CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, unless otherwise specified	Total		Class A [Member]	Class B [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Common Stock [Member] Class A [Member]	Common Stock [Member] Class B [Member]	Additional Paid-in Capital (APIC) [Member]
Balance at Dec. 31, 2010	$ 220,333				$ 195,477	$ (39)	$ 217	$ 953	$ 23,725
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared on Class A common stock	(522)				(522)
Cash dividends declared on Class B common stock	(2,690)				(2,690)
Issuance of restricted common stock	0							13	(13)
Forfeiture of restricted common stock	0							(2)	2
Foreign currency translation adjustment	(236)					(236)
Unrealized holding gains (losses) on marketable securities arising during the year net of taxes	(507)					(507)
Reclassification adjustment for unrealized holding gains included in net earnings, net of taxes	(74)					(74)
Reclassification adjustment for unrealized holding losses included in net earnings, net of taxes	0
Reduction in APIC pool associated with tax deficiencies related to restricted stock awards	(3)								(3)
Stock-based compensation expense	1,709								1,709
Change in unfunded SERP liability, net of taxes	(694)					(694)
Net earnings	3,764		620	3,144	3,764
Balance at Dec. 31, 2011	221,080				196,029	(1,550)	217	964	25,420
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared on Class A common stock	(522)				(522)
Cash dividends declared on Class B common stock	(2,697)				(2,697)
Issuance of restricted common stock	0							13	(13)
Forfeiture of restricted common stock	0							(3)	3
Repurchase/retirement of Class B common stock	(6,644)							(37)	(6,607)
Foreign currency translation adjustment	281					281
Unrealized holding gains (losses) on marketable securities arising during the year net of taxes	(251)					(251)
Reclassification adjustment for unrealized holding gains included in net earnings, net of taxes	0
Reclassification adjustment for unrealized holding losses included in net earnings, net of taxes	569					569
Reduction in APIC pool associated with tax deficiencies related to restricted stock awards	(118)								(118)
Stock-based compensation expense	1,767								1,767
Change in unfunded SERP liability, net of taxes	(476)					(476)
Net earnings	2,373	[1]	372	2,001	2,373
Balance at Dec. 31, 2012	215,362				195,183	(1,427)	217	937	20,452
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared on Class A common stock	(522)				(522)
Cash dividends declared on Class B common stock	(2,576)				(2,576)
Issuance of restricted common stock	0							16	(16)
Forfeiture of restricted common stock	0							(2)	2
Repurchase/retirement of Class B common stock	(3,356)			(10,000)				(18)	(3,338)
Foreign currency translation adjustment	977					977
Unrealized holding gains (losses) on marketable securities arising during the year net of taxes	87					87
Reclassification adjustment for unrealized holding gains included in net earnings, net of taxes	(61)					(61)
Reclassification adjustment for unrealized holding losses included in net earnings, net of taxes	0
Reduction in APIC pool associated with tax deficiencies related to restricted stock awards	(65)								(65)
Stock-based compensation expense	1,879								1,879
Change in unfunded SERP liability, net of taxes	1,069					1,069
Net earnings	15,908	[1]	2,868	13,040	15,908
Balance at Dec. 31, 2013	$ 228,702				$ 207,993	$ 645	$ 217	$ 933	$ 18,914

[1] Quarterly amounts of earnings per share may not agree to the total for the year due to rounding.