Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Class A [Member] Retained Earnings [Member]	Common Class A [Member] AOCI Attributable to Parent [Member]	Common Class A [Member] Common Stock, Common Class A [Member]	Common Class A [Member] Common Stock, Common Class B [Member]	Common Class A [Member] Additional Paid-in Capital [Member]	Common Class A [Member]	Common Class B [Member] Retained Earnings [Member]	Common Class B [Member] AOCI Attributable to Parent [Member]	Common Class B [Member] Common Stock, Common Class A [Member]	Common Class B [Member] Common Stock, Common Class B [Member]	Common Class B [Member] Additional Paid-in Capital [Member]	Common Class B [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Common Stock, Common Class A [Member]	Common Stock, Common Class B [Member]	Additional Paid-in Capital [Member]	Total
Balance at Dec. 31, 2019													$ 157,063	$ (24,065)	$ 214	$ 1,013	$ 33,826	$ 168,051
Net earnings						$ 2,089						$ 10,706	12,795	0	0	0	0	12,795
Cash dividends declared on common stock	$ (515)	$ 0	$ 0	$ 0	$ 0	(515)	$ (2,852)	$ 0	$ 0	$ 0	$ 0	(2,852)
Issuance of restricted common stock													0	0	0	11	(11)	0
Forfeiture of restricted common stock													0	0	0	(3)		0
Forfeiture of restricted common stock, APIC																	3
Foreign currency translation adjustment, net of taxes													0	6,890	0	0	0	6,890
Unrealized holding (losses) gains on marketable securities arising during the period, net of taxes of $0 and $7													0	7	0	0	0	7
Stock-based compensation expense													0	0	0	0	2,318	2,318
Change in unfunded SERP liability, net of taxes													0	(895)	0	0	0	(895)
Balance at Dec. 31, 2020													166,491	(18,063)	214	1,021	36,136	185,799
Net earnings						4,076						20,745	24,821	0	0	0	0	24,821
Cash dividends declared on common stock	$ (515)	$ 0	$ 0	$ 0	$ 0	$ (515)	$ (2,862)	$ 0	$ 0	$ 0	$ 0	$ (2,862)
Issuance of restricted common stock													0	0	0	21	(21)	0
Forfeiture of restricted common stock													0	0	0	(4)		0
Forfeiture of restricted common stock, APIC																	4
Foreign currency translation adjustment, net of taxes													0	(1,769)	0	0	0	(1,769)
Unrealized holding (losses) gains on marketable securities arising during the period, net of taxes of $0 and $7													0	(106)	0	0	0	(106)
Stock-based compensation expense													0	0	0	0	2,300	2,300
Change in unfunded SERP liability, net of taxes													0	1,075	0	0	0	1,075
Balance at Dec. 31, 2021													$ 187,935	$ (18,863)	$ 214	$ 1,038	$ 38,419	$ 208,743