Segment Information (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		$ 734,194	$ 562,550
Reconciliation of segment adjusted operating income (loss) to net income (loss) from continuing operations before income taxes:
Adjusted income (loss) derived from operating activities		(57)	(64,328)
Earnings (losses) from unconsolidated affiliates		2	2
Investment income (loss)		465	721
Interest expense		(61,386)	(56,518)
Other, net		(14,089)	(13,510)
Income (loss) from continuing operations before income taxes		(120,042)	(173,237)
ASSETS
Total assets	[1]	8,299,830		$ 8,401,984
U.S. Drilling
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		241,002	161,934
Canada Drilling
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		31,887	27,808
International Drilling
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		368,845	338,223
Drilling Solutions
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		(62,648)	27,365
Rig Technologies
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		64,669	44,076
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		(57)	(64,328)
Operating segment | U.S. Drilling
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		241,002	161,934
Reconciliation of segment adjusted operating income (loss) to net income (loss) from continuing operations before income taxes:
Adjusted income (loss) derived from operating activities		(19,746)	(63,182)
ASSETS
Total assets		3,152,505		3,203,560
Operating segment | Canada Drilling
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		31,887	27,808
Reconciliation of segment adjusted operating income (loss) to net income (loss) from continuing operations before income taxes:
Adjusted income (loss) derived from operating activities		(592)	(4,011)
ASSETS
Total assets		346,240		347,773
Operating segment | International Drilling
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		368,845	338,223
Reconciliation of segment adjusted operating income (loss) to net income (loss) from continuing operations before income taxes:
Adjusted income (loss) derived from operating activities		24,536	11,974
ASSETS
Total assets		3,517,325		3,540,829
Operating segment | Drilling Solutions
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		62,648	27,365
Reconciliation of segment adjusted operating income (loss) to net income (loss) from continuing operations before income taxes:
Adjusted income (loss) derived from operating activities		8,721	(978)
ASSETS
Total assets		192,276		182,162
Operating segment | Rig Technologies
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		64,669	44,076
Reconciliation of segment adjusted operating income (loss) to net income (loss) from continuing operations before income taxes:
Adjusted income (loss) derived from operating activities		(12,976)	(8,131)
ASSETS
Total assets		461,216		459,665
Other reconciling items (3)
Operating revenues and earnings (losses) from unconsolidated affiliates:
Revenue		34,857	36,856
Reconciliation of segment adjusted operating income (loss) to net income (loss) from continuing operations before income taxes:
Adjusted income (loss) derived from operating activities		(44,977)	$ (39,604)
ASSETS
Total assets		$ 630,268		$ 667,995

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