Segments and Geographic Area Analysis - Summary of Information about Disaggregated Revenue by Primary Geographical Market (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
Total revenues	$ 216,706	$ 268,861	$ 450,248	$ 564,371
Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues	207,273	265,353	433,970	553,279
Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues	9,433	3,508	16,278	11,092
United States [Member]
Segment Reporting Information [Line Items]
Total revenues	119,026	163,374	259,606	329,950
United States [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues	117,423	162,202	256,055	326,641
United States [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues	1,603	1,172	3,551	3,309
South America [Member]
Segment Reporting Information [Line Items]
Total revenues	29,116	26,288	82,429	80,557
South America [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues	29,139	26,288	82,423	80,556
South America [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues	(23)		6	1
Europe [Member]
Segment Reporting Information [Line Items]
Total revenues	42,343	20,480	68,858	33,250
Europe [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues	39,413	18,738	64,022	30,130
Europe [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues	2,930	1,742	4,836	3,120
Australia [Member]
Segment Reporting Information [Line Items]
Total revenues	26,221		39,355
Australia [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues	21,298		31,470
Australia [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues	$ 4,923		$ 7,885
Australia/Asia [Member]
Segment Reporting Information [Line Items]
Total revenues		58,719		120,614
Australia/Asia [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues		58,125		115,952
Australia/Asia [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues		$ 594		$ 4,662