Schedule of Aggregate Capitalized Costs Related to Oil and Natural Gas Production Activities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Capitalized Costs, Oil and Gas Producing Activities, Net [Abstract]
Proved royalty interest	$ 319,487	$ 311,954
Unproved royalty interests	32,463	37,580
Accumulated amortization	(144,445)	(130,342)
Net royalty interests in oil and natural gas properties	$ 207,505	$ 219,192

Amount of accumulated depreciation, depletion, amortization and valuation allowance relating to oil and gas producing activities.

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-Name Accounting Standards Codification
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-SubTopic 235
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Capitalized costs of unproven properties that include fee ownership or a lease, concession, or other interest representing the right to extract oil or gas subject to such terms as may be imposed by the conveyance of that interest.

+ References

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Net amount of capitalized costs relating to oil and gas producing activities.

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Capitalized costs of proved properties incurred for any combination mineral interests acquisitions; wells and related equipment; support equipment and facilities; and uncompleted wells and equipment and other costs not previously disclosed within this table.

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