General Information (Details Textuals) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2011 USD ($)	Jun. 30, 2010 USD ($)	Jun. 30, 2011 USD ($)	Jun. 30, 2010 USD ($)	Dec. 31, 2010 USD ($)	Jul. 21, 2011	Jun. 30, 2011	Jun. 30, 2011 Cold stacked jack-up rigs in U.S. Gulf of Mexico [Member]	Jun. 30, 2011 Independent-leg, cantilevered jack-up rig [Member]	Jun. 30, 2011 Mat-supported jack-up rig [Member]	Jun. 30, 2011 Cold stacked semisubmersible rigs [Member]	Jun. 30, 2011 Cold stacked rigs located in U.S. Gulf of Mexico [Member]	Jun. 30, 2011 Cold stacked rigs located in Malaysia [Member]
Property, Plant and Equipment [Line Items]
Number of cold stacked rigs by type of rig								4	1	3	4	2	2
General Information (Textuals) [Abstract]
Net book value of cold stacked rigs	$ 91.0		$ 91.0		$ 78.0
Outstanding common stock owned by Loews Corporation						50.40%
Construction deposits					154.4
Period considered to treat short-term, highly liquid investments as cash equivalents			Three months or less
Net foreign currency transaction (losses)	(1.6)	(4.0)	(3.2)	(3.5)
Initial term of contracts minimum months			2 months
Initial term of contracts maximum months			60 months
Amount of previously recorded U.S. income tax expense reversed in current period			$ 15.0
Sum and probability of occurrence scenarios			100.00%
Reduction in assumed dayrates for the cold-stacked rigs			5.00%
Number of new drillships	3
Total number of cold stacked rigs					7		8