Summary Of Significant Accounting Policies (Computations Of Basic And Diluted EPS) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended												12 Months Ended
	Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Earnings Per Share [Abstract]
Net income applicable to common shareholders	$ (171,567)		$ 14,865		$ 44,641		$ 65,727		$ 16,753	$ 46,016	$ 41,313	$ 25,857	$ (46,334)	$ 129,939	$ (127,102)
Less: Undistributed net income allocable to participating securities														(1,599)
Net income (loss) applicable to common shareholders													(46,334)	128,340	(127,102)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent													(23,684)	(95,221)	106,657
Add: Undistributed net income from discontinued operations allocable to participating securities														1,172
Income (Loss) from Continuing Operations Attributable to Parent, Total	(99,679)		10,362		2,425		16,874		17,487	15,999	10,547	(9,315)	(70,018)	34,291	(20,445)
Weighted average number of shares outstanding - basic													104,449	104,528	103,857
Stock options, Shares														64
Undistributed earnings reallocated to participating securities, value														2
Convertible preferred stock														40
Convertible preferred stock, Shares														361
Income (loss) from continuing operations applicable to Helix common shareholders - Diluted													(70,018)	34,333	(20,445)
Income (loss) from discontinued operations, net of tax	(71,888)	[1]	4,503	[1]	42,216	[1]	48,853	[1]	(734)	30,017	30,766	35,172	23,684	95,221	(106,657)
Net income per common share - Diluted													$ (46,334)	$ 129,554	$ (127,102)
Weighted average number of shares outstanding, diluted, total													104,449	104,953	103,857

[1] Our net loss in the fourth quarter of 2012 includes a $138.6 million impairment charge associated with the sale of ERT (Note 3).