QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended												12 Months Ended
	Jun. 30, 2016		Mar. 31, 2016	[1]	Dec. 31, 2015		Sep. 30, 2015		Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2014
Quarterly Financial Data [Abstract]
Revenue	$ 1,113,900		$ 977,274		$ 830,437		$ 822,442		$ 865,506	$ 817,797	$ 815,423	$ 814,726	$ 3,744,053	$ 3,313,452	$ 3,564,562
Income from operations	81,084		63,676		55,482		64,508		75,079	53,715	47,528	60,059	264,750	236,381	257,403
Net income attributable to CACI	$ 43,599	[2]	$ 34,116	[2]	$ 30,452	[2]	$ 34,632	[2]	$ 41,384	$ 29,039	$ 24,642	$ 31,130	$ 142,799	$ 126,195	$ 135,316
Basic earnings per share (in dollars per share)	$ 1.79	[2]	$ 1.41	[2]	$ 1.26	[2]	$ 1.43	[2]	$ 1.71	$ 1.20	$ 1.03	$ 1.32	$ 5.89	$ 5.27	$ 5.78
Diluted earnings per share (in dollars per share)	$ 1.75	[2]	$ 1.38	[2]	$ 1.23	[2]	$ 1.40	[2]	$ 1.68	$ 1.18	$ 1.01	$ 1.29	$ 5.76	$ 5.17	$ 5.38
Weighted-average shares outstanding:
Weighted-average basic shares outstanding (in shares)	24,319		24,277		24,246		24,208		24,180	24,165	23,890	23,565	24,262	23,948	23,429
Weighted-average diluted shares outstanding (in shares)	24,900	[2]	24,801	[2]	24,786	[2]	24,721	[2]	24,613	24,527	24,314	24,104	24,802	24,388	25,155

[1] Acquisition of NSS on February 1, 2016.

[2] Quarterly FY2016 balances have been adjusted to reflect the adoption of ASU 2016-09 as of the beginning of the fiscal year. See Note 3 for additional information.