Financial Instruments (Summary Of Unrealized Gain And Losses) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Financial Instruments [Abstract]
Net gain (loss) recognized during the period on equity securities	$ 305	$ 2	$ 244	$ 195
Less: net gain / loss recognized during the period on equity securities sold during the period
Unrealized gain (loss) recognized during the reporting period on equity securities still held at the reporting date	$ 305	$ 2	$ 244	$ 195