Stock-Based Compensation - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended								12 Months Ended	0 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Stock Option	Dec. 31, 2012 Stock Option	Dec. 31, 2011 Stock Option	Dec. 31, 2013 2009 McDermott International, Inc. Long-Term Incentive Plan	May 31, 2009 2009 McDermott International, Inc. Long-Term Incentive Plan	Dec. 31, 2013 2001 Directors and Officers Long-Term Incentive Plan	Oct. 11, 2002 Thrift Plan	Dec. 31, 2013 Thrift Plan	Dec. 31, 2012 Thrift Plan	Dec. 31, 2011 Thrift Plan	Nov. 12, 1991 Thrift Plan
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Unrecognized estimated compensation expense for nonvested awards, net	$ 33.2
Shares authorized for issuance								9,000,000						15,000,000
Options to purchase shares, maximum expiration term							7 years		10 years
Percentage of fair market value that options to purchase are granted, minimum									100.00%
Additional shares authorized for issuance										15,000,000
Matching employer contributions percentage of the first 6% of compensation											50.00%
Defined contribution plan matching percent of compensation											6.00%
Common stock issued											0	0	0
Common stock dividend yield				0.00%
Total intrinsic value of stock options exercised				0.5	1.9	8.4
Cash received from exercise of stock options				0.3	1.4	4.8
Weighted-average fair value of stock options granted				$ 4.78	$ 6.93	$ 9.53
Fair value of shares vested				3.7	3.6	3.2
Tax benefits realized related to stock options exercised	0	0	0
Tax benefits realized related to restricted stock and restricted stock units	$ 0	$ 0	$ 0