Ownership Of Cal Dive International, Inc. (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	0 Months Ended	1 Months Ended	3 Months Ended		12 Months Ended				1 Months Ended
	Jun. 10, 2009	Jan. 31, 2009	Mar. 31, 2011	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2010 Cal Dive International Inc [Member]	Dec. 31, 2008 IPO [Member]	Jun. 30, 2009 Secondary Public Offering [Member]	Sep. 23, 2009 Second Secondary Public Offering [Member]	Sep. 24, 2009 Second Secondary Public Offering [Member]
Subsidiary or Equity Method Investee [Line Items]
Sale of subsidiary/equity method investee shares by parent company		13.6								22.6	20.6	2.6
Gain on sale of Cal Dive common stock		$ (2,900,000)			$ 753,000		$ 77,343,000
Ownership percentage in Cal Dive		51.00%							57.20%	26.00%
Proceeds from sale of Cal Dive common stock		86,000,000	3,600,000		3,588,000		418,168,000			182,900,000		221,500,000
Repurchase of shares by subsidiary										1.6
Proceeds from repurchase of common stock										14,000,000
Common stock, per share										$ 8.50		$ 10
Gain associated with the re-measurement of remaining ownership	27,100,000
Remaining ownership interest	26.00%
Other than temporary impairment non-cash				2,200,000	10,563,000	2,240,000
Remaining shares of Cal Dive common stock, shares						0.5
Outstanding shares, percentage						1.00%
Gain (loss) on investment in Cal Dive common stock	59,400,000				753,000		77,343,000					17,900,000
Equity investments				$ 187,031,000	$ 175,656,000	$ 187,031,000		$ 2,800,000