Contracts in Progress (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Contractors [Abstract]
Costs incurred on uncompleted contracts	$ 778,561	$ 554,109
Estimated earnings	130,924	97,687
Costs incurred and estimated earnings on uncompleted contracts	909,485	651,796
Less: Billings to date	(893,217)	(623,919)
Costs and estimated earnings in excess of billings on uncompleted contracts, net	16,268	27,877
Costs and estimated earnings in excess of billings on uncompleted contracts	47,513	44,581
Billings in excess of costs and estimated earnings on uncompleted contracts	(31,245)	$ (16,704)
Costs and estimated earnings in excess of billings on completed contracts, net of billings	$ 1,100