Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Capital in Excess of Par Value [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Dec. 31, 2019	$ 66,236	$ 270	$ 112,096	$ 86,673	$ (114,261)	$ (18,542)
Balance, shares at Dec. 31, 2019		27,018,000			12,311,000
Employee Stock Purchase Plan share issuance	63		(65)		$ 128
Employee Stock Purchase Plan share issuance, shares					(14,000)
Restricted stock plan share issuance/forfeiture	(160)		(4,973)		$ 4,813
Restricted stock plan share issuance/forfeiture, shares					(462,000)
Equity-based compensation	1,149		1,149
Net Income	2,903			2,903
Foreign currency adjustment	(56)					(56)
Pension gain adjustment, net of tax	61					61
Balance at Jun. 26, 2020	70,196	$ 270	108,207	89,576	$ (109,320)	(18,537)
Balance, shares at Jun. 26, 2020		27,018,000			11,835,000
Balance at Mar. 27, 2020	67,200	$ 270	109,112	87,817	$ (110,818)	(19,181)
Balance, shares at Mar. 27, 2020		27,018,000			11,950,000
Employee Stock Purchase Plan share issuance	35		(42)		$ 77
Employee Stock Purchase Plan share issuance, shares					(9,000)
Restricted stock plan share issuance/forfeiture	(79)		(1,500)		$ 1,421
Restricted stock plan share issuance/forfeiture, shares					(106,000)
Equity-based compensation	637		637
Net Income	1,759			1,759
Foreign currency adjustment	732					732
Pension gain adjustment, net of tax	(88)					(88)
Balance at Jun. 26, 2020	70,196	$ 270	108,207	89,576	$ (109,320)	(18,537)
Balance, shares at Jun. 26, 2020		27,018,000			11,835,000
Balance at Dec. 31, 2020	$ 79,508	$ 270	109,407	94,312	$ (109,114)	(15,367)
Balance, shares at Dec. 31, 2020	27,017,824	27,018,000			11,842,000
Employee Stock Purchase Plan share issuance	$ 84		(2)		$ 86
Employee Stock Purchase Plan share issuance, shares					(9,000)
Stock Option Plan share issuance, net	366		(427)		$ 793
Stock Option Plan share issuance, net, shares					(82,000)
Restricted stock plan share issuance/forfeiture	(389)		(1,117)		$ 728
Restricted stock plan share issuance/forfeiture, shares					(61,000)
Equity-based compensation	1,272		1,272
Net Income	3,341			3,341
Foreign currency adjustment	(1,991)					(1,991)
Pension gain adjustment, net of tax	606					606
Balance at Jul. 02, 2021	$ 82,797	$ 270	109,133	97,653	$ (107,507)	(16,752)
Balance, shares at Jul. 02, 2021	27,017,824	27,018,000			11,690,000
Balance at Apr. 02, 2021	$ 80,074	$ 270	108,385	95,820	$ (107,339)	(17,062)
Balance, shares at Apr. 02, 2021		27,018,000			11,636,000
Employee Stock Purchase Plan share issuance	48		5		$ 43
Employee Stock Purchase Plan share issuance, shares					(5,000)
Stock Option Plan share issuance, net	143		(40)		$ 183
Restricted stock plan share issuance/forfeiture	(293)		101		$ (394)
Restricted stock plan share issuance/forfeiture, shares					59,000
Equity-based compensation	682		682
Net Income	1,833			1,833
Foreign currency adjustment	254					254
Pension gain adjustment, net of tax	56					56
Balance at Jul. 02, 2021	$ 82,797	$ 270	$ 109,133	$ 97,653	$ (107,507)	$ (16,752)
Balance, shares at Jul. 02, 2021	27,017,824	27,018,000			11,690,000