Effect of Increase in Cost of Insurance and Claims (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2015	Sep. 27, 2014	Sep. 26, 2015	Sep. 27, 2014
Change in Accounting Estimate [Line Items]
Operating income	$ 63,980	$ 59,577	$ 179,058	$ 163,163
Net income	$ 39,348	$ 36,755	$ 109,834	$ 100,318
Earnings per share	$ 0.91	$ 0.82	$ 2.50	$ 2.23
Diluted earnings per share	$ 0.90	$ 0.82	$ 2.49	$ 2.22
Development of Prior Year Self Insured Claims Estimates
Change in Accounting Estimate [Line Items]
Operating income	$ 47	$ 372	$ 5,521	$ 7,119
Net income	$ 29	$ 230	$ 3,412	$ 4,400
Earnings per share	$ 0.00	$ 0.01	$ 0.08	$ 0.10
Diluted earnings per share	$ 0.00	$ 0.01	$ 0.08	$ 0.10