Segments and Geographic Area Analysis - Additional Information (Detail)	12 Months Ended
Dec. 31, 2017 Country Segment	Dec. 31, 2016 Country	Dec. 31, 2015 Country
Segment Reporting Information [Line Items]
Number of reportable segments \| Segment	1
Number of countries with rigs	4
Geographic Concentration Risk [Member] \| Contract Drilling Revenues [Member]
Segment Reporting Information [Line Items]
Concentration risk benchmark	Individual international country may, from time to time, comprise a material percentage of our total contract drilling revenues
Concentration risk percentage	5.00%	5.00%	5.00%
Geographic Concentration Risk [Member] \| Long-lived Tangible Assets [Member]
Segment Reporting Information [Line Items]
Concentration risk benchmark	No other countries had more than a 5% concentration
Concentration risk percentage	5.00%	5.00%	5.00%
Number of other Countries	0	0	0
Customer Concentration Risk [Member] \| Revenues [Member]
Segment Reporting Information [Line Items]
Concentration risk benchmark	Contributed more than 10% of our total revenues
Concentration risk percentage	10.00%	10.00%	10.00%

Number of countries where we have rigs currently operating or in the process of mobilizing thereto.

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Number of other countries with more than 5 % concentration of assets.

+ References

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Identifies or describes the benchmark that serves as the denominator in the calculation of the percentage of concentration risk.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
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-Section 50
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-URI http://asc.fasb.org/extlink&oid=84177426&loc=d3e6351-108592

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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=84177426&loc=d3e6351-108592

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Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

No definition available.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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