CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Allowance for accounts receivable	$ 648	$ 671
Accumulated amortization on other intangibles, deferred costs and investments	$ 15,524	$ 14,711
Preferred Stock, Shares Authorized	1,500	1,500
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Treasury stock, shares (in shares)	1,751	1,735
Class A Common Stock
Common Stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common Stock, Shares Authorized	35,000	35,000
Common Stock, Shares, Issued	6,785	6,771
Common Stock, Shares, Outstanding	6,785	6,771
Class B Common Stock
Common Stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common Stock, Shares Authorized	3,500	3,500
Common Stock, Shares, Issued	938	954
Common Stock, Shares, Outstanding	938	954