CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Total CACI Shareholders' Equity	Noncontrolling Interest
Beginning balance at Jun. 30, 2019	$ 2,371,466	$ 4,231	$ 576,277	$ 2,410,164	$ (43,156)	$ (576,185)	$ 2,371,331	$ 135
Beginning balance, shares at Jun. 30, 2019		42,314				17,434
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	67,977			67,977			67,977
Stock-based compensation expense	7,038		7,038				7,038
Tax withholdings on restricted share vestings	(10,860)	$ 8	(10,868)				(10,860)
Tax withholdings on restricted share vestings (in shares)		78
Change in fair value of interest rate swap agreements, net	(4,964)				(4,964)		(4,964)
Currency translation adjustment	(5,308)				(5,308)		(5,308)
Repurchases of common stock	(1,717)		(112)			$ (1,605)	(1,717)
Repurchases of common stock (in shares)						8
Treasury stock issued under stock purchase plans	1,619		13			$ 1,606	1,619
Treasury stock issued under stock purchase plans (in shares)						(8)
Ending balance at Sep. 30, 2019	2,425,251	$ 4,239	572,348	2,478,141	(53,428)	$ (576,184)	2,425,116	135
Ending balance, shares at Sep. 30, 2019		42,392				17,434
Beginning balance at Jun. 30, 2020	2,661,310	$ 4,253	573,744	2,731,644	(72,285)	$ (576,181)	2,661,175	135
Beginning balance, shares at Jun. 30, 2020		42,525				17,432
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	93,644			93,644			93,644
Stock-based compensation expense	7,847		7,847				7,847
Tax withholdings on restricted share vestings	(1,176)	$ 1	(1,177)				(1,176)
Tax withholdings on restricted share vestings (in shares)		12
Change in fair value of interest rate swap agreements, net	2,252				2,252		2,252
Currency translation adjustment	7,793				7,793		7,793
Repurchases of common stock	(2,074)		80			$ (2,154)	(2,074)
Repurchases of common stock (in shares)						10
Treasury stock issued under stock purchase plans	2,173		19			$ 2,154	2,173
Treasury stock issued under stock purchase plans (in shares)						(10)
Ending balance at Sep. 30, 2020	$ 2,771,769	$ 4,254	$ 580,513	$ 2,825,288	$ (62,240)	$ (576,181)	$ 2,771,634	$ 135
Ending balance, shares at Sep. 30, 2020		42,537				17,432