Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenue	$ 28,951	$ 27,032	$ 87,661	$ 81,016
Direct	12,267	11,468	36,706	33,741
Selling, general and administrative	8,430	7,139	22,021	21,766
Depreciation and amortization	1,132	1,086	3,376	3,146
Total operating expenses	21,829	19,693	62,103	58,653
Operating income	7,122	7,339	25,558	22,363
Interest income	29	12	58	34
Interest expense	(18)	(38)	(68)	(158)
Other, net	40	(4)	76	112
Total other income (expense)	51	(30)	66	(12)
Income before income taxes	7,173	7,309	25,624	22,351
Provision for income taxes	3,020	2,580	9,198	7,558
Net income	4,153	4,729	16,426	14,793
Common Class A [Member]
Net income	$ 2,062	$ 2,345	$ 8,151	$ 7,339
Basic Earnings Per Share:
Basic earnings per share (in dollars per share)	$ 0.10	$ 0.11	$ 0.39	$ 0.35
Diluted Earnings Per Share:
Diluted earnings per share (in dollars per share)	0.09	0.11	0.38	0.35
Dividends Per Share of Common Stock:
Dividends per share (in dollars per share)	$ 0.10	$ 0.08	$ 0.30	$ 0.24
Weighted average shares and share equivalents outstanding:
Weighted average shares and share equivalents outstanding, basic (in shares)	20,788	20,716	20,759	20,712
Weighted average shares and share equivalents outstanding, diluted (in shares)	21,740	21,068	21,537	21,017
Common Class B [Member]
Net income	$ 2,091	$ 2,384	$ 8,275	$ 7,454
Basic Earnings Per Share:
Basic earnings per share (in dollars per share)	$ 0.59	$ 0.67	$ 2.34	$ 2.11
Diluted Earnings Per Share:
Diluted earnings per share (in dollars per share)	0.57	0.66	2.28	2.08
Dividends Per Share of Common Stock:
Dividends per share (in dollars per share)	$ 0.60	$ 0.48	$ 1.80	$ 1.44
Weighted average shares and share equivalents outstanding:
Weighted average shares and share equivalents outstanding, basic (in shares)	3,514	3,511	3,514	3,503
Weighted average shares and share equivalents outstanding, diluted (in shares)	3,620	3,556	3,595	3,557