CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Revenue	$ 1,087,860	$ 1,057,530	$ 2,173,674	$ 2,130,810
Costs of revenue:
Direct costs	727,160	705,321	1,466,838	1,433,542
Indirect costs and selling expenses	254,180	253,822	515,424	511,160
Depreciation and amortization	18,258	18,132	35,846	36,195
Total costs of revenue	999,598	977,275	2,018,108	1,980,897
Income from operations	88,262	80,255	155,566	149,913
Interest expense and other, net	10,956	12,325	22,203	24,814
Income before income taxes	77,306	67,930	133,363	125,099
Income tax expense (benefit)	(65,489)	25,510	(51,478)	46,016
Net income	$ 142,795	$ 42,420	$ 184,841	$ 79,083
Basic earnings per share	$ 5.80	$ 1.74	$ 7.53	$ 3.25
Diluted earnings per share	$ 5.66	$ 1.69	$ 7.33	$ 3.16
Weighted-average basic shares outstanding	24,622	24,387	24,555	24,363
Weighted-average diluted shares outstanding	25,211	25,069	25,228	24,998