Summary Of Significant Accounting Policies (Schedule Of Long-Term Investments Measured At Fair Value Using Significant Unobservable Inputs (Level 3 Inputs)) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Summary Of Significant Accounting Policies [Abstract]
Balance as of January 1	$ 24,673	$ 35,297
Net unrealized gains included in other comprehensive income	1,476	526
Sales of investments at par value	(15,825)	(11,150)
Balance as of December 31	10,324	24,673
Unrealized losses still held	$ 1,851	$ 3,327