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, 2018
Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Trading securities $ 12,000  
Fair Value [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Trading securities 12,000 $ 48,000
Money market funds 1,000 36,000
Total 13,000 84,000
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 12,000 48,000
Money market funds 1,000 36,000
Total 13,000 84,000
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