Segment Information - Segment Revenues, Depreciation and Amortization, and Operating (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 29, 2024	Oct. 01, 2023	Sep. 29, 2024	Oct. 01, 2023
Segment Reporting Information [Line Items]
Total revenues	$ 275.9	$ 274.6	$ 853.2	$ 763.3
Depreciation and amortization:
Total depreciation and amortization	10.3	8.2	30.0	24.0
Operating income:
Total operating income	6.5	12.2	26.0	19.4
Kratos Government Solutions
Segment Reporting Information [Line Items]
Total revenues	211.7	217.9	643.8	606.5
Unmanned Systems
Segment Reporting Information [Line Items]
Total revenues	64.2	56.7	209.4	156.8
Operating segments | Kratos Government Solutions
Segment Reporting Information [Line Items]
Total revenues	211.7	217.9	643.8	606.5
Depreciation and amortization:
Total depreciation and amortization	7.1	6.0	20.1	17.8
Operating income:
Total operating income	13.5	15.9	45.6	35.2
Operating segments | Unmanned Systems
Segment Reporting Information [Line Items]
Total revenues	64.2	56.7	209.4	156.8
Depreciation and amortization:
Total depreciation and amortization	3.2	2.2	9.9	6.2
Operating income:
Total operating income	0.4	2.6	3.6	3.2
Corporate activities
Operating income:
Total operating income	(7.4)	(6.3)	(23.2)	(19.0)
Service revenues
Segment Reporting Information [Line Items]
Total revenues	103.9	106.5	316.9	301.8
Service revenues | Operating segments | Kratos Government Solutions
Segment Reporting Information [Line Items]
Total revenues	102.0	104.4	311.3	296.8
Service revenues | Operating segments | Unmanned Systems
Segment Reporting Information [Line Items]
Total revenues	1.9	2.1	5.6	5.0
Product sales
Segment Reporting Information [Line Items]
Total revenues	172.0	168.1	536.3	461.5
Product sales | Operating segments | Kratos Government Solutions
Segment Reporting Information [Line Items]
Total revenues	109.7	113.5	332.5	309.7
Product sales | Operating segments | Unmanned Systems
Segment Reporting Information [Line Items]
Total revenues	$ 62.3	$ 54.6	$ 203.8	$ 151.8