Acquisitions - Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 01, 2019	Jun. 30, 2018	Jun. 30, 2017
Business Acquisition [Line Items]
Goodwill	$ 3,322,982		$ 2,620,835	$ 2,577,435
LGS
Business Acquisition [Line Items]
Accounts receivable		$ 92,876
Prepaid expenses and other current assets		21,033
Property and equipment		23,282
Identifiable intangible assets		147,650
Goodwill		521,630
Accounts receivable, long-term		2,180
Other long-term assets		877
Accounts payable		(10,309)
Accrued compensation and benefits		(22,339)
Other accrued expenses and current liabilities		(9,185)
Deferred income taxes		71
Other long-term liabilities		(8,288)
Total estimated consideration		$ 759,478