of the Fourth Judicial Circuit in Montgomery County, Illinois. The lawsuit alleges, among other items, breach of contract by Hillsboro resulting from a wrongful declaration of force majeure at Hillsboro’s Deer Run mine in July 2015. In late March 2015, elevated carbon monoxide readings were detected at the Deer Run mine, and coal production at the mine was idled. In July 2015, the Partnership received the notice declaring a force majeure event at the mine as a result of the elevated carbon monoxide levels. The effect of a valid force majeure declaration would relieve Foresight Energy of its obligation to pay us minimum deficiency payments in arrears of $7.5 million per quarter, or $30.0 million per year. Foresight Energy's failure to make the deficiency payment with respect to the second, third and fourth quarters of 2015 and the first, second and third quarters of 2016 resulted in a cumulative $38.5 million negative cash impact to us. Such amount will increase for each quarter during which mining operations continue to be idled. The Partnership does not currently have an estimate as to when the mine will resume coal production. If the mine remains idled for an extended period or if the mine is permanently closed, the Partnership's financial condition and future cash flows will be adversely affected. In April 2016, a subsidiary of the Partnership filed a lawsuit against Macoupin Energy, LLC ("Macoupin"), a subsidiary of Foresight Energy, in Macoupin County, Illinois. The lawsuit alleges that Macoupin has failed to comply with the terms of its coal mining, rail loadout and rail loop leases by incorrectly recouping previously paid minimum royalties. Foresight Energy’s failure to properly calculate its recoupable balance and failure to make payments in accordance with these lease agreements with respect to certain periods resulted in a cumulative $5.8 million negative cash impact to us. While the Partnership plans to pursue its claim, a valuation allowance for the receivable amount has been recorded. It is possible that the Partnership’s current estimate of the valuation allowance related to this matter could change, perhaps materially, in the future.

Major Customers

Major Customers	9 Months Ended
	Sep. 30, 2016
Risks and Uncertainties [Abstract]
Major Customers	Major Customers Revenues from customers that exceeded ten percent of total revenues and other income for either the three or nine months ended September 30, 2016 and 2015 are as follows (in thousands except for percentages): Three Months Ended Nine Months Ended 2016 2015 2016 2015 (Unaudited) (Unaudited) Revenues Percent Revenues Percent Revenues Percent Revenues Percent Foresight Energy $ 20,635 21% $ 18,677 16% $ 47,648 15% $ 68,556 21% Alpha Natural Resources $ 3,829 4% $ 15,429 14% $ 14,420 5% $ 33,201 10%

Unit-Based Compensation

Unit-Based Compensation	9 Months Ended
	Sep. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Unit-Based Compensation	Unit-Based Compensation At the time of the Partnership's initial public offering, GP Natural Resource Partners LLC adopted the Natural Resource Partners Long-Term Incentive Plan (the "Long-Term Incentive Plan") for directors of GP Natural Resource Partners LLC and employees of its affiliates who perform services for the Partnership. The Compensation, Nominating and Governance Committee ("CNG Committee") of GP Natural Resource Partners LLC’s board of directors administers the Long-Term Incentive Plan and has historically approved annual awards of phantom units that vest four years from the date of grant. In February 2016, the CNG Committee adopted and the Board approved a new cash-based long-term incentive plan to the employees of its affiliates who perform services for the Partnership. Subject to the rules of the exchange upon which the common units are listed at the time, the board of directors and the compensation committee of the board of directors have the right to alter or amend the Long-Term Incentive Plan or any part of the Long-Term Incentive Plan from time to time. Except upon the occurrence of unusual or nonrecurring events, no change in any outstanding grant may be made that would materially reduce the benefit intended to be made available to a participant without the consent of the participant. Phantom units are incentive based equity awards issued to employees over a vesting period that entitle the grantee to receive the cash equivalent to the value of a unit of the Partnership's common units upon each vesting. The Partnership records compensation cost equal to the fair value of the award at the measurement date, which is determined to be the earlier of the performance commitment date or the service completion date. In addition, compensation cost for unvested phantom unit awards is adjusted quarterly for any changes in the Partnership’s unit price. Under the plan a grantee will receive the market value of a common unit in cash upon vesting. Market value is defined as the average closing price over the 20 trading days prior to the vesting date. The compensation committee may make grants under the Long-Term Incentive Plan to employees and directors containing such terms as it determines, including the vesting period. Outstanding grants vest upon a change in control of the Partnership, the general partner, or GP Natural Resource Partners LLC. If a grantee’s employment or membership on the board of directors terminates for any reason, outstanding grants will be automatically forfeited unless and to the extent the compensation committee provides otherwise. In connection with the phantom unit awards, the Compensation, Nominating and Governance Committee also granted tandem Distribution Equivalent Rights ("DERs"), which entitle the holders to receive distributions equal to the distributions paid on the Partnership’s common units between the date the units are granted and the vesting date. The DERs are payable in cash upon vesting but may be subject to forfeiture if the grantee ceases employment prior to vesting. A summary of activity in the outstanding grants during 2016 is as follows (in thousands): Phantom Units Outstanding grants at January 1, 2016 126 Grants during the period — Grants vested and paid during the period (28 ) Forfeitures during the period (10 ) Outstanding grants at September 30, 2016 88 Grants typically vest at the end of a four -year period and are paid in cash upon vesting. The Partnership recorded expenses related to its Long-Term Incentive Plan of $0.7 million and $0.8 million for the three and nine months ended September 30, 2016 , respectively. The Partnership also recorded a credit to expenses related to its Long-Term Incentive plan of $0.2 million and $1.7 million for the three and nine months ended September 30, 2015, respectively due to the decline in the market price of the Partnership's common units during the period. In connection with the Long-Term Incentive Plan, payments are typically made during the first quarter of the year. Payments of $1.5 million and $4.4 million were made during the nine months ended September 30, 2016 and 2015, respectively. The unaccrued cost associated with unvested outstanding grants and related DERs at September 30, 2016 and December 31, 2015, was $0.8 million and $0.7 million , respectively.

Cash Distributions

Cash Distributions	9 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Cash Distributions	Cash Distributions The following table shows the distributions paid by the Partnership during the nine months ended September 30, 2016 and 2015: Total Distributions (In thousands) Date Paid Period Covered by Distribution Distribution per Common Unit Common Units GP Interest Total 2016 February 12, 2016 October 1 - December 31, 2015 $ 0.45 $ 5,503 $ 113 $ 5,616 May 13, 2016 January 1 - March 31, 2016 0.45 5,503 113 5,616 August 12, 2016 April 1 - June 30, 2016 0.45 5,505 112 5,617 2015 February 13, 2015 October 1 - December 31, 2014 $ 3.50 $ 42,804 $ 874 $ 43,678 May 14, 2015 January 1 - March 31, 2015 0.90 11,007 225 11,232 August 14, 2015 April 1 - June 30, 2015 0.90 11,009 223 11,232

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	9 Months Ended
	Sep. 30, 2016
Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Information	Supplemental Cash Flow Information The Partnership's supplemental cash flow information of continuing operations is summarized as follows (in thousands): Nine Months Ended 2016 2015 (Unaudited) Cash paid for interest $ 54,749 $ 55,761 Plant, equipment and mineral rights funded with accounts payable or accrued liabilities — 4,465

Deferred Revenue and Deferred R

Deferred Revenue and Deferred Revenue - Affiliate	9 Months Ended
	Sep. 30, 2016
Deferred Revenue Disclosure [Abstract]
Deferred Revenue and Deferred Revenue - Affiliate	Deferred Revenue and Deferred Revenue—Affiliate Most of the Partnership’s coal and aggregates lessees must make minimum annual or quarterly payments which are generally recoupable over certain time periods. These minimum payments are recorded as deferred revenue when received. The deferred revenue attributable to the minimum payment is recognized as revenue based upon the underlying mineral lease when the lessee recoups the minimum payment through production or in the period immediately following the expiration of the lessee’s ability to recoup the payments. The Partnership’s deferred revenue (including affiliate) consist of the following (in thousands): September 30, December 31, (Unaudited) Deferred revenue $ 40,050 $ 80,812 Deferred revenue—affiliate 74,663 82,853 Total deferred revenue (including affiliate) $ 114,713 $ 163,665 The Partnership recognized the following amounts of deferred revenue (including affiliate) attributable to previously paid minimums as Coal royalty and other revenue (in thousands): Three Months Ended Nine Months Ended 2016 2015 2016 2015 (Unaudited) (Unaudited) Coal royalty and other $ 3,662 $ 539 $ 48,705 $ 2,308 Coal royalty and other—affiliates 6,093 2,695 11,750 10,172 Total coal royalty and other (including affiliates) $ 9,755 $ 3,234 $ 60,455 $ 12,480 Lease Modifications, Termination and Forfeitures of Minimum Royalty Balances During the nine months ended September 30, 2016, the Partnership entered into agreements with certain lessees to either modify or terminate existing coal related leases that resulted in the Partnership recognizing $40.4 million of deferred revenue as follows: • An agreement that terminated a central Appalachia coal royalty lease and resulted in the lessee forfeiting the right to recoup $26.2 million of minimum royalties previously paid to the Partnership. The Partnership agreed to transfer its coal mineral rights that were subject to this former lease to the lessee. This terminated lease had no current or planned production and the mineral rights transferred had zero net book value on the Partnership's consolidated Balance Sheets as of March 31, 2016. As a result of this transaction, in April 2016 the Partnership recognized $26.2 million of revenue. • Lease modifications of existing coal royalty leases resulted in lessee forfeiture of rights to recoup previously paid minimum royalties and the reduction in lessee recoupment time. As a result of these modifications, in the first and second quarters of 2016 the Partnership recognized $10.7 million of revenue. • The Partnership recognized $3.5 million of revenue from various other coal and aggregates lease modifications, terminations and forfeitures during the nine months ended September 30, 2016. During the nine months ended September 30, 2015, there was less than $0.1 million of revenue recognized from coal and aggregate lease modifications, terminations or forfeitures.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2016
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events The following represents material events that have occurred subsequent to September 30, 2016 through the time of the Partnership’s filing of its Quarterly Report on Form 10-Q with the SEC: Distribution Declared On October 26, 2016 the Board of Directors of GP Natural Resource Partners LLC declared a distribution of $0.45 per unit to be paid by the Partnership on November 14, 2016 to unitholders of record on November 7, 2016. Closing of Oil and Gas Royalty Sale In November 2016, the Partnership sold its mineral fee interests in Grant County, Oklahoma for $7.5 million and recorded a gain of approximately $1.8 million .

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Principles of Consolidation and 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. Certain reclassifications have been made to prior period amounts to conform to the current period financial statement presentation. As described in Note 2. Discontinued Operations , the Partnership has classified the assets and liabilities, operating results and cash flows of its non-operated oil and gas working interest assets as discontinued operations in its consolidated financial statements for all periods presented. As described in Note 3. Segment Information , the Partnership has reclassified certain prior period amounts to conform to the way it internally manages and monitors segment performance. In particular, prior year general and administrative charges that were allocated to operating segments have been reclassified to Operating and maintenance expenses and Operating and maintenance expenses—affiliates on the Consolidated Statements of Comprehensive Income. The prior period reclassifications for new segments had no impact on the Partnership's consolidated financial position, net income (loss) or cash flows. On January 1, 2016, the Partnership adopted a new accounting standard using a retrospective approach that required the presentation of the Partnership's debt issuance costs as a direct deduction from the related debt liability, rather than recorded as an asset. The adoption resulted in a reclassification that reduced other current assets and short-term debt by $0.2 million and reduced other assets and long-term debt (including affiliate) by $13.8 million on the Partnership’s Consolidated Balance Sheet at December 31, 2015. On January 26, 2016, the board of directors of the Partnership's general partner approved a 1-for-10 reverse split on its common units, effective following market close on February 17, 2016. Pursuant to the authorization provided, the Partnership completed the 1-for-10 reverse unit split and its common units began trading on a reverse unit split-adjusted basis on the New York Stock Exchange on February 18, 2016. As a result of the reverse unit split, every 10 outstanding common units were combined into one common unit. The reverse unit split reduced the number of common units outstanding from 122.3 million units to 12.2 million units. All unit and per unit data included in these consolidated financial statements has been retroactively restated to reflect the reverse unit split. In the second quarter of 2016, the Partnership determined its net cash provided by operating activities and net cash used by financing activities were understated by $8.0 million for the three months ended March 31, 2016. The Consolidated Statement of Cash Flows for the nine months ended September 30, 2016 has been corrected for this error. In the Partnership's opinion, all adjustments considered necessary for a fair presentation have been included. The interim financial statements should be read in conjunction with the audited financial statements and related notes included in the Partnership’s Annual Report on Form 10-K for the year ended December 31, 2015. Interim results are not necessarily indicative of the results for a full year.
Recently Issued Accounting Standards Not Yet Adopted	Recently Issued Accounting Standards Not Yet Adopted The Financial Accounting Standards Board ("FASB") amended its guidance on revenue recognition. The core principle of this amendment is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance will also require enhanced disclosures, provide more comprehensive guidance for transactions such as service revenue and contract modifications, and enhance guidance for multiple-element arrangements. The Partnership is required to adopt this guidance in the first quarter of 2018 using one of two retrospective application methods. The Partnership is currently evaluating the provisions of this guidance and has not determined the impact this guidance may have on its consolidated financial statements and related disclosure or decided upon the method of adoption. The FASB issued guidance on management’s responsibility to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern and to provide related footnote disclosures. The new guidance will require a formal assessment of going concern by management based on criteria prescribed in the new guidance, but will not impact the Partnership's financial position or results of operations. This guidance is effective for annual periods ending after December 15, 2016, and interim periods thereafter. Early adoption is permitted for annual or interim reporting periods for which the financial statements have not previously been issued. The Partnership is evaluating the impact this guidance will have on its consolidated financial statements and related disclosure and reviewing its policies and processes to ensure compliance with this new guidance upon adoption. The FASB issued authoritative guidance which intended to simplify the measurement of inventory. This guidance requires an entity to measure inventory at the lower of cost or net realizable value, and defines net realizable value as the estimated selling price in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. This guidance is effective for annual and interim periods ending after December 15, 2016. The Partnership is currently evaluating the impact of this guidance on its consolidated financial statements. The FASB issued authoritative lease guidance that requires lessees to recognize assets and liabilities on the balance sheet for the present value of the rights and obligations created by all leases with terms of more than 12 months. The guidance also requires disclosures designed to give financial statement users information on the amount, timing, and uncertainty of cash flows arising from leases. The guidance is effective for annual and interim periods ending after December 31, 2018. The Partnership is currently evaluating the impact of the provisions of this guidance on its consolidated financial statements. The FASB issued authoritative guidance that replaces the incurred loss impairment methodology in the current standard with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The guidance is effective for annual and interim periods ending after December 31, 2019. The Partnership is currently evaluating the impact of the provisions of this guidance on its consolidated financial statements. The FASB issued authoritative guidance to clarify how certain cash receipts and cash payments are presented and classified in the statement of cash flows in order to reduce current and potential future diversity in practice. The guidance is effective for annual and interim periods ending after December 31, 2017. The Partnership is currently evaluating the impact of the provisions of this guidance on its consolidated financial statements.

Discontinued Operations (Tables

Discontinued Operations (Tables)	9 Months Ended
	Sep. 30, 2016
Discontinued Operations and Disposal Groups [Abstract]
Summary of Financial Results of Discontinued Operations	The following table (in thousands) presents summarized financial results of the Partnership's discontinued operations in the Consolidated Statements of Comprehensive Income: Three Months Ended Nine Months Ended September 30, September 30, 2016 2015 2016 2015 (Unaudited) (Unaudited) Revenues and other income: Oil and gas $ 41 $ 11,447 $ 16,476 $ 38,558 Gain on asset sales 8,468 — 8,284 451 Total revenues and other income 8,509 11,447 24,760 39,009 Operating expenses: Operating and maintenance expenses (including affiliates) 928 4,584 11,180 15,171 Depreciation, depletion and amortization — 10,187 7,527 35,648 Asset impairments — 265,135 564 265,135 Total operating expenses 928 279,906 19,271 315,954 Interest expense (469 ) (806 ) (3,488 ) (3,021 ) Income (loss) from discontinued operations $ 7,112 $ (269,265 ) $ 2,001 $ (279,966 ) The following table (in thousands) presents the carrying amounts of the Partnership's assets and liabilities of discontinued operations in the Consolidated Balance Sheets: September 30, December 31, (Unaudited) ASSETS Current assets: Cash and cash equivalents $ — $ 10,569 Accounts receivable, net 991 7,053 Other — 222 Total current assets 991 17,844 Mineral rights, net — 109,505 Other non-current assets — 657 Total assets of discontinued operations $ 991 $ 128,006 LIABILITIES Current liabilities: Other (including affiliates) (1) $ 835 $ 4,388 Total current liabilities 835 4,388 Long-term debt, net (2) — 83,600 Other non-current liabilities — 1,637 Total liabilities of discontinued operations $ 835 $ 89,625 (1) See Note 10. Related Party Transactions for additional information on the Partnership's related party assets and liabilities. (2) The Partnership identified the NRP Oil and Gas reserve based lending facility (the "RBL Facility") as specifically attributed to its non-operated oil and gas working interest assets and included the interest from this debt in discontinued operations. See Note 8. Debt and Debt—Affiliate for additional information on the Partnership's debt related to discontinued operations. The following table (in thousands) presents supplemental cash flow information of the Partnership's discontinued operations: Nine Months Ended September 30, 2016 2015 (Unaudited) Cash paid for interest $ 1,906 $ 2,156 Plant, equipment and mineral rights funded with accounts payable or accrued liabilities — 3,336

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2016
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	Total Assets of Continuing Operations September 30, 2016 1,007,034 257,661 195,617 60,103 1,520,415 December 31, 2015 1,078,778 261,942 200,348 961 1,542,029

Equity Investment (Tables)

Equity Investment (Tables)	9 Months Ended
	Sep. 30, 2016
Equity Method Investments and Joint Ventures [Abstract]
Schedule of Summarized Financial Information	equity in the earnings of Ciner Wyoming is summarized as follows (in thousands): Three Months Ended Nine Months Ended 2016 2015 2016 2015 (Unaudited) (Unaudited) Income allocation to NRP’s equity interests $ 11,973 $ 13,806 $ 34,357 $ 40,319 Amortization of basis difference (1,220 ) (1,189 ) (3,615 ) (3,580 ) Equity in earnings of unconsolidated investment $ 10,753 $ 12,617 $ 30,742 $ 36,739 The results of Ciner Wyoming’s operations are summarized as follows (in thousands): Three Months Ended Nine Months Ended 2016 2015 2016 2015 (Unaudited) (Unaudited) Sales $ 121,003 $ 117,340 $ 352,085 $ 359,970 Gross profit 30,673 32,750 87,656 96,565 Net Income 24,436 28,175 70,118 82,283 The financial position of Ciner Wyoming is summarized as follows (in thousands): September 30, December 31, (Unaudited) Current assets $ 142,549 $ 144,695 Noncurrent assets 232,462 233,845 Current liabilities 57,071 43,018 Noncurrent liabilities 100,000 116,808

Plant and Equipment (Tables)

Plant and Equipment (Tables)	9 Months Ended
	Sep. 30, 2016
Property, Plant and Equipment [Abstract]
Plant and Equipment	The Partnership’s plant and equipment consist of the following (in thousands): September 30, December 31, (Unaudited) Plant and equipment at cost $ 77,377 $ 92,049 Construction in process 1,717 646 Less accumulated depreciation (26,578 ) (32,020 ) Total plant and equipment, net $ 52,516 $ 60,675

Mineral Rights (Tables)

Mineral Rights (Tables)	9 Months Ended
	Sep. 30, 2016
Extractive Industries [Abstract]
Mineral Rights	The Partnership’s mineral rights consist of the following (in thousands): September 30, 2016 (Unaudited) Carrying Value Accumulated Depletion Net Book Value Coal Royalty and Other $ 1,270,295 $ (454,261 ) $ 816,034 VantaCore 112,700 (4,553 ) 108,147 Total $ 1,382,995 $ (458,814 ) $ 924,181 December 31, 2015 Carrying Value Accumulated Depletion Net Book Value Coal Royalty and Other $ 1,317,158 $ (442,254 ) $ 874,904 VantaCore 112,700 (3,082 ) 109,618 Total $ 1,429,858 $ (445,336 ) $ 984,522
Schedule of Impairment on Mineral Rights	During the three and nine months ended September 30, 2016 and 2015, the Partnership identified facts and circumstances that indicated that the carrying value of certain of its mineral rights exceed future cash flows from those assets and recorded non-cash impairment expense as follows (in thousands): Three Months Ended Nine Months Ended Impaired Asset Description 2016 2015 2016 2015 (Unaudited) Coal properties (1) $ 3,817 $ 247,815 $ 3,908 $ 249,362 Oil and gas royalty properties (2) 36 70,527 36 70,527 Aggregates royalty properties (3) 1,411 43,361 1,677 43,361 Total $ 5,264 $ 361,703 $ 5,621 $ 363,250 (1) The Partnership recorded $3.8 million and $3.9 million of coal property impairments during the three and nine months ended September 30, 2016, respectively. Total coal property impairment expense for the nine months ended September 30, 2015 was $249.4 million . The Partnership recorded $1.5 million of coal property impairment during the three months ended June 30, 2015 and the fair value measurement of these impaired assets recorded at fair value was $0.0 million at June 30, 2015. The Partnership recorded the remaining $247.8 million of coal property impairment during the three months ended September 30, 2015 and the fair value measurement of these impaired assets recorded at fair value was $28.4 million at September 30, 2015. These impairments primarily resulted from the continued deterioration and expectations of further reductions in global and domestic coal demand due to reduced global steel demand, sustained low natural gas prices, and continued regulatory pressure on the electric power generation industry. NRP compared net capitalized costs of its coal properties to estimated undiscounted future net cash flows. If the net capitalized cost exceeded the undiscounted future cash flows, the Partnership recorded an impairment for the excess of net capitalized cost over fair value. Significant inputs used to determine fair value include estimates of future cash flow, discount rate and useful economic life. Estimated cash flows are the product of a process that began with current realized pricing as of the measurement date and included an adjustment for risk related to the future realization of cash flows. (2) The Partnership recorded $70.5 million of oil and gas royalty property impairment during the three and nine months ended September 30, 2015. The fair value measurement of these impaired assets recorded at fair value were $13.0 million at September 30, 2015. This impairment primarily resulted from declines in future expected realized commodity prices and reduced expected drilling activity on its acreage. NRP compared net capitalized costs of its oil and gas royalty properties to estimated undiscounted future net cash flows. If the net capitalized cost exceeded the undiscounted future net cash flows, the Partnership recorded an impairment for the excess of net capitalized cost over fair value. A discounted cash flow method was used to estimate fair value. Significant inputs used to determine the fair value include estimates of: (i) oil and gas reserves and risk-adjusted probable and possible reserves; (ii) future commodity prices; (iii) production costs, (iv) capital expenditures, (v) production and (vi) discount rates. The underlying commodity prices embedded in the Partnership's estimated cash flows are the product of a process that begins with NYMEX forward curve pricing as of the measurement date, adjusted for estimated location and quality differentials. (3) The Partnership recorded $1.4 million and $1.7 million of aggregates royalty property impairments during the three and nine months ended September 30, 2016, respectively. The Partnership recorded $43.4 million of aggregates royalty property impairments during the three and nine months ended September 30, 2015. The fair value measurement of these impaired assets recorded at fair value was $13.1 million at September 30, 2015. This impairment primarily resulted from greenfield development projects that have not performed as projected, leading to recent lease concessions on minimums and royalties combined with the continued regional market decline for certain properties. NRP compared net capitalized costs of its aggregates properties to estimated undiscounted future net cash flows. If the net capitalized cost exceeded the undiscounted cash flows, the Partnership recorded an impairment for the excess of net capitalized cost over fair value. A discounted cash flow model was used to estimate fair value. Significant inputs used to determine fair value include estimates of future cash flow, discount rate and useful economic life. Estimated cash flows are the product of a process that began with current realized pricing as of the measurement date and included an adjustment for risk related to the future realization of cash flows.

Intangible Assets (Including 30

Intangible Assets (Including Affiliate) (Tables)	9 Months Ended
	Sep. 30, 2016
Related Party Transaction [Line Items]
Intangible Assets	The Partnership's intangible assets consist of permits, aggregate-related trade names and other agreements as follows (in thousands): September 30, December 31, (Unaudited) Intangible assets $ 5,077 $ 5,076 Less accumulated amortization (1,838 ) (1,146 ) Total intangible assets, net $ 3,239 $ 3,930
Affiliated Entity
Related Party Transaction [Line Items]
Intangible Assets	The Partnership's intangible assets—affiliate relate to above market coal transportation contracts with subsidiaries of Foresight Energy LP ("Foresight Energy"), pursuant to which it receives throughput fees for the handling and transportation of coal. September 30, December 31, (Unaudited) Intangible assets—affiliate $ 81,109 $ 81,109 Less accumulated amortization—affiliate (30,441 ) (28,112 ) Total intangible assets, net—affiliate $ 50,668 $ 52,997

Debt and Debt - Affiliate (Tabl

Debt and Debt - Affiliate (Tables)	9 Months Ended
	Sep. 30, 2016
Debt Disclosure [Abstract]
Long-Term Debt	As of September 30, 2016 and December 31, 2015, debt and debt—affiliate consisted of the following (in thousands): September 30, December 31, (Unaudited) NRP LP debt: 9.125% senior notes, with semi-annual interest payments in April and October, due October 2018, $300 million issued at 99.007% and $125 million issued at 99.5% $ 425,000 $ 425,000 Opco debt (1): Revolving credit facility, due June 2018 260,000 290,000 Senior notes 4.91% with semi-annual interest payments in June and December, with annual principal payments in June, due June 2018 9,233 13,850 8.38% with semi-annual interest payments in March and September, with annual principal payments in March, due March 2019 64,286 85,714 5.05% with semi-annual interest payments in January and July, with annual principal payments in July, due July 2020 30,769 38,462 5.55% with semi-annual interest payments in June and December, with annual principal payments in June, due June 2023 18,900 21,600 4.73% with semi-annual interest payments in June and December, with annual principal payments in December, due December 2023 60,000 60,000 5.82% with semi-annual interest payments in March and September, with annual principal payments in March, due March 2024 120,000 135,000 8.92% with semi-annual interest payments in March and September, with annual principal payments in March, due March 2024 36,364 40,909 5.03% with semi-annual interest payments in June and December, with annual principal payments in December, due December 2026 148,077 148,077 5.18% with semi-annual interest payments in June and December, with annual principal payments in December, due December 2026 42,308 42,308 5.31% utility local improvement obligation, with annual principal and interest payments in February, due March 2021 $ 961 $ 1,153 NRP Oil and Gas debt: Revolving credit facility — 85,000 Total debt at face value $ 1,215,898 $ 1,387,073 Net unamortized debt discount (1,511 ) (2,077 ) Net unamortized debt issuance costs (1) (13,806 ) (14,040 ) Total debt, net $ 1,200,581 $ 1,370,956 Less: current portion of long-term debt 158,597 80,745 Less: debt classified as non-current liabilities of discontinued operations — 83,600 Total long-term debt $ 1,041,984 $ 1,206,611 (1) See Note 1. Basis of Presentation for discussion of debt issuance costs reclassification upon adoption of new accounting standard on January 1, 2016.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Contractual Override, Note Receivable and Long-Term Debt	The following table (in thousands) shows the carrying value and estimated fair value of the Partnership's debt, debt—affiliate and contracts receivable—affiliate: September 30, 2016 December 31, 2015 Carrying Estimated Carrying Estimated (Unaudited) Debt and debt—affiliate: NRP Senior Notes (1) $ 419,397 $ 391,531 $ 417,296 $ 277,313 Opco Senior Notes and utility local improvement obligation (2) 527,016 489,090 584,890 383,065 Opco Revolving Credit Facility (3) 254,168 260,000 285,170 290,000 NRP Oil and Gas RBL Facility (3) — — 83,600 85,000 Assets: Contracts receivable—affiliate, current and long-term (2) $ 47,542 $ 32,861 $ 49,948 $ 34,498 (1) The Level 1 fair value is based upon quotations obtained for identical instruments on the closing trading prices near period end. (2) The Level 3 fair value is estimated by management using quotations obtained for comparable instruments on the closing trading prices near period end. (3) The Level 3 fair value approximates the outstanding borrowing amount because the interest rates are variable and reflective of market rates and the terms of the credit facility allow the Partnership to repay this debt at any time without penalty.

Related Party Transactions (Tab

Related Party Transactions (Tables)	9 Months Ended
	Sep. 30, 2016
Related Party Transactions [Abstract]
Summary of Reimbursements	Direct general and administrative expenses charged to the Partnership by WPPLP and Quintana Minerals Corporation are as follows (in thousands): Three Months Ended Nine Months Ended 2016 2015 2016 2015 (Unaudited) (Unaudited) Operating and maintenance expenses—affiliates, net $ 1,980 $ 1,540 $ 6,591 $ 7,068 General and administrative—affiliates 867 2,424 2,670 3,809

Unit-Based Compensation (Tables

Unit-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Activity in Outstanding Grants	A summary of activity in the outstanding grants during 2016 is as follows (in thousands): Phantom Units Outstanding grants at January 1, 2016 126 Grants during the period — Grants vested and paid during the period (28 ) Forfeitures during the period (10 ) Outstanding grants at September 30, 2016 88

Cash Distributions (Tables)

Cash Distributions (Tables)	9 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Schedule of distributions paid	The following table shows the distributions paid by the Partnership during the nine months ended September 30, 2016 and 2015: Total Distributions (In thousands) Date Paid Period Covered by Distribution Distribution per Common Unit Common Units GP Interest Total 2016 February 12, 2016 October 1 - December 31, 2015 $ 0.45 $ 5,503 $ 113 $ 5,616 May 13, 2016 January 1 - March 31, 2016 0.45 5,503 113 5,616 August 12, 2016 April 1 - June 30, 2016 0.45 5,505 112 5,617 2015 February 13, 2015 October 1 - December 31, 2014 $ 3.50 $ 42,804 $ 874 $ 43,678 May 14, 2015 January 1 - March 31, 2015 0.90 11,007 225 11,232 August 14, 2015 April 1 - June 30, 2015 0.90 11,009 223 11,232

Supplemental Cash Flow Inform36

Supplemental Cash Flow Information (Tables)	9 Months Ended
	Sep. 30, 2016
Supplemental Cash Flow Information [Abstract]
Schedule of cash flow, supplemental disclosures	The Partnership's supplemental cash flow information of continuing operations is summarized as follows (in thousands): Nine Months Ended 2016 2015 (Unaudited) Cash paid for interest $ 54,749 $ 55,761 Plant, equipment and mineral rights funded with accounts payable or accrued liabilities — 4,465

Deferred Revenue and Deferred37

Deferred Revenue and Deferred Revenue - Affiliate (Tables)	9 Months Ended
	Sep. 30, 2016
Deferred Revenue Disclosure [Abstract]
Schedule of Deferred Revenue	The Partnership’s deferred revenue (including affiliate) consist of the following (in thousands): September 30, December 31, (Unaudited) Deferred revenue $ 40,050 $ 80,812 Deferred revenue—affiliate 74,663 82,853 Total deferred revenue (including affiliate) $ 114,713 $ 163,665 The Partnership recognized the following amounts of deferred revenue (including affiliate) attributable to previously paid minimums as Coal royalty and other revenue (in thousands): Three Months Ended Nine Months Ended 2016 2015 2016 2015 (Unaudited) (Unaudited) Coal royalty and other $ 3,662 $ 539 $ 48,705 $ 2,308 Coal royalty and other—affiliates 6,093 2,695 11,750 10,172 Total coal royalty and other (including affiliates) $ 9,755 $ 3,234 $ 60,455 $ 12,480

Basis of Presentation - Additio

Basis of Presentation - Additional Information (Detail)

Jun. 30, 2018USD ($)

Dec. 31, 2017USD ($)

Jun. 30, 2017USD ($)

Dec. 31, 2016USD ($)

Feb. 18, 2016shares

Oct. 31, 2014USD ($)

Sep. 30, 2013USD ($)

Mar. 31, 2016USD ($)

Sep. 30, 2016USD ($)shares

Sep. 30, 2015USD ($)

Sep. 30, 2016USD ($)shares

Feb. 17, 2016shares

Dec. 31, 2015USD ($)shares

Schedule Of Significant Accounting Policies [Line Items]

Deferred issuance costs

$ 13,806,000

$ 13,806,000

$ 14,040,000

Total debt

$ 1,200,581,000

1,200,581,000

$ 1,370,956,000

Repayments of Debt

$ 262,200,000

Common units outstanding (in shares) | shares

12,200,000

12,232,006

12,232,006

122,300,000

12,232,006

Immaterial error correction

$ 8,000,000

Proceeds from Sale of Property, Plant, and Equipment

$ 9,800,000

$ 3,700,000

$ 192,000,000

NRP LP

Schedule Of Significant Accounting Policies [Line Items]

Rate of senior notes (percent)

9.125%

Repayment of principal amount

$ 122,600,000

NRP LP | 9.125% senior notes, with semi-annual interest payments in April and October, maturing October 2018

Schedule Of Significant Accounting Policies [Line Items]

Debt Instrument, face amount

$ 425,000,000

$ 425,000,000

Rate of senior notes (percent)

9.125%

9.125%

Opco

Schedule Of Significant Accounting Policies [Line Items]

Repayment of principal amount

$ 289,000,000

Opco | Floating Rate Revolving Credit Facility Due June Two Thousand Eighteen [Member]

Schedule Of Significant Accounting Policies [Line Items]

Total debt

$ 260,000,000

$ 260,000,000

Opco | Floating Rate Revolving Credit Facility Due June Two Thousand Eighteen [Member] | Scenario, Forecast [Member]

Schedule Of Significant Accounting Policies [Line Items]

Repayment of principal amount

$ 30,000,000

$ 50,000,000

Opco | Floating Rate Revolving Credit Facility Due October Two Thousand Seventeen [Member] | Scenario, Forecast [Member]

Schedule Of Significant Accounting Policies [Line Items]

Repayment of principal amount

$ 150,000,000

$ 30,000,000

$ 80,800,000

Opco | Senior Notes

Schedule Of Significant Accounting Policies [Line Items]

Total debt

529,900,000

$ 529,900,000

Repayments of Debt

$ 56,000,000

$ 56,000,000

Revolving Credit Facility | Opco

Schedule Of Significant Accounting Policies [Line Items]

Ratio of Indebtedness

2.95

Common Unitholders

Schedule Of Significant Accounting Policies [Line Items]

Reverse split ratio, common units

0.1

Maximum | Opco

Schedule Of Significant Accounting Policies [Line Items]

Ratio of Indebtedness

4

Maximum | Revolving Credit Facility | Opco

Schedule Of Significant Accounting Policies [Line Items]

Ratio of Indebtedness

4

Short-term Debt | Accounting Standards Update 2015-03

Schedule Of Significant Accounting Policies [Line Items]

Deferred issuance costs

$ 200,000

Other Current Assets | Accounting Standards Update 2015-03

Schedule Of Significant Accounting Policies [Line Items]

Deferred issuance costs

200,000

Other Noncurrent Assets | Accounting Standards Update 2015-03

Schedule Of Significant Accounting Policies [Line Items]

Deferred issuance costs

13,800,000

Long-term Debt | Accounting Standards Update 2015-03

Schedule Of Significant Accounting Policies [Line Items]

Deferred issuance costs

$ 13,800,000

Discontinued Operations - Summa

Discontinued Operations - Summary of Financial Results of Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014
ASSETS
Cash and cash equivalents	$ 0	$ 11,491	$ 0	$ 11,491	$ 10,569	$ 1,105
Total current assets	991		991		17,844
LIABILITIES
Total current liabilities	835		835		4,388
Net Cash Provided by (Used in) Discontinued Operations [Abstract]
Plant, equipment and mineral rights funded with accounts payable or accrued liabilities			0	4,465
Discontinued Operations, Held-for-sale [Member]
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Oil and gas revenues and other income	41	11,447	16,476	38,558
Gain on asset sales	8,468	0	8,284	451
Total revenues and other income	8,509	11,447	24,760	39,009
Operating and maintenance expenses (including affiliates)	928	4,584	11,180	15,171
Depreciation, depletion and amortization	0	10,187	7,527	35,648
Asset impairments	0	265,135	564	265,135
Total operating expenses	928	279,906	19,271	315,954
Interest expense	(469)	(806)	(3,488)	(3,021)
Income (loss) from discontinued operations	7,112	$ (269,265)	2,001	(279,966)
ASSETS
Cash and cash equivalents	0		0		10,569
Accounts receivable, net (including affiliates)	991		991		7,053
Other	0		0		222
Total current assets	991		991		17,844
Mineral rights, net	0		0		109,505
Other non-current assets	0		0		657
Total assets of discontinued operations	991		991		128,006
LIABILITIES
Other (including affiliates)	835		835		4,388
Total current liabilities	835		835		4,388
Long-term debt, net	0		0		83,600
Other non-current liabilities	0		0		1,637
Total liabilities of discontinued operations	$ 835		835		$ 89,625
Net Cash Provided by (Used in) Discontinued Operations [Abstract]
Cash paid for interest			1,906	2,156
Plant, equipment and mineral rights funded with accounts payable or accrued liabilities			$ 0	$ 3,336

Discontinued Operations - Addit

Discontinued Operations - Additional Information (Details) - Discontinued Operations, Held-for-sale [Member] - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Jun. 30, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Consideration			$ 116.1
Capital expenditures related to the Partnership's discontinued operations	$ 3.1	$ 36

Segment Information - Additiona

Segment Information - Additional Information (Details) $ in Thousands	Feb. 01, 2016operation	Feb. 29, 2016operation	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)segment	Sep. 30, 2015USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | segment					3
General and administrative			$ 4,268	$ 1,809	$ 10,676	$ 6,014
Ciner Wyoming
Segment Reporting Information [Line Items]
Percentage of partnership interest owned (percent)			49.00%		49.00%
Texas, Georgia, Tennessee
Segment Reporting Information [Line Items]
Disposition of reserves and related royalty rights, number of operations | operation	3	3
Operating Expense [Member]
Segment Reporting Information [Line Items]
General and administrative				$ 4,800		$ 15,100

Segment Information - Schedule

Segment Information - Schedule of Segment Reporting Information, by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
Revenues and other income	$ 91,448	$ 112,199	$ 284,667	$ 326,874
Gain on asset sales, net	6,426	1,833	27,280	6,903
Operating and maintenance expenses (including affiliates)	35,304	39,490	97,772	114,428
Depreciation, depletion and amortization (including affiliates)	12,831	16,437	34,509	47,028
Asset impairments	5,697	361,703	7,681	365,506
Other expense, net	22,488	22,905	67,236	66,960
Net income (loss) from continuing operations	16,419	(330,736)	91,403	(269,968)
Net income (loss) from discontinued operations	7,112	(269,265)	2,001	(279,996)
Total assets	1,521,406		1,521,406		$ 1,670,035
Corporate and Financing
Segment Reporting Information [Line Items]
Revenues and other income	0	0	0	0
Gain on asset sales, net	0	0	0	0
Operating and maintenance expenses (including affiliates)	0	0	0	0
Depreciation, depletion and amortization (including affiliates)	0	0	0	0
Asset impairments	0	0	0	0
Other expense, net	22,488	22,905	67,236	66,960
Net income (loss) from continuing operations	(27,623)	(27,138)	(80,582)	(76,783)
Net income (loss) from discontinued operations	0	0	0	0
Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenues and other income	0		0
Coal Royalty and Other
Segment Reporting Information [Line Items]
Revenues and other income	27,504	40,431	116,336	112,139
Coal Royalty and Other | Operating Segments
Segment Reporting Information [Line Items]
Revenues and other income	48,938	59,966	165,844	183,077
Gain on asset sales, net	6,425	2,256	27,270	6,927
Operating and maintenance expenses (including affiliates)	8,391	6,832	24,232	23,772
Depreciation, depletion and amortization (including affiliates)	9,070	12,659	23,496	34,529
Asset impairments	5,697	361,703	7,681	365,506
Other expense, net	0	0	0	0
Net income (loss) from continuing operations	32,250	(318,972)	137,802	(233,803)
Net income (loss) from discontinued operations	0	0	0	0
Coal Royalty and Other | Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenues and other income	45		97
Soda Ash
Segment Reporting Information [Line Items]
Revenues and other income	10,753	12,617	30,742	36,739
Soda Ash | Operating Segments
Segment Reporting Information [Line Items]
Revenues and other income	10,753	12,617	30,742	36,739
Gain on asset sales, net	0	0	0	0
Operating and maintenance expenses (including affiliates)	0	0	0	0
Depreciation, depletion and amortization (including affiliates)	0	0	0	0
Asset impairments	0	0	0	0
Other expense, net	0	0	0	0
Net income (loss) from continuing operations	10,753	12,617	30,742	36,739
Net income (loss) from discontinued operations	0	0	0	0
Soda Ash | Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenues and other income	0		0
VantaCore
Segment Reporting Information [Line Items]
Revenues and other income	31,757	39,616	88,081	107,058
VantaCore | Operating Segments
Segment Reporting Information [Line Items]
Revenues and other income	31,757	39,616	88,081	107,058
Gain on asset sales, net	1	(423)	10	(24)
Operating and maintenance expenses (including affiliates)	26,913	32,658	73,540	90,656
Depreciation, depletion and amortization (including affiliates)	3,761	3,778	11,013	12,499
Asset impairments	0	0	0	0
Other expense, net	0	0	0	0
Net income (loss) from continuing operations	1,039	2,757	3,441	3,879
Net income (loss) from discontinued operations	0	$ 0	0	$ 0
VantaCore | Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenues and other income	(45)		(97)
Continuing Operations
Segment Reporting Information [Line Items]
Total assets	1,520,415		1,520,415		1,542,029
Continuing Operations | Corporate and Financing
Segment Reporting Information [Line Items]
Total assets	60,103		60,103		961
Continuing Operations | Coal Royalty and Other | Operating Segments
Segment Reporting Information [Line Items]
Total assets	1,007,034		1,007,034		1,078,778
Continuing Operations | Soda Ash | Operating Segments
Segment Reporting Information [Line Items]
Total assets	257,661		257,661		261,942
Continuing Operations | VantaCore | Operating Segments
Segment Reporting Information [Line Items]
Total assets	$ 195,617		$ 195,617		$ 200,348

Equity Investment - Additional

Equity Investment - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Distributions from equity method Investment				$ 34,300	$ 34,545
Weighted average useful life of assets (in years)				28 years
Ciner Wyoming
Schedule of Equity Method Investments [Line Items]
Percentage of partnership interest owned (percent)				49.00%
Distributions from equity method Investment				$ 34,300	$ 34,500
Increase in fair value of property, plant and equipment				$ 150,900		$ 154,800
Anadarko Holding Company [Member] | Ciner Wyoming
Schedule of Equity Method Investments [Line Items]
Equity Investment Contingent Consideration Paid	$ 7,200	$ 3,800	$ 500

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, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Net income	$ 23,531	$ (598,757)	$ 93,404	$ (549,934)
Current assets	160,965		160,965		$ 121,129
Current liabilities	211,300		211,300		136,409
Ciner Wyoming
Schedule of Equity Method Investments [Line Items]
Income allocation to NRP’s equity interests	11,973	13,806	34,357	40,319
Amortization of basis difference	(1,220)	(1,189)	(3,615)	(3,580)
Equity in earnings of unconsolidated investment	10,753	12,617	30,742	36,739
Sales	121,003	117,340	352,085	359,970
Gross profit	30,673	32,750	87,656	96,565
Net income	24,436	$ 28,175	70,118	$ 82,283
Current assets	142,549		142,549		144,695
Noncurrent assets	232,462		232,462		233,845
Current liabilities	57,071		57,071		43,018
Noncurrent liabilities	$ 100,000		$ 100,000		$ 116,808

Plant and Equipment - Plant and

Plant and Equipment - Plant and Equipment (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Plant and equipment at cost	$ 77,377	$ 92,049
Construction in process	1,717	646
Less accumulated depreciation	(26,578)	(32,020)
Total plant and equipment, net	$ 52,516	$ 60,675

Plant and Equipment - Additiona

Plant and Equipment - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Property, Plant and Equipment [Abstract]
Depreciation expense on plant and equipment	$ 3.1	$ 3.9	$ 9.5	$ 12.9

Mineral Rights - Mineral Rights

Mineral Rights - Mineral Rights (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Carrying Value	$ 1,382,995	$ 1,429,858
Accumulated Depletion	(458,814)	(445,336)
Net Book Value	924,181	984,522
Coal Royalty and Other
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Carrying Value	1,270,295	1,317,158
Accumulated Depletion	(454,261)	(442,254)
Net Book Value	816,034	874,904
VantaCore
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Carrying Value	112,700	112,700
Accumulated Depletion	(4,553)	(3,082)
Net Book Value	$ 108,147	$ 109,618

Mineral Rights - Additional Inf

Mineral Rights - Additional Information (Detail) $ in Thousands	Feb. 01, 2016operation	Feb. 29, 2016operation	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)	Dec. 31, 2015USD ($)
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Asset impairments			$ 5,697	$ 361,703	$ 7,681	$ 365,506
Total depletion and amortization expense on mineral interests			8,600	11,600	21,900	30,900
Mineral rights, net			924,181		924,181		$ 924,181	$ 984,522
Proceeds from sale of oil and gas royalty properties					35,964	0
Gain on asset sales, net			6,426	1,833	27,280	6,903
Proceeds from Sale of Property, Plant, and Equipment					9,800	3,700	192,000
Appalachian Basin
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Proceeds from sale of oil and gas royalty properties					36,400
Gain on asset sales, net					18,600
Texas, Georgia, Tennessee
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Gain on asset sales, net					1,500
Disposition of reserves and related royalty rights, number of operations | operation	3	3
Proceeds from sale of hard mineral reserves					10,000
Disposal Group, Held-for-sale, Not Discontinued Operations [Member]
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Mineral rights, net			5,500		5,500		$ 5,500
Other Mineral Rights
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Gain on asset sales, net					6,800	3,300
Oil And Gas Mineral Rights [Member]
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Asset impairments			36	70,527	36	70,527
Hard Mineral Royalty Property [Member]
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Asset impairments			$ 1,411	$ 43,361	$ 1,677	$ 43,361

Mineral Rights Schedule of Impa

Mineral Rights Schedule of Impairment Expense (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Jun. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Property, Plant and Equipment [Line Items]
Asset impairments	$ 5,697	$ 361,703		$ 7,681	$ 365,506
Coal Mineral Rights [Member]
Property, Plant and Equipment [Line Items]
Asset impairments	3,817	247,815	$ 1,500	3,908	249,362
Fair value of impaired assets		28,400	$ 0		28,400
Oil And Gas Mineral Rights [Member]
Property, Plant and Equipment [Line Items]
Asset impairments	36	70,527		36	70,527
Fair value of impaired assets		13,000			13,000
Hard Mineral Royalty Property [Member]
Property, Plant and Equipment [Line Items]
Asset impairments	1,411	43,361		1,677	43,361
Fair value of impaired assets		13,100			13,100
Mining Properties and Mineral Rights [Member]
Property, Plant and Equipment [Line Items]
Asset impairments	$ 5,264	$ 361,703		$ 5,621	$ 363,250

Intangible Assets (Including 50

Intangible Assets (Including Affiliate) - Intangible Assets - Affiliate (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Related Party Transaction [Line Items]
Intangible assets	$ 5,077	$ 5,076
Less accumulated amortization	(1,838)	(1,146)
Total intangible assets, net	3,239	3,930
Affiliated Entity
Related Party Transaction [Line Items]
Intangible assets	81,109	81,109
Less accumulated amortization	(30,441)	(28,112)
Total intangible assets, net	$ 50,668	$ 52,997

Intangible Assets (Including 51

Intangible Assets (Including Affiliate) - Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible assets	$ 5,077	$ 5,076
Less accumulated amortization	(1,838)	(1,146)
Total intangible assets, net	$ 3,239	$ 3,930

Intangible Assets (Including 52

Intangible Assets (Including Affiliate) - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Related Party Transaction [Line Items]
Amortization of intangible assets	$ 0.2	$ 0.2	$ 0.7	$ 0.7
Affiliated Entity
Related Party Transaction [Line Items]
Amortization of intangible assets	$ 0.9	$ 0.7	$ 2.3	$ 2.5

Debt and Debt - Affiliate - Lon

Debt and Debt - Affiliate - Long-Term Debt (Detail)	9 Months Ended
	Sep. 30, 2016USD ($)	Dec. 31, 2015USD ($)	Jun. 30, 2015USD ($)	Oct. 31, 2014USD ($)	Sep. 30, 2013USD ($)
Debt Instrument [Line Items]
Principal balance	$ 1,215,898,000	$ 1,387,073,000
Net unamortized debt discount	(1,511,000)	(2,077,000)
Net unamortized debt issuance costs	(13,806,000)	(14,040,000)
Total debt	1,200,581,000	1,370,956,000
Less - current portion of long term debt	158,597,000	80,745,000
Less: debt classified as non-current liabilities of discontinued operations	0	83,600,000
Total long-term debt	$ 1,041,984,000	1,206,611,000
NRP LP
Debt Instrument [Line Items]
Rate of senior notes (percent)					9.125%
Floating rate revolving credit facility				$ 125,000,000	$ 300,000,000
Senior Note issue percentage				99.50%	99.007%
NRP LP | 9.125% senior notes, with semi-annual interest payments in April and October, maturing October 2018
Debt Instrument [Line Items]
Rate of senior notes (percent)	9.125%
Principal balance	$ 425,000,000	425,000,000
Opco
Debt Instrument [Line Items]
Ratio Of Ebitda To Consolidated Fixed Charges	3.5
Opco | Floating Rate Revolving Credit Facility Due October Two Thousand Seventeen [Member]
Debt Instrument [Line Items]
Floating rate revolving credit facility			$ 300,000,000
Principal balance		290,000,000
Opco | Floating Rate Revolving Credit Facility Due June Two Thousand Eighteen [Member]
Debt Instrument [Line Items]
Floating rate revolving credit facility	$ 260,000,000
Principal balance	260,000,000
Total debt	$ 260,000,000
Opco | 4.91% senior notes, with semi-annual interest payments in June and December, with annual principal payments in June, maturing in June 2018
Debt Instrument [Line Items]
Rate of senior notes (percent)	4.91%
Principal balance	$ 9,233,000	13,850,000
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]
Rate of senior notes (percent)	8.38%
Principal balance	$ 64,286,000	85,714,000
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]
Rate of senior notes (percent)	5.05%
Principal balance	$ 30,769,000	38,462,000
Opco | 5.31% utility local improvement obligation, with annual principal and interest payments, maturing in March 2021
Debt Instrument [Line Items]
Rate of senior notes (percent)	5.31%
Principal balance	$ 961,000	1,153,000
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]
Rate of senior notes (percent)	5.55%
Principal balance	$ 18,900,000	21,600,000
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]
Rate of senior notes (percent)	4.73%
Principal balance	$ 60,000,000	60,000,000
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]
Rate of senior notes (percent)	5.82%
Principal balance	$ 120,000,000	135,000,000
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]
Rate of senior notes (percent)	8.92%
Principal balance	$ 36,364,000	40,909,000
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]
Rate of senior notes (percent)	5.03%
Principal balance	$ 148,077,000	148,077,000
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]
Rate of senior notes (percent)	5.18%
Principal balance	$ 42,308,000	42,308,000
NRP Oil and Gas | Reserve Based Revolving Credit Facility Due 2019
Debt Instrument [Line Items]
Principal balance	0	$ 85,000,000
Senior Notes Offering Price One [Member] | NRP LP | 9.125% senior notes, with semi-annual interest payments in April and October, maturing October 2018
Debt Instrument [Line Items]
Floating rate revolving credit facility	$ 300,000,000
Senior Note issue percentage	99.007%
Senior Notes Offering Price Two [Member] | NRP LP | 9.125% senior notes, with semi-annual interest payments in April and October, maturing October 2018
Debt Instrument [Line Items]
Floating rate revolving credit facility	$ 125,000,000
Senior Note issue percentage	99.50%

Debt and Debt - Affiliate - Add

Debt and Debt - Affiliate - Additional Information (Detail)	Jun. 30, 2018USD ($)	Dec. 31, 2017USD ($)	Jun. 30, 2017USD ($)	Dec. 31, 2016USD ($)	Jun. 30, 2016	Oct. 31, 2014USD ($)	Sep. 30, 2013USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2015	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)	Dec. 31, 2015USD ($)	Jun. 30, 2015USD ($)
Debt Instrument [Line Items]
Principal balance								$ 1,215,898,000		$ 1,215,898,000		$ 1,215,898,000	$ 1,387,073,000
Principal payments on its senior notes												$ 262,200,000
Ciner Wyoming
Debt Instrument [Line Items]
Percentage of partnership interest owned (percent)								49.00%		49.00%		49.00%
Ciner Wyoming | Revolving Credit Facility
Debt Instrument [Line Items]
Percentage of partnership interest owned (percent)								49.00%		49.00%		49.00%
NRP LP
Debt Instrument [Line Items]
Rate of senior notes (percent)							9.125%
Floating rate revolving credit facility						$ 125,000,000	$ 300,000,000
Senior Note issue percentage						99.50%	99.007%
Repayment of principal amount						$ 122,600,000
NRP LP | 9.125% senior notes, with semi-annual interest payments in April and October, maturing October 2018
Debt Instrument [Line Items]
Rate of senior notes (percent)								9.125%		9.125%		9.125%
Principal balance								$ 425,000,000		$ 425,000,000		$ 425,000,000	425,000,000
NRP LP | Minimum
Debt Instrument [Line Items]
Fixed charge coverage ratio								1		1		1
NRP LP | Maximum
Debt Instrument [Line Items]
Fixed charge coverage ratio								2		2		2
Opco
Debt Instrument [Line Items]
Repayment of principal amount							$ 289,000,000
Ratio Of Ebitda To Consolidated Fixed Charges										3.5
Percentage of consolidated net tangible assets debt of subsidiaries not permitted to exceed										10.00%
Opco | Revolving Credit Facility
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity, Right to Delay Commitment Reduction, Period					90 days
Line of Credit Facility, Current Borrowing Capacity, Right to Delay Commitment Reduction, Threshold, Percent					66.70%
Fixed charge coverage ratio								5.46		5.46		5.46
Debt Instrument, Interest Rate During Period								4.87%	3.05%	4.24%	2.41%
Commitment fee on the unused portion of the borrowing base under the credit facility (percent)										0.50%
Ratio of Indebtedness										2.95
Debt Instrument, Covenant, Asset Sales								$ 300,000,000		$ 300,000,000		$ 300,000,000
Debt Instrument, Asset Sales Proceeds, Required to Repay Outstanding Debt, Percent					75.00%
Ratio Of Ebitda To Consolidated Fixed Charges										3.5
Secured Debt								680,500,000		$ 680,500,000		680,500,000	709,900,000
Opco | Floating Rate Revolving Credit Facility Due October Two Thousand Seventeen [Member]
Debt Instrument [Line Items]
Floating rate revolving credit facility														$ 300,000,000
Principal balance													290,000,000
Opco | Floating Rate Revolving Credit Facility Due June Two Thousand Eighteen [Member]
Debt Instrument [Line Items]
Floating rate revolving credit facility								260,000,000		260,000,000		260,000,000
Principal balance								$ 260,000,000		$ 260,000,000		$ 260,000,000
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]
Rate of senior notes (percent)								8.38%		8.38%		8.38%
Principal balance								$ 64,286,000		$ 64,286,000		$ 64,286,000	85,714,000
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]
Rate of senior notes (percent)								8.92%		8.92%		8.92%
Principal balance								$ 36,364,000		$ 36,364,000		$ 36,364,000	40,909,000
Opco | Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Covenant, Asset Sales								300,000,000		300,000,000		300,000,000
Debt Instrument, Asset Sales Proceeds, Required to Repay Outstanding Debt, Percent					25.00%
Principal balance								$ 529,900,000		529,900,000		$ 529,900,000	585,900,000
Principal payments on its senior notes										$ 56,000,000	$ 56,000,000
Partnership leverage ratio										3.75
Additional interest accrue								2.00%		2.00%		2.00%
Opco | Maximum
Debt Instrument [Line Items]
Ratio of Indebtedness										4
Opco | Maximum | Revolving Credit Facility
Debt Instrument [Line Items]
Ratio of Indebtedness										4
Opco | Scenario, Forecast [Member] | Floating Rate Revolving Credit Facility Due October Two Thousand Seventeen [Member]
Debt Instrument [Line Items]
Repayment of principal amount	$ 150,000,000	$ 30,000,000	$ 80,800,000
Opco | Scenario, Forecast [Member] | Floating Rate Revolving Credit Facility Due June Two Thousand Eighteen [Member]
Debt Instrument [Line Items]
Floating rate revolving credit facility		$ 150,000,000	180,000,000	$ 210,000,000
Repayment of principal amount			$ 30,000,000	$ 50,000,000
Opco | Federal Funds Rate | Revolving Credit Facility
Debt Instrument [Line Items]
Basis spread on variable rate (percent)					0.50%
Opco | London Interbank Offered Rate (LIBOR) | Revolving Credit Facility
Debt Instrument [Line Items]
Basis spread on variable rate (percent)										1.00%
Opco | London Interbank Offered Rate (LIBOR) | Minimum | Revolving Credit Facility, Basis Spread Condition One | Revolving Credit Facility
Debt Instrument [Line Items]
Additional basis spread (percent)					2.50%
Opco | London Interbank Offered Rate (LIBOR) | Minimum | Revolving Credit Facility, Basis Spread Condition Two | Revolving Credit Facility
Debt Instrument [Line Items]
Additional basis spread (percent)					3.50%
Opco | London Interbank Offered Rate (LIBOR) | Maximum | Revolving Credit Facility, Basis Spread Condition One | Revolving Credit Facility
Debt Instrument [Line Items]
Additional basis spread (percent)					3.50%
Opco | London Interbank Offered Rate (LIBOR) | Maximum | Revolving Credit Facility, Basis Spread Condition Two | Revolving Credit Facility
Debt Instrument [Line Items]
Additional basis spread (percent)					4.50%
NRP Oil and Gas | Revolving Credit Facility
Debt Instrument [Line Items]
Borrowings outstanding													$ 85,000,000

Fair Value Measurements - Contr

Fair Value Measurements - Contractual Override, Note Receivable and Long-Term Debt (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Contracts receivable—affiliate, current and long-term	$ 47,542	$ 49,948
Carrying Value	1,215,898	1,387,073
Opco Revolving Credit Facility And Term Loan Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying Value	254,168	285,170
Nrp Oil And Gas Revolving Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying Value	0	83,600
Nrp Lp Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying Value	419,397	417,296
Opco Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying Value	527,016	584,890
Fair Value, Inputs, Level 1 [Member] | Nrp Lp Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	391,531	277,313
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Contracts receivable—affiliate, current and long-term	32,861	34,498
Level 3 | Opco Revolving Credit Facility And Term Loan Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	260,000	290,000
Level 3 | Nrp Oil And Gas Revolving Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	0	85,000
Level 3 | Opco Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	$ 489,090	$ 383,065

Related Party Transactions - Su

Related Party Transactions - Summary of Reimbursements (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Related Party Transaction [Line Items]
Operating and maintenance expenses—affiliates, net	$ 4,062	$ 1,744	$ 9,948	$ 8,090
General and administrative—affiliates	867	2,424	2,670	3,809
Affiliated Entity | Western Pocahontas Properties and Quintana Minerals Corporation
Related Party Transaction [Line Items]
Operating and maintenance expenses—affiliates, net	1,980	1,540	6,591	7,068
General and administrative—affiliates	$ 867	$ 2,424	$ 2,670	$ 3,809

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Thousands, shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Related Party Transaction [Line Items]
Non-cash contributions			$ 200
Amount payable to related parties	$ 829		829		$ 801
Operating and maintenance expenses—affiliates, net	4,062	$ 1,744	9,948	$ 8,090
Revenues and other income	91,448	112,199	284,667	326,874
Deferred revenue—affiliates	74,663		74,663		82,853
Contracts receivable—affiliate, current and long-term	47,542		47,542		49,948
Accounts receivable	7,057		7,057		6,345
General Partner
Related Party Transaction [Line Items]
Non-cash contributions			200
Quintana Minerals
Related Party Transaction [Line Items]
Amount payable to related parties	500		500		1,100
Operating and maintenance expenses—affiliates, net	400	1,200	200	600
Western Pocahontas Properties
Related Party Transaction [Line Items]
Amount payable to related parties	500		500		300
Cline Affiliates
Related Party Transaction [Line Items]
Operating and maintenance expenses—affiliates, net	400	300	$ 1,000	1,000
Rate of interest in the partnerships general partner (percent)			31.00%
Related party transaction number of units hold by the related party in partnerships' general partner (in shares)			0.5
Accounts receivable	6,900		$ 6,900		6,400
Net amount receivable					4,900
Accounts receivable					1,500
Cline Affiliates
Related Party Transaction [Line Items]
Deferred revenue—affiliates	74,700		74,700		82,600
Net amount receivable	2,700		2,700
Accounts receivable	1,400		1,400
Foresight Energy Lp | Coal Sales
Related Party Transaction [Line Items]
Revenues and other income	20,600	18,700	47,600	68,600
Sugar Camp
Related Party Transaction [Line Items]
Contracts receivable—affiliate, current and long-term	77,700		77,700		81,200
Unearned income	32,700		32,700		35,300
Net amount receivable	45,000		45,000		45,900
Accounts receivable	2,100		2,100		2,000
Corsa
Related Party Transaction [Line Items]
Deferred revenue—affiliates	300		300		300
Accounts receivable	200		200		200
Royalty Revenue from Coal	800	900	1,900	2,400
Western Pocahontas Properties Limited Partnership | Affiliated Entity
Related Party Transaction [Line Items]
Operating and maintenance expenses—affiliates, net	0	(100)	700	0
Other assets—affiliate	$ 1,000		$ 1,000		1,100
Senior Notes Due 2018 | Cline Trust Company
Related Party Transaction [Line Items]
Partnership common units owned (in shares)	0.5		0.5
Principal amount of partnership purchased			$ 20,000
Rate of senior notes (percent)	9.125%		9.125%
Senior notes due	$ 19,900		$ 19,900
Discontinued Operations, Held-for-sale [Member] | Quintana Minerals
Related Party Transaction [Line Items]
Amount payable to related parties	100		100		$ 700
Foresight Energy Lp
Related Party Transaction [Line Items]
Revenues	$ 20,635	$ 18,677	$ 47,648	$ 68,556

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended	18 Months Ended
	Sep. 30, 2016	Jun. 30, 2016
Lawsuit Against Hillsboro Energy LLC
Commitments And Contingencies [Line Items]
Minimum quarterly deficiency payments	$ 7.5
Minimum deficiency payments	30
Loss contingency		$ 38.5
Lawsuit Against Macoupin Energy, LLC
Commitments And Contingencies [Line Items]
Damages sought, value	$ 5.8

Major Customers (Details)

Major Customers (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Foresight Energy Lp
Concentration Risk [Line Items]
Revenues	$ 20,635	$ 18,677	$ 47,648	$ 68,556
Alpha Natural Resources [Member]
Concentration Risk [Line Items]
Revenue From Lease Assignment Fees, Nonrecurring		6,000
Revenues	$ 3,829	$ 15,429	$ 14,420	$ 33,201
Sales Revenue | Customer Concentration Risk | Foresight Energy Lp
Concentration Risk [Line Items]
Concentration risk (percent)	21.00%	16.00%	15.00%	21.00%
Sales Revenue | Customer Concentration Risk | Alpha Natural Resources [Member]
Concentration Risk [Line Items]
Concentration risk (percent)	4.00%	14.00%	5.00%	10.00%

Unit-Based Compensation - Addit

Unit-Based Compensation - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of Grants (in years)			4 years
Unaccrued cost associated with outstanding grants and related DERs	$ 0.8		$ 0.8		$ 0.7
Incentive Fee Expense	$ 0.7		0.8
Incentive Fee Expense, Adjustment		$ (0.2)		$ (1.7)
General Partner
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payments of Stock Issuance Costs			$ 1.5	$ 4.4
Phantom Share Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of Grants (in years)			4 years
Number of trading days (in days)			20 days

Unit-Based Compensation - Summ

Unit-Based Compensation - Summary of Activity in Outstanding Grants (Details)	9 Months Ended
	Sep. 30, 2016shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding grants at beginning of period (in shares)	126,000
Grants during the period (in shares)	0
Grants vested and paid during the period (in shares)	(28,000)
Forfeitures during the period (in shares)	(10,000)
Outstanding grants at the end of the period (in shares)	88,000

Cash Distributions (Details)

Cash Distributions (Details) - USD ($) $ / shares in Units, $ in Thousands	Aug. 12, 2016	May 13, 2016	Feb. 12, 2016	Aug. 14, 2015	May 14, 2015	Feb. 13, 2015	Sep. 30, 2016	Sep. 30, 2015
Equity [Abstract]
Distributions per common unit (in dollars per share)	$ 0.45	$ 0.45	$ 0.45	$ 0.90	$ 0.90	$ 3.50
Distributions paid to common unitholders'	$ 5,505	$ 5,503	$ 5,503	$ 11,009	$ 11,007	$ 42,804	$ 16,849	$ 66,142
Distributions paid to general partners	112	113	113	223	225	874
Total distributions paid	$ 5,617	$ 5,616	$ 5,616	$ 11,232	$ 11,232	$ 43,678	$ 16,849

Supplemental Cash Flow Inform63

Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Supplemental Cash Flow Information [Abstract]
Cash paid for interest	$ 54,749	$ 55,761
Plant, equipment and mineral rights funded with accounts payable or accrued liabilities	$ 0	$ 4,465

Deferred Revenue and Deferred64

Deferred Revenue and Deferred Revenue - Affiliate - Schedule of Deferred Revenue (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended	9 Months Ended
	Apr. 30, 2016	Sep. 30, 2016	Sep. 30, 2015	Jun. 30, 2016	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Deferred Revenue Arrangement [Line Items]
Deferred revenue		$ 40,050			$ 40,050		$ 80,812
Deferred revenue—affiliates		74,663			74,663		82,853
Total deferred revenue (including affiliate)		114,713			114,713		$ 163,665
Coal Royalty and Other
Deferred Revenue Arrangement [Line Items]
Deferred revenue recognized		3,662	$ 539		48,705	$ 2,308
Deferred revenue recognized, including related party		9,755	3,234		60,455	12,480
Coal Royalty and Other | Affiliated Entity
Deferred Revenue Arrangement [Line Items]
Deferred revenue recognized		6,093	$ 2,695		11,750	10,172
Leasing Arrangement [Member]
Deferred Revenue Arrangement [Line Items]
Deferred revenue recognized					$ 40,000
Central Appalachia Coal Royalty Lease Termination [Member]
Deferred Revenue Arrangement [Line Items]
Deferred revenue recognized	$ 26,200
Lease Modifications of Existing Coal Royalty Leases
Deferred Revenue Arrangement [Line Items]
Deferred revenue recognized		$ 4,000		$ 11,000		$ 0

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands

Oct. 26, 2016

Aug. 12, 2016

May 13, 2016

Feb. 12, 2016

Aug. 14, 2015

May 14, 2015

Feb. 13, 2015

Nov. 30, 2016

Sep. 30, 2016

Sep. 30, 2015

Sep. 30, 2016

Sep. 30, 2015

Jun. 30, 2016

Subsequent Event [Line Items]

Distribution declared (in dollars per share)

$ 0.45

$ 0.45

$ 0.45

$ 0.90

$ 0.90

$ 3.50

Proceeds from sale of oil and gas royalty properties

$ 35,964

$ 0

Gain on asset sales, net

$ 6,426

$ 1,833

$ 27,280

$ 6,903

Subsequent Event

Subsequent Event [Line Items]

Distribution declared (in dollars per share)

$ 0.45

Discontinued Operations, Held-for-sale [Member]

Subsequent Event [Line Items]

Disposal Group, Including Discontinued Operation, Consideration

$ 116,100

Grant County Oklahoma [Member] | Subsequent Event

Subsequent Event [Line Items]

Proceeds from sale of oil and gas royalty properties

$ 7,500

Gain on asset sales, net

$ 1,800