Annual report pursuant to Section 13 and 15(d)

- Fair Value Measurements (Estimated Fair Value Of Other Financial Assets And Liabilities) (Details)

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- Fair Value Measurements (Estimated Fair Value Of Other Financial Assets And Liabilities) (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, including current portion, estimated fair value $ 160,149 $ 162,275
Purchase of investments 5,000  
Proceeds from sale of investments 4,430  
Net loss on sale of investments 600  
Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, including current portion, estimated fair value 0 0
Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, including current portion, estimated fair value 166,691 159,367
Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, including current portion, estimated fair value $ 0 $ 0