Accounts Receivable And Contracts In Progress (Components Of Contracts In Progress) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Accounts Notes And Loans Receivable [Line Items]
Costs and earnings in excess of billings for contracts in progress	$ 49,793	$ 53,876
Costs and earnings in excess of billings for completed contracts	25,122	27,319
Total contract revenues in excess of billings	74,915	81,195
Total billings in excess of contract revenues	(4,971)	(7,061)
Costs And Earnings In Excess Of Billings [Member]
Accounts Notes And Loans Receivable [Line Items]
Costs and earnings for contracts in progress	360,254	230,159
Amounts billed	(310,461)	(176,283)
Billings In Excess Of Costs And Earnings [Member]
Accounts Notes And Loans Receivable [Line Items]
Costs and earnings for contracts in progress	280,115	200,489
Amounts billed	$ (285,086)	$ (207,550)