Quarterly report pursuant to Section 13 or 15(d)

Trading Securities (Schedule Of Fair Value Of Assets Measured On Recurring Basis) (Details)

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Trading Securities (Schedule Of Fair Value Of Assets Measured On Recurring Basis) (Details) - USD ($)
Sep. 30, 2017
Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Trading securities $ 22,000 $ 59,000
Fair Value Measurements At Reporting Date Using Quoted Prices in Active Markets (Level 1) [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Trading securities 22,000 59,000
Money market funds 36,000 36,000
Total 58,000 95,000
Fair Value Measurements At Reporting Date Using Significant Other Observable Inputs (Level 2) [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Trading securities
Money market funds
Total
Fair Value Measurements At Reporting Date Using Significant Unobservable Inputs (Level 3) [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Trading securities
Money market funds
Total
Fair Value [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Trading securities 22,000 59,000
Money market funds 36,000 36,000
Total $ 58,000 $ 95,000