Summary Of Major Accounting Policies - Acquisitions (Details) (USD $)	Dec. 31, 2011
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Purchase Price	$ 291,617,000
Business Acquisition, Purchase Price Allocation, Goodwill Amount	193,814,000
Business Acquisition, Purchase Price Allocation, Intangible Assets Not Amortizable	53,372,000
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net	44,431,000
Norse Cutting and Abandonment AS [Member]
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Purchase Price	50,296,000
Business Acquisition, Purchase Price Allocation, Goodwill Amount	17,777,000
Business Acquisition, Purchase Price Allocation, Intangible Assets Not Amortizable	15,945,000
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net	16,574,000
AGR Field Operations [Member]
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Purchase Price	220,011,000
Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Costs	2,000,000
Business Acquisition, Purchase Price Allocation, Goodwill Amount	165,201,000
Business Acquisition, Purchase Price Allocation, Intangible Assets Not Amortizable	32,067,000
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net	22,743,000
Mechanica AS [Member]
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Purchase Price	17,214,000
Business Acquisition, Purchase Price Allocation, Goodwill Amount	8,877,000
Business Acquisition, Purchase Price Allocation, Intangible Assets Not Amortizable	5,360,000
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net	2,977,000
Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Purchase Price	4,096,000
Business Acquisition, Purchase Price Allocation, Goodwill Amount	1,959,000
Business Acquisition, Purchase Price Allocation, Intangible Assets Not Amortizable	0
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net	$ 2,137,000