Contract Assets and Liabilities (Schedule Of Contract Assets) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Contract with Customer, Contract Asset, Contract Liability, and Receivable [Abstract]
Retainage receivable	$ 683,966	$ 648,441
Costs and estimated earnings in excess of billings:
Claims	821,206	752,783
Unapproved change orders	430,138	415,489
Other unbilled costs and profits	95,630	68,462
Total costs and estimated earnings in excess of billings	1,346,974	1,236,734
Capitalized contract costs	82,625	74,452
Total contract assets	$ 2,113,565	$ 1,959,627