Segments and Geographic Area Analysis - Revenues from Contract Drilling Services by Equipment Type (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting Information [Line Items]
Contract drilling	$ 357,683	$ 339,636	$ 1,113,410	$ 1,140,568
Revenues related to reimbursable expenses	8,340	9,542	26,128	67,900
Total revenues	366,023	349,178	1,139,538	1,208,468
Ultra-Deepwater Rigs [Member]
Segment Reporting Information [Line Items]
Contract drilling	275,859	217,275	801,859	757,338
Deepwater [Member]
Segment Reporting Information [Line Items]
Contract drilling	35,634	66,011	170,482	192,319
Mid-Water [Member]
Segment Reporting Information [Line Items]
Contract drilling	39,616	56,350	124,444	160,716
Total Floaters [Member]
Segment Reporting Information [Line Items]
Contract drilling	351,109	$ 339,636	1,096,785	1,110,373
Jack-ups [Member]
Segment Reporting Information [Line Items]
Contract drilling	$ 6,574		$ 16,625	$ 30,195

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=63488584&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=68075638&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.

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