CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Current Assets
Accounts receivable, allowance for doubtful accounts	$ 1,847	$ 1,747
Stockholders' Equity:
Preferred stock, par value (in dollars per share)	$ 0	$ 0
Preferred stock, authorized (in shares)	1,000,000	1,000,000
Preferred stock, issued (in shares)	0	0
Class A Common Stock [Member]
Stockholders' Equity:
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, authorized (in shares)	10,000,000	10,000,000
Common stock, outstanding (in shares)	2,174,912	2,174,912
Common stock, treasury shares (in shares)	1,072,769	1,072,769
Class B Common Stock [Member]
Stockholders' Equity:
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, authorized (in shares)	30,000,000	30,000,000
Common stock, outstanding (in shares)	9,758,652	9,701,977
Common stock, treasury shares (in shares)	3,218,307	3,218,307