Costs And Estimated Earnings On Uncompleted Contracts (Summary Of Costs And Estimated Earnings On Uncompleted Contracts) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Costs And Estimated Earnings On Uncompleted Contracts [Abstract]
Costs incurred on uncompleted contracts	$ 31,404	$ 34,577
Estimated earnings	10,541	11,185
Billings to date	(24,771)	(36,027)
Costs and estimated earnings on uncompleted contracts	$ 17,174	$ 9,735