Contract Assets And Liabilities (Schedule Of Contract Assets) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Contract Assets and Liabilities [Abstract]
Retainage receivable	$ 573,151	$ 562,375
Claims	717,409	705,993
Unapproved change orders	356,854	362,264
Other unbilled costs and profits	80,939	55,287
Total costs and estimated earnings in excess of billings	1,155,202	1,123,544
Capitalized contract costs	83,509	80,294
Total contract assets	$ 1,811,862	$ 1,766,213