Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 28, 2020	Jun. 30, 2019	Jun. 28, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Total Revenues	$ 170.4	$ 187.9	$ 339.3	$ 348.3
Kratos Government Solutions
Disaggregation of Revenue [Line Items]
Total Revenues	128.4	145.4	255.3	270.9
Kratos Government Solutions | U.S. Government
Disaggregation of Revenue [Line Items]
Total Revenues	90.0	96.3	174.7	183.1
Kratos Government Solutions | International
Disaggregation of Revenue [Line Items]
Total Revenues	24.9	28.4	52.9	53.3
Kratos Government Solutions | U.S. Commercial and other customers
Disaggregation of Revenue [Line Items]
Total Revenues	13.5	20.7	27.7	34.5
Kratos Government Solutions | Fixed price
Disaggregation of Revenue [Line Items]
Total Revenues	98.2	122.5	202.6	231.6
Kratos Government Solutions | Cost plus fee
Disaggregation of Revenue [Line Items]
Total Revenues	20.8	14.3	35.2	23.5
Kratos Government Solutions | Time and materials
Disaggregation of Revenue [Line Items]
Total Revenues	9.4	8.6	17.5	15.8
Unmanned Systems
Disaggregation of Revenue [Line Items]
Total Revenues	42.0	42.5	84.0	77.4
Unmanned Systems | U.S. Government
Disaggregation of Revenue [Line Items]
Total Revenues	39.4	37.6	78.8	67.7
Unmanned Systems | International
Disaggregation of Revenue [Line Items]
Total Revenues	2.5	4.5	4.9	9.0
Unmanned Systems | U.S. Commercial and other customers
Disaggregation of Revenue [Line Items]
Total Revenues	0.1	0.4	0.3	0.7
Unmanned Systems | Fixed price
Disaggregation of Revenue [Line Items]
Total Revenues	28.6	34.0	55.9	61.2
Unmanned Systems | Cost plus fee
Disaggregation of Revenue [Line Items]
Total Revenues	12.8	8.1	26.9	15.5
Unmanned Systems | Time and materials
Disaggregation of Revenue [Line Items]
Total Revenues	$ 0.6	$ 0.4	$ 1.2	$ 0.7