Quarterly Financial Data (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2011
Quarterly Financial Data [Abstract]
Revenue	$ 912,931	$ 906,196	$ 931,627	$ 931,236	$ 948,873	$ 927,962	$ 973,243	$ 924,395	$ 3,681,990	$ 3,774,473	$ 3,577,780
Income from operations	67,902	68,620	69,582	64,737	76,708	72,781	74,706	75,654	270,841	299,849	251,401
Net income attributable to CACI	$ 37,938	$ 38,367	$ 39,676	$ 35,708	$ 43,397	$ 40,856	$ 41,061	$ 42,140	$ 151,689	$ 167,454	$ 144,218
Basic earnings per share	$ 1.64	$ 1.67	$ 1.74	$ 1.55	$ 1.64	$ 1.54	$ 1.55	$ 1.46	$ 6.59	$ 6.18	$ 4.76
Diluted earnings per share	$ 1.56	$ 1.62	$ 1.69	$ 1.49	$ 1.59	$ 1.45	$ 1.51	$ 1.41	$ 6.35	$ 5.96	$ 4.61
Weighted-average basic shares outstanding	23,136	23,021	22,852	23,032	26,407	26,537	26,450	28,915	23,010	27,077	30,281
Weighted-average diluted shares outstanding	24,318	23,706	23,537	23,980	27,247	28,086	27,270	29,842	23,885	28,111	31,300