Correction of Immaterial Errors (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Prepaid expenses and other current assets	$ 10,884	$ 9,988
Non-current contract assets	318,976	288,098
Total assets	1,223,306	863,013
Deferred income taxes	179,978	150,344
Retained earnings	1,458,330	1,228,659	$ 967,297	$ 686,063
Total stockholders' equity	466,353	361,960	377,974	268,759
Total liabilities and stockholders' equity	$ 1,223,306	863,013
Previously Reported [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Prepaid expenses and other current assets		12,628
Non-current contract assets		325,510
Total assets		903,065
Deferred income taxes		159,071
Retained earnings		1,259,984	997,250	703,547
Total stockholders' equity		393,285
Total liabilities and stockholders' equity		903,065
Restatement Adjustment [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Prepaid expenses and other current assets		(2,640)
Non-current contract assets		(37,412)
Total assets		(40,052)
Deferred income taxes		(8,727)
Retained earnings		(31,325)	$ (29,953)	$ (17,484)
Total stockholders' equity		(31,325)
Total liabilities and stockholders' equity		$ (40,052)