Segment Information - Schedule of Segment Revenues, Depreciation and Amortization, and Operating (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 25, 2023	Jun. 26, 2022	Jun. 25, 2023	Jun. 26, 2022
Segment Reporting Information [Line Items]
Total revenues	$ 256.9	$ 224.2	$ 488.7	$ 420.4
Depreciation and amortization:
Total depreciation and amortization	7.9	6.9	15.8	13.9
Operating income (loss):
Total operating income (loss)	6.7	(1.9)	7.2	(3.1)
Corporate activities
Operating income (loss):
Total operating income (loss)	(6.1)	(6.4)	(12.7)	(13.7)
Kratos Government Solutions
Segment Reporting Information [Line Items]
Total revenues	204.8	167.8	388.6	311.4
Depreciation and amortization:
Total depreciation and amortization	5.9	5.0	11.8	10.1
Kratos Government Solutions | Reportable Segments
Operating income (loss):
Total operating income (loss)	11.6	9.5	19.3	15.1
Unmanned Systems
Segment Reporting Information [Line Items]
Total revenues	52.1	56.4	100.1	109.0
Depreciation and amortization:
Total depreciation and amortization	2.0	1.9	4.0	3.8
Unmanned Systems | Reportable Segments
Operating income (loss):
Total operating income (loss)	1.2	(5.0)	0.6	(4.5)
Service revenues
Segment Reporting Information [Line Items]
Total revenues	103.7	78.8	195.3	146.7
Service revenues | Kratos Government Solutions
Segment Reporting Information [Line Items]
Total revenues	102.2	77.2	192.4	144.0
Service revenues | Unmanned Systems
Segment Reporting Information [Line Items]
Total revenues	1.5	1.6	2.9	2.7
Product sales
Segment Reporting Information [Line Items]
Total revenues	153.2	145.4	293.4	273.7
Product sales | Kratos Government Solutions
Segment Reporting Information [Line Items]
Total revenues	102.6	90.6	196.2	167.4
Product sales | Unmanned Systems
Segment Reporting Information [Line Items]
Total revenues	$ 50.6	$ 54.8	$ 97.2	$ 106.3