Segments and Geographic Area Analysis (Details) (USD $) In Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Revenues from contract drilling services by equipment-type
Contract drilling	$ 869,646	$ 811,739	$ 1,658,519	$ 1,656,177
Revenues related to reimbursable expenses	19,850	10,864	37,366	26,107
Total revenues	889,496	822,603	1,695,885	1,682,284
High Specification Floaters [Member]
Revenues from contract drilling services by equipment-type
Contract drilling	452,289	340,387	813,355	724,175
Intermediate Semisubmersibles [Member]
Revenues from contract drilling services by equipment-type
Contract drilling	356,840	389,094	736,339	769,795
Jack-ups [Member]
Revenues from contract drilling services by equipment-type
Contract drilling	60,512	82,223	108,730	162,172
Other [Member]
Revenues from contract drilling services by equipment-type
Contract drilling	$ 5	$ 35	$ 95	$ 35

Repayment received or receivable for expenses incurred on behalf of a client or customer, other than those reimbursements received by landlords from tenants.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 605
-SubTopic 45
-Section 45
-Paragraph 23
-URI http://asc.fasb.org/extlink&oid=6743974&loc=d3e60722-111653

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Revenue from oil and gas-related services including well services (such as drilling, rigs and analytic evaluations), transportation, and other supporting contractor services, during the reporting period.

+ References

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Aggregate revenue recognized during the period (derived from goods sold, services rendered, insurance premiums, or other activities that constitute an entity's earning process). For financial services companies, also includes investment and interest income, and sales and trading gains.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 5
-Section 03
-Paragraph 1

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

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