DEBT (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Jun. 30, 2015	Jun. 30, 2012
Long-term debt disclosure
Total debt	$ 674,780		$ 322,110
Convertible notes due 2019, net
Long-term debt disclosure
Total debt	324,780		$ 322,110
Aggregate principal amount of convertible senior notes issued				$ 370,000
Interest rate on convertible senior notes (as a percent)				2.875%
Interest expense recognized	5,600	$ 5,400
Revolving credit facility
Long-term debt disclosure
Total debt	350,000
Maximum availability under the revolving credit facility	650,000
Available under the revolving credit facility	300,000
Outstanding amount under credit facility	$ 350,000
Revolving credit facility | LIBOR
Long-term debt disclosure
Effective interest rate (as percent)	1.46%
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%