Earnings Per Share - Anti-dilutive Options (Details) - shares
shares in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2017
Jul. 01, 2016
Jun. 30, 2017
Jul. 01, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Anti-dilutive stock options (in shares) 13 12 23 23
Anti-dilutive stock options        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Anti-dilutive stock options (in shares) 13 10 22 21
Anti-dilutive restricted stock units        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Anti-dilutive stock options (in shares) 0 2 1 2