Condensed Consolidated Balance Sheets (Parenthetical) $ in Thousands	Jun. 30, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares
Accounts receivable, allowance | $	$ 82	$ 59
Treasury stock, shares	11,634,806	11,634,806
Class B Common Stock [Member]
Common Stock, votes per share	10	10
Common Stock, par value | $ / shares	$ 0.01	$ 0.01
Common Stock, shares authorized	14,000,000	14,000,000
Common Stock, shares issued	11,758,218	11,758,218
Common Stock, shares outstanding	11,758,218	11,758,218
Common Stock [Member]
Common Stock, votes per share	1	1
Common Stock, par value | $ / shares	$ 0.01	$ 0.01
Common Stock, shares authorized	62,000,000	62,000,000
Common Stock, shares issued	42,918,485	40,403,058
Common Stock, shares outstanding	31,283,679	28,768,252