Impairments (Schedule Of Changes In Goodwill) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020		Mar. 31, 2019
Impairments [Abstract]
Balance, beginning of period	$ 37,248	[1]	$ 37,248
Impairment losses	(22,384)
Balance, end of period	$ 14,864		$ 37,248

[1] See Note 1 for a summary of adjustments.