Business Segments (Reconciliation of Segment Results to Consolidated Income Before Income Taxes) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Business Segments [Abstract]
Income (loss) from construction operations	$ (341,717)	$ 54,815	$ (318,804)	$ 53,890
Other income, net	900	1,050	1,322	1,830
Interest expense	(17,522)	(15,998)	(33,947)	(31,063)
INCOME (LOSS) BEFORE INCOME TAXES	$ (358,339)	$ 39,867	$ (351,429)	$ 24,657