DEBT (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016	Jun. 30, 2016	Jun. 30, 2012
Long-term debt disclosure
Principal	$ 670,000		$ 670,000		$ 645,000
Unamortized Discount	(28,246)		(28,246)		(36,943)
Debt Issuance Costs	(5,873)		(5,873)		(7,372)
Total debt	635,881		635,881		600,685
Repayment of revolving credit facility			45,000	$ 50,000
Convertible notes due 2019
Long-term debt disclosure
Principal	370,000		370,000		370,000
Unamortized Discount	(28,246)		(28,246)		(36,943)
Debt Issuance Costs	(2,972)		(2,972)		(3,934)
Total debt	338,782		338,782		329,123
Aggregate principal amount of convertible senior notes issued						$ 370,000
Interest rate on convertible senior notes (as a percent)						2.875%
Interest expense recognized	5,900	$ 5,700	17,600	17,100
Revolving credit facility
Long-term debt disclosure
Principal	300,000		300,000		275,000
Debt Issuance Costs	(2,901)		(2,901)		(3,438)
Total debt	297,099		297,099		$ 271,562
Interest expense recognized	2,900	$ 2,600	7,200	$ 5,600
Maximum availability under the revolving credit facility	650,000		650,000
Outstanding amount under credit facility	300,000		300,000
Available under the revolving credit facility	350,000		$ 350,000
Repayment of revolving credit facility	$ 45,000
Revolving credit facility | LIBOR
Long-term debt disclosure
Revolving credit facility, basis spread on interest rate (as a percent)			2.25%
Effective interest rate (as percent)	3.41%		3.41%
Revolving credit facility | Minimum | LIBOR
Long-term debt disclosure
Revolving credit facility, basis spread on interest rate (as a percent)			1.25%
Revolving credit facility | Maximum | LIBOR
Long-term debt disclosure
Revolving credit facility, basis spread on interest rate (as a percent)			3.00%