Stock Repurchases (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Dec. 26, 2015
Number of shares
Repurchased at beginning of period	12,483,556	11,538,680	10,921,933
Repurchases	963,790	944,876	616,747
Repurchased at end of period	13,447,346	12,483,556	11,538,680
Aggregate Purchase Price
Repurchased at beginning balance	$ 607,750	$ 446,092	$ 307,387
Repurchases	144,602	161,658	138,705
Repurchased at end of period	$ 752,352	$ 607,750	$ 446,092