Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues:
Oil and gas sales	$ 9,942	$ 15,908	$ 29,848	$ 55,411
Gain (loss) on commodity derivative instruments	(273)		(463)
Total revenue	9,669	15,908	29,385	55,411
Operating expenses:
Production and ad valorem taxes	745	891	2,205	2,940
Marketing and transportation	562	584	1,567	1,933
Amortization of royalty interests in oil and natural gas properties	3,542	3,184	10,485	9,624
General, administrative, and other	2,806	3,168	8,618	8,728
Total operating expenses	7,655	7,827	22,875	23,225
Operating income	2,014	8,081	6,510	32,186
Other income (expense):
Other income	31	58	94	134
Interest expense	(490)	(650)	(1,706)	(1,838)
Total other income (expense)	(459)	(592)	(1,612)	(1,704)
Income before income taxes	1,555	7,489	4,898	30,482
Provision for income taxes	243	1,132	400	3,920
Net income	1,312	6,357	4,498	26,562
Net income attributable to non-controlling interests	(723)	(3,473)	(2,278)	(14,540)
Net income attributable to common shareholders	$ 589	$ 2,884	$ 2,220	$ 12,022
Earnings per common share:
Common shares (basic and diluted)	$ 0.01	$ 0.06	$ 0.05	$ 0.26
Weighted average number of shares outstanding:
Common shares (basic and diluted)	46,055	45,899	46,008	45,871