Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues	$ 251,071	$ 242,780	$ 250,176
Gain on litigation settlement	25,000	0	0
Gain on asset sales, net	2,441	3,545	29,068
Total revenues and other income	278,512	246,325	279,244
Operating expenses
Operating and maintenance expenses	17,894	16,771	20,737
Operating and maintenance expenses—affiliates	11,615	8,112	9,153
Depreciation, depletion and amortization	21,689	22,406	28,581
Amortization expense—affiliate	0	1,008	3,185
General and administrative	12,838	13,513	16,979
General and administrative—affiliates	3,658	4,989	3,591
Asset impairments	18,280	2,967	15,861
Total operating expenses	85,974	69,766	98,087
Income from operations	192,538	176,559	181,157
Other expense, net
Interest expense, net	(70,178)	(82,028)	(90,008)
Interest expense—affiliate	0	0	(523)
Debt modification expense	0	(7,939)	0
Loss on extinguishment of debt	0	(4,107)	0
Total other expense, net	(70,178)	(94,074)	(90,531)
Net income from continuing operations	122,360	82,485	90,626
Income from discontinued operations	17,687	6,182	6,266
Net income	140,047	88,667	96,892
Net income attributable to non-controlling interest	(510)	0	0
Net income attributable to NRP	139,537	88,667	96,892
Less: income attributable to preferred unitholders	(30,000)	(25,453)	0
Net income attributable to common unitholders and general partner	109,537	63,214	96,892
Net income attributable to common unitholders	107,346	61,950	95,229
Net income attributable to the general partner	$ 2,191	$ 1,264	$ 1,663
Income from continuing operations per common unit
Income from continuing operations per common unit (basic)	$ 7.35	$ 4.57	$ 7.28
Income from continuing operations per common unit (diluted)	5.90	3.68	7.28
Basic and diluted net income per common unit (in dollars per share):
Net income per common unit (basic)	8.77	5.06	7.78
Net income per common unit (diluted)	$ 6.76	$ 3.96	$ 7.78
Comprehensive income (loss) from unconsolidated investment and other	$ (149)	$ (1,647)	$ 486
Comprehensive income	139,898	87,020	97,378
Comprehensive income attributable to non-controlling interest	(510)	0	0
Comprehensive income attributable to NRP	139,388	87,020	97,378
Coal Royalty and Other
Revenues	178,394	158,399	144,520
Coal royalty and other—affiliates	484	23,402	46,259
Soda Ash
Revenues	48,306	$ 40,457	$ 40,061
Transportation and processing services | Coal Royalty and Other
Revenues	23,887
Transportation and processing services—affiliate | Coal Royalty and Other
Coal royalty and other—affiliates	$ 0