Accounts Receivable And Contracts In Progress (Schedule Of Accounts Receivable) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Receivables [Abstract]
Completed contracts	$ 21,547	$ 18,727
Contracts in progress	57,039	53,137
Retainage	18,021	21,399
Accounts receivable, gross	96,607	93,263
Allowance for doubtful accounts	(747)	(747)
Total accounts receivable—net	95,860	92,516
Current portion of accounts receivable—net	91,385	88,091
Long-term accounts receivable and retainage	$ 4,475	$ 4,425