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OPERATIONS, SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND RECENTLY ADOPTED AND RECENTLY ISSUED ACCOUNTING STANDARDS - Recently Adopted Accounting Standards (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Mar. 31, 2019	Mar. 31, 2019	Jul. 01, 2018	Jun. 30, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated (losses) earnings	$ (74,563)	$ (74,563)		$ (89,898)
Increase (decrease) fair value of equity securities	1,781	(3,318)
Carrying value of equity securities	$ 19,500	$ 19,500		$ 19,200
Contango
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Investment shares owned (in shares)	809,744	809,744
Rubicon
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Investment shares owned (in shares)	3,597,823	3,597,823
ASU 2016-01 \| Retrospective Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated (losses) earnings			$ 1,200