Parker Wellbore Quarterly report pursuant to Section 13 or 15(d)

Income Tax Benefit/Expense - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Income Tax Expense Benefit [Line Items]
Income tax expense	$ 6,695,000	$ 15,042,000	$ 31,155,000	$ 33,345,000
Reduction in pre-tax earnings	$ 17,500,000	$ 35,700,000

The sum of the current income tax expense or benefit and the deferred income tax expense or benefit pertaining to continuing operations.