Marketable Securities (Schedule Of Marketable Securities Classified As Cash Equivalents) (Details)1 (USD $)	Dec. 31, 2012	Dec. 31, 2011
Gain (Loss) on Investments [Line Items]
Cost	$ 2,824,000	$ 685,000
Unrealized Gains
Unrealized Losses
Recorded Basis	2,824,000	685,000
US States Government And Agency Obligations [Member]
Gain (Loss) on Investments [Line Items]
Cost		30,000
Unrealized Gains
Unrealized Losses
Recorded Basis		30,000
Corporate Debt Securities And Certificates Of Deposit [Member]
Gain (Loss) on Investments [Line Items]
Cost	2,824,000	655,000
Unrealized Gains
Unrealized Losses
Recorded Basis	$ 2,824,000	$ 655,000