Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Disaggregation of Revenue [Line Items]
Total Revenues	$ 187.9	$ 151.2	$ 348.3	$ 294.2
Kratos Government Solutions
Disaggregation of Revenue [Line Items]
Total Revenues	145.4	115.6	270.9	230.8
Kratos Government Solutions | U.S. Government
Disaggregation of Revenue [Line Items]
Total Revenues	96.3	77.7	183.1	154.5
Kratos Government Solutions | International
Disaggregation of Revenue [Line Items]
Total Revenues	28.4	23.4	53.3	44.4
Kratos Government Solutions | U.S. Commercial and other customers
Disaggregation of Revenue [Line Items]
Total Revenues	20.7	14.5	34.5	31.9
Kratos Government Solutions | Fixed price
Disaggregation of Revenue [Line Items]
Total Revenues	122.5	101.5	231.6	203.3
Kratos Government Solutions | Cost plus fee
Disaggregation of Revenue [Line Items]
Total Revenues	14.3	7.2	23.5	14.4
Kratos Government Solutions | Time and materials
Disaggregation of Revenue [Line Items]
Total Revenues	8.6	6.9	15.8	13.1
Unmanned Systems
Disaggregation of Revenue [Line Items]
Total Revenues	42.5	35.6	77.4	63.4
Unmanned Systems | U.S. Government
Disaggregation of Revenue [Line Items]
Total Revenues	37.6	28.9	67.7	53.0
Unmanned Systems | International
Disaggregation of Revenue [Line Items]
Total Revenues	4.5	6.6	9.0	10.3
Unmanned Systems | U.S. Commercial and other customers
Disaggregation of Revenue [Line Items]
Total Revenues	0.4	0.1	0.7	0.1
Unmanned Systems | Fixed price
Disaggregation of Revenue [Line Items]
Total Revenues	34.0	29.1	61.2	51.0
Unmanned Systems | Cost plus fee
Disaggregation of Revenue [Line Items]
Total Revenues	8.1	5.9	15.5	11.4
Unmanned Systems | Time and materials
Disaggregation of Revenue [Line Items]
Total Revenues	$ 0.4	$ 0.6	$ 0.7	$ 1.0