Annual report pursuant to Section 13 and 15(d)

Trading Securities (Schedule Of Fair Value Of Assets) (Details)

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Trading Securities (Schedule Of Fair Value Of Assets) (Details) - USD ($)
Dec. 31, 2016
Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Trading securities $ 59,000 $ 324,000
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 59,000 324,000
Money market funds 36,000 333,000
Total 95,000 657,000
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 59,000 324,000
Money market funds 36,000 333,000
Total $ 95,000 $ 657,000