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
	Sep. 30, 2018	Jul. 01, 2018	Jun. 30, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated (losses) earnings	$ (92,467)		$ (89,898)
Change in fair value of equity securities	(1,468)
Carrying value of equity securities	$ 17,800		$ 19,200
Contango
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Investment shares owned (in shares)	682,556
Rubicon
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Investment shares owned (in shares)	3,379,913
ASU 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated (losses) earnings		$ 1,200