Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Common Class A [Member]
Other income (expense):
Net income	$ 2,568	$ 1,738
Denominator for net income per share - basic:
Basic earnings per share (in dollars per share)	$ 0.12	$ 0.08
Diluted Earnings Per Share:
Diluted earnings per share (in dollars per share)	0.12	0.08
Dividends Per Share of Common Stock:
Dividends per share (in dollars per share)	$ 0.08	$ 0.06
Weighted average shares and share equivalents outstanding:
Weighted average shares and share equivalents outstanding, basic (in shares)	20,710	20,792
Weighted average shares and share equivalents outstanding, diluted (in shares)	20,948	21,033
Common Class B [Member]
Other income (expense):
Net income	$ 2,605	$ 1,742
Denominator for net income per share - basic:
Basic earnings per share (in dollars per share)	$ 0.74	$ 0.50
Diluted Earnings Per Share:
Diluted earnings per share (in dollars per share)	0.73	0.49
Dividends Per Share of Common Stock:
Dividends per share (in dollars per share)	$ 0.48	$ 0.36
Weighted average shares and share equivalents outstanding:
Weighted average shares and share equivalents outstanding, basic (in shares)	3,489	3,478
Weighted average shares and share equivalents outstanding, diluted (in shares)	3,531	3,524
Revenue	$ 27,870	$ 26,270
Direct	11,539	11,799
Selling, general and administrative	7,357	7,627
Depreciation and amortization	968	1,015
Total operating expenses	19,864	20,441
Operating income	8,006	5,829
Interest income	11	17
Interest expense	(85)	(63)
Other, net	$ 74	(1)
Total other expense		(47)
Income before income taxes	$ 8,006	5,782
Provision for income taxes	2,833	2,302
Net income	$ 5,173	$ 3,480