Marketable Securities (Schedule Of Marketable Securities Classified As Cash Equivalents) (Details) (USD $)	Mar. 31, 2013	Dec. 31, 2012
Gain (Loss) on Investments [Line Items]
Cost	$ 1,055,000	$ 2,824,000
Unrealized Gains
Unrealized Losses
Recorded Basis	1,055,000	2,824,000
US States Government And Agency Obligations [Member]
Gain (Loss) on Investments [Line Items]
Cost	300,000
Recorded Basis	300,000
Corporate Debt Securities And Certificates Of Deposit [Member]
Gain (Loss) on Investments [Line Items]
Cost	755,000	2,824,000
Unrealized Gains
Unrealized Losses
Recorded Basis	$ 755,000	$ 2,824,000