Business Segments - Income (Loss) from Continuing Operations Before Income Taxes (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Operating income (loss)		$ (80,281)	$ (38,016)	$ (111,387)	$ (270,891)
Other operating income, net	[1]	771	3,791	10,321	18,501
Interest income		817	101	4,600	1,149
Interest expense		(12,376)	(9,584)	(38,668)	(26,929)
Other		281	78	666	226
Loss before income taxes		(91,559)	(47,421)	(144,789)	(296,445)
Other Operations
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Operating income (loss)		(4,861)	(6,516)	(13,727)	(13,030)
Corporate
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Operating income (loss)		(23,005)	(31,735)	(70,876)	(119,483)
Operating Segments | Contract Drilling
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Operating income (loss)		(42,704)	(20,397)	(60,058)	(155,465)
Operating Segments | Pressure Pumping
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Operating income (loss)		(1,487)	$ 16,841	44,539	$ (1,414)
Operating Segments | Directional Drilling
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Operating income (loss)		$ (8,995)		$ (21,586)

[1] Other operating income, net includes net gains associated with the disposal of assets related to corporate strategy decisions of the executive management group. Accordingly, the related gains have been excluded from the operating results of specific segments. This caption also includes certain legal-related expenses and settlements, net of insurance reimbursements.