Costs and estimated earnings in excess of billings (Tables)

3 Months Ended

Mar. 31, 2015

Costs and estimated earnings in excess of billings [Abstract]

Costs and estimated earnings in excess of billings

	March 31,		December 31,
	2015		2014
	(in thousands)
Unbilled costs and profits incurred to date*	$	241,631	$	253,078
Unapproved change orders		235,242		161,375
Claims		318,637		311,949
	$	795,510	$	726,402

*  Represents the excess of contract costs and profits recognized to date on the percentage of completion accounting method over the amount of contract billings to date on certain contracts.