Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Common Stock [Member] Common Class A [Member]	Common Stock [Member] Common Class B [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Treasury Stock [Member]	Total
Balance (in shares) at Jul. 02, 2017	51,227,779	33,901,603				19,989,731
Balance at Jul. 02, 2017	$ 513	$ 339	$ 337,726	$ 32,638	$ (187)	$ (88,790)	$ 282,239
Net income				49,014			49,014
Translation adjustment					(11)		(11)
Stock-based compensation (in shares)	596,402
Stock-based compensation	$ 5		2,996				3,001
Exercise of stock options (in shares)	34,000
Exercise of stock options			179				179
Acquisition of Class A treasury stock (in shares)						1,260,515
Acquisition of Class A treasury stock						$ (12,075)	(12,075)
Balance (in shares) at Apr. 01, 2018	51,912,721	33,847,063				21,250,246
Balance at Apr. 01, 2018	$ 519	$ 338	340,901	81,652	(198)	$ (100,865)	322,347
Conversion of Class B stock into Class A stock (in shares)	54,540	(54,540)
Conversion of Class B stock into Class A stock	$ 1	$ (1)
Balance (in shares) at Dec. 31, 2017	51,879,967	33,847,063				21,157,054
Balance at Dec. 31, 2017	$ 519	$ 338	339,805	90,115	(160)	$ (99,875)	330,742
Net income				(8,463)			(8,463)
Translation adjustment					(38)		(38)
Stock-based compensation (in shares)	2,754
Stock-based compensation			932				932
Exercise of stock options (in shares)	30,000
Exercise of stock options			164				164
Acquisition of Class A treasury stock (in shares)						93,192
Acquisition of Class A treasury stock						$ (990)	(990)
Balance (in shares) at Apr. 01, 2018	51,912,721	33,847,063				21,250,246
Balance at Apr. 01, 2018	$ 519	$ 338	340,901	81,652	(198)	$ (100,865)	322,347
Balance (in shares) at Jul. 01, 2018	52,071,293	33,822,823				21,258,790
Balance at Jul. 01, 2018	$ 520	$ 338	341,783	73,429	(200)	$ (100,966)	314,904
Net income				43,071			43,071
Translation adjustment					(58)		(58)
Stock-based compensation (in shares)	411,600
Stock-based compensation	$ 4		4,527				$ 4,531
Exercise of stock options (in shares)	448,234						448,234
Exercise of stock options	$ 4		925				$ 929
Acquisition of Class A treasury stock (in shares)						1,230,303
Acquisition of Class A treasury stock						$ (14,765)	(14,765)
Balance (in shares) at Mar. 31, 2019	52,931,127	33,822,823				22,489,093
Balance at Mar. 31, 2019	$ 528	$ 338	347,235	116,830	(258)	$ (115,731)	348,942
Other				330			330
Balance (in shares) at Dec. 31, 2018	52,749,203	33,822,823				22,383,738
Balance at Dec. 31, 2018	$ 527	$ 338	344,769	125,071	(261)	$ (114,371)	356,073
Net income				(8,241)			(8,241)
Translation adjustment					3		3
Stock-based compensation (in shares)	1,924
Stock-based compensation			1,903				1,903
Exercise of stock options (in shares)	180,000
Exercise of stock options	$ 1		563				564
Acquisition of Class A treasury stock (in shares)						105,355
Acquisition of Class A treasury stock						$ (1,360)	(1,360)
Balance (in shares) at Mar. 31, 2019	52,931,127	33,822,823				22,489,093
Balance at Mar. 31, 2019	$ 528	$ 338	$ 347,235	$ 116,830	$ (258)	$ (115,731)	$ 348,942