Segment Information - Segment Revenues, Depreciation and Amortization, and Operating (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 25, 2023	Jun. 30, 2024	Jun. 25, 2023
Segment Reporting Information [Line Items]
Total revenues	$ 300.1	$ 256.9	$ 577.3	$ 488.7
Depreciation and amortization:
Total depreciation and amortization	10.4	7.9	19.7	15.8
Operating income:
Total operating income	12.5	6.7	19.5	7.2
Kratos Government Solutions
Segment Reporting Information [Line Items]
Total revenues	214.3	204.8	432.1	388.6
Unmanned Systems
Segment Reporting Information [Line Items]
Total revenues	85.8	52.1	145.2	100.1
Operating segments | Kratos Government Solutions
Segment Reporting Information [Line Items]
Total revenues	214.3	204.8	432.1	388.6
Depreciation and amortization:
Total depreciation and amortization	6.9	5.9	13.0	11.8
Operating income:
Total operating income	15.5	11.6	32.1	19.3
Operating segments | Unmanned Systems
Segment Reporting Information [Line Items]
Total revenues	85.8	52.1	145.2	100.1
Depreciation and amortization:
Total depreciation and amortization	3.5	2.0	6.7	4.0
Operating income:
Total operating income	3.6	1.2	3.2	0.6
Corporate activities
Operating income:
Total operating income	(6.6)	(6.1)	(15.8)	(12.7)
Service revenues
Segment Reporting Information [Line Items]
Total revenues	106.5	103.7	213.0	195.3
Service revenues | Operating segments | Kratos Government Solutions
Segment Reporting Information [Line Items]
Total revenues	104.7	102.2	209.3	192.4
Service revenues | Operating segments | Unmanned Systems
Segment Reporting Information [Line Items]
Total revenues	1.8	1.5	3.7	2.9
Product sales
Segment Reporting Information [Line Items]
Total revenues	193.6	153.2	364.3	293.4
Product sales | Operating segments | Kratos Government Solutions
Segment Reporting Information [Line Items]
Total revenues	109.6	102.6	222.8	196.2
Product sales | Operating segments | Unmanned Systems
Segment Reporting Information [Line Items]
Total revenues	$ 84.0	$ 50.6	$ 141.5	$ 97.2