Costs And Estimated Earnings On Uncompleted Contracts (Narrative) (Details) - customer	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Costs And Estimated Earnings On Uncompleted Contracts [Abstract]
Costs and estimated earnings in excess of billings on uncompleted contracts, net of billings in excess of costs and estimated earnings on uncompleted contracts, percentage comprised by significant customers	81.60%	95.90%
Number of significant customers	8	8