QUARTERLY FINANCIAL DATA (UNAUDITED) - Schedule of Quarterly Condensed Financial Operating Results (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
Quarterly Financial Data [Abstract]
Revenue	$ 1,137,389	$ 1,086,418	$ 1,057,530	$ 1,073,280	$ 1,113,900	$ 977,274	$ 830,437	$ 822,442	$ 4,354,617	$ 3,744,053	$ 3,313,452
Income from operations	80,094	67,254	80,255	69,658	81,084	63,676	55,482	64,508	297,261	264,750	236,381
Net income attributable to CACI	$ 44,231	$ 40,357	$ 42,420	$ 36,663	$ 43,599	$ 34,116	$ 30,452	$ 34,632	$ 163,671	$ 142,799	$ 126,195
Basic earnings per share	$ 1.81	$ 1.65	$ 1.74	$ 1.51	$ 1.79	$ 1.41	$ 1.26	$ 1.43	$ 6.71	$ 5.89	$ 5.27
Diluted earnings per share	$ 1.76	$ 1.61	$ 1.69	$ 1.47	$ 1.75	$ 1.38	$ 1.23	$ 1.40	$ 6.53	$ 5.76	$ 5.17
Weighted-average basic shares outstanding	24,459	24,419	24,387	24,340	24,319	24,277	24,246	24,208	24,401	24,262	23,948
Weighted-average diluted shares outstanding	25,172	25,106	25,069	24,928	24,900	24,801	24,786	24,721	25,069	24,802	24,388