Derivatives (Summary Of The Fair Value Of The Equity Index Put Options) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Option Indexed to Issuer's Equity [Line Items]
Equity index put option liability	$ 6,632		$ 6,632		$ 5,584
Net derivative gain (loss)	2,456	$ (189)	(1,048)	$ 3,395
Equity Index Put Option Contracts [Member] | Derivatives Not Designated As Hedging Instruments [Member]
Option Indexed to Issuer's Equity [Line Items]
Equity index put option liability	6,632		6,632		$ 5,584
Net derivative gain (loss)	$ 2,456	$ (189)	$ (1,048)	$ 3,395