DEBT (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2013	Apr. 29, 2015	Mar. 31, 2015	Jun. 30, 2012
Long-term debt disclosure
Total debt	$ 322,110	$ 311,860
Interest payments on notes	10,638	10,638	$ 10,490
Convertible notes due 2019, net
Long-term debt disclosure
Total debt	322,110	311,860
Aggregate principal amount of convertible senior notes issued						$ 370,000
Interest rate on convertible senior notes (as a percent)						2.875%
Interest expense recognized	22,100	21,400	$ 20,700
Interest payments on notes	10,600	$ 10,600
Revolving credit facility
Long-term debt disclosure
Maximum availability under the revolving credit facility	650,000			$ 650,000	$ 450,000
Amount of accordion feature					$ 150,000
Outstanding amount under credit facility	$ 0
Revolving credit facility | LIBOR
Long-term debt disclosure
Effective interest rate (as percent)	1.25%
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%