Segment Information - Schedule of Segment Revenues, Depreciation and Amortization, and Operating (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 27, 2022	Mar. 28, 2021
Segment Reporting Information [Line Items]
Total revenues	$ 196.2	$ 194.2
Depreciation and amortization:
Total depreciation and amortization	7.0	6.3
Operating income (loss) from continuing operations:
Total operating income (loss) from continuing operations	(1.2)	4.9
Corporate activities
Operating income (loss) from continuing operations:
Total operating income (loss) from continuing operations	(7.3)	(6.4)
Kratos Government Solutions
Segment Reporting Information [Line Items]
Total revenues	143.6	138.3
Depreciation and amortization:
Total depreciation and amortization	5.1	4.4
Kratos Government Solutions | Reportable Segments
Operating income (loss) from continuing operations:
Total operating income (loss) from continuing operations	5.6	7.1
Unmanned Systems
Segment Reporting Information [Line Items]
Total revenues	52.6	55.9
Depreciation and amortization:
Total depreciation and amortization	1.9	1.9
Unmanned Systems | Reportable Segments
Operating income (loss) from continuing operations:
Total operating income (loss) from continuing operations	0.5	4.2
Service revenues
Segment Reporting Information [Line Items]
Total revenues	67.9	57.3
Service revenues | Kratos Government Solutions
Segment Reporting Information [Line Items]
Total revenues	66.8	56.1
Service revenues | Unmanned Systems
Segment Reporting Information [Line Items]
Total revenues	1.1	1.2
Product sales
Segment Reporting Information [Line Items]
Total revenues	128.3	136.9
Product sales | Kratos Government Solutions
Segment Reporting Information [Line Items]
Total revenues	76.8	82.2
Product sales | Unmanned Systems
Segment Reporting Information [Line Items]
Total revenues	$ 51.5	$ 54.7