Contract Assets And Liabilities (Schedule Of Contract Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Contract with Customer, Contract Asset, Contract Liability, and Receivable [Abstract]
Retainage receivable	$ 648,441	$ 562,375
Claims	752,783	705,993
Unapproved change orders	415,489	362,264
Other unbilled costs and profits	68,462	55,287
Total costs and estimated earnings in excess of billings	1,236,734	1,123,544
Capitalized contract costs	74,452	80,294
Total contract assets	$ 1,959,627	$ 1,766,213