Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Common Class A [Member]
Other income (expense):
Net income	$ 2,260	$ 2,028	$ 4,994	$ 3,765
Basic Earnings Per Share:
Basic earnings per share (in dollars per share)	$ 0.11	$ 0.10	$ 0.24	$ 0.18
Diluted Earnings Per Share:
Diluted earnings per share (in dollars per share)	0.11	0.10	0.24	0.18
Dividends Per Share of Common Stock:
Dividends per share (in dollars per share)	$ 0.08	$ 0.06	$ 0.16	$ 0.12
Weighted average shares and share equivalents outstanding:
Weighted average shares and share equivalents outstanding, basic (in shares)	20,711	20,790	20,711	20,791
Weighted average shares and share equivalents outstanding, diluted (in shares)	20,992	21,029	21,002	21,031
Common Class B [Member]
Other income (expense):
Net income	$ 2,298	$ 2,036	$ 5,071	$ 3,780
Basic Earnings Per Share:
Basic earnings per share (in dollars per share)	$ 0.65	$ 0.58	$ 1.44	$ 1.08
Diluted Earnings Per Share:
Diluted earnings per share (in dollars per share)	0.64	0.57	1.41	1.07
Dividends Per Share of Common Stock:
Dividends per share (in dollars per share)	$ 0.48	$ 0.36	$ 0.96	$ 0.72
Weighted average shares and share equivalents outstanding:
Weighted average shares and share equivalents outstanding, basic (in shares)	3,508	3,478	3,498	3,478
Weighted average shares and share equivalents outstanding, diluted (in shares)	3,565	3,522	3,557	3,523
Revenue	$ 26,114	$ 24,464	$ 53,984	$ 50,734
Direct	10,734	10,440	22,273	22,239
Selling, general and administrative	7,270	6,636	14,627	14,263
Depreciation and amortization	1,092	1,024	2,060	2,039
Total operating expenses	19,096	18,100	38,960	38,541
Operating income	7,018	6,364	15,024	12,193
Interest income	11	16	22	32
Interest expense	(36)	(57)	(121)	(120)
Other, net	43	2	118	2
Total other income (expense)	18	(39)	19	(86)
Income before income taxes	7,036	6,325	15,043	12,107
Provision for income taxes	(2,478)	(2,261)	(4,978)	(4,563)
Net income	$ 4,558	$ 4,064	$ 10,065	$ 7,544