Stock-Based Compensation And Employee Stock Option Plan (Schedule Of Stock Options Outstanding And Exercisable) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2010	Dec. 31, 2012 Class A [Member]	Dec. 31, 2010 Class A [Member]	Dec. 31, 2010 Class B [Member]	Dec. 31, 2012 Class B [Member]	Dec. 31, 2011 Class B [Member]
Equity And Stock-Based Compensation [Line Items]
Common Stock Options Outstanding, Beginning balance			622,350	589,750	150,000	185,100	185,100
Common Stock Options Outstanding, Granted			206,000	122,600	35,100
Common Stock Options Outstanding, Exercised	(95,000)		(136,000)	(90,000)
Common Stock Options Outstanding, Expired			(20,000)
Common Stock Options Outstanding, Ending balance			672,350	622,350	185,100	185,100	185,100
Weighted Average Exercise Price of Options Outstanding, Beginning price			$ 5.65	$ 5.51	$ 10.24	$ 9.90	$ 9.90
Weighted Average Exercise Price of Options Outstanding, Granted	$ 5.94	$ 5.17	$ 5.94	$ 5.17	$ 8.47
Weighted Average Exercise Price of Options Outstanding, Exercised			$ 4.68	$ 2.76
Weighted Average Exercise Price of Options Outstanding, Expired			$ 3.75
Weighted Average Exercise Price of Options Outstanding, Ending price			$ 6.24	$ 5.65	$ 9.90	$ 9.90	$ 9.90
Common Stock Exercisable Options, Outstanding Beginning balance			544,383	534,750	150,000	185,100	167,550
Common Stock Exercisable Options, Outstanding Ending balance			546,350	449,750	150,000	185,100	167,550
Weighted Average Price of Exercisable Options, Outstanding Beginning balance			$ 5.86	$ 5.62	$ 10.24	$ 9.90	$ 10.05
Weighted Average Price of Exercisable Options, Outstanding Ending balance			$ 6.26	$ 6.22	$ 10.24	$ 9.90	$ 10.05