Business Segment, Customer And Geographic Information (Summarized Financial Information Reportable Segments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2009
Revenue from external customers	$ 948,873	$ 927,962	$ 973,243	$ 924,395	$ 963,162	$ 913,369	$ 867,278	$ 833,971	$ 3,774,473	$ 3,577,780	$ 3,149,131
Net income attributable to CACI	43,397	40,856	41,061	42,140	45,901	36,427	33,235	28,655	167,454	144,218	106,515
Net assets	1,164,445				1,309,616				1,164,445	1,309,616	1,173,155	1,029,608
Goodwill	1,406,953				1,266,285				1,406,953	1,266,285	1,161,861
Total long-term assets	1,707,084				1,538,053				1,707,084	1,538,053	1,404,020
Total assets	2,392,876				2,320,131				2,392,876	2,320,131	2,244,766
Capital expenditures									18,284	14,388	22,503
Depreciation and amortization									55,962	56,067	53,039
Domestic Operations [Member]
Revenue from external customers									3,659,367	3,459,715	3,032,341
Net income attributable to CACI									159,421	135,158	98,649
Net assets	1,061,360				1,211,517				1,061,360	1,211,517	1,090,795
Goodwill	1,325,814				1,200,091				1,325,814	1,200,091	1,105,055
Total long-term assets	1,605,380				1,457,505				1,605,380	1,457,505	1,333,876
Total assets	2,238,134				2,176,380				2,238,134	2,176,380	2,122,510
Capital expenditures									16,613	13,264	20,954
Depreciation and amortization									52,865	53,179	50,095
International Operations [Member]
Revenue from external customers									115,106	118,065	116,790
Net income attributable to CACI									8,033	9,060	7,866
Net assets	103,085				98,099				103,085	98,099	82,360
Goodwill	81,139				66,194				81,139	66,194	56,806
Total long-term assets	101,704				80,548				101,704	80,548	70,144
Total assets	154,742				143,751				154,742	143,751	122,256
Capital expenditures									1,671	1,124	1,549
Depreciation and amortization									$ 3,097	$ 2,888	$ 2,944