Goodwill and Intangible Assets - Goodwill (Details) - USD ($) $ in Millions	Jul. 01, 2018	Dec. 31, 2017
Goodwill [Line Items]
Gross value	$ 679.0	$ 679.0
Less accumulated impairment	253.3	253.3
Net	425.7	425.7
Kratos Government Solutions
Goodwill [Line Items]
Gross value	567.9	567.9
Less accumulated impairment	239.5	239.5
Net	328.4	328.4
Unmanned Systems
Goodwill [Line Items]
Gross value	111.1	111.1
Less accumulated impairment	13.8	13.8
Net	$ 97.3	$ 97.3