Business Segments - Income (loss) from Continuing Operations Before Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income (loss)	$ 497,361		$ 525,601		$ 200,925
Net gain on asset disposals	33,806	[1]	4,999	[1]	22,812	[1]
Interest income	554		187		1,674
Interest expense	(22,750)		(15,652)		(12,772)
Other	508		582		927
Income from continuing operations before income taxes	475,673		510,718		190,754
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income (loss)	509,398		563,505		215,132
Operating Segments | Contract Drilling
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income (loss)	349,393		346,083		140,483
Operating Segments | Pressure Pumping
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income (loss)	132,795		193,440		62,194
Operating Segments | Oil and Natural Gas
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income (loss)	27,210		23,982		12,455
Corporate and other
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income (loss)	$ (45,843)		$ (42,903)		$ (37,019)

[1] Net gains or losses associated with the disposal of assets relate to corporate strategy decisions of the executive management group. Accordingly, the related gains or losses have been separately presented and excluded from the results of specific segments.