Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Stock Appreciation Rights (SARs) [Member] Common Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balance (in shares) at Dec. 31, 2017		15,081,947
Balance at Dec. 31, 2017		$ 15	$ 49,103	$ 83,129	$ (7,279)	$ 124,968
ASC 606 adjustment to opening retained earnings				11,245		11,245
Common shares issued upon exercise of options (in shares)		87,347
Common shares issued upon exercise of options			878	(151)		727
Restricted shares issued in acquisition (in shares)		150,094
Restricted shares issued in acquisition			3,762			3,762
Common shares issued upon exercise of Stock Appreciation Rights (SARs) (in shares)	3,428	37,930,000
Share-based compensation expense			2,264			2,264
Tax withheld on exercise of Stock Appreciation Rights (SARs)			(17)			(17)
Tax benefit from vesting of acquisition-related restricted stock			445			445
Cash dividends declared				(5,836)		$ (5,836)
Common stock reacquired and retired (in shares)		(158,359)				(58,216)
Common stock reacquired and retired			(576)	(2,330)		$ (2,906)
Net earnings				16,975		16,975
Cash flow hedges, net of taxes					203	203
Pensions, net of taxes					(391)	(391)
Change in currency translation adjustment, net of taxes					(518)	(518)
Cash flow hedges, net of taxes						203
Balance (in shares) at Dec. 31, 2018		15,202,387
Balance at Dec. 31, 2018		$ 15	55,859	103,032	(7,985)	150,921
Common shares issued upon exercise of options (in shares)		62,994
Common shares issued upon exercise of options			460	(177)		283
Restricted shares issued in acquisition (in shares)		69,530
Restricted shares issued in acquisition						0
Common shares issued upon exercise of Stock Appreciation Rights (SARs) (in shares)
Share-based compensation expense			1,484			1,484
Tax benefit from vesting of acquisition-related restricted stock			30			30
Cash dividends declared				(6,046)		$ (6,046)
Common stock reacquired and retired (in shares)		(107,307)				(49,091)
Net earnings				12,066		$ 12,066
Cash flow hedges, net of taxes					(22)	(22)
Pensions, net of taxes					449	449
Change in currency translation adjustment, net of taxes					74	74
Common stock reacquired and retired			(391)	(1,294)		(1,685)
Cash flow hedges, net of taxes						$ (22)
Balance (in shares) at Dec. 31, 2019		15,227,604				15,227,604
Balance at Dec. 31, 2019		$ 15	57,442	107,581	(7,484)	$ 157,554
Common shares issued upon exercise of options (in shares)						154,396
Common shares issued upon exercise of options			2,110	(183)		$ 1,927
Restricted shares issued in acquisition (in shares)		49,784
Restricted shares issued in acquisition						0
Common shares issued upon exercise of Stock Appreciation Rights (SARs) (in shares)		157,730
Share-based compensation expense			2,530			2,530
Tax withheld on exercise of Stock Appreciation Rights (SARs)			(66)			(66)
Tax benefit from vesting of acquisition-related restricted stock			(13)			(13)
Cash dividends declared				(6,111)		$ (6,111)
Common stock reacquired and retired (in shares)		(43,458)				(43,458)
Net earnings				41,026		$ 41,026
Change in currency translation adjustment, net of taxes					(1,021)	(1,021)
Common stock reacquired and retired			(159)	(341)		(500)
Cash flow hedges, net of taxes					(22)	(22)
Pensions, net of taxes					(3,674)	$ (3,674)
Balance (in shares) at Dec. 31, 2020		15,391,660				15,391,660
Balance at Dec. 31, 2020		$ 15	$ 61,844	$ 141,972	$ (12,201)	$ 191,630