Long-Term Debt - Additional Information (Detail) (USD $)	12 Months Ended	1 Months Ended			12 Months Ended								12 Months Ended		1 Months Ended	12 Months Ended					12 Months Ended							12 Months Ended			1 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 22, 2011 Senior credit facility	Apr. 20, 2011 Senior credit facility	Feb. 23, 2011 Senior credit facility	Dec. 31, 2011 Senior credit facility	Oct. 31, 2011 Senior credit facility	Apr. 30, 2011 Senior credit facility	Mar. 15, 2011 Senior credit facility	Dec. 31, 2010 Senior credit facility	Dec. 31, 2009 Senior credit facility	Dec. 31, 2011 Senior credit facility LIBOR	Dec. 31, 2011 Senior credit facility Eurodollar Rate	Dec. 31, 2011 Senior credit facility Senior Floating Rate Notes Due 2014 Not Refinanced	Dec. 31, 2011 Senior credit facility Secured Debt	Mar. 31, 2011 Other notes payable Drilling rig fleet and related oil field services equipment	Dec. 31, 2011 Other notes payable Mortgage	Dec. 31, 2011 Senior Floating Rate Notes due 2014	Dec. 31, 2010 Senior Floating Rate Notes due 2014	Dec. 31, 2009 Senior Floating Rate Notes due 2014	Dec. 31, 2011 Senior Floating Rate Notes due 2014 Fixed to Floating Interest Rate Swap April 1st 2011 Through April 1st 2013	Dec. 31, 2011 8.625% Senior Notes due 2015	Apr. 30, 2011 8.625% Senior Notes due 2015	Mar. 31, 2011 8.625% Senior Notes due 2015	Mar. 01, 2011 8.625% Senior Notes due 2015	Mar. 31, 2011 8.625% Senior Notes due 2015 Tendered by March 14, 2011	Mar. 31, 2011 8.625% Senior Notes due 2015 Tendered After March 14, 2011	Mar. 31, 2011 8.625% Senior Notes due 2015 Note Redeemed On April 1, 2011	Dec. 31, 2011 9.875% Senior Notes due 2016	Dec. 31, 2011 8.0% Senior Notes due 2018	Dec. 31, 2011 8.75% Senior Notes due 2020	Mar. 31, 2011 7.5% Senior Notes due 2021	Dec. 31, 2011 7.5% Senior Notes due 2021
Debt Disclosure [Line Items]
Senior Notes issued																															$ 900,000,000	$ 900,000,000
Long-term debt, interest rate above LIBOR																	3.625%
Net proceeds from Senior Notes issued																															880,600,000	880,600,000
Long-term debt, maturity date					Apr. 15, 2014								Jan. 31, 2014			Nov. 15, 2022	Apr. 01, 2014											May 15, 2016	Jun. 01, 2018	Jan. 15, 2020		Mar. 15, 2021
Long-term debt, fixed interest rate																6.08%					8.625%							9.875%	8.00%	8.75%		7.50%
Long-term debt, average annual interest rates					2.69%				2.70%	2.33%							3.93%	3.97%	4.57%
Long-term debt, redemption description																																Prior to March 15, 2016, the 7.5% Senior Notes are redeemable, in whole or in part, at a specified redemption price plus accrued and unpaid interest. On or after March 15, 2016, the 7.5% Senior Notes are redeemable, in whole or in part, prior to their maturity at other various specified redemption prices. The notes are jointly and severally guaranteed unconditionally, in full, on an unsecured basis by certain of the Company’s wholly owned subsidiaries.
Long-term debt, issuance date																					2008-05							2009-05	2008-05	2009-12	2011-03
Aggregate senior notes outstanding principal amount																								650,000,000
Long-term debt maturity term					Senior Credit Facility. The senior credit facility is available to be drawn on subject to limitations based on its terms and certain financial covenants. The senior credit facility matures on April 15, 2014, unless the Company’s Senior Floating Rate Notes due 2014 (the “Senior Floating Rate Notes”) have not been refinanced by December 31, 2013, in which case the senior credit facility will mature on January 31, 2014.
Long-term debt, ratio of current assets to current liabilities					1.0
Long-term debt, guarantee					The obligations under the senior credit facility are guaranteed by certain Company subsidiaries and are secured by first priority liens on all shares of capital stock of each of the Company’s material present and future subsidiaries; all intercompany debt of the Company; and substantially all of the Company’s assets, including proved oil and natural gas reserves representing at least 80% of the discounted present value (as defined in the senior credit facility) of proved oil and natural gas reserves considered by the lenders in determining the borrowing base for the senior credit facility.
Long-term debt, interest rate determination reference					(a) the London Interbank Offered Rate (“LIBOR”) plus an applicable margin between 2.00% and 3.00% per annum or (b) the “base rate,” which is the highest of (i) the federal funds rate plus 0.5%, (ii) the prime rate published by Bank of America or (iii) the Eurodollar rate (as defined in the senior credit facility) plus 1.00% per annum, plus, in each case under scenario (b), an applicable margin between 1.00% and 2.00% per annum. Interest is payable quarterly for base rate loans and at the applicable maturity date for LIBOR loans, except that if the interest period for a LIBOR loan is six months, interest is paid at the end of each three-month period.
Long-term debt, interest rate in addition to federal funds rate					0.50%
Long-term debt, amendment description		On December 22, 2011, the senior credit facility was further amended to establish that, for any fiscal quarter ending prior to March 31, 2013, if the ratio of the Company's secured indebtedness to EBITDA is less than 1.5:1.0, then compliance with the Company’s Consolidated Leverage Ratio covenant is not required. Terms capitalized in the preceding sentence have the meaning given to them in the senior credit facility agreement, as amended.	On April 20, 2011, the senior credit facility was amended to permit the Company to pay cash dividends on its 7.0% convertible perpetual preferred stock.	On February 23, 2011, the senior credit facility was amended to, among other things, (a) exclude from the calculation of Consolidated Net Income the net income (loss) of a Royalty Trust, except to the extent of cash distributions received by the Company, (b) establish that an investment in a Royalty Trust and dispositions to, and of interests in, Royalty Trusts are permitted, (c) clarify that a Royalty Trust is not a Subsidiary, (d) allow the Company to net against its calculation of Consolidated Funded Indebtedness cash balances exceeding $10.0 million in the event no loans are outstanding under the senior credit facility at that time and (e) establish that, for any fiscal quarter ending prior to March 31, 2012, if the ratio of the Company’s secured indebtedness to EBITDA is less than 1.5:1.0, then compliance with the Company’s Consolidated Leverage Ratio covenant is not required. Terms capitalized in the preceding sentence have the meaning given to them in the senior credit facility agreement, as amended.
Threshold cash balances must exceed to be net against the calculation of consolidated funded indebtedness				10,000,000	10,000,000
Long-term debt, senior secured leverage ratio				1.5	1.5
Long-term debt, financial covenants	As of December 31, 2011, the senior credit facility contained financial covenants, including maintaining agreed levels for the (i) ratio of total funded debt to EBITDA, which may not exceed 4.5:1.0 at each quarter end, calculated using the last four completed fiscal quarters, unless, for any quarter ending prior to March 31, 2013, the ratio of the Company’s secured indebtedness to EBITDA is less than 1.5:1.0, calculated using the last four completed fiscal quarters, (ii) ratio of current assets to current liabilities, which must be at least 1.0:1.0 at each quarter end (in the current ratio calculation (as defined in the senior credit facility), any amounts available to be drawn under the senior credit facility are included in current assets, and unrealized assets and liabilities resulting from mark-to-market adjustments on the Company’s derivative contracts are disregarded) and (iii) ratio of the Company’s secured indebtedness to EBITDA, which may not exceed 2.0:1.0 at each quarter end, calculated using the last four completed fiscal quarters.
Minimum collateral amount of proved oil and gas reserves representing the discounted present value of reserves used in borrowing base determination	80.00%
Long-term debt, financial covenants compliance					As of September 30, 2011, the senior credit facility contained financial covenants, including maintaining agreed levels for the (i) ratio of total funded debt to EBITDA, which may not exceed 4.5:1.0 at each quarter end, calculated using the last four completed fiscal quarters, unless, for any quarter ending prior to March 31, 2012, the ratio of the Company’s secured indebtedness to EBITDA is less than 1.5:1.0, calculated using the last four completed fiscal quarters, (ii) ratio of current assets to current liabilities, which must be at least 1.0:1.0 at each quarter end (in the current ratio calculation (as defined in the senior credit facility), any amounts available to be drawn under the senior credit facility are included in current assets, and unrealized assets and liabilities resulting from mark-to-market adjustments on the Company’s derivative contracts are disregarded) and (iii) ratio of the Company’s secured indebtedness to EBITDA, which may not exceed 2.0:1.0 at each quarter end, calculated using the last four completed fiscal quarters.
Long-term debt, debt to EBITDA ratio maximum					4.5									1.5
Long-term debt, interest rate, minimum applicable margin					1.00%						2.00%
Long-term debt, interest rate, maximum applicable margin					2.00%						3.00%
Long-term debt, interest rate, applicable margin												1.00%
Long-term debt, borrowing base								850,000,000
Long-term debt, amended borrowing base						790,000,000	790,000,000	790,000,000
Long-term debt, additional costs as a result of amendments to the credit agreement and changes to the borrowing base					900,000
Senior credit facility, outstanding	0
Letters of credit, outstanding	28,500,000
Other Notes Payable, principal balance paid															4,300,000
Long-term debt, quarterly installment of principal and interest																500,000
Long-term debt, notional interest rate swap to fix variable interest rate																	350,000,000
Long-term debt, fixed rate of interest rate swap																				6.69%
Debt issuance costs																	9,400,000											7,900,000	16,000,000	9,700,000	19,400,000
Cash tender to purchase outstanding aggregate principal amount, total consideration per $1,000 principal amount																									1,046.88	1,016.88	1,043.13
Aggregate senior notes outstanding principal amount purchased																						35,800,000	614,200,000
Percentage of aggregate senior notes outstanding principal amount purchased																							94.50%
Loss on extinguishment of debt	$ (38,232,000)																				$ (38,232,000)
Debt, redeemable period																																Mar. 15, 2016