Condensed Consolidated Statements of Income (unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenue	$ 22,407	$ 21,386	$ 69,667	$ 64,425
Operating expenses:
Direct	9,452	8,769	29,196	26,333
Selling, general and administrative	6,019	5,821	18,903	17,541
Depreciation and amortization	907	1,149	2,788	3,606
Total operating expenses	16,378	15,739	50,887	47,480
Operating income	6,029	5,647	18,780	16,945
Other income (expense):
Interest income	14	8	45	20
Interest expense	(91)	(134)	(309)	(416)
Other, net	(4)	(29)	28	(16)
Total other expense	(81)	(155)	(236)	(412)
Income before income taxes	5,948	5,492	18,544	16,533
Provision for income taxes	2,135	1,915	6,827	5,168
Net income	$ 3,813	$ 3,577	$ 11,717	$ 11,365
Common Class A [Member]
Other income (expense):
Earnings per share, basic (in Dollars per share)	$ 0.09	$ 0.09	$ 0.28	$ 0.28
Earnings per share, diluted (in Dollars per share)	$ 0.09	$ 0.09	$ 0.28	$ 0.27
Dividends per share of common stock (in Dollars per share)		$ 0.04	$ 0.05	$ 0.13
Weighted average shares and share equivalents outstanding, basic (in Shares)	20,672	20,373	20,671	20,262
Weighted average shares and share equivalents outstanding, diluted (in Shares)	21,111	20,883	21,087	20,823
Common Class B [Member]
Other income (expense):
Earnings per share, basic (in Dollars per share)	$ 0.55	$ 0.53	$ 1.70	$ 1.68
Earnings per share, diluted (in Dollars per share)	$ 0.54	$ 0.51	$ 1.67	$ 1.64
Dividends per share of common stock (in Dollars per share)		$ 0.26	$ 0.31	$ 0.78
Weighted average shares and share equivalents outstanding, basic (in Shares)	3,445	3,395	3,445	3,377
Weighted average shares and share equivalents outstanding, diluted (in Shares)	3,514	3,480	3,513	3,470