CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Oil and natural gas properties, unproved property costs	$ 1,089,576	$ 1,063,884
Other property and equipment accumulated depreciation and amortization	$ 11,267	$ 11,048
Series B Cumulative Convertible Preferred Units
Partners' equity, preferred units, outstanding (in shares)	14,711	14,711
Common Units
Partners' equity - units, outstanding (in shares)	205,956	108,363
Subordinated Units
Partners' equity - units, outstanding (in shares)	0	96,329

Capitalized costs of unproved properties incurred for any combination mineral interests acquisitions and other costs not previously disclosed within this table.

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