Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Total Revenues	$ 168.9	$ 160.4
Kratos Government Solutions
Disaggregation of Revenue [Line Items]
Total Revenues	126.9	125.5
Kratos Government Solutions | U.S. Government
Disaggregation of Revenue [Line Items]
Total Revenues	84.7	86.8
Kratos Government Solutions | International
Disaggregation of Revenue [Line Items]
Total Revenues	28.0	24.9
Kratos Government Solutions | U.S. Commercial and other customers
Disaggregation of Revenue [Line Items]
Total Revenues	14.2	13.8
Kratos Government Solutions | Fixed price
Disaggregation of Revenue [Line Items]
Total Revenues	104.4	109.1
Kratos Government Solutions | Cost plus fee
Disaggregation of Revenue [Line Items]
Total Revenues	14.4	9.2
Kratos Government Solutions | Time and materials
Disaggregation of Revenue [Line Items]
Total Revenues	8.1	7.2
Unmanned Systems
Disaggregation of Revenue [Line Items]
Total Revenues	42.0	34.9
Unmanned Systems | U.S. Government
Disaggregation of Revenue [Line Items]
Total Revenues	39.4	30.1
Unmanned Systems | International
Disaggregation of Revenue [Line Items]
Total Revenues	2.4	4.5
Unmanned Systems | U.S. Commercial and other customers
Disaggregation of Revenue [Line Items]
Total Revenues	0.2	0.3
Unmanned Systems | Fixed price
Disaggregation of Revenue [Line Items]
Total Revenues	27.3	27.2
Unmanned Systems | Cost plus fee
Disaggregation of Revenue [Line Items]
Total Revenues	14.1	7.4
Unmanned Systems | Time and materials
Disaggregation of Revenue [Line Items]
Total Revenues	$ 0.6	$ 0.3