Earnings Per Share (Computations Of Basic And Diluted EPS) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share [Abstract]
Net income applicable to Helix	$ 75,586	$ 44,593	$ 187,087	$ 73,419
Income from discontinued operations, net of tax		(44)		(1,073)
Net income from continuing operations	75,586	44,549	187,087	72,346
Less: Undistributed net income allocable to participating securities	(392)	(337)	(980)	(525)
Net income applicable to common shareholders - continuing operations	75,194	44,212	186,107	71,821
Less: Undistributed net income from discontinued operations allocable to participating securities				(8)
Net income applicable to common shareholders - discontinued operations				1,065
Weighted average number of shares outstanding - basic	104,997	105,029	105,038	105,036
Share-based awards other than participating securities, Shares	341	107	336	116
Undistributed earnings reallocated to participating securities, value	1		3
Net income applicable to Helix - Diluted	75,195	44,212	186,110	71,821
Weighted average number of shares outstanding, diluted, total	105,338	105,136	105,374	105,152
Income from discontinued operations, net of tax		$ 44		$ 1,073