Earnings per Share (Computations Of Basic And Diluted EPS) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earnings Per Share [Abstract]
Net income applicable to Helix	$ 44,593	$ 14,865	$ 73,419	$ 125,233
Income from discontinued operations	(44)	(4,503)	(1,073)	(95,572)
Income (loss) from continuing operations	44,549	10,362	72,346	29,661
Less: Undistributed net income allocable to participating securities	(337)	(104)	(525)	(299)
Income applicable to common shareholders - continuing operations	44,212	10,258	71,821	29,362
Less: Undistributed net income from discontinued operations allocable to participating securities		(45)	(8)	(962)
Income applicable to common shareholders - discontinued operations	44	4,458	1,065	94,610
Weighted average number of shares outstanding - basic	105,029	104,256	105,036	104,450
Share-based awards other than participating securities, Shares	107	112	116	86
Undistributed earnings reallocated to participating securities, value				2
Covertible preferred stock		10		30
Convertible preferred stock, Shares		361		361
Net income applicable to Helix - Diluted	44,212	10,268	71,821	29,394
Weighted average number of shares outstanding, diluted, total	105,136	104,729	105,152	104,897
Income from discontinued operations, net of tax	$ 44	$ 4,503	$ 1,073	$ 95,572