Segment (Schedule Of Revenues From External Customers) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas	$ 940,347	$ 1,107,365	$ 1,158,985
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas	302,112	397,389	645,769
Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas	57,656	137,610	137,195
Brazil [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas	63,039
Spain [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas	52,477	113,546	85,161
Bermuda [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas	47,513	83,600
Mexico [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas	36,653	82,657	49,157
France [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas	33,333	80,923	24,657
People's Republic Of China (Including Hong Kong) [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas	99,039	47,967	44,135
United Kingdom [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas	1,498	40,741	57,976
Australia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas	153,235	40,067
Luxembourg [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas	17,698	31,107	70,678
Norway [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas	68,305	29,809
The Netherlands [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas	6,366	18,501	26,721
Other[Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas	$ 1,423	$ 3,448	$ 17,536