CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Preferred Stock	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, 2014	$ 1,359,166		$ 4,144	$ 537,334	$ 1,392,954	$ (382)	$ (577,167)	$ 1,356,883	$ 2,283
Beginning balance, shares at Jun. 30, 2014			41,441				17,941
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to CACI	126,195				126,195			126,195
Noncontrolling interest	101								101
Stock-based compensation expense	14,072			14,072				14,072
Exercise of stock options and vesting of restricted stock units	(2,844)		$ 18	(2,862)				(2,844)
Exercise of stock options and vesting of restricted stock units (in shares)			181
Lapse of statute of limitations for uncertain tax position	438			438				438
Change in fair value of interest rate swap agreements, net	(2,398)					(2,398)		(2,398)
Currency translation adjustment	(11,943)					(11,943)		(11,943)
Repurchases of common stock	(3,400)			(158)			$ (3,242)	(3,400)
Repurchases of common stock (in shares)							44
Treasury stock issued upon settlement of warrants	(9)			(973)			$ 964	(9)
Treasury stock issued upon settlement of warrants (in shares)							(498)
Treasury stock issued under stock purchase plans	3,380			128			$ 3,252	3,380
Treasury stock issued under stock purchase plans (in shares)							(49)
Post-retirement benefit costs	(237)					(237)		(237)
Distributions to noncontrolling interest	(2,249)								(2,249)
Ending balance at Jun. 30, 2015	1,480,272		$ 4,162	547,979	1,519,149	(14,960)	$ (576,193)	1,480,137	135
Ending balance, shares at Jun. 30, 2015			41,622				17,438
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to CACI	142,799				142,799			142,799
Stock-based compensation expense	17,919			17,919				17,919
Exercise of stock options and vesting of restricted stock units	(7,451)		$ 14	(7,465)				(7,451)
Exercise of stock options and vesting of restricted stock units (in shares)			136
Change in fair value of interest rate swap agreements, net	(5,992)					(5,992)		(5,992)
Currency translation adjustment	(19,961)					(19,961)		(19,961)
Repurchases of common stock	(3,230)			(192)			$ (3,038)	(3,230)
Repurchases of common stock (in shares)							37
Treasury stock issued under stock purchase plans	3,127			83			$ 3,044	3,127
Treasury stock issued under stock purchase plans (in shares)							(40)
Post-retirement benefit costs	(170)					(170)		(170)
Ending balance at Jun. 30, 2016	1,607,313		$ 4,176	558,324	1,661,948	(41,083)	$ (576,187)	1,607,178	135
Ending balance, shares at Jun. 30, 2016			41,758				17,435
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to CACI	163,671				163,671			163,671
Stock-based compensation expense	21,945			21,945				21,945
Vesting of restricted stock units	(10,943)		$ 14	(10,957)				(10,943)
Vesting of restricted stock units (in shares)			138
Change in fair value of interest rate swap agreements, net	14,587					14,587		14,587
Currency translation adjustment	(2,804)					(2,804)		(2,804)
Repurchases of common stock	(4,386)			(236)			$ (4,150)	(4,386)
Repurchases of common stock (in shares)							41
Treasury stock issued under stock purchase plans	4,154			4			$ 4,150	4,154
Treasury stock issued under stock purchase plans (in shares)							(41)
Post-retirement benefit costs	184					184		184
Ending balance at Jun. 30, 2017	$ 1,793,721		$ 4,190	$ 569,080	$ 1,825,619	$ (29,116)	$ (576,187)	$ 1,793,586	$ 135
Ending balance, shares at Jun. 30, 2017			41,896				17,435