STOCKHOLDERS' EQUITY STOCKHOLDERS' EQUITY - TREASURY STOCK (Details) - USD ($) $ in Millions		1 Months Ended	9 Months Ended
	Apr. 29, 2015	Feb. 28, 2017	Dec. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Class of Stock [Line Items]
Treasury Stock Issued During Period, Shares, Withholding Tax			134,698
Re-issuance of treasury stock in connection with convertible notes exchange transaction (in shares)		277,244
Long-term Debt | Class A common stock
Class of Stock [Line Items]
Treasury Stock, Shares, Acquired	272,100
Treasury Stock, Value, Acquired, Cost Method	$ 2.7
Forward Contracts [Member] | Class A common stock
Class of Stock [Line Items]
Adjustments to Additional Paid in Capital, Forward Contract Indexed	$ 11.4
Forward Contracts Indexed to Issuer's Equity, Indexed Shares				1,179,138	1,179,138