ACCOUNTS PAYABLE AND ACCRUED LIABILITIES - Schedule of Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jun. 30, 2020
Accounts Payable and Accrued Liabilities [Abstract]
Accounts payable—trade	$ 31,274	$ 41,469
Accrued salaries and commissions	110,743	155,496
Accrued liabilities	83,199	78,793
Accrued sales and other tax liabilities	43,716	50,255
Accrued interest on Senior Notes	25,646	30,761
Amounts payable in respect of restructuring and other Special charges	14,661	12,185
Asset retirement obligations	4,229	4,355
Total	$ 313,468	$ 373,314