STOCKHOLDERS' EQUITY - Series A-1 Preferred Stock (Details) - Series A-1 preferred shares - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Mar. 31, 2018	Jun. 30, 2018
Class of Stock [Line Items]
Value of shares	$ 19.9
Number of shares retired (in shares)	153,000
Reduction in the value of the preferred stock	$ 15.3
Reduction in the accretive value of the preferred stock	4.6
Issuance costs	$ 1.0
Deemed dividend		$ 4.6