Revenue Recognition - Disaggregation of Revenue (Details) $ in Millions	3 Months Ended
	Apr. 01, 2018 USD ($)
Disaggregation of Revenue [Line Items]
Total Revenues	$ 143.0
Kratos Government Solutions
Disaggregation of Revenue [Line Items]
Total Revenues	115.2
Kratos Government Solutions | Department of Defense (DoD)
Disaggregation of Revenue [Line Items]
Total Revenues	73.5
Kratos Government Solutions | Non-DoD
Disaggregation of Revenue [Line Items]
Total Revenues	3.3
Kratos Government Solutions | Total US Government
Disaggregation of Revenue [Line Items]
Total Revenues	76.8
Kratos Government Solutions | US Commercial
Disaggregation of Revenue [Line Items]
Total Revenues	17.4
Kratos Government Solutions | Non-US Government
Disaggregation of Revenue [Line Items]
Total Revenues	7.5
Kratos Government Solutions | Non-US Commercial
Disaggregation of Revenue [Line Items]
Total Revenues	13.5
Kratos Government Solutions | Fixed price
Disaggregation of Revenue [Line Items]
Total Revenues	101.8
Kratos Government Solutions | Cost plus fee
Disaggregation of Revenue [Line Items]
Total Revenues	7.2
Kratos Government Solutions | Time and materials
Disaggregation of Revenue [Line Items]
Total Revenues	6.2
Unmanned Systems
Disaggregation of Revenue [Line Items]
Total Revenues	27.8
Unmanned Systems | Department of Defense (DoD)
Disaggregation of Revenue [Line Items]
Total Revenues	24.1
Unmanned Systems | Non-DoD
Disaggregation of Revenue [Line Items]
Total Revenues	0.1
Unmanned Systems | Total US Government
Disaggregation of Revenue [Line Items]
Total Revenues	24.2
Unmanned Systems | US Commercial
Disaggregation of Revenue [Line Items]
Total Revenues	0.0
Unmanned Systems | Non-US Government
Disaggregation of Revenue [Line Items]
Total Revenues	3.5
Unmanned Systems | Non-US Commercial
Disaggregation of Revenue [Line Items]
Total Revenues	0.1
Unmanned Systems | Fixed price
Disaggregation of Revenue [Line Items]
Total Revenues	21.9
Unmanned Systems | Cost plus fee
Disaggregation of Revenue [Line Items]
Total Revenues	5.5
Unmanned Systems | Time and materials
Disaggregation of Revenue [Line Items]
Total Revenues	$ 0.4