CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Redeemable Noncontrolling Interest	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit	Accumulated Deficit Cumulative Effect, Period of Adoption, Adjustment
Balance, beginning of period at Dec. 31, 2017			$ 0.0
Balance, end of period at Dec. 30, 2018			0.0
Balance, beginning of period (in shares) at Dec. 31, 2017				103,300,000
Balance, beginning of period at Dec. 31, 2017	$ 511.5	$ (0.2)		$ 0.0	$ 1,233.7	$ (1.4)	$ (720.8)	$ (0.2)
Increase (Decrease) in Stockholders' Equity
Stock-based compensation	7.2				7.2
Issuance of common stock for employee stock purchase plan, options and warrants (in shares)				400,000
Issuance of common stock for employee stock purchase plan, options and warrants	3.7				3.7
Restricted stock issued and related taxes (in shares)				100,000
Restricted stock issued and related taxes	(0.1)				(0.1)
Pro forma net income attributable to Kratos	(3.5)						(3.5)
Other comprehensive income (loss), net of tax	0.7					0.7
Balance, end of period (in shares) at Dec. 30, 2018				103,800,000
Balance, end of period at Dec. 30, 2018	519.3			$ 0.0	1,244.5	(0.7)	(724.5)
Redeemable Noncontrolling Interest
Net income (loss)			0.1
Changes in noncontrolling interest			14.9
Balance, end of period at Dec. 29, 2019			15.0
Increase (Decrease) in Stockholders' Equity
Stock-based compensation	11.0				11.0
Issuance of common stock for employee stock purchase plan, options and warrants (in shares)				800,000
Issuance of common stock for employee stock purchase plan, options and warrants	4.9				4.9
Restricted stock issued and related taxes (in shares)				200,000
Restricted stock issued and related taxes	(0.9)				(0.9)
Issuance of common stock for acquisitions (in shares)				1,800,000
Issuance of common stock for acquisitions	27.0				27.0
Pro forma net income attributable to Kratos	12.5						12.5
Other comprehensive income (loss), net of tax	$ 0.3					0.3
Balance, end of period (in shares) at Dec. 29, 2019	106,635,508			106,600,000
Balance, end of period at Dec. 29, 2019	$ 574.1			$ 0.0	1,286.5	(0.4)	(712.0)
Redeemable Noncontrolling Interest
Net income (loss)			(0.2)
Balance, end of period at Dec. 27, 2020			$ 14.8
Increase (Decrease) in Stockholders' Equity
Stock-based compensation	21.0				21.0
Issuance of common stock for employee stock purchase plan, options and warrants (in shares)				400,000
Issuance of common stock for employee stock purchase plan, options and warrants	4.8				4.8
Restricted stock issued and related taxes (in shares)				200,000
Restricted stock issued and related taxes	(1.4)				(1.4)
Issuance of common stock for acquisitions (in shares)				15,800,000
Issuance of common stock for acquisitions	245.4				245.4
Pro forma net income attributable to Kratos	79.6						79.6
Other comprehensive income (loss), net of tax	$ 1.8					1.8
Balance, end of period (in shares) at Dec. 27, 2020	123,047,147			123,000,000.0
Balance, end of period at Dec. 27, 2020	$ 925.3			$ 0.0	$ 1,556.3	$ 1.4	$ (632.4)