Contract Assets (Schedule Of Changes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Change In Contract With Customer Asset [Abstract]
Beginning balance, December 31	$ 140,082	$ 146,496
Revenue recognized	2,076,680	2,387,333
Amounts collected or invoiced	(2,055,701)	(2,393,747)
Ending balance, June 30	$ 161,061	$ 140,082