Income Taxes (By Country) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Disclosure [Line Items]
Income (Loss) Before Income Taxes	$ (111,998)	$ (103,934)	$ 55,743
Current Tax Expense	31,822	5,945	2,580
Deferred Tax Expense Related to U.K. Tax Rate Change	8,587	25,424	(3,317)
Deferred Tax Benefit	(26,181)	(4,308)
Foreign Currency Gains (Losses) On Deferred Tax Liabilities			(51)
Total Income Tax Expense (Benefit)	14,228	27,061	(788)
Net Income (Loss)	(126,226)	(130,995)	56,531
[GB]
Income Tax Disclosure [Line Items]
Income (Loss) Before Income Taxes	(22,959)	(9,806)	90,160
Current Tax Expense	31,796	5,926	2,734
Deferred Tax Expense Related to U.K. Tax Rate Change	8,587	25,424	(2,388)
Deferred Tax Benefit	(26,181)	(4,308)
Foreign Currency Gains (Losses) On Deferred Tax Liabilities			0
Total Income Tax Expense (Benefit)	14,202	27,042	346
Net Income (Loss)	(37,161)	(36,848)	89,814
[DomesticCountryMember]
Income Tax Disclosure [Line Items]
Income (Loss) Before Income Taxes	(91,383)	(99,409)	(30,978)
Current Tax Expense	0	4
Deferred Tax Expense Related to U.K. Tax Rate Change	0	0
Deferred Tax Benefit	0	0
Foreign Currency Gains (Losses) On Deferred Tax Liabilities			0
Total Income Tax Expense (Benefit)	0	4	0
Net Income (Loss)	(91,383)	(99,413)	(30,978)
[ForeignCountryMember]
Income Tax Disclosure [Line Items]
Income (Loss) Before Income Taxes	2,344	5,281	(3,439)
Current Tax Expense	26	15	(154)
Deferred Tax Expense Related to U.K. Tax Rate Change	0	0	(929)
Deferred Tax Benefit	0	0
Foreign Currency Gains (Losses) On Deferred Tax Liabilities			(51)
Total Income Tax Expense (Benefit)	26	15	(1,134)
Net Income (Loss)	$ 2,318	$ 5,266	$ (2,305)