Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock Common Class A	Common Stock Common Class B	Additional Paid-in Capital	Accumulated Other Comprehensive (Loss) Income, net of tax	Retained Earnings
Balance at Dec. 30, 2017	$ 423,523	$ 86	$ 30	$ 372,590	$ (1,288)	$ 52,105
Balance (in shares) at Dec. 30, 2017		8,603,000	3,018,000
Net income	9,310					9,310
Stock options exercised and restricted shares activities (in shares)		188,000
Stock options exercised and restricted shares activities	20,234	$ 2		20,232
Stock-based compensation expense	1,491			1,491
Repurchase of Class A Common Stock (in shares)		(91,000)
Repurchase of Class A Common Stock	(16,639)	$ (1)				(16,638)
Currency translation adjustment	11				(11)
One time effect of adoption of ASU 2014-09, Revenue from Contracts with Customers, net of tax of $329	(982)					(982)
One time effect of adoption of ASU 2018-02, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income					(210)	210
Balance at Mar. 31, 2018	436,926	$ 87	$ 30	394,313	(1,509)	44,005
Balance (in shares) at Mar. 31, 2018		8,700,000	3,018,000
Balance at Dec. 29, 2018	460,317	$ 86	$ 29	405,711	(1,197)	55,688
Balance (in shares) at Dec. 29, 2018		8,580,000	2,918,000
Net income	$ 23,694					23,694
Stock options exercised and restricted shares activities (in shares)	33,983	54,000
Stock options exercised and restricted shares activities	$ 3,704			3,704
Stock-based compensation expense	2,066			2,066
Currency translation adjustment	37				37
Balance at Mar. 30, 2019	$ 489,818	$ 86	$ 29	$ 411,481	$ (1,160)	$ 79,382
Balance (in shares) at Mar. 30, 2019		8,634,000	2,918,000