ACCOUNTS RECEIVABLE - Schedule of Total Accounts Receivable (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Jun. 30, 2020
Accounts Receivable Net [Abstract]
Billed and billable receivables	$ 763,921	$ 779,339
Unbilled receivables	115,930	61,888
Total accounts receivable, current	879,851	841,227
Unbilled receivables, long-term	12,159	9,629
Total accounts receivable	$ 892,010	$ 850,856