Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Operating revenues	$ 524,165	$ 438,352	$ 1,474,009	$ 1,690,647
U.S. Drilling
Disaggregation of Revenue [Line Items]
Operating revenues	173,441	130,243	477,346	578,928
Canada Drilling
Disaggregation of Revenue [Line Items]
Operating revenues	6,034	10,774	39,336	39,929
International Drilling
Disaggregation of Revenue [Line Items]
Operating revenues	270,008	248,392	772,128	886,580
Drilling Solutions
Disaggregation of Revenue [Line Items]
Operating revenues	45,880	29,324	120,697	117,837
Rig Technologies
Disaggregation of Revenue [Line Items]
Operating revenues	42,053	28,466	102,353	104,198
Other
Disaggregation of Revenue [Line Items]
Operating revenues	(13,251)	(8,847)	(37,851)	(36,825)
Operating segment | Lower 48
Disaggregation of Revenue [Line Items]
Operating revenues	176,596	122,422	475,362	559,143
Operating segment | U.S. Offshore Gulf Of Mexico
Disaggregation of Revenue [Line Items]
Operating revenues	36,697	28,954	101,414	109,725
Operating segment | Alaska
Disaggregation of Revenue [Line Items]
Operating revenues	5,903	6,935	19,086	32,085
Operating segment | Canada
Disaggregation of Revenue [Line Items]
Operating revenues	7,420	11,476	43,663	43,635
Operating segment | Middle East & Asia
Disaggregation of Revenue [Line Items]
Operating revenues	211,167	200,582	594,796	648,741
Operating segment | Latin America
Disaggregation of Revenue [Line Items]
Operating revenues	76,256	44,798	200,495	182,220
Operating segment | Europe, Africa & CIS
Disaggregation of Revenue [Line Items]
Operating revenues	23,377	32,032	77,044	151,923
Operating segment | U.S. Drilling
Disaggregation of Revenue [Line Items]
Operating revenues	173,441	130,243	477,346	578,928
Operating segment | U.S. Drilling | Lower 48
Disaggregation of Revenue [Line Items]
Operating revenues	132,639	96,433	363,536	445,478
Operating segment | U.S. Drilling | U.S. Offshore Gulf Of Mexico
Disaggregation of Revenue [Line Items]
Operating revenues	35,063	26,943	95,222	102,681
Operating segment | U.S. Drilling | Alaska
Disaggregation of Revenue [Line Items]
Operating revenues	5,739	6,867	18,588	30,769
Operating segment | Canada Drilling
Disaggregation of Revenue [Line Items]
Operating revenues	6,034	10,774	39,336	39,929
Operating segment | Canada Drilling | Canada
Disaggregation of Revenue [Line Items]
Operating revenues	6,034	10,774	39,336	39,929
Operating segment | International Drilling
Disaggregation of Revenue [Line Items]
Operating revenues	270,008	248,392	772,128	886,580
Operating segment | International Drilling | Middle East & Asia
Disaggregation of Revenue [Line Items]
Operating revenues	179,617	176,617	522,142	571,108
Operating segment | International Drilling | Latin America
Disaggregation of Revenue [Line Items]
Operating revenues	70,692	43,881	184,531	177,800
Operating segment | International Drilling | Europe, Africa & CIS
Disaggregation of Revenue [Line Items]
Operating revenues	19,699	27,894	65,455	137,672
Operating segment | Drilling Solutions
Disaggregation of Revenue [Line Items]
Operating revenues	45,880	29,324	120,697	117,837
Operating segment | Drilling Solutions | Lower 48
Disaggregation of Revenue [Line Items]
Operating revenues	26,917	15,769	66,801	70,805
Operating segment | Drilling Solutions | U.S. Offshore Gulf Of Mexico
Disaggregation of Revenue [Line Items]
Operating revenues	1,634	2,011	6,192	7,044
Operating segment | Drilling Solutions | Alaska
Disaggregation of Revenue [Line Items]
Operating revenues	163	66	484	1,296
Operating segment | Drilling Solutions | Canada
Disaggregation of Revenue [Line Items]
Operating revenues	340	187	998	995
Operating segment | Drilling Solutions | Middle East & Asia
Disaggregation of Revenue [Line Items]
Operating revenues	10,872	10,096	29,320	31,630
Operating segment | Drilling Solutions | Latin America
Disaggregation of Revenue [Line Items]
Operating revenues	5,564	902	15,788	4,284
Operating segment | Drilling Solutions | Europe, Africa & CIS
Disaggregation of Revenue [Line Items]
Operating revenues	390	293	1,114	1,783
Operating segment | Rig Technologies
Disaggregation of Revenue [Line Items]
Operating revenues	42,053	28,466	102,353	104,198
Operating segment | Rig Technologies | Lower 48
Disaggregation of Revenue [Line Items]
Operating revenues	17,040	10,220	45,025	42,860
Operating segment | Rig Technologies | Alaska
Disaggregation of Revenue [Line Items]
Operating revenues	1	2	14	20
Operating segment | Rig Technologies | Canada
Disaggregation of Revenue [Line Items]
Operating revenues	1,046	515	3,329	2,711
Operating segment | Rig Technologies | Middle East & Asia
Disaggregation of Revenue [Line Items]
Operating revenues	20,678	13,869	43,334	46,003
Operating segment | Rig Technologies | Latin America
Disaggregation of Revenue [Line Items]
Operating revenues		15	176	136
Operating segment | Rig Technologies | Europe, Africa & CIS
Disaggregation of Revenue [Line Items]
Operating revenues	3,288	3,845	10,475	12,468
Other reconciling items | Other
Disaggregation of Revenue [Line Items]
Operating revenues	(13,251)	(8,847)	(37,851)	(36,825)
Other reconciling items | Other | Other
Disaggregation of Revenue [Line Items]
Operating revenues	(13,251)	(8,847)	(37,851)	(36,825)
Other reconciling items (3)
Disaggregation of Revenue [Line Items]
Operating revenues	$ 13,251	$ 8,847	$ 37,851	$ 36,825