Segment Information (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2020 USD ($) segment	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Financial information with respect to reportable segments
Number of reportable segments | segment									5
Operating revenues and earnings (losses) from unconsolidated affiliates:
Total operating revenues	$ 443,396	$ 438,352	$ 533,931	$ 718,364	$ 714,261	$ 758,076	$ 771,406	$ 799,640	$ 2,134,043	$ 3,043,383	$ 3,057,619
Reconciliation of segment adjusted operating income (loss) to net income (loss) from continuing operations before income taxes:
Adjusted operating income (loss)									(171,461)	89,145	58,621
Earnings (losses) from unconsolidated affiliates										(5)	1
Investment income (loss)									1,438	10,218	(9,499)
Interest expense									(206,274)	(204,311)	(227,124)
(Gain)/loss on debt buybacks and exchanges									228,274	11,468	(5,268)
Impairments and other charges									(410,631)	(301,939)	(139,178)
Other, net									(28,567)	(33,224)	(29,532)
Income (loss) from continuing operations before income taxes									(705,567)	(588,922)	(518,794)
Depreciation and amortization:
Depreciation and amortization									853,699	876,091	866,870
Capital expenditures
Capital expenditures									189,706	423,967	453,435
ASSETS
Total assets	5,503,428				6,760,658				5,503,428	6,760,658
Operating segment
Reconciliation of segment adjusted operating income (loss) to net income (loss) from continuing operations before income taxes:
Adjusted operating income (loss)									(171,461)	89,145	58,621
Other reconciling items
Operating revenues and earnings (losses) from unconsolidated affiliates:
Total operating revenues									(46,829)	(102,985)	(120,876)
Reconciliation of segment adjusted operating income (loss) to net income (loss) from continuing operations before income taxes:
Adjusted operating income (loss)									(118,346)	(160,274)	(166,815)
Depreciation and amortization:
Depreciation and amortization									(2,383)	8,758	4,461
Capital expenditures
Capital expenditures									251	(5,676)	2,592
ASSETS
Total assets	443,153				666,731				443,153	666,731
U.S. Drilling | Operating segment
Operating revenues and earnings (losses) from unconsolidated affiliates:
Total operating revenues									713,057	1,240,936	1,083,227
Reconciliation of segment adjusted operating income (loss) to net income (loss) from continuing operations before income taxes:
Adjusted operating income (loss)									(96,176)	64,313	(21,298)
Depreciation and amortization:
Depreciation and amortization									398,326	419,680	394,586
Capital expenditures
Capital expenditures									44,606	184,705	222,338
ASSETS
Total assets	1,871,008				2,369,200				1,871,008	2,369,200
Canada Drilling | Operating segment
Operating revenues and earnings (losses) from unconsolidated affiliates:
Total operating revenues									54,753	68,274	105,000
Reconciliation of segment adjusted operating income (loss) to net income (loss) from continuing operations before income taxes:
Adjusted operating income (loss)									(11,766)	(14,483)	(6,166)
Depreciation and amortization:
Depreciation and amortization									24,784	29,766	37,172
Capital expenditures
Capital expenditures									2,018	5,020	12,981
ASSETS
Total assets	174,123				202,706				174,123	202,706
International Drilling | Operating segment
Operating revenues and earnings (losses) from unconsolidated affiliates:
Total operating revenues									1,131,673	1,324,142	1,469,038
Reconciliation of segment adjusted operating income (loss) to net income (loss) from continuing operations before income taxes:
Adjusted operating income (loss)									(56,205)	(8,903)	74,221
Depreciation and amortization:
Depreciation and amortization									377,599	372,883	383,227
Capital expenditures
Capital expenditures									127,888	209,728	172,565
ASSETS
Total assets	2,688,912				2,979,494				2,688,912	2,979,494
Drilling Solutions | Operating segment
Operating revenues and earnings (losses) from unconsolidated affiliates:
Total operating revenues									149,834	252,790	250,242
Reconciliation of segment adjusted operating income (loss) to net income (loss) from continuing operations before income taxes:
Adjusted operating income (loss)									6,167	59,465	37,626
Depreciation and amortization:
Depreciation and amortization									40,074	32,289	31,037
Capital expenditures
Capital expenditures									12,306	23,598	30,709
ASSETS
Total assets	100,278				218,004				100,278	218,004
Rig Technologies | Operating segment
Operating revenues and earnings (losses) from unconsolidated affiliates:
Total operating revenues									131,555	260,226	270,988
Reconciliation of segment adjusted operating income (loss) to net income (loss) from continuing operations before income taxes:
Adjusted operating income (loss)									(13,481)	(11,247)	(25,762)
Depreciation and amortization:
Depreciation and amortization									15,299	12,715	16,387
Capital expenditures
Capital expenditures									2,637	6,592	$ 12,250
ASSETS
Total assets	$ 225,954				$ 324,523				$ 225,954	$ 324,523