Segment Information - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 26, 2021 USD ($) segment	Dec. 27, 2020 USD ($)	Dec. 29, 2019 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment	2
Total revenues	$ 811.5	$ 747.7	$ 717.5
Percentage of foreign revenue to total revenue (as a percent)	21.00%	19.00%	18.00%
Kratos Government Solutions
Segment Reporting Information [Line Items]
Total revenues	$ 579.6	$ 560.7
Assets of foreign subsidiaries	166.2	148.2	$ 124.7
Non-US
Segment Reporting Information [Line Items]
Total revenues	$ 169.8	$ 139.5	$ 132.5