Quarterly Financial Data (Unaudited) Restatement of Previously Issued Unaudited Consolidated Financial Statements (Details) - USD ($) $ / shares in Units, $ in Thousands	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017
Series D redeemable convertible preferred stock, par value (in dollars per share)	$ 0.10	$ 0.10
Cash and cash equivalents	$ 287,796	$ 71,926	$ 96,165	$ 101,954
Accounts Receivable, after Allowance for Credit Loss, Current	56,301	47,784
Current contract assets	291,497	294,193
Prepaid expenses and other current assets	10,884	9,988
Prepaid income taxes	3,962	2,509
Assets, Current	650,440	426,400
Property, equipment and leasehold improvements, net	5,963	7,234
Computer software development costs, net	928	1,306
Goodwill	137,055	78,383
Intangible assets, net	42,851	33,607
Non-current contract assets	318,976	288,098
Contract costs	28,614	24,982
Deferred tax assets	1,735	1,669
Other non-current assets	1,839	1,334
Assets	1,223,306	863,013
Accounts payable	3,988	5,891
Accrued expenses and other current liabilities	43,556	54,594
Income taxes payable	1,799	14,952
Current borrowings	135,163	220,000
Current deferred revenue	43,168	25,318
Liabilities, Current	234,498	320,755
Non-current deferred revenue	13,913	19,573
Deferred income taxes	179,978	150,344
Other non-current liabilities	3,107	10,381
Series D redeemable convertible preferred stock, $0.10 par value—Authorized—3,636 shares as of June 30, 2020 and 2019 Issued and outstanding—none as of June 30, 2020 and 2019	0	0
Common stock, $0.10 par value—Authorized—210,000,000 shares Issued—103,988,707 shares at June 30, 2020 and 103,642,292 shares at June 30, 2019 Outstanding—67,718,692 shares at June 30, 2020 and 68,624,566 shares at June 30, 2019	10,399	10,365
Additional paid-in capital	769,411	739,099
Retained earnings	1,458,330	1,228,659	967,297	686,063
Accumulated other comprehensive income	(5,288)	336
Treasury Stock, Value	(1,766,499)	(1,616,499)
Stockholders' Equity Attributable to Parent	466,353	361,960	377,974	268,759
Total liabilities and stockholders' equity	$ 1,223,306	$ 863,013
Series D redeemable convertible preferred stock, authorized	3,636	3,636
Series D redeemable convertible preferred stock, issued	0	0
Series D redeemable convertible preferred stock, outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, authorized	210,000,000	210,000,000
Common stock, issued	103,988,707	103,642,292
Common stock, outstanding	67,718,692	68,624,566
Treasury stock, shares	36,270,015	35,017,726
Restatement Adjustment [Member]
Prepaid expenses and other current assets		$ (2,640)
Non-current contract assets		(37,412)
Assets		(40,052)
Deferred income taxes		(8,727)
Retained earnings		(31,325)	(29,953)	(17,484)
Stockholders' Equity Attributable to Parent		(31,325)
Total liabilities and stockholders' equity		(40,052)
Previously Reported [Member]
Prepaid expenses and other current assets		12,628
Non-current contract assets		325,510
Assets		903,065
Deferred income taxes		159,071
Retained earnings		1,259,984	$ 997,250	$ 703,547
Stockholders' Equity Attributable to Parent		393,285
Total liabilities and stockholders' equity		$ 903,065