Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Operating revenues	$ 460,511	$ 718,364
U.S. Drilling
Disaggregation of Revenue [Line Items]
Operating revenues	142,299	274,901
Canada Drilling
Disaggregation of Revenue [Line Items]
Operating revenues	20,989	25,591
International Drilling
Disaggregation of Revenue [Line Items]
Operating revenues	246,838	337,110
Drilling Solutions
Disaggregation of Revenue [Line Items]
Operating revenues	35,706	55,384
Rig Technologies
Disaggregation of Revenue [Line Items]
Operating revenues	25,748	42,150
Other
Disaggregation of Revenue [Line Items]
Operating revenues	(11,069)	(16,772)
Operating segment | Lower 48
Disaggregation of Revenue [Line Items]
Operating revenues	140,521	276,475
Operating segment | U.S. Offshore Gulf Of Mexico
Disaggregation of Revenue [Line Items]
Operating revenues	29,929	42,221
Operating segment | Alaska
Disaggregation of Revenue [Line Items]
Operating revenues	5,708	16,593
Operating segment | Canada Drilling
Disaggregation of Revenue [Line Items]
Operating revenues	22,343	27,932
Operating segment | Middle East & Asia
Disaggregation of Revenue [Line Items]
Operating revenues	186,256	227,768
Operating segment | Latin America
Disaggregation of Revenue [Line Items]
Operating revenues	60,487	87,198
Operating segment | Europe, Africa & CIS
Disaggregation of Revenue [Line Items]
Operating revenues	26,336	56,949
Operating segment | U.S. Drilling
Disaggregation of Revenue [Line Items]
Operating revenues	142,299	274,901
Operating segment | U.S. Drilling | Lower 48
Disaggregation of Revenue [Line Items]
Operating revenues	109,534	220,229
Operating segment | U.S. Drilling | U.S. Offshore Gulf Of Mexico
Disaggregation of Revenue [Line Items]
Operating revenues	27,193	39,056
Operating segment | U.S. Drilling | Alaska
Disaggregation of Revenue [Line Items]
Operating revenues	5,572	15,616
Operating segment | Canada Drilling
Disaggregation of Revenue [Line Items]
Operating revenues	20,989	25,591
Operating segment | Canada Drilling | Canada Drilling
Disaggregation of Revenue [Line Items]
Operating revenues	20,989	25,591
Operating segment | International Drilling
Disaggregation of Revenue [Line Items]
Operating revenues	246,838	337,110
Operating segment | International Drilling | Middle East & Asia
Disaggregation of Revenue [Line Items]
Operating revenues	168,187	201,177
Operating segment | International Drilling | Latin America
Disaggregation of Revenue [Line Items]
Operating revenues	55,908	84,219
Operating segment | International Drilling | Europe, Africa & CIS
Disaggregation of Revenue [Line Items]
Operating revenues	22,743	51,714
Operating segment | Drilling Solutions
Disaggregation of Revenue [Line Items]
Operating revenues	35,706	55,384
Operating segment | Drilling Solutions | Lower 48
Disaggregation of Revenue [Line Items]
Operating revenues	18,448	35,715
Operating segment | Drilling Solutions | U.S. Offshore Gulf Of Mexico
Disaggregation of Revenue [Line Items]
Operating revenues	2,736	3,165
Operating segment | Drilling Solutions | Alaska
Disaggregation of Revenue [Line Items]
Operating revenues	136	986
Operating segment | Drilling Solutions | Canada Drilling
Disaggregation of Revenue [Line Items]
Operating revenues	454	729
Operating segment | Drilling Solutions | Middle East & Asia
Disaggregation of Revenue [Line Items]
Operating revenues	8,991	11,037
Operating segment | Drilling Solutions | Latin America
Disaggregation of Revenue [Line Items]
Operating revenues	4,567	2,827
Operating segment | Drilling Solutions | Europe, Africa & CIS
Disaggregation of Revenue [Line Items]
Operating revenues	374	925
Operating segment | Rig Technologies
Disaggregation of Revenue [Line Items]
Operating revenues	25,748	42,150
Operating segment | Rig Technologies | Lower 48
Disaggregation of Revenue [Line Items]
Operating revenues	12,539	20,531
Operating segment | Rig Technologies | Alaska
Disaggregation of Revenue [Line Items]
Operating revenues		(9)
Operating segment | Rig Technologies | Canada Drilling
Disaggregation of Revenue [Line Items]
Operating revenues	900	1,612
Operating segment | Rig Technologies | Middle East & Asia
Disaggregation of Revenue [Line Items]
Operating revenues	9,078	15,554
Operating segment | Rig Technologies | Latin America
Disaggregation of Revenue [Line Items]
Operating revenues	12	152
Operating segment | Rig Technologies | Europe, Africa & CIS
Disaggregation of Revenue [Line Items]
Operating revenues	3,219	4,310
Other reconciling items | Other
Disaggregation of Revenue [Line Items]
Operating revenues	(11,069)	(16,772)
Other reconciling items | Other | Other
Disaggregation of Revenue [Line Items]
Operating revenues	(11,069)	(16,772)
Other reconciling items (3)
Disaggregation of Revenue [Line Items]
Operating revenues	$ 11,069	$ 16,772