Contracts in Progress (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Contractors [Abstract]
Costs incurred on uncompleted contracts	$ 624,503	$ 554,109
Estimated earnings	88,226	97,687
Costs incurred and estimated earnings on uncompleted contracts	712,729	651,796
Less: Billings to date	(679,129)	(623,919)
Costs and estimated earnings in excess of billings on uncompleted contracts, net	33,600	27,877
Costs and estimated earnings in excess of billings on uncompleted contracts	45,152	44,581
Billings in excess of costs and estimated earnings on uncompleted contracts	(11,552)	$ (16,704)
Costs and estimated earnings in excess of billings on completed contracts, net of billings	$ 800