Net Income (Loss) Per Share (Reconciliation Of Earnings Attributable To Common Stockholders, Basic And Diluted) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Net income (loss) attributable to common stockholders	$ 178,000	$ (42,000)
Participating share-based earnings	(1,000)	0
Basic income (loss) from continuing operations attributable to common stockholders	177,000	(42,000)
Diluted income (loss) from continuing operations attributable to common stockholders	$ 177,000	$ (42,000)