Long-Term Contracts (Details) (USD $) In Millions, unless otherwise specified				1 Months Ended
	Mar. 31, 2012	Dec. 31, 2011	Jan. 30, 2010 Shell Offshore Inc. Gulf of Mexico Bullwinkle Platform [Member]	Dec. 31, 2007 Wild Well [Member] Well	Mar. 31, 2012 Wild Well [Member]	Dec. 31, 2011 Wild Well [Member]	Mar. 31, 2010 Wild Well [Member]
Long-Term Contracts (Textual) [Abstract]
Percentage of ownership acquired by Wild Well in Shell Offshore Inc.'s Gulf of Mexico Bullwinkle platform			100.00%
Performance bonds required to be obtained by Wild Well							$ 50.0
Amounts to be funded in Escrow account by Wild Well							50.0
Escrowed cash included in intangible and other long-term assets, net					50.3	50.2
Contractual arrangements fixed sum				750
Number of downed oil and gas platforms and related well facilities decommissioned				7
Costs and estimated earnings in excess of billings included in other current assets	$ 132.4	$ 133.4			$ 129.7	$ 129.7