Income Taxes (Components of Income (Loss) from Continuing Operations Before Income Taxes and Income Tax Expense) (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2018	[1]	Sep. 30, 2018	[1]	Jun. 30, 2018	[1]	Mar. 31, 2018	[1]	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
Income (loss) from continuing operations before income taxes
United States													$ 14,907	$ (299,349)		$ (595,196)
Foreign													417,431	371,151		102,081
Income (loss) from continuing operations before income taxes	$ 106,200		$ 146,800		$ 82,300		$ 97,000		$ 2,400	$ (63,600)	$ (21,900)	$ 154,900	432,338	71,802	[2]	(493,115)	[2]
Income tax expense (benefit)
Federal - Current													(9,765)
Federal - Deferred													(131,200)	156,065		(197,450)
Total Federal income tax expense (benefit)													(140,965)	156,065		(197,450)
State													3,299	4,230		13,984
Foreign - Current													202,775	122,318		146,861
Foreign - Deferred													(55,779)	100,125		(182,567)
Total Foreign income tax expense (benefit)													146,996	222,443		(35,706)
Total income tax expense (benefit)													$ 9,330	$ 382,738	[2]	$ (219,172)	[2]

[1] 2018 includes noncontrolling interest in MP GOM.

[2] Reclassified to conform to current presentation (see Note B).