Segment Information - Narrative (Details) $ in Millions	12 Months Ended
Dec. 25, 2022 USD ($) segment	Dec. 26, 2021 USD ($)	Dec. 27, 2020 USD ($)
Segment Reporting Information [Line Items]
Number of reportable (in segments) \| segment	2
Operating income	$ (2.6)	$ 27.9	$ 29.3
Litigation settlement charges	5.5	0.0	0.0
Total revenues	$ 898.3	$ 811.5	$ 747.7
Percentage of foreign revenue to total revenue (percent)	19.00%	21.00%	19.00%
Company's C5ISR
Segment Reporting Information [Line Items]
Litigation settlement charges	$ 3.4
Company's Training Solutions
Segment Reporting Information [Line Items]
Litigation settlement charges	3.0
Kratos Government Solutions
Segment Reporting Information [Line Items]
Operating income	6.4
Litigation settlement charges	5.5
Total revenues	676.6	$ 579.6
Assets of foreign subsidiaries	178.3	166.2	$ 148.2
Non-US
Segment Reporting Information [Line Items]
Total revenues	$ 173.1	$ 169.8	$ 139.5

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