Segment Information (Details Textual) (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Segment Reporting Information [Line Items]
Equity in (earnings) losses of unconsolidated affiliates, net of dividends	$ (68,668,000)	$ 13,776,000
Investments in unconsolidated affiliates accounted for using equity method	303,100,000		371,000,000
Full-cost ceiling test writedown	13,700,000		13,700,000
Segment Information (Textual) [Abstract]
Investments in unconsolidated affiliates (oil and gas)	5,600,000	15,200,000
Full-cost ceiling test writedown	(68,212,000)
Oil and Gas [Member]
Segment Reporting Information [Line Items]
Equity in (earnings) losses of unconsolidated affiliates, net of dividends	(62,600,000)	15,200,000
Investments in unconsolidated affiliates accounted for using equity method	234,300,000		294,100,000
Full-cost ceiling test writedown	417,000,000	385,400,000
Subtotal Contract Drilling [Member]
Segment Reporting Information [Line Items]
Equity in (earnings) losses of unconsolidated affiliates, net of dividends	(6,100,000)	1,100,000
Investments in unconsolidated affiliates accounted for using equity method	$ 68,800,000		$ 76,900,000