Contract Assets and Liabilities (Schedule Of Contract Assets) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Contract with Customer, Contract Asset, Contract Liability, and Receivable [Abstract]
Retainage receivable	$ 637,124	$ 648,441
Costs and estimated earnings in excess of billings:
Claims	840,176	752,783
Unapproved change orders	448,600	415,489
Other unbilled costs and profits	99,234	68,462
Total costs and estimated earnings in excess of billings	1,388,010	1,236,734
Capitalized contract costs	72,543	74,452
Total contract assets	$ 2,097,677	$ 1,959,627