Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Capital in Excess of Par Value [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (loss) [Member]
Balance at Dec. 31, 2018	$ 64,228	$ 270	$ 116,427	$ 82,548	$ (120,406)	$ (14,611)
Balance, shares at Dec. 31, 2018		27,018,000			12,746,000
Employee Stock Purchase Plan share issuance	110		$ (126)		$ 236
Employee Stock Purchase Plan share issuance, shares					(25,000)
Stock Option Plan share issuance, net	91				$ 558
Stock Option Plan share issuance, shares			467,000		41,000
Restricted stock plan share issuance/forfeiture	(153)		$ (3,237)		$ 3,084
Restricted stock plan share issuance/forfeiture, shares					(147,000)
Deferred compensation plan share issuance			(2,034)		$ 2,034
Deferred compensation plan share issuance, shares					(215,000)
Equity-based compensation	1,161		1,161
Net Income	2,454			2,454
Foreign currency adjustment	(2,019)					(2,019)
Change in pension, net of taxes of $2 and $0 in the 2020 and 2019 third quarters, respectively, and $1 and $0 in the first three quarters of 2020 and 2019, respectively	356					356
Balance at Sep. 27, 2019	66,228	$ 270	111,724	85,002	$ (114,494)	(16,274)
Balance, shares at Sep. 27, 2019		27,018,000			12,318,000
Balance at Jun. 28, 2019	66,041	$ 270	113,684	84,123	$ (117,044)	(14,992)
Balance, shares at Jun. 28, 2019		27,018,000			12,565,000
Employee Stock Purchase Plan share issuance	32		(34)		$ 66
Employee Stock Purchase Plan share issuance, shares					(7,000)
Stock Option Plan share issuance, net	90		(468)		$ 558
Stock Option Plan share issuance, shares					40,000
Restricted stock plan share issuance/forfeiture			(1,926)		$ 1,926
Restricted stock plan share issuance/forfeiture, shares					(200,000)
Equity-based compensation	468		468
Net Income	879			879
Foreign currency adjustment	(1,540)					(1,540)
Change in pension, net of taxes of $2 and $0 in the 2020 and 2019 third quarters, respectively, and $1 and $0 in the first three quarters of 2020 and 2019, respectively	258					258
Balance at Sep. 27, 2019	66,228	$ 270	111,724	85,002	$ (114,494)	(16,274)
Balance, shares at Sep. 27, 2019		27,018,000			12,318,000
Balance at Dec. 31, 2019	$ 66,236	$ 270	112,096	86,673	$ (114,261)	(18,542)
Balance, shares at Dec. 31, 2019	27,017,824	27,018,000			12,311,000
Employee Stock Purchase Plan share issuance	$ 102		(104)		$ 206
Employee Stock Purchase Plan share issuance, shares					(22,000)
Restricted stock plan share issuance/forfeiture	(160)		(4,930)		$ 4,770
Restricted stock plan share issuance/forfeiture, shares					(453,000)
Equity-based compensation	1,805		1,805
Net Income	5,734			5,734
Foreign currency adjustment	2,061					2,061
Change in pension, net of taxes of $2 and $0 in the 2020 and 2019 third quarters, respectively, and $1 and $0 in the first three quarters of 2020 and 2019, respectively	(74)					(74)
Balance at Sep. 25, 2020	$ 75,704	$ 270	108,867	92,407	$ (109,285)	(16,555)
Balance, shares at Sep. 25, 2020	27,017,824	27,018,000			11,836,000
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
Employee Stock Purchase Plan share issuance	39		(39)		$ 78
Employee Stock Purchase Plan share issuance, shares					(8,000)
Restricted stock plan share issuance/forfeiture			43		$ (43)
Restricted stock plan share issuance/forfeiture, shares					9,000
Equity-based compensation	656		656
Net Income	2,831			2,831
Foreign currency adjustment	2,117					2,117
Change in pension, net of taxes of $2 and $0 in the 2020 and 2019 third quarters, respectively, and $1 and $0 in the first three quarters of 2020 and 2019, respectively	(135)					(135)
Balance at Sep. 25, 2020	$ 75,704	$ 270	$ 108,867	$ 92,407	$ (109,285)	$ (16,555)
Balance, shares at Sep. 25, 2020	27,017,824	27,018,000			11,836,000