Business Segments (Reconciliation Of Segment Results To Consolidated Income Before Income Taxes) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Business Segments [Abstract]
Income from construction operations	$ 57,696	$ (341,717)	$ 104,923	$ (318,804)
Other income (expense)	(797)	900	(316)	1,322
Interest expense	(16,464)	(17,522)	(32,900)	(33,947)
INCOME (LOSS) BEFORE INCOME TAXES	$ 40,435	$ (358,339)	$ 71,707	$ (351,429)