Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Common Class A [Member]
Other income (expense):
Net income	$ 2,028	$ 2,022	$ 3,765	$ 4,744
Basic Earnings Per Share:
Basic earnings per share (in dollars per share)	$ 0.10	$ 0.10	$ 0.18	$ 0.23
Diluted Earnings Per Share:
Diluted earnings per share (in dollars per share)	0.10	$ 0.10	0.18	$ 0.22
Dividends Per Share of Common Stock:
Dividends per share (in dollars per share)	$ 0.06		$ 0.12
Weighted average shares and share equivalents outstanding:
Weighted average shares and share equivalents outstanding, basic (in shares)	20,790	20,771	20,791	20,757
Weighted average shares and share equivalents outstanding, diluted (in shares)	21,029	21,073	21,031	21,098
Common Class B [Member]
Other income (expense):
Net income	$ 2,036	$ 2,029	$ 3,780	$ 4,761
Basic Earnings Per Share:
Basic earnings per share (in dollars per share)	$ 0.58	$ 0.58	$ 1.08	$ 1.37
Diluted Earnings Per Share:
Diluted earnings per share (in dollars per share)	0.57	$ 0.57	1.07	$ 1.34
Dividends Per Share of Common Stock:
Dividends per share (in dollars per share)	$ 0.36		$ 0.72
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)	3,522	3,539	3,523	3,540
Revenue	$ 24,464	$ 24,001	$ 50,734	$ 50,031
Direct	10,440	10,773	22,239	21,102
Selling, general and administrative	6,636	5,984	14,263	12,349
Depreciation and amortization	1,024	926	2,039	1,861
Total operating expenses	18,100	17,683	38,541	35,312
Operating income	6,364	6,318	12,193	14,719
Interest income	16	19	32	36
Interest expense	(57)	(78)	(120)	(160)
Other, net	2	7	2	14
Total other expense	(39)	(52)	(86)	(110)
Income before income taxes	6,325	6,266	12,107	14,609
Provision for income taxes	2,261	2,215	4,563	5,104
Net income	$ 4,064	$ 4,051	$ 7,544	$ 9,505