Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Common Class A [Member]
Other income (expense):
Net income	$ 2,060	$ 2,272	$ 5,825	$ 7,016
Basic Earnings Per Share:
Basic earnings per share (in dollars per share)	$ 0.10	$ 0.11	$ 0.28	$ 0.34
Diluted Earnings Per Share:
Diluted earnings per share (in dollars per share)	0.10	$ 0.11	0.28	$ 0.33
Dividends Per Share of Common Stock:
Dividends per share (in dollars per share)	$ 0.06		$ 0.18
Weighted average shares and share equivalents outstanding:
Weighted average shares and share equivalents outstanding, basic (in shares)	20,726	20,771	20,769	20,761
Weighted average shares and share equivalents outstanding, diluted (in shares)	20,937	21,035	21,002	21,078
Common Class B [Member]
Other income (expense):
Net income	$ 2,078	$ 2,280	$ 5,858	$ 7,041
Basic Earnings Per Share:
Basic earnings per share (in dollars per share)	$ 0.59	$ 0.66	$ 1.67	$ 2.03
Diluted Earnings Per Share:
Diluted earnings per share (in dollars per share)	0.59	$ 0.64	1.65	$ 1.99
Dividends Per Share of Common Stock:
Dividends per share (in dollars per share)	$ 0.36		$ 1.08
Weighted average shares and share equivalents outstanding:
Weighted average shares and share equivalents outstanding, basic (in shares)	3,478	3,474	3,478	3,472
Weighted average shares and share equivalents outstanding, diluted (in shares)	3,521	3,536	3,522	3,538
Revenue	$ 25,244	$ 23,682	$ 75,979	$ 73,713
Direct	11,006	9,769	33,246	30,871
Selling, general and administrative	6,620	5,805	20,883	18,154
Depreciation and amortization	1,070	949	3,109	2,810
Total operating expenses	18,696	16,523	57,238	51,835
Operating income	6,548	7,159	18,741	21,878
Interest income	14	22	46	58
Interest expense	(52)	(76)	(172)	(236)
Other, net	(25)	2	(22)	16
Total other expense	(63)	(52)	(148)	(162)
Income before income taxes	6,485	7,107	18,593	21,716
Provision for income taxes	2,346	2,555	6,910	7,659
Net income	$ 4,139	$ 4,552	$ 11,683	$ 14,057