Contract Assets (Schedule Of Changes) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Change in Contract with Customer, Asset [Abstract]
Beginning balance, December 31	$ 161,061	$ 140,082
Revenue recognized	915,600	1,109,396
Amounts collected or invoiced	(923,020)	(1,093,932)
Ending balance, March 31	$ 153,641	$ 155,546