EARNINGS PER SHARE - Additional Information (Detail) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Earnings Per Share Disclosure [Line Items]
Antidilutive securities excluded from earnings per share computation, shares	0.5	0.2	0.1

Antidilutive Securities Excluded from Earnings Per Share Computation, Amount

No definition available.

Name:	mdr_AntidilutiveSecuritiesExcludedFromEarningsPerShareComputationAmount
Namespace Prefix:	mdr_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant