Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Earnings Per Share [Abstract]
Net loss attributable to McDermott International, Inc.	$ (10,830)	$ (149,423)	$ (60,783)	$ (128,870)
Weighted average common shares (basic)	237,395,580	236,199,438	237,178,369	236,070,311
Effect of dilutive securities:
Stock options, restricted stock and restricted stock units
Adjusted weighted average common shares and assumed exercises of stock options and vesting of stock awards (diluted)	237,395,580	236,199,438	237,178,369	236,070,311
Basic loss per share
Net loss attributable to McDermott International, Inc.	$ (0.05)	$ (0.63)	$ (0.26)	$ (0.55)
Diluted earnings loss per share:
Net loss attributable to McDermott International, Inc.	$ (0.05)	$ (0.63)	$ (0.26)	$ (0.55)