Financial Instruments (Summary Of Unrealized Gain And Losses) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Financial Instruments [Abstract]
Net gain recognized during the period on equity securities	$ 196	$ 305	$ 695	$ 244
Less: net gain / loss recognized during the period on equity securities sold during the period
Unrealized gain recognized during the reporting period on equity securities still held at the reporting date	$ 196	$ 305	$ 695	$ 244