Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Capital in Excess of Par Value	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss
Balance at beginning of year (in shares) at Dec. 31, 2019		9,043,771
Balance at beginning of year at Dec. 31, 2019	$ 108,001	$ 9,190	$ 18,077	$ 86,496	$ (5,761)	$ (1)
Net income	12,533			12,533
Adjustment for foreign currency translation	(2,494)					(2,494)
Stock-based compensation	451		451
Shares repurchased held in treasury (in shares)		(47,504)
Shares repurchased held in treasury	(1,756)				(1,756)
Balance at end of period (in shares) at Mar. 31, 2020		8,996,267
Balance at end of period at Mar. 31, 2020	$ 116,735	$ 9,190	18,528	99,029	(7,517)	(2,495)
Balance at beginning of year (in shares) at Dec. 31, 2020	9,287,625	9,061,039
Balance at beginning of year at Dec. 31, 2020	$ 122,422	$ 9,288	19,841	101,609	(9,015)	699
Net income	3,596			4,810
Adjustment for foreign currency translation	631					631
Stock-based compensation	422		422
Shares issued (in shares)		5,776
Shares issued	0	$ 5	(5)
Shares repurchased held in treasury (in shares)		(268)
Shares repurchased held in treasury	$ (13)				(13)
Balance at end of period (in shares) at Mar. 31, 2021	9,293,401	9,066,547
Balance at end of period at Mar. 31, 2021	$ 127,058	$ 9,293	$ 20,258	$ 105,205	$ (9,028)	$ 1,330