Segment Information - Schedule of Segment Revenues, Depreciation and Amortization, and Operating (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 26, 2022	Jun. 27, 2021	Jun. 26, 2022	Jun. 27, 2021
Segment Reporting Information [Line Items]
Total revenues	$ 224.2	$ 205.1	$ 420.4	$ 399.3
Depreciation and amortization:
Total depreciation and amortization	6.9	7.0	13.9	13.3
Operating income (loss) from continuing operations:
Total operating income (loss) from continuing operations	(1.9)	3.3	(3.1)	8.2
Corporate activities
Operating income (loss) from continuing operations:
Total operating income (loss) from continuing operations	(6.4)	(6.7)	(13.7)	(13.1)
Kratos Government Solutions
Segment Reporting Information [Line Items]
Total revenues	167.8	144.8	311.4	283.1
Depreciation and amortization:
Total depreciation and amortization	5.0	4.5	10.1	8.9
Kratos Government Solutions | Reportable Segments
Operating income (loss) from continuing operations:
Total operating income (loss) from continuing operations	9.5	5.9	15.1	13.0
Unmanned Systems
Segment Reporting Information [Line Items]
Total revenues	56.4	60.3	109.0	116.2
Depreciation and amortization:
Total depreciation and amortization	1.9	2.5	3.8	4.4
Unmanned Systems | Reportable Segments
Operating income (loss) from continuing operations:
Total operating income (loss) from continuing operations	(5.0)	4.1	(4.5)	8.3
Service revenues
Segment Reporting Information [Line Items]
Total revenues	78.8	58.0	146.7	115.3
Service revenues | Kratos Government Solutions
Segment Reporting Information [Line Items]
Total revenues	77.2	56.7	144.0	112.8
Service revenues | Unmanned Systems
Segment Reporting Information [Line Items]
Total revenues	1.6	1.3	2.7	2.5
Product sales
Segment Reporting Information [Line Items]
Total revenues	145.4	147.1	273.7	284.0
Product sales | Kratos Government Solutions
Segment Reporting Information [Line Items]
Total revenues	90.6	88.1	167.4	170.3
Product sales | Unmanned Systems
Segment Reporting Information [Line Items]
Total revenues	$ 54.8	$ 59.0	$ 106.3	$ 113.7