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Fair Value Of Financial Instruments (Narrative) (Details) - USD ($)
9 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair value, Transfers between levels $ 0 $ 0  
Fair Value, Measurements, Nonrecurring [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Assets measured at fair value $ 0   $ 0