Effect of Increase in Cost of Insurance and Claims (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2015	Jun. 28, 2014	Jun. 27, 2015	Jun. 28, 2014
Change in Accounting Estimate [Line Items]
Operating income	$ 66,033	$ 58,572	$ 115,078	$ 103,586
Net income	$ 40,471	$ 35,925	$ 70,486	$ 63,563
Earnings per share	$ 0.92	$ 0.80	$ 1.59	$ 1.41
Diluted earnings per share	$ 0.92	$ 0.80	$ 1.59	$ 1.40
Development of Prior Year Self Insured Claims Estimates
Change in Accounting Estimate [Line Items]
Operating income	$ 833	$ 4,856	$ 5,474	$ 6,747
Net income	$ 515	$ 3,001	$ 3,383	$ 4,170
Earnings per share	$ 0.01	$ 0.07	$ 0.08	$ 0.09
Diluted earnings per share	$ 0.01	$ 0.07	$ 0.08	$ 0.09