Receivables - Additional Information (Details) - USD ($)
$ in Thousands
Jun. 26, 2015
Dec. 31, 2014
Sep. 27, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]      
Estimated unbilled contract receivables not expected to be collected within the next 12 months $ 3,600    
Exelis indemnified receivable obligation 10,525 $ 11,411  
Other accrued liabilities | Indemnified Receivable      
Accounts, Notes, Loans and Financing Receivable [Line Items]      
Exelis indemnified receivable obligation $ 10,500   $ 11,400