Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jul. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Oil and natural gas interests, based on the full cost method of accounting, amount excluded from depletion		$ 1,480,346	$ 1,551,767
Common Units
Limited partners' capital account, units issued (in shares)		67,831,342	67,805,707
Limited partners' capital account, units outstanding (in shares)		67,831,342	67,805,707
Class B Units
Limited partners' capital account, units issued (in shares)		90,709,946	90,709,946
Limited partners' capital account, units outstanding (in shares)	90,709,946	90,709,946	90,709,946