Segment Information (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		$ 779,425	$ 662,103	$ 2,275,539	$ 1,856,008
Reconciliation of segment adjusted operating income (loss) to net income (loss) from continuing operations before income taxes:
Adjusted income (loss) derived from operating activities		31,728	(33,385)	42,555	(123,900)
Earnings (losses) from unconsolidated affiliates			4	1	6
Investment income (loss)		(1,342)	373	(4,041)	208
Interest expense		(51,415)	(54,607)	(173,393)	(165,813)
Other, net		(22,907)	(5,559)	(114,597)	(29,173)
Income (loss) from continuing operations before income taxes		(83,221)	(133,994)	(375,200)	(442,203)
ASSETS
Total assets (1)	[1]	7,960,547		7,960,547		$ 8,401,984
U.S. Drilling
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		273,996	222,747	779,393	572,025
Canada Drilling
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		26,645	18,073	75,974	63,002
International Drilling
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		377,125	374,106	1,123,956	1,092,667
Drilling Solutions
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		(60,923)	37,506	183,430	96,700
Rig Technologies
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		63,641	50,032	209,631	155,293
Operating segment
Reconciliation of segment adjusted operating income (loss) to net income (loss) from continuing operations before income taxes:
Adjusted income (loss) derived from operating activities		31,728	(33,385)	42,555	(123,900)
Operating segment | U.S. Drilling
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		273,996	222,747	779,393	572,025
Reconciliation of segment adjusted operating income (loss) to net income (loss) from continuing operations before income taxes:
Adjusted income (loss) derived from operating activities		2,578	(53,536)	(30,275)	(172,797)
ASSETS
Total assets (1)		3,078,789		3,078,789		3,203,560
Operating segment | Canada Drilling
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		26,645	18,073	75,974	63,002
Reconciliation of segment adjusted operating income (loss) to net income (loss) from continuing operations before income taxes:
Adjusted income (loss) derived from operating activities		(1,895)	(7,494)	(7,095)	(16,519)
ASSETS
Total assets (1)		318,653		318,653		347,773
Operating segment | International Drilling
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		377,125	374,106	1,123,956	1,092,667
Reconciliation of segment adjusted operating income (loss) to net income (loss) from continuing operations before income taxes:
Adjusted income (loss) derived from operating activities		25,680	32,316	74,702	80,464
ASSETS
Total assets (1)		3,225,052		3,225,052		3,540,829
Operating segment | Drilling Solutions
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		60,923	37,506	183,430	96,700
Reconciliation of segment adjusted operating income (loss) to net income (loss) from continuing operations before income taxes:
Adjusted income (loss) derived from operating activities		9,506	5,864	25,773	8,658
ASSETS
Total assets (1)		229,984		229,984		182,162
Operating segment | Rig Technologies
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		63,641	50,032	209,631	155,293
Reconciliation of segment adjusted operating income (loss) to net income (loss) from continuing operations before income taxes:
Adjusted income (loss) derived from operating activities		(4,141)	(10,535)	(20,550)	(23,706)
ASSETS
Total assets (1)		429,546		429,546		459,665
Other reconciling items (3)
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		22,905	40,361	96,845	123,679
Reconciliation of segment adjusted operating income (loss) to net income (loss) from continuing operations before income taxes:
Adjusted income (loss) derived from operating activities		(39,285)	$ (40,820)	(125,725)	$ (123,531)
ASSETS
Total assets (1)		$ 678,523		$ 678,523		$ 667,995

[1] The condensed consolidated balance sheet as of September 30, 2018 and December 31, 2017 include assets and liabilities of variable interest entities. See Note 3—Joint Ventures for additional information.