Summary of Significant Accounting Policies - New Accounting Pronouncements (Details) - Predecessor - USD ($) $ in Millions	3 Months Ended
Jun. 30, 2017	Mar. 31, 2017
Business Acquisition [Line Items]
Decrease in fair value of mineral interests	$ 3.5	$ 3.5
Decrease to additional paid in capital	$ 3.5

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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