EARNINGS PER SHARE - Calculation of Basic and Diluted Earnings per Share (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
Earnings Per Share [Abstract]
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
Weighted-average number of basic shares outstanding during the period	24,459	24,419	24,387	24,340	24,319	24,277	24,246	24,208	24,401	24,262	23,948
Dilutive effect of SSARs/stock options and RSUs/restricted shares after application of treasury stock method									668	540	384
Dilutive effect of the warrants											56
Weighted-average number of diluted shares outstanding during the period	25,172	25,106	25,069	24,928	24,900	24,801	24,786	24,721	25,069	24,802	24,388
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