Weighted-Average Shares (Tables)
 3 Months Ended
Apr. 01, 2018
Earnings Per Share [Abstract]  
Calculation of Weighted-Average Shares
Weighted-average shares were calculated as follows (in thousands):
 
Three-months Ended
 
April 1, 2018
 
April 2, 2017
Basic weighted-average common shares outstanding
173,280

 
172,646

Effect of dilutive stock options
6,361

 
5,708

Weighted-average common and common-equivalent shares outstanding
179,641

 
178,354