Marketable Securities (Schedule Of Marketable Securities Classified As Cash Equivalents) (Details) (USD $)	Jun. 30, 2012	Dec. 31, 2011
Gain (Loss) on Investments [Line Items]
Cost	$ 2,977,000	$ 685,000
Unrealized Gains
Unrealized Losses
Recorded Basis	2,977,000	685,000
US States Government And Agency Obligations [Member]
Gain (Loss) on Investments [Line Items]
Cost	543,000	30,000
Unrealized Gains
Unrealized Losses
Recorded Basis	543,000	30,000
Corporate Debt Securities And Certificates Of Deposit [Member]
Gain (Loss) on Investments [Line Items]
Cost	2,434,000	655,000
Unrealized Gains
Unrealized Losses
Recorded Basis	$ 2,434,000	$ 655,000