Costs And Estimated Earnings In Excess Of Billings (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Costs and estimated earnings in excess of billings [Abstract]
Claims	$ 435,890	$ 407,164
Unapproved change orders	183,759	270,019
Other unbilled costs and profits	200,594	227,992
Total costs and estimated earnings in excess of billings	$ 820,243	$ 905,175