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Estimated Useful Lives of Property and Equipment (Detail) | 12 Months Ended
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Dec. 31, 2012
Drilling Rigs and Other Equipment | Minimum |
Property, Plant and Equipment [Line Items] |
Property, Plant and Equipment, Useful Life | 1 year 3 months
Drilling Rigs and Other Equipment | Maximum |
Property, Plant and Equipment [Line Items] |
Property, Plant and Equipment, Useful Life | 15 years
Buildings | Minimum |
Property, Plant and Equipment [Line Items] |
Property, Plant and Equipment, Useful Life | 15 years
Buildings | Maximum |
Property, Plant and Equipment [Line Items] |
Property, Plant and Equipment, Useful Life | 20 years
Other | Minimum |
Property, Plant and Equipment [Line Items] |
Property, Plant and Equipment, Useful Life | 3 years
Other | Maximum |
Property, Plant and Equipment [Line Items] |
Property, Plant and Equipment, Useful Life | 12 years

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- Details
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- Definition Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. + References No definition available. + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration