Operations by Business Segment and Geographic Area - Revenues and Long-Lived Assets by Location (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Segment Reporting Information [Line Items]
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Foreign Countries	$ 1,318,049	$ 973,530	$ 962,061
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Entity's Country of Domicile	874,614	943,515	860,020
Revenues	2,192,663	1,917,045	1,822,081
Long-Lived Assets	1,378,104	1,010,666	977,495
Foreign [Member]
Segment Reporting Information [Line Items]
Long-Lived Assets	825,465	527,588	490,042
Norway [Member]
Segment Reporting Information [Line Items]
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Foreign Countries	310,891	212,854	230,874
Long-Lived Assets	436,043	165,942	170,617
West Africa [Member]
Segment Reporting Information [Line Items]
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Foreign Countries	284,642	260,377	280,707
Long-Lived Assets	120,732	106,028	95,326
United Kingdom [Member]
Segment Reporting Information [Line Items]
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Foreign Countries	256,565	156,114	156,748
Long-Lived Assets	65,830	70,730	63,334
Asia and Australia [Member]
Segment Reporting Information [Line Items]
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Foreign Countries	217,094	136,518	135,721
Long-Lived Assets	72,518	76,835	76,622
Brazil [Member]
Segment Reporting Information [Line Items]
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Foreign Countries	155,532	135,510	97,401
Long-Lived Assets	99,709	79,484	63,653
Other [Member]
Segment Reporting Information [Line Items]
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Foreign Countries	93,325	72,157	60,610
Long-Lived Assets	30,633	28,569	20,490
United States [Member]
Segment Reporting Information [Line Items]
Long-Lived Assets	$ 552,639	$ 483,078	$ 487,453