Company's Effective Tax Rate Differs From Statutory Federal Tax Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2018	Dec. 29, 2017	Dec. 30, 2016
Schedule Of Company Effective Tax Rate Differs From Statutory Federal Tax Rate [Line Items]
Tax at federal statutory rate	$ 19,597	$ 28,878	$ 24,193
Re-measurement of deferred tax assets to lower enacted domestic tax rate	0	15,137	0
Mandatory repatriation of foreign earnings	0	1,370	0
State taxes, net of federal benefit	4,391	2,806	2,423
Non-deductible expenses	335	417	274
Non-deductible stock-based compensation	20	18	11
Excess tax benefit from equity incentive plans	(3,310)	(5,831)	(4,321)
Difference between statutory rate and foreign effective tax rate	(217)	(1,339)	(889)
Other	247	(252)	(49)
Total	$ 21,063	$ 41,204	$ 21,642
Effective tax rate	22.60%	49.90%	31.30%