Summary of Significant Accounting Policies - Basic and Diluted Net Income Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019
Schedule Of Computation Of Basic And Diluted Earnings Per Common Share [Line Items]
Document Period End Date			Jun. 27, 2020
Net income	$ 58,616	$ 7,207	$ 40,481	$ 29,727
Weighted-average shares outstanding	27,923	28,079	28,110	27,970
Dilutive effect of employee stock options and restricted shares	357	684	304	809
Diluted weighted-average shares outstanding	28,280	28,763	28,414	28,779
Basic income per share	$ 2.10	$ 0.26	$ 1.44	$ 1.06
Diluted income per share	$ 2.07	$ 0.25	$ 1.42	$ 1.03
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	200		300	100