Segment Information - Revenues, Operating Income (Loss) and Assets by Reportable Segments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 28, 2025	Dec. 29, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Total revenues	$ 1,346.8	$ 1,136.3	$ 1,037.1
Total costs	1,038.9	849.1	768.5
Selling, general and administrative expenses	240.2	217.2	198.7
Research and development expenses	40.0	40.3	38.4
Total segment operating income	25.6	29.0	31.1
Merger and acquisition related items	(2.1)	(0.7)	(0.4)
Loss on extinguishment of debt	(0.5)	0.0	0.0
Other income (expense), net	2.5	0.5	0.5
Income before income taxes	34.0	26.5	11.1
Total capital expenditures	95.3	58.2	52.4
Depreciation and amortization	47.1	40.3	33.2
Total assets	2,467.2	1,950.9
Operating segments
Segment Reporting Information [Line Items]
Total revenues	1,346.8	1,136.3	1,037.1
Total costs	1,038.9	849.1	768.5
Selling, general and administrative expenses	204.7	187.4	173.3
Research and development expenses	40.0	40.3	38.4
Total segment operating income	63.2	59.5	56.9
Total capital expenditures	95.2	57.8	51.8
Total assets	1,911.6	1,636.1
Unallocated amounts
Segment Reporting Information [Line Items]
Merger and acquisition related items	(2.1)	(0.7)	(0.4)
Stock compensation expense	(35.5)	(29.8)	(25.4)
Interest income (expense), net	5.9	(3.0)	(20.5)
Other income (expense), net	2.5	0.5	0.5
Income before income taxes	34.0	26.5	11.1
Corporate capital expenditures
Segment Reporting Information [Line Items]
Total capital expenditures	0.1	0.4	0.6
Total assets	555.6	314.8
Service revenues
Segment Reporting Information [Line Items]
Total revenues	469.0	423.4	402.6
Total costs	356.8	310.0	303.2
Service revenues | Operating segments
Segment Reporting Information [Line Items]
Total revenues	469.0	423.4	402.6
Total costs	356.8	310.0	303.2
Product sales
Segment Reporting Information [Line Items]
Total revenues	877.8	712.9	634.5
Total costs	682.1	539.1	465.3
Product sales | Operating segments
Segment Reporting Information [Line Items]
Total revenues	877.8	712.9	634.5
Total costs	682.1	539.1	465.3
Kratos Government Solutions | Operating segments
Segment Reporting Information [Line Items]
Total revenues	1,054.8	865.8	824.9
Total costs	797.7	627.0	600.2
Selling, general and administrative expenses	158.8	146.1	136.7
Research and development expenses	37.7	36.1	35.3
Total segment operating income	60.6	56.6	52.7
Total capital expenditures	57.3	30.5	26.9
Depreciation and amortization	32.1	27.1	24.1
Total assets	1,472.9	1,250.4
Kratos Government Solutions | Service revenues | Operating segments
Segment Reporting Information [Line Items]
Total revenues	460.3	416.3	395.9
Total costs	350.1	304.7	298.3
Kratos Government Solutions | Product sales | Operating segments
Segment Reporting Information [Line Items]
Total revenues	594.5	449.5	429.0
Total costs	447.6	322.3	301.9
Unmanned Systems
Segment Reporting Information [Line Items]
Total revenues	292.0	270.5	212.2
Unmanned Systems | Operating segments
Segment Reporting Information [Line Items]
Total revenues	292.0	270.5	212.2
Total costs	241.2	222.1	168.3
Selling, general and administrative expenses	45.9	41.3	36.6
Research and development expenses	2.3	4.2	3.1
Total segment operating income	2.6	2.9	4.2
Total capital expenditures	37.9	27.3	24.9
Depreciation and amortization	15.0	13.2	9.1
Total assets	438.7	385.7
Unmanned Systems | Service revenues | Operating segments
Segment Reporting Information [Line Items]
Total revenues	8.7	7.1	6.7
Total costs	6.7	5.3	4.9
Unmanned Systems | Product sales | Operating segments
Segment Reporting Information [Line Items]
Total revenues	283.3	263.4	205.5
Total costs	$ 234.5	$ 216.8	$ 163.4