Equity And Stock-Based Compensation (Summary Of Vested Stock Options) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Equity And Stock-Based Compensation [Line Items]
Weighted average remaining years of contractual life	2 years 10 months 21 days	2 years 4 months 24 days	4 years 8 months 12 days
Aggregate intrinsic value vested	$ 1,401,321	$ 2,476,230	$ 646,032
Class A [Member]
Equity And Stock-Based Compensation [Line Items]
Number of options	256,065	348,000	490,350
Weighted average exercise price	$ 7.64	$ 6.82	$ 6.85
Class B [Member]
Equity And Stock-Based Compensation [Line Items]
Number of options		185,100	185,100
Weighted average exercise price		$ 9.90	$ 9.90