Business Segment, Customer And Geographic Information (Summarized Financial Information Reportable Segments) (Details) (USD $) In Thousands	3 Months Ended										12 Months Ended
	Jun. 30, 2011		Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010		Mar. 31, 2010	Dec. 31, 2009	Sep. 30, 2009	Jun. 30, 2011		Jun. 30, 2010		Jun. 30, 2009		Jun. 30, 2008
Revenue from external customers	$ 963,162		$ 913,369	$ 867,278	$ 833,971	$ 848,717		$ 784,169	$ 776,727	$ 739,518	$ 3,577,780		$ 3,149,131		$ 2,730,162	[1]
Net income attributable to CACI	45,901		36,427	33,235	28,655	29,900		26,708	26,052	23,855	144,218	[2]	106,515	[2]	89,698	[1],[2]
Net assets	1,309,616	[2]				1,173,155	[2]				1,309,616	[2]	1,173,155	[2]	1,029,608	[2]	959,067	[2]
Goodwill	1,266,285					1,161,861					1,266,285		1,161,861		1,083,750
Total long-term assets	1,538,053					1,404,020					1,538,053		1,404,020		1,281,247
Total assets	2,320,131					2,244,766					2,320,131		2,244,766		2,006,079
Capital expenditures											14,388		22,503		12,369	[3]
Depreciation and amortization											56,067		53,039		46,592	[1]
Domestic Operations [Member]
Revenue from external customers											3,459,715		3,032,341		2,650,769
Net income attributable to CACI											135,158		98,649		84,772
Net assets	1,211,517					1,090,795					1,211,517		1,090,795		971,685
Goodwill	1,200,091					1,105,055					1,200,091		1,105,055		1,031,980
Total long-term assets	1,457,505					1,333,876					1,457,505		1,333,876		1,214,944
Total assets	2,176,380					2,122,510					2,176,380		2,122,510		1,907,677
Capital expenditures											13,264		20,954		11,692
Depreciation and amortization											53,179		50,095		44,788
International Operations [Member]
Revenue from external customers											118,065		116,790		79,393
Net income attributable to CACI											9,060		7,866		4,926
Net assets	98,099					82,360					98,099		82,360		57,923
Goodwill	66,194					56,806					66,194		56,806		51,770
Total long-term assets	80,548					70,144					80,548		70,144		66,303
Total assets	143,751					122,256					143,751		122,256		98,402
Capital expenditures											1,124		1,549		677
Depreciation and amortization											$ 2,888		$ 2,944		$ 1,804

[1] Certain amounts for the year ended June 30, 2009 have been adjusted to reflect the retroactive application of new accounting standards. See Note 3.

[2] Certain amounts as of and for the years ended June 30, 2008 and 2009 have been adjusted to reflect the retroactive application of new accounting standards. See Note 3.

[3] Certain amounts for the year ended June 30, 2009 have been adjusted to reflect the retroactive application of new accounting standards. See Note 3.