CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total	Common Stock Class A Common Stock	Common Stock Class B Common Stock	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive (Loss) Income
Balance, beginning of period at Dec. 31, 2019	$ 289,392	$ 5,397	$ 1,569	$ 8,911	$ 284,852	$ (11,337)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	3,078	124		2,954
Conversion of Class B to Class A shares	0	1	(1)
Purchase of treasury shares	(1,002)	(32)		(970)
Net income	14,793				14,793
Cash dividends on common stock	(5,375)				(5,375)
Current period other comprehensive income, net of tax	(697)					(697)
Reclassification adjustment to net income, net of tax	435					435
Balance, end of period at Dec. 31, 2020	300,624	5,490	1,568	10,895	294,270	(11,599)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	5,561	125		5,436
Conversion of Class B to Class A shares	0	1	(1)
Net income	48,125				48,125
Cash dividends on common stock	(5,617)				(5,617)
Current period other comprehensive income, net of tax	2,851					2,851
Reclassification adjustment to net income, net of tax	572					572
Balance, end of period at Dec. 31, 2021	$ 352,116	$ 5,616	$ 1,567	$ 16,331	$ 336,778	$ (8,176)