Segments (Schedule Of Revenues By Country Based On Customer Location) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 306,199	$ 268,845	$ 252,422	$ 279,899	$ 326,671	$ 323,438	$ 279,962	$ 228,914	$ 1,107,365	$ 1,158,985	$ 993,400
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
United States Revenues									397,389	645,769	534,294
Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas									137,610	137,195	92,094
Spain [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas									113,546	85,161	85,499
Bermuda [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas									83,600
Mexico [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas									82,657	49,157	22
France [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas									80,923	24,657	344
People's Republic Of China (Including Hong Kong) [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas									47,967	44,135	54,677
United Kingdom [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas									40,741	57,976	101,499
Australia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas									40,067
Luxembourg [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas									31,107	70,678	61,673
Norway [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas									29,809
The Netherlands [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas									18,501	26,721	59,509
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical areas									$ 3,448	$ 17,536	$ 3,789