CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Class A Common Stock	Class B Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Total
Balance at Dec. 31, 2019	$ 68	$ 9	$ 66,811	$ 162,822	$ (37,358)	$ 192,352
Balance, shares at Dec. 31, 2019	6,771	954
Net income	$ 0	$ 0	0	1,680	0	1,680
Dividends declared per common share	0	0	0	(1,919)	0	(1,919)
Compensation expense related to restricted stock awards	0	0	569	0	0	569
Purchase of shares held in treasury	0	0	0	0	(20)	(20)
401(k) plan contribution	0	0	(131)	0	382	251
Balance at Mar. 31, 2020	$ 68	$ 9	67,249	162,583	(36,996)	192,913
Balance, shares at Mar. 31, 2020	6,771	954
Balance at Dec. 31, 2019	$ 68	$ 9	66,811	162,822	(37,358)	192,352
Balance, shares at Dec. 31, 2019	6,771	954
Issuance of restricted stock (in shares)	0	0
Forfeiture of restricted stock (in shares)	(2)	0
Balance at Dec. 31, 2020	$ 68	$ 9	68,900	158,990	(37,425)	190,542
Balance, shares at Dec. 31, 2020	6,785	938
Net income	$ 0	$ 0	0	758	0	758
Compensation expense related to restricted stock awards	0	0	343	0	0	343
401(k) plan contribution	0	0	(200)	0	421	221
Balance at Mar. 31, 2021	$ 68	$ 9	$ 69,043	$ 159,748	$ (37,004)	$ 191,864
Balance, shares at Mar. 31, 2021	6,785	938