Bill Barrett (BBG) 10-K 2 Mar 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2015	Feb. 02, 2016	Jun. 30, 2015
Document Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	FY
Trading Symbol	BBG
Entity Registrant Name	BILL BARRETT CORPORATION
Entity Central Index Key	1,172,139
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		49,854,697
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 419,405,504

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 128,836	$ 165,904
Accounts receivable, net of allowance for doubtful accounts	43,461	112,209
Derivative assets	99,809	145,226
Prepayments and other current assets	2,211	2,766
Total current assets	274,317	426,105
Property and equipment - at cost, successful efforts method for oil and gas properties:
Proved oil and gas properties	2,000,210	2,009,292
Unproved oil and gas properties, excluded from amortization	79,198	148,834
Oil and gas properties held for sale, net of amortization and impairment	0	9,234
Furniture, equipment and other	26,021	39,963
Property, plant and equipment, gross	2,105,429	2,207,323
Accumulated depreciation, depletion, amortization and impairment	(934,745)	(454,202)
Total property and equipment, net	1,170,684	1,753,121
Deferred income tax asset	38,219	0
Derivative assets	19,662	49,750
Deferred financing costs and other noncurrent assets	12,347	15,508
Total	1,515,229	2,244,484
Current liabilities:
Accounts payable and accrued liabilities	64,337	126,252
Amounts payable to oil and gas property owners	15,657	19,187
Production taxes payable	26,578	38,060
Deferred income taxes	38,219	55,418
Current portion of long-term debt	440	25,770
Total current liabilities	145,231	264,687
Long-term debt	803,361	803,222
Asset retirement obligations	14,066	21,592
Liabilities associated with assets held for sale	0	146
Deferred income taxes	0	122,350
Derivatives and other noncurrent liabilities	3,155	2,999
Stockholders' equity:
Common stock, $0.001 par value; authorized 150,000,000 shares; 49,864,512 and 49,526,637 shares issued and outstanding at December 31, 2015 and 2014, respectively, with 1,471,508 and 1,407,141 shares subject to restrictions, respectively	48	48
Additional paid-in capital	921,318	913,619
Retained earnings (Accumulated deficit)	(371,950)	115,821
Treasury stock, at cost: zero shares at December 31, 2015 and 2014, respectively	0	0
Accumulated other comprehensive income		0
Total stockholders' equity	549,416	1,029,488
Total	$ 1,515,229	$ 2,244,484

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	49,864,512	49,526,637
Common stock, shares outstanding	49,864,512	49,526,637
Common stock, shares subject to restrictions	1,471,508	1,407,141
Treasury stock, shares	0	0

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating and Other Revenues:
Oil, gas and NGL production	$ 204,537	$ 464,137	$ 565,555
Other	3,355	8,154	2,538
Total operating and other revenues	207,892	472,291	568,093
Operating Expenses:
Lease operating expense	42,753	60,308	70,217
Gathering, transportation and processing expense	3,482	35,437	67,269
Production tax expense	12,197	31,333	27,172
Exploration expense	153	453	337
Impairment, dry hole costs and abandonment expense	575,310	46,881	238,398
(Gain) loss on divestitures	1,745	100,407	0
Depreciation, depletion and amortization	205,275	235,805	279,775
Unused commitments	19,099	4,434	0
General and administrative expense	53,890	53,361	64,902
Total operating expenses	913,904	568,419	748,070
Operating Income (Loss)	(706,012)	(96,128)	(179,977)
Other Income and Expense:
Interest and other income	565	1,294	1,646
Interest expense	(65,305)	(69,623)	(88,507)
Commodity derivative gain (loss)	104,147	197,447	(23,068)
Gain (loss) on extinguishment of debt	1,749	0	(21,460)
Total other income and expense	41,156	129,118	(131,389)
Income (Loss) before Income Taxes	(664,856)	32,990	(311,366)
(Provision for) Benefit from Income Taxes	177,085	(17,909)	118,633
Net income (loss)	$ (487,771)	$ 15,081	$ (192,733)
Net Income (Loss) Per Common Share, Basic	$ (10.10)	$ 0.31	$ (4.06)
Net Income (Loss) Per Common Share, Diluted	$ (10.10)	$ 0.31	$ (4.06)
Weighted Average Common Shares Outstanding, Basic	48,303,276	48,010,730	47,496,857
Weighted Average Common Shares Outstanding, Diluted	48,303,276	48,435,725	47,496,857

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net Income (Loss)	$ (487,771)	$ 15,081	$ (192,733)
Other Comprehensive Income (Loss), net of tax:
Effect of derivative financial instruments	0	(669)	(4,663)
Other comprehensive income (loss)	0	(669)	(4,663)
Comprehensive Income (Loss)	$ (487,771)	$ 14,412	$ (197,396)

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Activities:
Net Income (Loss)	$ (487,771)	$ 15,081	$ (192,733)
Adjustments to reconcile to net cash provided by operations:
Depreciation, depletion and amortization	205,275	235,805	279,775
Deferred income taxes	(176,797)	16,644	(117,050)
Impairment, dry hole costs and abandonment expense	575,310	46,881	238,398
Commodity derivative (gain) loss	(104,147)	(197,447)	23,068
Settlements of commodity derivatives	179,652	(1,888)	5,315
Stock compensation and other non-cash charges	10,040	11,352	16,027
Amortization of debt discounts and deferred financing costs	4,624	4,264	5,604
(Gain) loss on extinguishment of debt	(1,749)	0	21,460
(Gain) loss on sale of properties	1,745	100,407	(130)
APIC pool for excess tax benefits related to share-based compensation	0	0	1,259
Change in operating assets and liabilities:
Accounts receivable	20,995	32,163	14,294
Prepayments and other assets	311	1,643	1,394
Accounts payable, accrued and other liabilities	(18,798)	5,119	(35,600)
Amounts payable to oil and gas property owners	(3,530)	(7,132)	9,997
Production taxes payable	(11,482)	(1,175)	(5,813)
Net cash provided by (used in) operating activities	193,678	261,717	265,265
Investing Activities:
Additions to oil and gas properties, including acquisitions	(324,534)	(580,943)	(445,479)
Additions of furniture, equipment and other	(1,223)	(3,658)	(2,254)
Proceeds from sale of properties and other investing activities	123,122	555,296	310,704
Cash paid for short-term investments	(114,883)	0	0
Proceeds from the sale of short-term investments	115,000	0	0
Net cash provided by (used in) investing activities	(202,518)	(29,305)	(137,029)
Financing Activities:
Proceeds from debt	0	165,000	420,000
Principal and redemption premium payments on debt	(25,191)	(283,546)	(576,422)
Proceeds from stock option exercises	0	126	6,385
APIC pool for excess tax benefits related to share-based compensation	0	0	(1,259)
Deferred financing costs and other	(3,037)	(2,683)	(1,790)
Net cash provided by (used in) financing activities	(28,228)	(121,103)	(153,086)
Increase (Decrease) in Cash and Cash Equivalents	(37,068)	111,309	(24,850)
Beginning Cash and Cash Equivalents	165,904	54,595	79,445
Ending Cash and Cash Equivalents	$ 128,836	$ 165,904	$ 54,595

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings (Deficit) [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income [Member]
Balance at Dec. 31, 2012	$ 1,182,775	$ 47	$ 883,923	$ 293,473	$ 0	$ 5,332
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of options, restricted stock activity and shares exchanged for exercise and tax withholding	4,607	1	6,384		(1,778)
APIC pool for excess tax benefits related to share-based compensation	(1,259)		(1,259)
Stock-based compensation	16,991		16,991
Retirement of treasury stock	0		(1,778)		1,778
Net Income (Loss)	(192,733)			(192,733)
Effect of derivative financial instruments, net of taxes	(4,663)					(4,663)
Balance at Dec. 31, 2013	1,005,718	48	904,261	100,740	0	669
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of options, restricted stock activity and shares exchanged for exercise and tax withholding	(2,558)	0	126		(2,684)
Stock-based compensation	11,916		11,916
Retirement of treasury stock	0		(2,684)		2,684
Net Income (Loss)	15,081			15,081
Effect of derivative financial instruments, net of taxes	(669)					(669)
Balance at Dec. 31, 2014	1,029,488	48	913,619	115,821	0	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of options, restricted stock activity and shares exchanged for exercise and tax withholding	(1,173)	0	0		(1,173)
Stock-based compensation	10,468		10,468
Retirement of treasury stock	0		(1,173)		1,173
Settlement of convertible notes	1,596		1,596
Net Income (Loss)	(487,771)			(487,771)
Effect of derivative financial instruments, net of taxes	0
Balance at Dec. 31, 2015	$ 549,416	$ 48	$ 921,318	$ (371,950)	$ 0	$ 0

CONSOLIDATED STATEMENTS OF STO8

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Statement of Stockholders' Equity [Abstract]
Effect of derivative financial instruments, taxes	$ 410	$ 2,802

Organization

Organization	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization Bill Barrett Corporation, a Delaware corporation, together with its wholly-owned subsidiaries (collectively, the "Company") is an independent oil and gas company engaged in the exploration, development and production of oil, natural gas and NGLs. Since its inception in January 2002, the Company has conducted its activities principally in the Rocky Mountain region of the United States.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation. The accompanying Consolidated Financial Statements include the accounts of the Company. These statements have been prepared in accordance with accounting principles generally accepted in the United States of America ("GAAP"). All intercompany accounts and transactions have been eliminated in consolidation. Use of Estimates. In the course of preparing the Company's financial statements in accordance with GAAP, management makes various assumptions, judgments and estimates to determine the reported amount of assets, liabilities, revenues and expenses and in the disclosure of commitments and contingencies. Changes in these assumptions, judgments and estimates will occur as a result of the passage of time and the occurrence of future events and, accordingly, actual results could differ from amounts initially established. Areas requiring the use of assumptions, judgments and estimates relate to the expected cash settlement of the Company's 5% Convertible Senior Notes due 2028 ("Convertible Notes") in computing diluted earnings per share, volumes of oil, natural gas and NGL reserves used in calculating depreciation, depletion and amortization ("DD&A"), the amount of expected future cash flows used in determining possible impairments of oil and gas properties and the amount of future capital costs used in these calculations. Assumptions, judgments and estimates also are required in determining asset retirement obligations, the timing of dry hole costs, impairments of proved and unproved properties, valuing deferred tax assets and estimating fair values of derivative instruments and stock-based payment awards. Short-term Investments. Short-term investments have maturities of more than three months and less than one year. The Company's held-to-maturity securities entered into during 2015 have all matured as of December 31, 2015. Accounts Receivable. Accounts receivable is comprised of the following: As of December 31, 2015 2014 (in thousands) Accrued oil, gas and NGL sales $ 33,594 $ 35,099 Due from joint interest owners 8,373 27,937 Other (1) 1,508 49,187 Allowance for doubtful accounts (14 ) (14 ) Total accounts receivable $ 43,461 $ 112,209 (1) Other includes a receivable of $47.6 million (including $4.7 million due to another industry partner) related to a settlement agreement with the U.S. Department of Interior resulting in the cancellation of certain Cottonwood Gulch natural gas leases during the year ended December 31, 2014. Cash and Cash Equivalents. The Company considers all highly liquid investments with a remaining maturity of three months or less when purchased to be cash equivalents. Oil and Gas Properties. The Company's oil, gas and NGL exploration and production activities are accounted for using the successful efforts method. Under this method, all property acquisition costs and costs of exploratory and development wells are capitalized when incurred, pending determination of whether the well has found proved reserves. If an exploratory well does not find proved reserves, the costs of drilling the well are charged to expense and included within cash flows from investing activities in the Consolidated Statements of Cash Flows. If an exploratory well does find proved reserves, the costs remain capitalized and are included within additions to oil and gas properties within cash flows from investing activities in the Consolidated Statements of Cash Flows when paid. The costs of development wells are capitalized whether proved reserves are added or not. Oil and gas lease acquisition costs are also capitalized. Upon sale or retirement of depreciable or depletable property, the cost and related accumulated DD&A are eliminated from the accounts and the resulting gain or loss is recognized. Other exploration costs, including certain geological and geophysical expenses and delay rentals for oil and gas leases, are charged to expense as incurred. The sale of a partial interest in a proved property is accounted for as a cost recovery and no gain or loss is recognized as long as this treatment does not significantly affect the unit-of-production amortization rate. Maintenance and repairs are charged to expense, and renewals and betterments are capitalized to the appropriate property and equipment accounts. Unproved oil and gas property costs are transferred to proved oil and gas properties if the properties are subsequently determined to be productive or are assigned proved reserves. Proceeds from sales of partial interests in unproved leases are accounted for as a recovery of cost without recognizing any gain until all costs are recovered. Unproved oil and gas properties are assessed periodically for impairment based on remaining lease terms, drilling results, reservoir performance, commodity price outlooks, future plans to develop acreage and other relevant matters. Materials and supplies consist primarily of tubular goods and well equipment to be used in future drilling operations or repair operations and are carried at the lower of cost or market value. The following table sets forth the net capitalized costs and associated accumulated DD&A and non-cash impairments relating to the Company's oil, natural gas and NGL producing activities: As of December 31, 2015 2014 (in thousands) Proved properties $ 320,538 $ 390,482 Wells and related equipment and facilities 1,592,716 1,537,370 Support equipment and facilities 77,785 68,371 Materials and supplies 9,171 13,069 Total proved oil and gas properties $ 2,000,210 $ 2,009,292 Unproved properties 33,336 78,898 Wells and facilities in progress 45,862 69,936 Total unproved oil and gas properties, excluded from amortization $ 79,198 $ 148,834 Assets held for sale — 9,234 Accumulated depreciation, depletion, amortization and impairment (918,510 ) (427,954 ) Total oil and gas properties, net $ 1,160,898 $ 1,739,406 All exploratory wells are evaluated for economic viability within one year of well completion. Exploratory wells that discover potentially economic reserves in areas where a major capital expenditure would be required before production could begin, and where the economic viability of that major capital expenditure depends upon the successful completion of further exploratory work in the area, remain capitalized if the well finds a sufficient quantity of reserves to justify its completion as a producing well and the Company is making sufficient progress assessing the reserves and the economic and operating viability of the project. As of December 31, 2015 and 2014, there were no exploratory well costs that had been capitalized for a period greater than one year since the completion of drilling. The Company reviews proved oil and gas properties on a field-by-field basis for impairment on a quarterly basis or whenever events and circumstances indicate that a decline in the recoverability of their carrying value may have occurred. The Company estimates the expected undiscounted future cash flows of its oil and gas properties and compares such undiscounted future cash flows to the carrying amount of the oil and gas properties to determine if the carrying amount is recoverable. If the carrying value of a property exceeds the undiscounted future cash flows, the Company will impair the carrying value to fair value based on an analysis of quantitative and qualitative factors. The factors used to determine fair value include, but are not limited to, recent sales prices of comparable properties, the present value of future revenues, net of estimated operating and development costs using estimates of reserves, future commodity pricing, future production estimates, anticipated capital expenditures and various discount rates commensurate with the risk and current market conditions associated with realizing the expected cash flows projected. The Company recognized non-cash impairment charges, which were included within impairment, dry hole costs and abandonment expense in the Consolidated Statements of Operations, as follows: Year Ended December 31, 2015 2014 2013 (in thousands) Non-cash impairment of proved oil and gas properties $ 559,282 (1) $ 15,761 (2) $ 206,953 (4) Non-cash impairment of unproved oil and gas properties 13,156 (1) 24,082 (3) 19,598 (4) Non-cash impairment of inventory — 340 — Dry hole costs 123 101 1,124 Abandonment expense 2,749 6,597 10,723 Total non-cash impairment, dry hole costs and abandonment expense $ 575,310 $ 46,881 $ 238,398 (1) Due to the continued decline in oil prices, the Company recognized a non-cash impairment charge associated with the Company's Uinta Oil Program proved and unproved oil and gas properties for the year ended December 31, 2015. (2) As a result of the Powder River Oil Divestiture (see Note 4 ), the carrying values of the remaining properties were analyzed relative to their estimated fair market value. As a result, the Company recognized impairment of $14.8 million . These properties were classified as held for sale as of December 31, 2014. The remaining impairment of $1.0 million related to the West Tavaputs Divestiture (see Note 4 ) based on a true up of previously estimated carrying value. (3) As a result of unfavorable drilling and completion results in the Paradox Basin, the Company recognized an impairment of $11.6 million related to unproved oil and gas properties. In addition, the Company recognized an impairment of $6.1 million related to certain unproved oil and gas properties in the Uinta Basin as a result of having no future plans to evaluate certain acreage positions. The Company recognized an impairment of $6.4 million to unproved oil and gas properties as the result of the Powder River Oil Divestiture discussed in (2) above. (4) As a result of an analysis of remaining carrying values relative to fair market values resulting from the West Tavaputs Divestiture (see Note 4 ), $207.0 million and $2.5 million of proved and unproved property impairment, respectively, was incurred during the year ended December 31, 2013. As a result of having no future plans to evaluate remaining acreage and estimated market value below carrying value within various exploration projects, an additional $17.1 million of unproved property impairment was incurred during the year ended December 31, 2013. The provision for DD&A of oil and gas properties is calculated on a field-by-field basis using the unit-of-production method. Natural gas and NGLs are converted to an oil equivalent, Boe, at the standard rate of six Mcf to one Boe and forty-two gallons to one Boe, respectively. Estimated future dismantlement, restoration and abandonment costs are taken into consideration by this calculation. Accounts Payable and Accrued Liabilities. Accounts payable and accrued liabilities are comprised of the following: As of December 31, 2015 2014 (in thousands) Accrued drilling, completion and facility costs $ 32,895 $ 68,124 Accrued lease operating, gathering, transportation and processing expenses 4,930 12,526 Accrued general and administrative expenses 10,962 8,482 Accrued interest payable 13,918 14,284 Accrued payables for property sales 167 16,296 Trade payables and other 1,465 6,540 Total accounts payable and accrued liabilities $ 64,337 $ 126,252 Environmental Liabilities. Environmental expenditures that relate to an existing condition caused by past operations and that do not contribute to current or future revenue generation are expensed. Environmental liabilities are accrued when environmental assessments and/or clean-ups are probable, and the costs can be reasonably estimated. Revenue Recognition. Oil, gas and NGL revenues are recognized when production is sold to a purchaser at a fixed or determinable price, when delivery has occurred and title has transferred, and collectability of the revenue is reasonably assured. The Company uses the sales method to account for gas and NGL imbalances. Under this method, revenues are recorded on the basis of gas and NGLs actually sold by the Company. In addition, the Company records revenues for its share of gas and NGLs sold by other owners that cannot be volumetrically balanced in the future due to insufficient remaining reserves. The Company also reduces revenues for other owners' gas and NGLs sold by the Company that cannot be volumetrically balanced in the future due to insufficient remaining reserves. The Company's remaining over- and under- produced gas and NGLs balancing positions are taken into account in determining the Company's proved oil, gas and NGL reserves. Imbalances at December 31, 2015 and 2014 were not material. Derivative Instruments and Hedging Activities. The Company periodically uses derivative financial instruments to achieve a more predictable cash flow from its oil, natural gas and NGL sales by reducing its exposure to price fluctuations. Derivative instruments are recorded at fair market value and are included in the Consolidated Balance Sheets as assets or liabilities. Income Taxes. Income taxes are provided for the tax effects of transactions reported in the financial statements and consist of taxes currently payable plus deferred income taxes related to certain income and expenses recognized in different periods for financial and income tax reporting purposes. Deferred income tax assets and liabilities represent the future tax return consequences of those differences, which will either be taxable or deductible when assets are recovered or liabilities are settled. Deferred income taxes also include tax credits and net operating losses that are available to offset future income taxes. Deferred income taxes are measured by applying currently enacted tax rates. Deferred tax assets are regularly reviewed, considering all positive and negative evidence, including scheduled reversals of deferred tax liabilities, projected future taxable income, taxable strategies and results of recent operations. The assumptions about future taxable income require significant judgment to determine whether it is more likely than not that the deferred tax asset is expected to be realized. The Company accounts for uncertainty in income taxes for tax positions taken or expected to be taken in a tax return. Only tax positions that meet the more-likely-than-not recognition threshold are recognized. The Company does not have any uncertain tax positions recorded as of December 31, 2015 . Earnings/Loss Per Share. Basic net income (loss) per common share is calculated by dividing net income (loss) attributable to common stock by the weighted average number of common shares outstanding during each period. Diluted net income (loss) per common share is calculated by dividing net income (loss) attributable to common stock by the weighted average number of common shares outstanding and other dilutive securities. Potentially dilutive securities for the diluted net income per common share calculations consist of nonvested shares of common stock, in-the-money outstanding stock options to purchase the Company's common stock and shares into which the Convertible Notes are convertible. In satisfaction of its obligation upon conversion of the Convertible Notes, the Company may elect to deliver, at its option, cash, shares of its common stock or a combination of cash and shares of its common stock. As of December 31, 2015 , the Company expected to settle the remaining Convertible Notes in cash. Therefore, the treasury stock method was used to measure the potentially dilutive impact of shares associated with that remaining conversion feature. The Company has the right at any time with at least 30 days' notice to call the Convertible Notes and the holders have the right to require the Company to purchase the notes on March 20, 2018 and March 20, 2023. The Convertible Notes have not been dilutive since their issuance in March 2008 and, therefore, did not impact the diluted net income per common share calculation for the year ended December 31, 2014. When there is a loss from continuing operations, as was the case for the years ended December 31, 2015 and 2013, all potentially dilutive shares are anti-dilutive and are consequently excluded from the calculation of diluted earnings per share. The diluted net income per common share excludes the anti-dilutive effect of 1,406,938 stock options and nonvested shares of common stock for the year ended December 31, 2014. The following table sets forth the calculation of basic and diluted net income (loss) per share: Year Ended December 31, 2015 2014 2013 (in thousands, except per share amounts) Net income (loss) $ (487,771 ) $ 15,081 $ (192,733 ) Basic weighted-average common shares outstanding in period 48,303 48,011 47,497 Add dilutive effects of stock options and nonvested shares of common stock — 425 — Diluted weighted-average common shares outstanding in period 48,303 48,436 47,497 Basic net income (loss) per common share $ (10.10 ) $ 0.31 $ (4.06 ) Diluted net income (loss) per common share $ (10.10 ) $ 0.31 $ (4.06 ) Industry Segment and Geographic Information. The Company operates in one industry segment, which is the development and production of crude oil, natural gas and NGLs, and all of the Company's operations are conducted in the continental United States. Consequently, the Company currently reports as a single industry segment. New Accounting Pronouncements. In November 2015, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2015-17, Balance Sheet Classification of Deferred Taxes . The objective of this update is to require deferred tax liabilities and assets be classified as noncurrent in a classified statement of financial position. ASU 2015-17 is effective for the annual periods beginning after December 15, 2017, and interim periods within annual periods beginning after December 15, 2018. The standard will be adopted retrospectively and will not have a significant impact on the Company's disclosures and financial statements. In April 2015, the FASB issued ASU 2015-03, Simplifying the Presentation of Debt Issuance Costs . The objective of this update is to require that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct reduction from the carrying amount of that debt liability, consistent with debt discounts. ASU 2015-03 is effective for the annual periods beginning after December 15, 2015, and for interim periods within that annual period. The standard will be adopted retrospectively and will not have a significant impact on the Company's disclosures and financial statements. In August 2014, the FASB issued ASU 2014-15, Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern. The objective of this update is to provide guidance in GAAP about management's responsibility to evaluate whether there is substantial doubt about an entity's ability to continue as a going concern and to provide related footnote disclosures. ASU 2014-15 is effective for the annual period ending after December 15, 2016, and for annual periods and interim periods thereafter. The standard will be adopted prospectively. In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers. The objective of this update is to clarify the principles for recognizing revenue and to develop a common revenue standard. ASU 2015-14 deferred the effective reporting periods of ASU 2014-09, and it is now effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. The Company is currently evaluating the potential impact that the adoption will have on the Company's disclosures and financial statements.

Supplemental Disclosures of Cas

Supplemental Disclosures of Cash Flow Information	12 Months Ended
	Dec. 31, 2015
Supplemental Cash Flow Elements [Abstract]
Supplemental Disclosures of Cash Flow Information	Supplemental Disclosures of Cash Flow Information Supplemental cash flow information is as follows: Year Ended December 31, 2015 2014 2013 (in thousands) Cash paid for interest, net of amount capitalized $ 61,047 $ 65,935 $ 94,205 Cash paid for income taxes 2 1 1,163 Supplemental disclosures of non-cash investing and financing activities: Accrued receivables - oil and gas properties (1) — 42,872 — Accrued liabilities - oil and gas properties 33,805 72,297 75,340 Change in asset retirement obligations, net of disposals (9,101 ) (22,740 ) (6,996 ) Retirement of treasury stock (1,173 ) (2,684 ) (1,778 ) Fair value of properties exchanged in non-cash transactions — 77,078 — Transfer of lease financing obligation — 36,075 45,190 (1) Includes a receivable of $42.9 million related to a settlement agreement with the U.S. Department of Interior resulting in the cancellation of certain Cottonwood Gulch natural gas leases in 2014.

Divestitures and Assets Held fo

Divestitures and Assets Held for Sale	12 Months Ended
	Dec. 31, 2015
Discontinued Operations and Disposal Groups [Abstract]
Divestitures	Divestitures and Assets Held for Sale 2015 Divestitures. On February 27, 2015, the Company sold its remaining Powder River Basin assets, which included 19,492 net mineral acres. The Company received $9.3 million in cash proceeds, after initial closing estimates. These assets were classified as held for sale in the Consolidated Balance Sheet as of December 31, 2014. Upon the classification as held for sale, the assets were analyzed relative to their fair market values. The Company recognized proved and unproved property impairment of $14.8 million and $6.4 million , respectively, during the year ended December 31, 2014, with respect to these properties. Also during the year ended December 31, 2015, the Company sold certain non-core assets located in the DJ Basin with two separate transactions closing on October 21, 2015 and November 30, 2015, respectively. These asset sales included approximately 23,000 net acres ( 76% proved developed) and interests in legacy vertical producing wells for cash proceeds of $30.7 million . The divestiture proceeds are subject to customary purchase price adjustments and will be finalized in 2016. On November 30, 2015, the Company sold certain non-core assets located in the Uinta Basin, which included approximately 17,600 net acres and interests in producing wells for cash proceeds of $26.0 million . The divestiture proceeds are subject to customary purchase price adjustments and will be finalized in 2016. 2014 Divestitures. During the year ended December 31, 2014, the Company completed the sale or exchange of the majority of its Powder River Basin assets (the "Powder River Oil Divestiture") in four separate transactions with effective dates of April 1, 2014 and closing dates during the three months ended September 30, 2014. The sale resulted in net cash proceeds of $30.0 million after closing adjustments. The divestiture proceeds were subject to customary purchase price adjustments and were finalized during 2015. Three transactions involved the cumulative sale of 17,497 net mineral acres. The fourth transaction involved an exchange of 29,015 net mineral acres in the Powder River Basin for 7,856 net mineral acres within the southern block of the Company's operated Northeast Wattenberg area of the Denver-Julesburg Basin, valued at $71.0 million . Assets sold or exchanged as part of the overall Powder River Oil Divestiture included $86.2 million in proved and $40.6 million in unproved oil and gas properties, net of accumulated depreciation, depletion, amortization and impairment of $33.1 million and $1.3 million in asset retirement obligations. A loss on sale of $24.4 million related to these transactions is included within operating expenses in the Consolidated Statements of Operations. On September 30, 2014, the Company completed the sale of its Gibson Gulch natural gas program in the Piceance Basin (the "Piceance Divestiture"). The Company received $498.7 million in cash proceeds, after closing adjustments. The divestiture proceeds were subject to customary purchase price adjustments and were finalized during 2015. In addition to the cash proceeds, the Company recognized non-cash proceeds of $22.4 million related to the buyer's assumption of certain of the Company's asset retirement obligation and $36.1 million related to the transfer of the Company's lease financing obligation described in Note 5 (the "Lease Financing Obligation"). A loss on sale of $79.5 million related to this transaction is included within operating expenses in the Consolidated Statements of Operations. The carrying amounts by major asset class within the disposal group for the Piceance Divestiture are summarized below (in thousands): Assets: Proved properties $ 1,320,745 Furniture, equipment and other 4,907 Accumulated depreciation, depletion, amortization and impairment (688,864 ) Total assets $ 636,788 Liabilities: Asset retirement obligation $ 22,448 Lease financing obligation 36,075 Other liabilities 84 Total liabilities $ 58,607 Net assets $ 578,181 2013 Divestitures. On December 10, 2013, the Company completed the sale of its West Tavaputs natural gas assets in the Uinta Basin (the "West Tavaputs Divestiture"). The Company received $308.7 million in cash proceeds after closing adjustments. The divestiture proceeds were subject to customary purchase price adjustments and were finalized during 2014. The Company recognized an impairment loss of $1.0 million during the year ended December 31, 2014 related to these assets based upon a true up of previously estimated carrying value. An initial impairment loss of $209.5 million related to these assets was recognized during the year ended December 31, 2013. On December 31, 2012, the Company completed the sale of natural gas assets including 100% of its Wind River Basin, 100% of the Powder River Basin coalbed methane assets, and a non-operating working interest in its Gibson Gulch-Piceance Basin development property (the "2012 Divestiture"). The Company received $325.3 million in cash proceeds and recognized a $4.5 million pre-tax loss included in other operating revenues for the year ended December 31, 2012. Due to final post-closing adjustments, the Company recognized an additional $3.1 million pre-tax loss included in other operating revenues for the year ended December 31, 2013.

Long-Term Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt The Company's outstanding debt is summarized below: As of December 31, 2015 As of December 31, 2014 Maturity Date Principal Carrying Amount Principal Carrying Amount (in thousands) Amended Credit Facility April 9, 2020 $ — $ — $ — $ — Convertible Notes (1)(2) March 15, 2028 579 579 25,344 25,344 7.625% Senior Notes (3) October 1, 2019 400,000 400,000 400,000 400,000 7.0% Senior Notes (4) October 15, 2022 400,000 400,000 400,000 400,000 Lease Financing Obligation (5) August 10, 2020 3,222 3,222 3,648 3,648 Total Debt $ 803,801 $ 803,801 $ 828,992 $ 828,992 Less: Current Portion of Long-Term Debt (6)(7) 440 440 25,770 25,770 Total Long-Term Debt $ 803,361 $ 803,361 $ 803,222 $ 803,222 (1) The aggregate estimated fair value of the Convertible Notes was approximately $0.5 million and $25.1 million as of December 31, 2015 and 2014 , respectively, based on reported market trades of these instruments. On March 20, 2015, the holders put 98% of the Convertible Notes to the Company, leaving $0.6 million principal amount remaining. (2) The Company has the right at any time, with at least 30 days' notice, to call the Convertible Notes, and the holders have the right to require the Company to purchase the notes on each of March 20, 2018 and March 20, 2023. (3) The aggregate estimated fair value of the 7.625% Senior Notes was approximately $270.2 million and $359.8 million as of December 31, 2015 and 2014 , respectively, based on reported market trades of these instruments. (4) The aggregate estimated fair value of the 7.0% Senior Notes was approximately $272.0 million and $366.0 million as of December 31, 2015 and 2014 , respectively, based on reported market trades of these instruments. (5) The aggregate estimated fair value of the Lease Financing Obligation was approximately $3.1 million and $3.5 million as of December 31, 2015 and 2014 , respectively. As there is no active public market for the Lease Financing Obligation, the aggregate estimated fair value was based on market-based parameters of comparable term secured financing instruments. (6) The current portion of long-term debt as of December 31, 2015 includes the current portion of the Lease Financing Obligation. (7) The current portion of long-term debt as of December 31, 2014 includes the current portion of the Lease Financing Obligation and the principal amount of the Convertible Notes. Amended Credit Facility The Company is party to a Third Amended and Restated Credit Agreement dated March 16, 2010 (the "Amended Credit Facility") with 13 lenders. The Company entered into two amendments to the Amended Credit Facility in 2015, a Third Amendment entered into in April and a Fourth Amendment entered into in September. The Third Amendment amended the definition of "Maturity Date" in the Amended Credit Facility to mean the earliest of (a) April 9, 2020 or (b) the date 181 days prior to the maturity of certain unsecured senior or senior subordinated debt of ours in existence as of the date of the Third Amendment or that may be incurred by us as of a future date, or any permitted refinancing debt in respect thereof. Due to the Third Amendment, the Company recognized interest expense of $1.6 million and a loss on extinguishment of debt of $0.8 million on the Consolidated Statements of Operations related to the acceleration of deferred financing charges during the year ended December 31, 2015 . The Fourth Amendment, among other things, reaffirmed the current borrowing base at $375.0 million and relaxed certain financial covenant requirements. As of December 31, 2015 , the Company had no amounts outstanding under the Amended Credit Facility. As credit support for future payment under a contractual obligation, a $26.0 million letter of credit has been issued under the Amended Credit Facility, which reduced the current available borrowing capacity of the Amended Credit Facility as of December 31, 2015 to $349.0 million . Interest rates under the Amended Credit Facility are LIBOR plus applicable margins of 1.5% to 2.5% or ABR plus 0.5% to 1.5% and the unused commitment fee is between 0.375% to 0.5% based on borrowing base utilization. There have not been any borrowings under the Amended Credit Facility in 2015. The average annual interest rate incurred on the Amended Credit Facility was 1.9% for the year ended December 31, 2014 . The borrowing base under the Amended Credit Facility is determined at the discretion of the lenders, based on the collateral value of our proved reserves that have been mortgaged to such lenders, and is subject to regular re-determinations on, or about April 1 and October 1 of each year, as well as following any property sales. Future borrowing bases will be computed based on proved oil, natural gas and NGL reserves, hedge positions and estimated future cash flows from those reserves calculated using future commodity pricing provided by our lenders, as well as any other outstanding debt. Lower commodity prices will impact the amount lenders will provide for a borrowing base. The Amended Credit Facility also contains certain financial covenants. The Company is currently in compliance with all financial covenants and has complied with all financial covenants since issuance. If we fail to comply with the covenants or other terms of any agreements governing our debt, our lenders and holders of our convertible notes and our senior notes may have the right to accelerate the maturity of that debt and foreclose upon the collateral, if any, securing that debt. Realization of any of these factors could adversely affect our financial condition. In September 2015, we obtained an amendment to the Amended Credit Facility that replaced our debt-to-EBITDAX covenant in the facility with a secured debt-to-EBITDAX and EBITDAX-to-interest through March 31, 2018. There can be no assurance that we will be able to obtain similar amendments, or waivers of covenant breaches, in the future if needed. 5% Convertible Senior Notes Due 2028 On March 12, 2008, the Company issued $172.5 million aggregate principal amount of Convertible Notes. On March 20, 2012, $147.2 million of the outstanding principal amount, or approximately 85% of the outstanding Convertible Notes, were put to the Company and redeemed by the Company at par. On March 20, 2015, $24.8 million of the remaining outstanding principal amount, or approximately 98% of the remaining outstanding Convertible Notes, were put to the Company and redeemed by the Company at par. The Company settled the notes in cash and recognized a gain on extinguishment of $2.6 million in the Consolidated Statements of Operations for the year ended December 31, 2015. After the redemption, $0.6 million aggregate principal amount of the Convertible Notes was outstanding as of December 31, 2015. The Convertible Notes mature on March 15, 2028 , unless earlier converted, redeemed or purchased by the Company. The Convertible Notes are senior unsecured obligations and rank equal in right of payment to all of the Company's existing and future senior unsecured indebtedness, are senior in right of payment to all of the Company's future subordinated indebtedness, and are effectively subordinated to all of the Company's secured indebtedness with respect to the collateral securing such indebtedness. The Convertible Notes are structurally subordinated to all present and future secured and unsecured debt and other obligations of the Company's subsidiaries. The Convertible Notes are fully and unconditionally guaranteed by the subsidiaries that guarantee the Company's indebtedness under the Amended Credit Facility, the 7.625% Senior Notes and the 7.0% Senior Notes. The Convertible Notes bear interest at a rate of 5% per annum, payable semi-annually in arrears on March 15 and September 15 of each year. Holders of the remaining Convertible Notes may require the Company to purchase all or a portion of their Convertible Notes for cash on each of March 20, 2018 and March 20, 2023 at a purchase price equal to 100% of the principal amount of the Convertible Notes to be repurchased, plus accrued and unpaid interest, if any, up to but excluding the applicable purchase date. The Company has the right, with at least 30 days' notice to call the Convertible Notes. 7.625% Senior Notes Due 2019 On September 27, 2011, the Company issued $400.0 million in principal amount of 7.625% Senior Notes due 2019 at par. The 7.625% Senior Notes mature on October 1, 2019 . Interest is payable in arrears semi-annually on April 1 and October 1 beginning April 1, 2012. The 7.625% Senior Notes are senior unsecured obligations of the Company and rank equal in right of payment with all of the Company's other existing and future senior unsecured indebtedness, including the Company's Convertible Notes and 7.0% Senior Notes. The 7.625% Senior Notes are redeemable at the Company's option at a redemption price of 103.813% of the principal amount of the notes on October 1, 2015. The 7.625% Senior Notes are fully and unconditionally guaranteed by the subsidiaries that guarantee the Company's indebtedness under the Amended Credit Facility, the Convertible Notes and the 7.0% Senior Notes. The 7.625% Senior Notes include certain covenants that limit the Company's ability to incur additional indebtedness, make restricted payments, create liens or sell assets and pay dividends. The Company is currently in compliance with all financial covenants and has complied with all financial covenants since issuance. 7.0% Senior Notes Due 2022 On March 12, 2012, the Company issued $400.0 million in aggregate principal amount of 7.0% Senior Notes due 2022 at par. The 7.0% Senior Notes mature on October 15, 2022 . Interest is payable in arrears semi-annually on April 15 and October 15 of each year. The 7.0% Senior Notes are senior unsecured obligations and rank equal in right of payment with all of the Company's other existing and future senior unsecured indebtedness, including the Company's Convertible Notes and 7.625% Senior Notes. The 7.0% Senior Notes are redeemable at the Company's option on October 15, 2017 at a redemption price of 103.5% of the principal amount of the notes. The 7.0% Senior Notes are fully and unconditionally guaranteed by the subsidiaries that guarantee the Company's indebtedness under the Amended Credit Facility, the Convertible Notes and the 7.625% Senior Notes. The 7.0% Senior Notes include certain covenants that limit the Company's ability to incur additional indebtedness, make restricted payments, create liens or sell assets and pay dividends. The Company is currently in compliance with all financial covenants and has complied with all financial covenants since issuance. Lease Financing Obligation Due 2020 The Company has a lease financing obligation with a balance of $3.2 million as of December 31, 2015 whereby the Company sold and subsequently leased back certain compressors and related facilities owned by the Company. The Lease Financing Obligation expires on August 10, 2020 , and the Company has the option to purchase the equipment at the end of the lease term for the then current fair market value. The Lease Financing Obligation also contains an early buyout option pursuant to which the Company may purchase the equipment for $1.8 million on February 10, 2019. The lease payments related to the equipment are recognized as principal and interest expense based on a weighted average implicit interest rate of 3.3% . See Note 14 for discussion of aggregate minimum future lease payments. The following table summarizes, for the periods indicated, the cash or accrued portion of interest expense related to the Amended Credit Facility, 9.875% Senior Notes that were redeemed in full on July 15, 2013, Convertible Notes, 7.625% Senior Notes, 7.0% Senior Notes and the Lease Financing Obligation along with the non-cash portion resulting from the amortization of the debt discount and transaction costs through interest expense: As of December 31, 2015 2014 2013 (in thousands) Amended Credit Facility (1) Cash interest $ 1,755 $ 4,837 $ 6,802 Non-cash interest (2) 2,704 2,342 2,342 9.875% Senior Notes (3) Cash interest $ — $ — $ 13,373 Non-cash interest — — 1,361 Convertible Notes (4) Cash interest $ 301 $ 1,264 $ 1,267 Non-cash interest 8 5 6 7.625% Senior Notes (5) Cash interest $ 30,500 $ 30,500 $ 30,500 Non-cash interest 1,082 1,090 1,070 7.0% Senior Notes (6) Cash interest $ 28,000 $ 28,000 $ 28,000 Non-cash interest 806 814 795 Lease Financing Obligation (7) Cash interest $ 110 $ 638 $ 2,852 Non-cash interest 24 12 30 (1) Cash interest includes amounts related to interest and commitment fees paid on the Amended Credit Facility and participation and fronting fees paid on the letter of credit. (2) For the year ended December 31, 2015, amount includes $1.6 million related to amending the Amended Credit Facility. (3) The stated interest rate for the 9.875% Senior Notes was 9.875% per annum with an effective interest rate of 11.2% per annum. The Company redeemed the 9.875% Senior Notes in full on July 15, 2013. (4) The stated interest rate for the Convertible Notes is 5% per annum. The effective interest rate of the Convertible Notes includes amortization of the debt discount, which represented the fair value of the equity conversion feature at the time of issue. The stated interest rate of 5% on the Convertible Notes is the effective interest rate of the $0.6 million remaining principal balance, as the related debt discount was fully amortized as of March 31, 2012. (5) The stated interest rate for the 7.625% Senior Notes is 7.625% per annum with an effective interest rate of 8.0% per annum. (6) The stated interest rate for the 7.0% Senior Notes is 7.0% per annum with an effective interest rate of 7.2% per annum. (7) The effective interest rate for the Lease Financing Obligation is 3.3% per annum. The decrease in cash interest for the year ended December 31, 2015 and 2014, respectively, is due to the Piceance Divestiture in 2014 and West Tavaputs Divestiture in 2013.

Asset Retirement Obligations

Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2015
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	Asset Retirement Obligations A reconciliation of the Company's asset retirement obligations for the year ended December 31, 2015 , 2014 and 2013 is as follows: Year Ended December 31, 2015 2014 2013 (in thousands) Beginning of period $ 22,852 $ 43,005 $ 47,616 Liabilities incurred 781 4,027 2,359 Liabilities settled (739 ) (6,283 ) (1,096 ) Disposition of properties (9,056 ) (23,722 ) (13,543 ) Accretion expense 1,425 2,587 3,481 Revisions to estimate (87 ) 3,238 4,188 End of period $ 15,176 $ 22,852 $ 43,005 Less: Liabilities associated with properties held for sale — 146 — Less: Current asset retirement obligations 1,110 1,114 3,805 Long-term asset retirement obligations $ 14,066 $ 21,592 $ 39,200 Declining commodity prices may also expose us to unexpected liability for plugging and abandoning wells, and associated reclamation, for assets that were sold to other industry parties in prior years. If such third parties become unable to fulfill their contract obligations to the Company as provided for in purchase and sale agreements, regulatory agencies and landowners may demand that the Company perform such activities. Recent case law in Wyoming has increased such exposure for companies that have divested assets to no longer viable entities, and the Company has received demands from the Bureau of Land Management and a large landowner to plug and abandon wells, and conduct associated reclamation, on properties the Company no longer owns. As of December 31, 2015 , any potential liability is not probable nor estimable.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Assets and Liabilities Measured on a Recurring Basis The Company's financial instruments, including cash and cash equivalents, accounts and notes receivable and accounts payable are carried at cost, which approximates fair value due to the short-term maturity of these instruments. The recorded value of the Amended Credit Facility, as discussed in Note 5 , approximates its fair value due to its floating rate structure based on the LIBOR spread and the Company's borrowing base utilization. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). The Company utilizes a mid-market pricing convention (the mid-point price between bid and ask prices) for valuation as a practical expedient for assigning fair value. The Company uses market data or assumptions that market participants would use in pricing the asset or liability, including assumptions about risk. These inputs can be readily observable, market corroborated or generally unobservable. The Company primarily applies the market and income approaches for recurring fair value measurements and utilizes the best available information. Therefore, the Company has been able to classify fair value balances based on the observability of those inputs. A fair value hierarchy was established that prioritizes the inputs used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). Level 1 – Quoted prices are available in active markets for identical assets or liabilities as of the reporting date. Active markets are those in which transactions for the asset or liability occur in sufficient frequency and volume to provide pricing information on an ongoing basis. Level 1 primarily consists of financial instruments such as exchange-traded derivatives, listed securities and U.S. government treasury securities. Level 2 – Pricing inputs are other than quoted prices in active markets included in Level 1, and are either directly or indirectly observable as of the reporting date. Level 2 includes those financial instruments that are valued using models or other valuation methodologies. These models are primarily industry-standard models that consider various assumptions, including quoted forward prices for commodities, time value, volatility factors and current market and contractual prices for the underlying instruments, as well as other relevant economic measures. Substantially all of these assumptions are observable in the marketplace throughout the full term of the instrument, can be derived from observable data or are supported by observable levels at which transactions are executed in the marketplace. Instruments in this category include non-exchange-traded derivatives such as over-the-counter forwards and options. Level 3 – Pricing inputs include significant inputs that are generally less observable than objective sources. These inputs may be used with internally developed methodologies that result in management's best estimate of fair value. At each balance sheet date, the Company performs an analysis of all applicable instruments and includes in Level 3 all of those whose fair value is based on significant unobservable inputs. The following tables set forth by level within the fair value hierarchy the Company's financial assets and financial liabilities that were measured at fair value on a recurring basis. Assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company's assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the valuation of assets and liabilities and their placement within the fair value hierarchy levels. As of December 31, 2015 Level 1 Level 2 Level 3 Total (in thousands) Assets Deferred Compensation Plan $ 1,231 $ — $ — $ 1,231 Cash Equivalents 60,065 — — 60,065 Commodity Derivatives — 119,471 — 119,471 Liabilities Commodity Derivatives $ — $ — $ — $ — As of December 31, 2014 Level 1 Level 2 Level 3 Total (in thousands) Assets Deferred Compensation Plan $ 1,069 $ — $ — $ 1,069 Cash Equivalents 75,066 — — 75,066 Commodity Derivatives — 195,176 — 195,176 Liabilities Commodity Derivatives $ — $ 200 $ — $ 200 All fair values reflected in the table above and on the Consolidated Balance Sheets have been adjusted for non-performance risk. For applicable financial assets carried at fair value, the credit standing of the counterparties is analyzed and factored into the fair value measurement of those assets. In addition, the fair value measurement of a liability has been adjusted to reflect the nonperformance risk of the Company. The following methods and assumptions were used to estimate the fair values of the assets and liabilities in the table above. Level 1 Fair Value Measurements – The Company maintains a non-qualified deferred compensation plan (as discussed in more detail in Note 11 ) which allows certain management employees to defer receipt of a portion of their compensation. The Company maintains assets for the deferred compensation plan in a rabbi trust. The assets of the rabbi trust are invested in publicly traded mutual funds and are recorded in prepayments and other current assets and deferred financing costs and other noncurrent assets on the Consolidated Balance Sheets. The Company also has highly liquid cash equivalents in money market funds and commercial paper. The deferred compensation plan financial assets are reported at fair value based on active market quotes, which represent Level 1 inputs. The cash equivalent investments are recorded at carrying value, which approximates fair value, and represents Level 1 inputs. The fair values of the Company's fixed rate 7.625% Senior Notes and 7.0% Senior Notes totaled $542.2 million and $725.8 million as of December 31, 2015 and 2014 , respectively. The fair values of the Company's fixed rate Senior Notes are based on active market quotes, which represent Level 1 inputs. Level 2 Fair Value Measurements – The fair value of crude oil, natural gas and NGL swaps and forwards are estimated using a combined income and market valuation methodology with a mid-market pricing convention based upon forward commodity price and volatility curves. The curves are obtained from independent pricing services reflecting broker market quotes. The Company did not make any adjustments to the obtained curves. The pricing services publish observable market information from multiple brokers and exchanges. No proprietary models are used by the pricing services for the inputs. The Company utilized the counterparties' valuations to assess the reasonableness of the Company's valuations. There is no active, public market for the Company's Amended Credit Facility, Convertible Notes or Lease Financing Obligation. The Convertible Notes fair value of $0.5 million and $25.1 million as of December 31, 2015 and 2014 , respectively, is measured based on market-based parameters of the various components of the Convertible Notes and over the counter trades. The Lease Financing Obligation fair values of $3.1 million and $3.5 million as of December 31, 2015 and 2014 , respectively, are measured based on market-based parameters of comparable term secured financing instruments. The fair value measurements for the Amended Credit Facility, Convertible Notes and Lease Financing Obligation represent Level 2 inputs. Level 3 Fair Value Measurements – As of December 31, 2015 and 2014 , the Company did not have assets or liabilities that were measured on a recurring basis classified under a Level 3 fair value hierarchy. Assets and Liabilities Measured on a Non-recurring Basis Oil and gas property costs are evaluated for impairment and reduced to fair value when there is an indication that the carrying costs may not be recoverable. If an impairment is necessary, the fair value is estimated by using either a market approach based on recent sales prices of comparable properties and/or indications from marketing activities or by using the income valuation technique which involves calculating the present value of future revenues. The present value, net of estimated operating and development costs, is calculated using estimates of reserves, future commodity pricing, future production estimates, anticipated capital expenditures and various discount rates commensurate with the risk and current market conditions associated with realizing the projected cash flows (predominantly all of which are designated as Level 3 inputs within the fair value hierarchy). During the year ended December 31, 2015 , the Company reduced its Uinta Oil Program assets to a fair value of $180.0 million at September 30, 2015, resulting in a non-cash impairment charge of $572.4 million . Properties classified as held for sale are valued using a market approach, based on an estimated selling price, as evidenced by current marketing activities, if possible. If an estimated selling price is not available, the Company utilizes the income valuation technique discussed above. No properties were classified as held for sale as of December 31, 2015 . The following table sets forth by level within the fair value hierarchy the Company's non-financial assets and liabilities that were measured at fair value on a nonrecurring basis as of December 31, 2015 . Net Carrying Value as of December 31, 2015 Fair Value Measurements Using Level 1 Level 2 Level 3 Impairment (in thousands) Proved property (1) $ 178,221 $ — $ — $ 178,221 $ 559,282 Unproved property (1) 5,539 — — 5,539 13,156 (1) See Note 2 for additional details on impairment expense recognized. During the year ended December 31, 2014 , the Company recognized impairment on proved and unproved property of $39.8 million . Included in the total impairment charges of $39.8 million was $21.1 million of impairment charges related to the remaining Powder River Basin assets for which the Company utilized third party purchase offers as the basis for determining fair value. This property was classified as held for sale as of December 31, 2014. The following table sets forth by level within the fair value hierarchy the Company's non-financial assets and liabilities that were measured at fair value on a nonrecurring basis as of December 31, 2014 . Net Carrying Value as of December 31, 2014 Fair Value Measurements Using Level 1 Level 2 Level 3 Impairment (in thousands) Proved property (1)(2) $ 6,700 $ — $ — $ 6,700 $ 15,761 Unproved property (1)(2) 44,900 — — 44,900 24,082 (1) See Note 2 for additional details on impairment expense recognized. (2) In its Annual Report on Form 10K for the year ended December 31, 2014, the Company inadvertently disclosed the total net carrying value of proved and unproved properties rather than the amount that was subject to fair value measurement.

Derivative Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	Derivative Instruments The Company uses financial derivative instruments as part of its price risk management program to achieve a more predictable cash flow from its production revenues by reducing its exposure to commodity price fluctuations. The Company has entered into financial commodity swap contracts related to the sale of a portion of the Company's production. The Company does not enter into derivative instruments for speculative or trading purposes. In addition to financial contracts, the Company at times may be party to various physical commodity contracts for the sale of oil, natural gas and NGLs that have varying terms and pricing provisions. These physical commodity contracts qualify for the normal purchase and normal sale exception and, therefore, are not subject to hedge or mark-to-market accounting. The financial impact of physical commodity contracts is included in oil, natural gas and NGL production revenues at the time of settlement. All derivative instruments, other than those that meet the normal purchase and normal sale exception, as mentioned above, are recorded at fair value and included on the Consolidated Balance Sheets as assets or liabilities. The following table summarizes the location, as well as the gross and net fair value amounts of all derivative instruments presented on the Consolidated Balance Sheets as of the dates indicated. As of December 31, 2015 Balance Sheet Gross Amounts of Recognized Assets Gross Amounts Offset in the Balance Sheet Net Amounts of Assets Presented in the Balance Sheet (in thousands) Derivative assets (current) $ 99,809 $ — $ 99,809 Derivative assets (noncurrent) 19,662 — 19,662 Total derivative assets $ 119,471 $ — $ 119,471 As of December 31, 2014 Balance Sheet Gross Amounts of Recognized Assets Gross Amounts Offset in the Balance Sheet Net Amounts of Assets Presented in the Balance Sheet (in thousands) Derivative assets (current) $ 145,426 $ (200 ) (1) $ 145,226 Derivative assets (noncurrent) 49,750 — 49,750 Total derivative assets $ 195,176 $ (200 ) $ 194,976 Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Balance Sheet Net Amounts of Liabilities Presented in the Balance Sheet (in thousands) Derivative liabilities $ (200 ) $ 200 (2) $ — Derivatives and other noncurrent liabilities — — — Total derivative liabilities $ (200 ) $ 200 $ — (1) Amounts are netted against derivative asset balances with the same counterparty and are therefore presented as a net asset on the Consolidated Balance Sheets. (2) Amounts are netted against derivative liability balances with the same counterparty and are therefore presented as a net liability on the Consolidated Balance Sheets. Effective January 1, 2012, the Company elected to discontinue hedge accounting prospectively. As a result, the mark-to-market value of all commodity hedge instruments within AOCI at December 31, 2011 was frozen in AOCI as of the de-designation date and was reclassified into earnings in future periods as the original hedged transactions occurred. All cash flow hedged transactions were completed by December 31, 2014. The following table summarizes the cash flow hedge gains, net of tax, and their locations on the Consolidated Balance Sheets and Consolidated Statements of Operations for the periods indicated: Derivatives Qualifying as Cash Flow Hedges Year Ended December 31, 2015 2014 2013 (in thousands) Amount of Gain (Loss) Recognized in AOCI Commodity Hedges $ — $ — $ — Amount of Gain (Loss) Reclassified from AOCI into Income (net of tax) (1)(2) Commodity Hedges $ — $ 669 $ 4,663 Amount of Gain (Loss) Recognized in Income on Ineffective Hedges Commodity Hedges $ — $ — $ — (1) Presented net of income tax expense of $0.4 million and $2.8 million for the years ended December 31, 2014 and 2013, respectively. (2) Gains reclassified from AOCI into income are included in the oil, gas and NGL production revenues in the Consolidated Statements of Operations. As of December 31, 2015 , the Company had financial instruments in place to hedge the following volumes for the periods indicated: For the Year 2016 For the Year 2017 Derivative Volumes Weighted Average Price Derivative Volumes Weighted Average Price Oil (Bbls) 2,478,600 $ 80.47 683,250 $ 75.61 Natural Gas (MMbtu) 1,830,000 4.10 — — The table below summarizes the commodity derivative gains and losses the Company recognized related to its oil, gas and NGL derivative instruments for the periods indicated: Year Ended December 31, 2015 2014 2013 (in thousands) Commodity derivative settlements on derivatives designated as cash flow hedges (1) $ — $ 1,070 $ 7,463 Total commodity derivative gain (loss) (2) 104,147 197,447 (23,068 ) (1) Included in oil, gas and NGL production revenues in the Consolidated Statements of Operations. (2) Included in commodity derivative gain (loss) in the Consolidated Statements of Operations. The Company's derivative financial instruments are generally executed with major financial or commodities trading institutions that expose the Company to market and credit risks and may, at times, be concentrated with certain counterparties or groups of counterparties. The Company had hedges in place with eight different counterparties as of December 31, 2015 . Although notional amounts are used to express the volume of these contracts, the amounts potentially subject to credit risk, in the event of non-performance by the counterparties, are substantially smaller. The creditworthiness of counterparties is subject to continual review by management, and the Company believes all of these institutions currently are acceptable credit risks. Full performance is anticipated, and the Company has no past due receivables from any of its counterparties. It is the Company's policy to enter into derivative contracts with counterparties that are lenders in the Amended Credit Facility, affiliates of lenders in the Amended Credit Facility or potential lenders in the Amended Credit Facility. The Company's derivative contracts are documented using an industry standard contract known as a Schedule to the Master Agreement and International Swaps and Derivative Association, Inc. ("ISDA") Master Agreement or other contracts. Typical terms for these contracts include credit support requirements, cross default provisions, termination events and set-off provisions. The Company is not required to provide any credit support to its counterparties other than cross collateralization with the properties securing the Amended Credit Facility. The Company has set-off provisions in its derivative contracts with lenders under its Amended Credit Facility which, in the event of a counterparty default, allow the Company to set-off amounts owed to the defaulting counterparty under the Amended Credit Facility or other obligations against monies owed the Company under derivative contracts. Where the counterparty is not a lender under the Company's Amended Credit Facility, the Company may not be able to set-off amounts owed by the Company under the Amended Credit Facility, even if such counterparty is an affiliate of a lender under such facility. The Company does not have any derivative balances that are offset by cash collateral.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The (expense) benefit for income taxes consisted of the following for the periods indicated: Year Ended December 31, 2015 2014 2013 (in thousands) Current: Federal $ — $ (1,220 ) $ 1,233 State — (44 ) 352 Foreign — (1 ) (2 ) Deferred: Federal 158,757 (10,246 ) 107,300 State 18,328 (6,398 ) 9,750 Total $ 177,085 $ (17,909 ) $ 118,633 Income tax (expense) benefit differed from the amounts computed by applying the U.S. federal income tax rate of 35% to pretax income from continuing operations as a result of the following: Year Ended December 31, 2015 2014 2013 (in thousands) Income tax (expense) benefit at the federal statutory rate $ 232,700 $ (11,546 ) $ 108,978 State income taxes, net of federal tax effect 19,399 (932 ) 6,702 Incentive stock compensation (69 ) (199 ) (678 ) Nondeductible political contributions and lobbying costs (11 ) (108 ) (96 ) Nondeductible officer compensation (110 ) (229 ) (138 ) Other permanent items (89 ) (89 ) (52 ) Valuation allowance (74,978 ) — — Deferred tax related to the changes in overall state tax rates (74 ) (5,230 ) 3,851 Other, net 317 424 66 Income tax (expense) benefit $ 177,085 $ (17,909 ) $ 118,633 The tax effects of temporary differences that give rise to significant components of the deferred tax assets and deferred tax liabilities at December 31, 2015 and 2014 are presented below: As of December 31, 2015 2014 (in thousands) Current: Deferred tax assets (liabilities): Derivative instruments $ (37,846 ) $ (54,933 ) Accrued expenses 230 229 Bad debt expense 5 5 Prepaid expenses (615 ) (702 ) Other 7 (17 ) Total current deferred tax assets (liabilities) $ (38,219 ) $ (55,418 ) Long-term: Deferred tax assets: Net operating loss carryforward $ 124,828 $ 56,529 Deferred offering costs — 1,182 Stock-based compensation 17,123 15,767 Deferred rent 622 787 Minimum tax credit carryforward 1,402 1,690 Deferred compensation 915 1,062 State tax credit carryforwards 5,641 5,110 Financing obligation 1,428 1,586 Other 269 250 Less: Valuation allowance (80,088 ) (5,110 ) Total long-term deferred tax assets 72,140 78,853 Deferred tax liabilities: Oil and gas properties (26,466 ) (182,385 ) Long-term derivative instruments (7,455 ) (18,818 ) Total long-term deferred tax assets (liabilities) (33,921 ) (201,203 ) Net long-term deferred tax assets (liabilities) $ 38,219 $ (122,350 ) At December 31, 2015 , the Company had approximately $333.8 million of federal tax net operating loss carryforwards which expire beginning in 2025. The Company has a federal alternative minimum tax credit carryforward of $1.4 million , which has no expiration date. In assessing the ability to realize the benefit of the deferred tax assets, management must consider whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. Management considers all available evidence (both positive and negative) in determining whether a valuation allowance is required. Such evidence includes the scheduled reversal of deferred tax liabilities, projected future taxable income and tax planning strategies in making this assessment, and judgment is required in considering the relative weight of negative and positive evidence. In regard to the Company's net deferred tax asset position, the Company considered all available evidence in assessing the need for a valuation allowance against the deferred tax asset. The Company recorded a $75.0 million valuation allowance for the year ended December 31, 2015. At December 31, 2015 , the Company had approximately $8.7 million of state income tax credit carryforwards that begin expiring in 2018. A valuation allowance against these credits was recorded in 2011. It is currently estimated that the state income tax credits will not be utilized because the Company does not project to have sufficient future taxable income in the appropriate jurisdictions, and therefore the valuation allowance on the full amount of the credit carryforwards will remain. At December 31, 2015 and 2014 , the Consolidated Balance Sheet reflected a net deferred tax liability of zero and $177.8 million , respectively. The Company accounts for uncertainty in income taxes for tax positions taken or expected to be taken in a tax return. The Company recognizes the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained upon examination by the taxing authorities, based on the technical merits. The Company did not have any additions, reductions or settlements of unrecognized tax benefits in the years ended December 2014 and 2013 . In 2015 , the Company generated no uncertain tax positions. The Company's policy is to classify accrued penalties and interest related to unrecognized tax benefits in the Company's income tax provision. As of December 31, 2015 , the Company did not have any accrued interest or penalties associated with any unrecognized tax benefits, nor was any interest expense recognized during the current year. The Company and its subsidiaries file income tax returns in the U.S. federal jurisdiction and in various states. With few exceptions, the Company is subject to U.S. federal tax examination for years 2012 through 2015 and is subject to state tax examination for years 2011 through 2015 .

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2015
Text Block [Abstract]
Stockholders' Equity	Stockholders' Equity Common and Preferred Stock. The Company's authorized capital structure consists of 75,000,000 shares of preferred stock, par value $0.001 per share and 150,000,000 shares of common stock, par value $0.001 per share. There are no issued and outstanding shares of preferred stock. Treasury Stock. The Company may occasionally acquire treasury stock, which is recorded at cost, in connection with the vesting and exercise of stock-based awards or for other reasons. As of December 31, 2015 , all treasury stock held by the Company was retired. The following table reflects the activity in the Company's common and treasury stock for the periods indicated: Year Ended December 31, 2015 2014 2013 Common Stock Outstanding: Shares at beginning of period 49,526,637 49,152,448 48,150,475 Exercise of common stock options — 7,926 259,699 Shares issued for 401(k) plan 31,699 36,533 47,235 Shares issued for directors' fees 44,892 44,551 52,081 Shares issued for nonvested shares of common stock 673,087 857,870 1,081,259 Shares retired or forfeited (411,803 ) (572,691 ) (438,301 ) Shares at end of period 49,864,512 49,526,637 49,152,448 Treasury Stock: Shares at beginning of period — — — Treasury stock acquired 109,473 116,813 96,880 Treasury stock retired (109,473 ) (116,813 ) (96,880 ) Shares at end of period — — — Accumulated Other Comprehensive Income. The components of accumulated other comprehensive income and related tax effects for the years ended December 31, 2013 and 2014 are as follows: Gross Tax Effect Net of Tax (in thousands) Accumulated other comprehensive income — December 31, 2012 $ 8,544 $ (3,212 ) $ 5,332 Reclassification adjustment for realized gains on hedges included in net income (7,465 ) 2,802 (4,663 ) Accumulated other comprehensive income — December 31, 2013 $ 1,079 $ (410 ) $ 669 Reclassification adjustment for realized gains on hedges included in net income (1,079 ) 410 (669 ) Accumulated other comprehensive income — December 31, 2014 (1) $ — $ — $ — (1) All cash flow hedged transactions were completed by December 31, 2014 resulting in a zero balance for AOCI.

Equity Incentive Compensation P

Equity Incentive Compensation Plans and Other Employee Benefits	12 Months Ended
	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Equity Incentive Compensation Plans and Other Employee Benefits	Equity Incentive Compensation Plans and Other Employee Benefits The Company maintains various stock-based compensation plans and other employee benefit plans as discussed below. Stock-based compensation is measured at the grant date based on the value of the awards, and the fair value is recognized on a straight-line basis over the requisite service period (usually the vesting period). The following table presents the non-cash stock-based compensation related to equity awards for the periods indicated: Year Ended December 31, 2015 2014 2013 (in thousands) Common stock options $ 652 $ 2,073 $ 4,696 Nonvested common stock 6,721 6,845 7,492 Nonvested common stock units (1) 1,115 1,065 1,272 Nonvested performance-based equity 1,652 990 2,174 Total $ 10,140 $ 10,973 $ 15,634 (1) Includes non-cash stock-based compensation related to director fees of $0.1 million , $0.1 million and $0.4 million for the years ended December 31, 2015 , 2014 and 2013 , respectively. Unrecognized compensation cost as of December 31, 2015 was $10.8 million related to grants of nonvested stock options and nonvested shares of common stock that are expected to be recognized over a weighted-average period of 1.9 years. Stock Options and Nonvested Common Stock. In May 2012, the Company's stockholders approved and the Company adopted its 2012 Equity Incentive Plan (the "2012 Incentive Plan"). The purpose of the 2012 Incentive Plan is to enhance the Company's ability to attract and retain officers, employees and directors and to provide such persons with an interest in the Company aligned with the interests of stockholders. The 2012 Incentive Plan provides for the grant of stock options (including incentive stock options and non-qualified stock options) and other awards, including performance units, performance shares, share awards, share units, restricted stock, cash incentive, and stock appreciation rights or SARs. The aggregate number of shares that the Company may issue under the 2012 Incentive Plan may not exceed 2,051,402 shares, subject to adjustment for future stock splits, stock dividends and similar changes in the Company's capitalization. Shares underlying grants that expire without being exercised or are forfeited are available for grant under the 2012 Incentive Plan. The aggregate number of shares of common stock subject to options, stock appreciation rights, or performance-based awards granted to a participant during any calendar year may not exceed 500,000 shares. The 2012 Incentive Plan provides that all awards granted under the 2012 Incentive Plan expire not more than 10 years from the grant date and have an exercise price of no less than the closing price of the Company's common stock on the date of grant. Currently, the Company's practice is to issue new shares upon stock option exercise. The Company does not expect to repurchase any shares in the open market or issue treasury shares to settle any such exercises. For the years ended December 31, 2015 , 2014 and 2013 , the Company did not pay cash to repurchase any stock option exercises. The fair value of each share-based option award under all of the Company's plans is estimated on the date of grant using a Black-Scholes pricing model that incorporates the assumptions noted in the following table. Estimated expected volatilities were based on historical volatility of the Company's common stock. The Company does not expect to declare or pay dividends in the foreseeable future; thus, the Company used a 0% expected dividend yield, which is comparable to most of its peers in the industry. The expected terms range from 0.09 years to 6.0 years, or a weighted average of 4.3 years to 4.6 years, based on 25% of each grant's vesting on each anniversary date and factoring in potential blackout dates, historic exercises and expectations of future employee behavior. The risk-free rate is based on the U.S. Treasury yield curve in effect on the date of grant and extrapolated to approximate the expected life of the award. The Company estimated a 4% to 10% annual compounded forfeiture rate for the year 2012 based on historical employee turnover and actual forfeitures. The Company did not grant any share-based option awards during the years 2015, 2014 or 2013. A summary of share-based option activity under all the Company's plans as of December 31, 2015 , and changes during the year then ended, is presented below: Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Outstanding at January 1, 2015 1,339,365 $ 32.47 Granted — $ — Exercised — $ — Forfeited or expired (421,544 ) $ 39.50 Outstanding at December 31, 2015 917,821 $ 29.25 1.32 $ — Vested and expected to vest, at December 31, 2015 through the life of the options 917,318 $ 28.17 1.51 $ — Vested and exercisable at December 31, 2015 862,646 $ 29.37 1.40 $ — The total intrinsic value of options exercised for the years ended December 31, 2015 , 2014 and 2013 were zero , $0.1 million and $0.5 million , respectively. With respect to stock option exercises, the Company received zero , $0.1 million and $6.4 million for the years ended December 31, 2015 , 2014 and 2013 , respectively. A summary of the Company's nonvested shares of common stock as of December 31, 2015 , 2014 and 2013 , and changes during the years then ended, is presented below: Year Ended December 31, 2015 2014 2013 Shares Weighted Average Grant Date Fair Value Shares Weighted Average Grant Date Fair Value Shares Weighted Average Grant Date Fair Value Outstanding at January 1, 793,064 $ 21.47 756,118 $ 22.17 579,188 $ 31.02 Granted 673,087 $ 11.85 542,209 $ 22.00 630,715 $ 17.98 Vested (294,957 ) $ 21.69 (292,168 ) $ 24.05 (270,482 ) $ 29.82 Forfeited or expired (168,247 ) $ 17.63 (213,095 ) $ 21.99 (183,303 ) $ 24.87 Outstanding at December 31, 1,002,947 $ 15.53 793,064 $ 21.47 756,118 $ 22.17 Common stock units were issued beginning on July 1, 2012 and will be converted to shares of common stock as they vest. As of December 31, 2015 , common stock units have only been issued for payment of director fees. A summary of the Company's nonvested share units of common stock as of December 31, 2015 , 2014 and 2013 , and changes during the years then ended, is presented in the table below: Year Ended December 31, 2015 2014 2013 Shares Weighted Average Fair Shares Weighted Average Shares Weighted Average Outstanding at January 1, 54,945 $ 23.84 55,778 $ 19.35 49,185 $ 18.50 Granted 135,439 $ 8.31 45,928 $ 24.49 56,464 $ 22.33 Vested (44,892 ) $ 18.38 (46,761 ) $ 22.25 (49,871 ) $ 18.96 Forfeited or expired — $ — — $ — — $ — Outstanding at December 31, 145,492 $ 11.07 54,945 $ 23.84 55,778 $ 19.35 The grant date fair value of equity awards vested for the years ended December 31, 2015 , 2014 and 2013 was $7.2 million , $8.0 million and $8.1 million , respectively. Performance Share and Cash Programs 2015 Program. In February 2015, the Compensation Committee of the Board of Directors of the Company approved a performance cash program (the "2015 Program") granting performance cash units that will settle in cash. The performance-based awards contingently vest in May 2018, depending on the level at which the performance goals are achieved. The performance goals, which will be measured over the three year period ending December 31, 2017, consist of the Company's total shareholder return ("TSR") ranking relative to a defined peer group's individual TSRs ("Relative TSR") (weighted at 60% ) and the percentage change in discretionary cash flow per debt adjusted share relative to a defined peer group's percentage calculation ("DCF per Debt Adjusted Share") (weighted at 40% ). The Relative TSR and DCF per Debt Adjusted Share goals will vest at 25% or 50% , respectively, of the total award for performance met at the threshold level, 100% at the target level and 200% at the stretch level. If the actual results for a metric are between the threshold and target levels or between the target and stretch levels, the vested number of units will be prorated based on the actual results compared to the threshold, target and stretch goals. If the threshold metrics are not met, no units will vest. In any event, the total number of units that could vest will not exceed 200% of the original number of performance cash units granted. At the end of the three year vesting period, any units that have not vested will be forfeited. A total of 422,345 units were granted under this program during the year ended December 31, 2015. The Company recognized $0.4 million in derivatives and other noncurrent liabilities in the Consolidated Balance Sheets as of December 31, 2015 and $0.4 million in general and administrative expense in the Consolidated Statements of Operations for the year ended December 31, 2015 , for the 2015 Program based on a unit price of $3.95 and the number of units expected to vest at the end of the three year period. 2014 Program. In February 2014, the Compensation Committee approved a new performance share program (the "2014 Program") pursuant to the 2012 Equity Incentive Plan. The performance-based awards contingently vest in May 2017, depending on the level at which the performance goals are achieved. The performance goals, which will be measured over the three year period ending December 31, 2016, consist of the Company's total shareholder return ("TSR") ranking relative to a defined peer group's individual TSRs ("Relative TSR") (weighted at 60% ) and the percentage change in discretionary cash flow per debt adjusted share relative to a defined peer group's percentage calculation ("DCF per Debt Adjusted Share") (weighted at 40% ). The Relative TSR and DCF per Debt Adjusted Share goals will vest at 25% of the total award for performance met at the threshold level, 100% at the target level and 200% at the stretch level. If the actual results for a metric are between the threshold and target levels or between the target and stretch levels, the vested number of shares will be prorated based on the actual results compared to the threshold, target and stretch goals. If the threshold metrics are not met, no shares will vest. In any event, the total number of shares of common stock that could vest will not exceed 200% of the original number of performance shares granted. At the end of the three year vesting period, any shares that have not vested will be forfeited. A total of 315,661 shares were granted under this program during the year ended December 31, 2014. All compensation expense related to the TSR metric will be recognized if the requisite service period is fulfilled, even if the market condition is not achieved. All compensation expense related to the DCF per Debt Adjusted Share metric will be based on the number of shares expected to vest at the end of the three year period. 2013 Program. In February 2013, the Compensation Committee approved a new performance share program (the "2013 Program") pursuant to the 2012 Equity Incentive Plan. The performance-based awards contingently vest in May 2016, depending on the level at which the performance goals are achieved. The performance goals, which will be measured over the three year period ending December 31, 2015, consist of the Company's Relative TSR (weighted at 33 1/3% ), the percentage change in discretionary cash flow per debt adjusted share relative to a defined peer group's percentage calculation ("DCF per Debt Adjusted Share") (weighted at 33 1/3% ) and percentage change in proved oil, natural gas and NGL reserves per debt adjusted share ("Reserves per Debt Adjusted Share") (weighted at 33 1/3% ). The Relative TSR and DCF per Debt Adjusted Share goals will vest at 25% of the total award for performance met at the threshold level, 100% at the target level and 200% at the stretch level. The Reserves per Debt Adjusted Share goal will vest at 50% of the total award for performance met at the threshold level, 100% at the target level and 200% at the stretch level. If the actual results for a metric are between the threshold and target levels or between the target and stretch levels, the vested number of shares will be prorated based on the actual results compared to the threshold, target and stretch goals. If the threshold metrics are not met, no shares will vest. In any event, the total number of shares of common stock that could vest will not exceed 200% of the original number of performance shares granted. At the end of the three year vesting period, any shares that have not vested will be forfeited. All compensation expense related to the Relative TSR metric will be recognized if the requisite service period is fulfilled, even if the market condition is not achieved. All compensation expense related to the DCF per Debt Adjusted Share metric and the Reserves per Debt Adjusted Share metric will be based upon the number of shares expected to vest at the end of the three year period. A total of 450,544 shares were granted under this program during the year ended December 31, 2013. Based upon the Company's performance through 2015, approximately 29.6% of the 2013 Program performance shares will vest in May 2016. 2012 Program. In March 2012, the Compensation Committee approved a new performance share program (the "2012 Program"). The performance-based awards vested in May 2015, on the level at which the performance goals were achieved. The performance goals, which were measured over the three year period ending December 31, 2014, consisted of the Company's TSR ranking relative to a defined peer group's individual TSR (weighted at 33 1/3% ), the percentage change in DCF per Debt Adjusted Share relative to a defined peer group's percentage calculation (weighted at 33 1/3% ) and the change in proved oil and natural gas reserves per debt adjusted share (weighted at 33 1/3% ). All compensation expense related to the DCF per Debt Adjusted Share and oil and natural gas reserves per debt adjusted share metrics will be based on the number of shares expected to vest at the end of the three year period. A total of 179,987 shares were granted under this program during the year ended December 31, 2012. Based on the Company's performance through 2014, none of the 2012 Program performance shares vested in May 2015. 2010 Program. In February 2010, the Compensation Committee approved a performance share program (the "2010 Program"). Upon commencement of the 2010 Program and during each subsequent year of the 2010 Program through 2013, the Compensation Committee met to approve target and stretch goals for certain operational or financial metrics that are selected by the Compensation Committee for the upcoming year and to determine whether metrics for the prior year have been met. As new goals are established each year for the performance-based awards, a new grant date and a new fair value are created for financial reporting purposes for those shares that could potentially vest in the upcoming year. Compensation expense is recognized based on an estimate of the extent to which the performance goals would be met. If such goals are not met, no compensation expense is recognized and any previously recognized compensation expense is reversed. The 2010 Program has both performance-based and market-based goals. All compensation expense related to the market-based goals was recognized if the requisite service period is fulfilled, even if the market condition was not achieved. Based on Company performance in 2010, 2011, 2012 and 2013, 25.9% , 26.6% , 0.0% and 19.8% , respectively, of the 2010 Program performance-based shares vested in February 2011, February 2012, February 2013 and February 2014, respectively, for a total of 72.3% of the total performance-based shares vested over the four year vesting period. A total of 59,582 , 57,944 , zero and 21,968 shares vested in February 2011, February 2012, February 2013 and February 2014, respectively. Based on the 2010 Program market-based goals, which were based on the Company's TSR ranking relative to a defined peer group's individual TSR, 37.5% , 12.5% , 0.0% and 33.4% vested in February 2011, 2012, 2013 and 2014, respectively, based on the Company's rankings as of December 31, 2010, 2011, 2012 and 2013, respectively, for a total of 83.4% of the total market-based shares vested over the four year vesting period. A total of 21,574 , 6,801 , zero and 9,242 shares vested in February 2011, February 2012, February 2013 and February 2014, respectively. A summary of the Company's non-vested performance-based shares of common stock as of December 31, 2015 , 2014 and 2013 , and changes during the years then ended, is presented below: Year Ended December 31, 2015 2014 2013 Shares Weighted Average Fair Shares Weighted Average Fair Shares Weighted Average Fair Outstanding at January 1, 614,077 $ 19.62 584,032 $ 19.80 291,606 $ 26.85 Granted — $ — 315,661 $ 23.86 450,544 $ 19.99 Modified, performance goals revised (1) — $ — — $ — (108,933 ) $ 27.75 Modified, performance goals revised (1) — $ — — $ — 108,933 $ 18.18 Vested (2) (11,623 ) $ 23.07 (42,833 ) $ 19.51 — $ — Forfeited or expired (133,893 ) $ 25.46 (242,783 ) $ 22.13 (158,118 ) $ 22.52 Outstanding at December 31, 468,561 $ 18.46 614,077 $ 19.62 584,032 $ 19.80 (1) As the Compensation Committee approved new performance metrics for the vesting of performance shares in the upcoming year, a new grant date was then created for any unvested awards that were granted in previous years, and a new fair value was established for financial reporting purposes. (2) The Compensation Committee approved a special retention award on July 18, 2013. A debt performance gate was required to be met as of December 31, 2013 in which the shares would vest on July 18, 2014, 2015 and 2016. The vested shares are included in the vested line item for the years ended December 31, 2015 and 2014. The grant date fair value of the performance-based shares vested in the years ended December 31, 2015 and 2014 was $0.3 million and $0.8 million , respectively. Director Fees. The Company's non-employee, or outside, directors, may elect to receive all or a portion of their annual retainer and meeting fees in the form of restricted stock units ("RSUs"), which are settled with shares of the Company's common stock, issued pursuant to the Company's 2012 Incentive Plan. After each quarter, RSUs with a value equal to the fees payable for that quarter, calculated using the closing price for the Company's common stock on the last trading day of the quarter, will be delivered to each outside director who elected before that quarter to receive RSUs for payment of director fees. These nonvested RSUs will vest immediately at the end of the applicable quarter. Once vested, the RSUs will settle at the end of the applicable quarter or such later date elected by the director. A summary of the Company's directors' fees and equity-based compensation for the years ended December 31, 2015 , 2014 and 2013 is presented below: Year Ended December 31, 2015 2014 2013 Director fees (shares) 14,892 3,928 16,151 Stock-based compensation (in thousands) $ 75 $ 75 $ 351 Other Employee Benefits-401(k) Savings Plan. The Company has an employee-directed 401(k) savings plan (the "401(k) Plan") for all eligible employees over the age of 21 . Under the 401(k) Plan, employees may make voluntary contributions based on a percentage of their pretax income, subject to statutory limitations. The Company matches 100% of each employee's contribution, up to 6% of the employee's pretax income, with 50% of the match made with the Company's common stock. Starting on April 1, 2015, the entire 6% match is now comprised of cash only. The Company's cash and common stock contributions are fully vested upon the date of match, and employees can immediately sell the portion of the match made with the Company's common stock. The Company made matching cash and common stock contributions of $1.2 million , $1.7 million and $1.9 million for the years ended December 31, 2015 , 2014 and 2013 , respectively. Deferred Compensation Plan. In 2010, the Company adopted a non-qualified deferred compensation plan for certain employees and officers whose eligibility to participate in the plan was determined by the Compensation Committee. The Company makes matching cash contributions on behalf of eligible employees up to 6% of the employee's cash compensation once the contribution limits are reached on the Company's 401(k) Plan. All amounts deferred and matched under the plan vest immediately. Deferred compensation, including accumulated earnings on the participant-directed investment selections, is distributable in cash at participant-specified dates or upon retirement, death, disability, change in control or termination of employment. The table below summarizes the activity in the plan during the years ended December 31, 2015 and 2014 , and the Company's ending deferred compensation liability as of December 31, 2015 and 2014 : Year Ended December 31, 2015 2014 (in thousands) Beginning deferred compensation liability balance $ 1,069 $ 941 Employee contributions 410 441 Company matching contributions 119 160 Distributions (346 ) (503 ) Participant earnings (losses) (21 ) 30 Ending deferred compensation liability balance $ 1,231 $ 1,069 Amount to be paid within one year $ 206 $ 220 Remaining balance to be paid beyond one year $ 1,025 $ 849 The Company has established a rabbi trust to offset the deferred compensation liability and protect the interests of the plan participants. The investments in the rabbi trust seek to offset the change in the value of the related liability. As a result, there is no expected impact on earnings or earnings per share from the changes in market value of the investment assets because the changes in market value of the trust assets are offset by changes in the value of the deferred compensation plan liability. The gains and losses from changes in fair value of the investments are included in interest and other income in the Consolidated Statements of Operations. The following table represents the Company's activity in the investment assets held in the rabbi trust during the years ended December 31, 2015 and 2014 : Year Ended December 31, 2015 2014 (in thousands) Beginning investment balance $ 1,069 $ 941 Investment purchases 529 601 Distributions (346 ) (503 ) Earnings (losses) (21 ) 30 Ending investment balance $ 1,231 $ 1,069

Significant Customers and Other

Significant Customers and Other Concentrations	12 Months Ended
	Dec. 31, 2015
Text Block [Abstract]
Significant Customers and Other Concentrations	Significant Customers and Other Concentrations Significant Customers. During 2015 , four customers individually accounted for over 10% of the Company's oil, gas and NGL production revenues. During 2014 , two customers individually accounted for over 10% of the Company's oil, gas and NGL production revenues. During 2013 , one customer individually accounted for over 10% of the Company's oil, gas and NGL production revenues. Although diversified among many companies, collectability is dependent upon the financial stability of each individual company and is influenced by the general economic conditions of the industry. Management believes that the loss of any individual purchaser would not have a long-term material adverse impact on the financial position or results of operations of the Company. Concentrations of Market Risk. The future results of the Company's oil and gas operations will be affected by the market prices of oil, natural gas and NGLs. A readily available market for oil, natural gas and NGLs in the future will depend on numerous factors beyond the control of the Company, including weather, imports, marketing of competitive fuels, proximity and capacity of oil and gas pipelines and other transportation facilities, any oversupply or undersupply of oil, gas and NGLs, the regulatory environment, the economic environment and other regional, national and international economic and political events, none of which can be predicted with certainty. The Company operates in the exploration, development and production phase of the oil and gas industry. Its receivables include amounts due from purchasers of oil and gas production and amounts due from joint venture partners for their respective portions of operating expenses and exploration and development costs. The Company believes that no single customer or joint venture partner exposes the Company to significant credit risk. While certain of these customers and joint venture partners are affected by periodic downturns in the economy in general or in their specific segment of the natural gas or oil industry, the Company believes that its level of credit-related losses due to such economic fluctuations has been and will continue to be immaterial to the Company's results of operations in the long-term. Trade receivables are generally not collateralized. The Company analyzes customers' and joint venture partners' historical credit positions and payment histories prior to extending credit. Concentrations of Credit Risk. Derivative financial instruments that hedge the price of oil, natural gas and NGLs are generally executed with major financial or commodities trading institutions which expose the Company to market and credit risks and may, at times, be concentrated with certain counterparties or groups of counterparties. The Company's policy is to execute financial derivatives only with major, creditworthy financial institutions. The Company has derivative instruments with eight different counterparties, of which all are lenders or affiliates of lenders in the Amended Credit Facility. The creditworthiness of counterparties is subject to continuing review, and the Company believes all of these institutions currently are acceptable credit risks. Full performance is anticipated, and the Company has no past due receivables from any of its counterparties. Where the counterparty is a lender under the Amended Credit Facility, the counterparty risk is mitigated to the extent that the Company is indebted to such lender under the Amended Credit Facility.

Equity Distribution Agreement

Equity Distribution Agreement	12 Months Ended
	Dec. 31, 2015
Equity Distribution Agreement [Abstract]
Equity Distribution Agreement [Text Block]	Equity Distribution Agreement On June 10, 2015, the Company entered into an Equity Distribution Agreement (the "Agreement") with Goldman, Sachs and Co. (the "Manager"). Pursuant to the terms of the Agreement, the Company may sell, from time to time through or to the Manager, shares of its common stock having an aggregate gross sales price of up to $100.0 million . Sales of the shares, if any, will be made by means of ordinary brokers' transactions through the facilities of the New York Stock Exchange, at market prices, in block transactions, to or through a market maker, through an electronic communications network or as otherwise agreed by the Company and the Manager. As of December 31, 2015, no shares have been sold pursuant to the Agreement.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Lease Financing Obligation. The Company has a Lease Financing Obligation with Bank of America Leasing & Capital, LLC as the lead bank as discussed in Note 5 . The aggregate undiscounted minimum future lease payments, including both principal and interest components, are presented below: As of December 31, 2015 (in thousands) 2016 $ 537 2017 537 2018 537 2019 1,825 2020 — Thereafter — Total $ 3,436 Transportation Charges . The Company is party to two firm transportation contracts to provide capacity on natural gas pipeline systems. The remaining term on these contracts is six years. The contracts require the Company to pay transportation charges regardless of the amount of pipeline capacity utilized by the Company. Beginning October 1, 2014, these transportation costs are included in unused commitments expense in the Consolidated Statements of Operations. As a result of previous divestitures in 2013 and 2014, the Company will likely not utilize the firm capacity on the natural gas pipelines. The amounts in the table below represent the Company's future minimum transportation charges. As of December 31, 2015 (in thousands) 2016 $ 18,692 2017 18,692 2018 18,692 2019 18,692 2020 18,692 Thereafter 10,902 Total $ 104,362 Lease and Other Commitments. The Company leases office space, vehicles and certain equipment under non-cancelable operating leases. Additionally, the Company has entered into various long-term agreements for telecommunication services. Future minimum annual payments under lease and other agreements are as follows: As of December 31, 2015 (in thousands) 2016 (1) $ 6,676 2017 2,892 2018 2,591 2019 633 2020 — Thereafter — Total $ 12,792 (1) Includes a contractual obligation of $3.2 million related to certain drilling commitments on sold properties. Litigation. The Company is subject to litigation, claims and governmental and regulatory proceedings arising in the course of ordinary business. It is the opinion of the Company's management that current claims and litigation involving the Company are not likely to have a material adverse effect on its consolidated balance sheets, cash flows or statements of operations.

Guarantor Subsidiaries

Guarantor Subsidiaries	12 Months Ended
	Dec. 31, 2015
Text Block [Abstract]
Guarantor Subsidiaries	Guarantor Subsidiaries In addition to the Amended Credit Facility, the 7.625% Senior Notes, the 7.0% Senior Notes and the Convertible Notes, which are registered securities, are jointly and severally guaranteed on a full and unconditional basis by the Company's 100% owned subsidiaries ("Guarantor Subsidiaries"). Presented below are the Company's condensed consolidating balance sheets, statements of operations, statements of other comprehensive income (loss) and statements of cash flows, as required by Rule 3-10 of Regulation S-X of the Securities Exchange Act of 1934, as amended. During the year ended December 31, 2014, Bill Barrett Corporation, as parent, merged two of the Company's 100% owned subsidiaries, CBM Production Company and GB Acquisition Corporation, into the parent company. During the year ended December 31, 2015, Bill Barrett Corporation, as parent, merged another 100% owned subsidiary, Elk Production Uintah, LLC, into the parent company. The condensed consolidating financial statements reflect the new guarantor structure for all periods presented. The following condensed consolidating financial statements have been prepared from the Company's financial information on the same basis of accounting as the Consolidated Financial Statements. Investments in the subsidiaries are accounted for under the equity method. Accordingly, the entries necessary to consolidate the Company and the Guarantor Subsidiaries are reflected in the intercompany eliminations column. Condensed Consolidating Balance Sheets As of December 31, 2015 Parent Guarantor Intercompany Consolidated (in thousands) Assets: Current assets $ 274,115 $ 202 $ — $ 274,317 Property and equipment, net 1,164,086 6,598 — 1,170,684 Intercompany receivable (payable) 21,412 (21,412 ) — — Investment in subsidiaries (14,664 ) — 14,664 — Noncurrent assets 70,228 — — 70,228 Total assets $ 1,515,177 $ (14,612 ) $ 14,664 $ 1,515,229 Liabilities and Stockholders' Equity: Current liabilities $ 145,231 $ — $ — $ 145,231 Long-term debt 803,361 — — 803,361 Deferred income taxes — — — — Other noncurrent liabilities 17,169 52 — 17,221 Stockholders' equity 549,416 (14,664 ) 14,664 549,416 Total liabilities and stockholders' equity $ 1,515,177 $ (14,612 ) $ 14,664 $ 1,515,229 As of December 31, 2014 Parent Guarantor Intercompany Consolidated (in thousands) Assets: Current assets $ 426,103 $ 2 $ — $ 426,105 Property and equipment, net 1,730,074 23,047 — 1,753,121 Intercompany receivable (payable) 22,840 (22,840 ) — — Investment in subsidiaries 163 — (163 ) — Noncurrent assets 65,258 — — 65,258 Total assets $ 2,244,438 $ 209 $ (163 ) $ 2,244,484 Liabilities and Stockholders' Equity: Current liabilities $ 264,687 $ — $ — $ 264,687 Long-term debt 803,222 — — 803,222 Deferred income taxes 122,350 — — 122,350 Other noncurrent liabilities 24,691 46 — 24,737 Stockholders' equity 1,029,488 163 (163 ) 1,029,488 Total liabilities and stockholders' equity $ 2,244,438 $ 209 $ (163 ) $ 2,244,484 Condensed Consolidating Statements of Operations Year Ended December 31, 2015 Parent Guarantor Intercompany Consolidated (in thousands) Operating and other revenues $ 207,282 $ 610 $ — $ 207,892 Operating expenses (844,577 ) (15,437 ) — (860,014 ) General and administrative (53,890 ) — — (53,890 ) Interest income and other income (expense) 41,156 — — 41,156 Income (loss) before income taxes and equity in earnings (loss) of subsidiaries (650,029 ) (14,827 ) — (664,856 ) (Provision for) Benefit from income taxes 177,085 — — 177,085 Equity in earnings (loss) of subsidiaries (14,827 ) — 14,827 — Net income (loss) $ (487,771 ) $ (14,827 ) $ 14,827 $ (487,771 ) Year Ended December 31, 2014 Parent Guarantor Intercompany Consolidated (in thousands) Operating and other revenues $ 472,288 $ 3 $ — $ 472,291 Operating expenses (514,721 ) (337 ) — (515,058 ) General and administrative (53,361 ) — — (53,361 ) Interest income and other income (expense) 129,118 — — 129,118 Income (loss) before income taxes and equity in earnings (loss) of subsidiaries 33,324 (334 ) — 32,990 (Provision for) Benefit from income taxes (17,909 ) — — (17,909 ) Equity in earnings (loss) of subsidiaries (334 ) — 334 — Net income (loss) $ 15,081 $ (334 ) $ 334 $ 15,081 Year Ended December 31, 2013 Parent Guarantor Intercompany Consolidated (in thousands) Operating and other revenues $ 568,055 $ 38 $ — $ 568,093 Operating expenses (682,898 ) (270 ) — (683,168 ) General and administrative (64,902 ) — — (64,902 ) Interest and other income (expense) (131,389 ) — — (131,389 ) Income (loss) before income taxes and equity in earnings (loss) of subsidiaries (311,134 ) (232 ) — (311,366 ) (Provision for) Benefit from income taxes 118,633 — — 118,633 Equity in earnings (loss) of subsidiaries (232 ) — 232 — Net income (loss) $ (192,733 ) $ (232 ) $ 232 $ (192,733 ) Condensed Consolidating Statements of Comprehensive Income (Loss) Year Ended December 31, 2015 Parent Guarantor Intercompany Consolidated (in thousands) Net Income (Loss) $ (487,771 ) $ (14,827 ) $ 14,827 $ (487,771 ) Other Comprehensive Income (Loss), net of tax: Effect of derivative financial instruments — — — — Other comprehensive income (loss) — — — — Comprehensive Income (Loss) $ (487,771 ) $ (14,827 ) $ 14,827 $ (487,771 ) Year Ended December 31, 2014 Parent Guarantor Intercompany Consolidated (in thousands) Net Income (Loss) $ 15,081 $ (334 ) $ 334 $ 15,081 Other Comprehensive Income (Loss), net of tax: Effect of derivative financial instruments (669 ) — — (669 ) Other comprehensive income (loss) (669 ) — — (669 ) Comprehensive Income (Loss) $ 14,412 $ (334 ) $ 334 $ 14,412 Year Ended December 31, 2013 Parent Issuer Guarantor Subsidiaries Intercompany Eliminations Consolidated (in thousands) Net Income (Loss) $ (192,733 ) $ (232 ) $ 232 $ (192,733 ) Other Comprehensive Income (Loss), net of tax: Effect of derivative financial instruments (4,663 ) — — (4,663 ) Other comprehensive income (loss) (4,663 ) — — (4,663 ) Comprehensive Income (Loss) $ (197,396 ) $ (232 ) $ 232 $ (197,396 ) Condensed Consolidating Statements of Cash Flows Year Ended December 31, 2015 Parent Guarantor Intercompany Consolidated (in thousands) Cash flows from operating activities $ 193,329 $ 349 $ — $ 193,678 Cash flows from investing activities: Additions to oil and gas properties, including acquisitions (325,613 ) 1,079 — (324,534 ) Additions to furniture, fixtures and other (1,223 ) — — (1,223 ) Proceeds from sale of properties and other investing activities 123,122 — — 123,122 Cash paid for short-term investments (114,883 ) — — (114,883 ) Proceeds from sale of short-term investments 115,000 — — 115,000 Intercompany transfers 1,428 — (1,428 ) — Cash flows from financing activities: Proceeds from debt — — — — Principal and redemption premium payments on debt (25,191 ) — — (25,191 ) Intercompany transfers — (1,428 ) 1,428 — Other financing activities (3,037 ) — — (3,037 ) Change in cash and cash equivalents (37,068 ) — — (37,068 ) Beginning cash and cash equivalents 165,904 — — 165,904 Ending cash and cash equivalents $ 128,836 $ — $ — $ 128,836 Year Ended December 31, 2014 Parent Guarantor Intercompany Consolidated (in thousands) Cash flows from operating activities $ 261,704 $ 13 $ — $ 261,717 Cash flows from investing activities: Additions to oil and gas properties, including acquisitions (571,215 ) (9,728 ) — (580,943 ) Additions to furniture, fixtures and other (3,658 ) — — (3,658 ) Proceeds from sale of properties and other investing activities 553,477 1,819 — 555,296 Intercompany transfers (7,896 ) — 7,896 — Cash flows from financing activities: Proceeds from debt 165,000 — — 165,000 Principal and redemption premium payments on debt (283,546 ) — — (283,546 ) Intercompany transfers — 7,896 (7,896 ) — Other financing activities (2,557 ) — — (2,557 ) Change in cash and cash equivalents 111,309 — — 111,309 Beginning cash and cash equivalents 54,595 — — 54,595 Ending cash and cash equivalents $ 165,904 $ — $ — $ 165,904 Year Ended December 31, 2013 Parent Guarantor Intercompany Consolidated (in thousands) Cash flows from operating activities $ 265,323 $ (58 ) $ — $ 265,265 Cash flows from investing activities: Additions to oil and gas properties, including acquisitions (439,785 ) (5,694 ) — (445,479 ) Additions to furniture, fixtures and other (2,254 ) — — (2,254 ) Proceeds from sale of properties and other investing activities 310,704 — — 310,704 Cash flows from financing activities: Proceeds from debt 420,000 — — 420,000 Principal and redemption premium payments on debt (576,422 ) — — (576,422 ) Intercompany transfers (5,752 ) 5,752 — — Other financing activities 3,336 — — 3,336 Change in cash and cash equivalents (24,850 ) — — (24,850 ) Beginning cash and cash equivalents 79,445 — — 79,445 Ending cash and cash equivalents $ 54,595 $ — $ — $ 54,595

Summary of Significant Accoun24

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation. The accompanying Consolidated Financial Statements include the accounts of the Company. These statements have been prepared in accordance with accounting principles generally accepted in the United States of America ("GAAP"). All intercompany accounts and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates. In the course of preparing the Company's financial statements in accordance with GAAP, management makes various assumptions, judgments and estimates to determine the reported amount of assets, liabilities, revenues and expenses and in the disclosure of commitments and contingencies. Changes in these assumptions, judgments and estimates will occur as a result of the passage of time and the occurrence of future events and, accordingly, actual results could differ from amounts initially established. Areas requiring the use of assumptions, judgments and estimates relate to the expected cash settlement of the Company's 5% Convertible Senior Notes due 2028 ("Convertible Notes") in computing diluted earnings per share, volumes of oil, natural gas and NGL reserves used in calculating depreciation, depletion and amortization ("DD&A"), the amount of expected future cash flows used in determining possible impairments of oil and gas properties and the amount of future capital costs used in these calculations. Assumptions, judgments and estimates also are required in determining asset retirement obligations, the timing of dry hole costs, impairments of proved and unproved properties, valuing deferred tax assets and estimating fair values of derivative instruments and stock-based payment awards.
Oil and Gas Properties	Oil and Gas Properties. The Company's oil, gas and NGL exploration and production activities are accounted for using the successful efforts method. Under this method, all property acquisition costs and costs of exploratory and development wells are capitalized when incurred, pending determination of whether the well has found proved reserves. If an exploratory well does not find proved reserves, the costs of drilling the well are charged to expense and included within cash flows from investing activities in the Consolidated Statements of Cash Flows. If an exploratory well does find proved reserves, the costs remain capitalized and are included within additions to oil and gas properties within cash flows from investing activities in the Consolidated Statements of Cash Flows when paid. The costs of development wells are capitalized whether proved reserves are added or not. Oil and gas lease acquisition costs are also capitalized. Upon sale or retirement of depreciable or depletable property, the cost and related accumulated DD&A are eliminated from the accounts and the resulting gain or loss is recognized. Other exploration costs, including certain geological and geophysical expenses and delay rentals for oil and gas leases, are charged to expense as incurred. The sale of a partial interest in a proved property is accounted for as a cost recovery and no gain or loss is recognized as long as this treatment does not significantly affect the unit-of-production amortization rate. Maintenance and repairs are charged to expense, and renewals and betterments are capitalized to the appropriate property and equipment accounts. Unproved oil and gas property costs are transferred to proved oil and gas properties if the properties are subsequently determined to be productive or are assigned proved reserves. Proceeds from sales of partial interests in unproved leases are accounted for as a recovery of cost without recognizing any gain until all costs are recovered. Unproved oil and gas properties are assessed periodically for impairment based on remaining lease terms, drilling results, reservoir performance, commodity price outlooks, future plans to develop acreage and other relevant matters. Materials and supplies consist primarily of tubular goods and well equipment to be used in future drilling operations or repair operations and are carried at the lower of cost or market value. The following table sets forth the net capitalized costs and associated accumulated DD&A and non-cash impairments relating to the Company's oil, natural gas and NGL producing activities: As of December 31, 2015 2014 (in thousands) Proved properties $ 320,538 $ 390,482 Wells and related equipment and facilities 1,592,716 1,537,370 Support equipment and facilities 77,785 68,371 Materials and supplies 9,171 13,069 Total proved oil and gas properties $ 2,000,210 $ 2,009,292 Unproved properties 33,336 78,898 Wells and facilities in progress 45,862 69,936 Total unproved oil and gas properties, excluded from amortization $ 79,198 $ 148,834 Assets held for sale — 9,234 Accumulated depreciation, depletion, amortization and impairment (918,510 ) (427,954 ) Total oil and gas properties, net $ 1,160,898 $ 1,739,406 All exploratory wells are evaluated for economic viability within one year of well completion. Exploratory wells that discover potentially economic reserves in areas where a major capital expenditure would be required before production could begin, and where the economic viability of that major capital expenditure depends upon the successful completion of further exploratory work in the area, remain capitalized if the well finds a sufficient quantity of reserves to justify its completion as a producing well and the Company is making sufficient progress assessing the reserves and the economic and operating viability of the project. As of December 31, 2015 and 2014, there were no exploratory well costs that had been capitalized for a period greater than one year since the completion of drilling. The Company reviews proved oil and gas properties on a field-by-field basis for impairment on a quarterly basis or whenever events and circumstances indicate that a decline in the recoverability of their carrying value may have occurred. The Company estimates the expected undiscounted future cash flows of its oil and gas properties and compares such undiscounted future cash flows to the carrying amount of the oil and gas properties to determine if the carrying amount is recoverable. If the carrying value of a property exceeds the undiscounted future cash flows, the Company will impair the carrying value to fair value based on an analysis of quantitative and qualitative factors. The factors used to determine fair value include, but are not limited to, recent sales prices of comparable properties, the present value of future revenues, net of estimated operating and development costs using estimates of reserves, future commodity pricing, future production estimates, anticipated capital expenditures and various discount rates commensurate with the risk and current market conditions associated with realizing the expected cash flows projected. The Company recognized non-cash impairment charges, which were included within impairment, dry hole costs and abandonment expense in the Consolidated Statements of Operations, as follows: Year Ended December 31, 2015 2014 2013 (in thousands) Non-cash impairment of proved oil and gas properties $ 559,282 (1) $ 15,761 (2) $ 206,953 (4) Non-cash impairment of unproved oil and gas properties 13,156 (1) 24,082 (3) 19,598 (4) Non-cash impairment of inventory — 340 — Dry hole costs 123 101 1,124 Abandonment expense 2,749 6,597 10,723 Total non-cash impairment, dry hole costs and abandonment expense $ 575,310 $ 46,881 $ 238,398 (1) Due to the continued decline in oil prices, the Company recognized a non-cash impairment charge associated with the Company's Uinta Oil Program proved and unproved oil and gas properties for the year ended December 31, 2015. (2) As a result of the Powder River Oil Divestiture (see Note 4 ), the carrying values of the remaining properties were analyzed relative to their estimated fair market value. As a result, the Company recognized impairment of $14.8 million . These properties were classified as held for sale as of December 31, 2014. The remaining impairment of $1.0 million related to the West Tavaputs Divestiture (see Note 4 ) based on a true up of previously estimated carrying value. (3) As a result of unfavorable drilling and completion results in the Paradox Basin, the Company recognized an impairment of $11.6 million related to unproved oil and gas properties. In addition, the Company recognized an impairment of $6.1 million related to certain unproved oil and gas properties in the Uinta Basin as a result of having no future plans to evaluate certain acreage positions. The Company recognized an impairment of $6.4 million to unproved oil and gas properties as the result of the Powder River Oil Divestiture discussed in (2) above. (4) As a result of an analysis of remaining carrying values relative to fair market values resulting from the West Tavaputs Divestiture (see Note 4 ), $207.0 million and $2.5 million of proved and unproved property impairment, respectively, was incurred during the year ended December 31, 2013. As a result of having no future plans to evaluate remaining acreage and estimated market value below carrying value within various exploration projects, an additional $17.1 million of unproved property impairment was incurred during the year ended December 31, 2013. The provision for DD&A of oil and gas properties is calculated on a field-by-field basis using the unit-of-production method. Natural gas and NGLs are converted to an oil equivalent, Boe, at the standard rate of six Mcf to one Boe and forty-two gallons to one Boe, respectively. Estimated future dismantlement, restoration and abandonment costs are taken into consideration by this calculation.
Environmental Liabilities	Environmental Liabilities. Environmental expenditures that relate to an existing condition caused by past operations and that do not contribute to current or future revenue generation are expensed. Environmental liabilities are accrued when environmental assessments and/or clean-ups are probable, and the costs can be reasonably estimated.
Revenue Recognition	Revenue Recognition. Oil, gas and NGL revenues are recognized when production is sold to a purchaser at a fixed or determinable price, when delivery has occurred and title has transferred, and collectability of the revenue is reasonably assured. The Company uses the sales method to account for gas and NGL imbalances. Under this method, revenues are recorded on the basis of gas and NGLs actually sold by the Company. In addition, the Company records revenues for its share of gas and NGLs sold by other owners that cannot be volumetrically balanced in the future due to insufficient remaining reserves. The Company also reduces revenues for other owners' gas and NGLs sold by the Company that cannot be volumetrically balanced in the future due to insufficient remaining reserves. The Company's remaining over- and under- produced gas and NGLs balancing positions are taken into account in determining the Company's proved oil, gas and NGL reserves. Imbalances at December 31, 2015 and 2014 were not material.
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities. The Company periodically uses derivative financial instruments to achieve a more predictable cash flow from its oil, natural gas and NGL sales by reducing its exposure to price fluctuations. Derivative instruments are recorded at fair market value and are included in the Consolidated Balance Sheets as assets or liabilities.
Income Taxes	Income Taxes. Income taxes are provided for the tax effects of transactions reported in the financial statements and consist of taxes currently payable plus deferred income taxes related to certain income and expenses recognized in different periods for financial and income tax reporting purposes. Deferred income tax assets and liabilities represent the future tax return consequences of those differences, which will either be taxable or deductible when assets are recovered or liabilities are settled. Deferred income taxes also include tax credits and net operating losses that are available to offset future income taxes. Deferred income taxes are measured by applying currently enacted tax rates. Deferred tax assets are regularly reviewed, considering all positive and negative evidence, including scheduled reversals of deferred tax liabilities, projected future taxable income, taxable strategies and results of recent operations. The assumptions about future taxable income require significant judgment to determine whether it is more likely than not that the deferred tax asset is expected to be realized. The Company accounts for uncertainty in income taxes for tax positions taken or expected to be taken in a tax return. Only tax positions that meet the more-likely-than-not recognition threshold are recognized. The Company does not have any uncertain tax positions recorded as of December 31, 2015 .
Earnings/Loss Per Share	Earnings/Loss Per Share. Basic net income (loss) per common share is calculated by dividing net income (loss) attributable to common stock by the weighted average number of common shares outstanding during each period. Diluted net income (loss) per common share is calculated by dividing net income (loss) attributable to common stock by the weighted average number of common shares outstanding and other dilutive securities. Potentially dilutive securities for the diluted net income per common share calculations consist of nonvested shares of common stock, in-the-money outstanding stock options to purchase the Company's common stock and shares into which the Convertible Notes are convertible. In satisfaction of its obligation upon conversion of the Convertible Notes, the Company may elect to deliver, at its option, cash, shares of its common stock or a combination of cash and shares of its common stock. As of December 31, 2015 , the Company expected to settle the remaining Convertible Notes in cash. Therefore, the treasury stock method was used to measure the potentially dilutive impact of shares associated with that remaining conversion feature. The Company has the right at any time with at least 30 days' notice to call the Convertible Notes and the holders have the right to require the Company to purchase the notes on March 20, 2018 and March 20, 2023. The Convertible Notes have not been dilutive since their issuance in March 2008 and, therefore, did not impact the diluted net income per common share calculation for the year ended December 31, 2014. When there is a loss from continuing operations, as was the case for the years ended December 31, 2015 and 2013, all potentially dilutive shares are anti-dilutive and are consequently excluded from the calculation of diluted earnings per share. The diluted net income per common share excludes the anti-dilutive effect of 1,406,938 stock options and nonvested shares of common stock for the year ended December 31, 2014. The following table sets forth the calculation of basic and diluted net income (loss) per share: Year Ended December 31, 2015 2014 2013 (in thousands, except per share amounts) Net income (loss) $ (487,771 ) $ 15,081 $ (192,733 ) Basic weighted-average common shares outstanding in period 48,303 48,011 47,497 Add dilutive effects of stock options and nonvested shares of common stock — 425 — Diluted weighted-average common shares outstanding in period 48,303 48,436 47,497 Basic net income (loss) per common share $ (10.10 ) $ 0.31 $ (4.06 ) Diluted net income (loss) per common share $ (10.10 ) $ 0.31 $ (4.06 )
Industry Segment and Geographic Information	Industry Segment and Geographic Information. The Company operates in one industry segment, which is the development and production of crude oil, natural gas and NGLs, and all of the Company's operations are conducted in the continental United States. Consequently, the Company currently reports as a single industry segment.
New Accounting Pronouncements	New Accounting Pronouncements. In November 2015, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2015-17, Balance Sheet Classification of Deferred Taxes . The objective of this update is to require deferred tax liabilities and assets be classified as noncurrent in a classified statement of financial position. ASU 2015-17 is effective for the annual periods beginning after December 15, 2017, and interim periods within annual periods beginning after December 15, 2018. The standard will be adopted retrospectively and will not have a significant impact on the Company's disclosures and financial statements. In April 2015, the FASB issued ASU 2015-03, Simplifying the Presentation of Debt Issuance Costs . The objective of this update is to require that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct reduction from the carrying amount of that debt liability, consistent with debt discounts. ASU 2015-03 is effective for the annual periods beginning after December 15, 2015, and for interim periods within that annual period. The standard will be adopted retrospectively and will not have a significant impact on the Company's disclosures and financial statements. In August 2014, the FASB issued ASU 2014-15, Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern. The objective of this update is to provide guidance in GAAP about management's responsibility to evaluate whether there is substantial doubt about an entity's ability to continue as a going concern and to provide related footnote disclosures. ASU 2014-15 is effective for the annual period ending after December 15, 2016, and for annual periods and interim periods thereafter. The standard will be adopted prospectively. In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers. The objective of this update is to clarify the principles for recognizing revenue and to develop a common revenue standard. ASU 2015-14 deferred the effective reporting periods of ASU 2014-09, and it is now effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. The Company is currently evaluating the potential impact that the adoption will have on the Company's disclosures and financial statements.

Summary of Significant Accoun25

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Summary of Accounts Receivable	Accounts Receivable. Accounts receivable is comprised of the following: As of December 31, 2015 2014 (in thousands) Accrued oil, gas and NGL sales $ 33,594 $ 35,099 Due from joint interest owners 8,373 27,937 Other (1) 1,508 49,187 Allowance for doubtful accounts (14 ) (14 ) Total accounts receivable $ 43,461 $ 112,209 (1) Other includes a receivable of $47.6 million (including $4.7 million due to another industry partner) related to a settlement agreement with the U.S. Department of Interior resulting in the cancellation of certain Cottonwood Gulch natural gas leases during the year ended December 31, 2014.
Net Capitalized Costs and Associated Accumulated DD&A and Non Cash Impairments	The following table sets forth the net capitalized costs and associated accumulated DD&A and non-cash impairments relating to the Company's oil, natural gas and NGL producing activities: As of December 31, 2015 2014 (in thousands) Proved properties $ 320,538 $ 390,482 Wells and related equipment and facilities 1,592,716 1,537,370 Support equipment and facilities 77,785 68,371 Materials and supplies 9,171 13,069 Total proved oil and gas properties $ 2,000,210 $ 2,009,292 Unproved properties 33,336 78,898 Wells and facilities in progress 45,862 69,936 Total unproved oil and gas properties, excluded from amortization $ 79,198 $ 148,834 Assets held for sale — 9,234 Accumulated depreciation, depletion, amortization and impairment (918,510 ) (427,954 ) Total oil and gas properties, net $ 1,160,898 $ 1,739,406
Non-Cash Impairment Charges, Included within Impairment, Dry Hole Costs and Abandonment Expense in Consolidated Statements of Operations	The Company recognized non-cash impairment charges, which were included within impairment, dry hole costs and abandonment expense in the Consolidated Statements of Operations, as follows: Year Ended December 31, 2015 2014 2013 (in thousands) Non-cash impairment of proved oil and gas properties $ 559,282 (1) $ 15,761 (2) $ 206,953 (4) Non-cash impairment of unproved oil and gas properties 13,156 (1) 24,082 (3) 19,598 (4) Non-cash impairment of inventory — 340 — Dry hole costs 123 101 1,124 Abandonment expense 2,749 6,597 10,723 Total non-cash impairment, dry hole costs and abandonment expense $ 575,310 $ 46,881 $ 238,398 (1) Due to the continued decline in oil prices, the Company recognized a non-cash impairment charge associated with the Company's Uinta Oil Program proved and unproved oil and gas properties for the year ended December 31, 2015. (2) As a result of the Powder River Oil Divestiture (see Note 4 ), the carrying values of the remaining properties were analyzed relative to their estimated fair market value. As a result, the Company recognized impairment of $14.8 million . These properties were classified as held for sale as of December 31, 2014. The remaining impairment of $1.0 million related to the West Tavaputs Divestiture (see Note 4 ) based on a true up of previously estimated carrying value. (3) As a result of unfavorable drilling and completion results in the Paradox Basin, the Company recognized an impairment of $11.6 million related to unproved oil and gas properties. In addition, the Company recognized an impairment of $6.1 million related to certain unproved oil and gas properties in the Uinta Basin as a result of having no future plans to evaluate certain acreage positions. The Company recognized an impairment of $6.4 million to unproved oil and gas properties as the result of the Powder River Oil Divestiture discussed in (2) above. (4) As a result of an analysis of remaining carrying values relative to fair market values resulting from the West Tavaputs Divestiture (see Note 4 ), $207.0 million and $2.5 million of proved and unproved property impairment, respectively, was incurred during the year ended December 31, 2013. As a result of having no future plans to evaluate remaining acreage and estimated market value below carrying value within various exploration projects, an additional $17.1 million of unproved property impairment was incurred during the year ended December 31, 2013.
Accounts Payable and Accrued Liabilities	Accounts Payable and Accrued Liabilities. Accounts payable and accrued liabilities are comprised of the following: As of December 31, 2015 2014 (in thousands) Accrued drilling, completion and facility costs $ 32,895 $ 68,124 Accrued lease operating, gathering, transportation and processing expenses 4,930 12,526 Accrued general and administrative expenses 10,962 8,482 Accrued interest payable 13,918 14,284 Accrued payables for property sales 167 16,296 Trade payables and other 1,465 6,540 Total accounts payable and accrued liabilities $ 64,337 $ 126,252
Calculation of Basic and Diluted Earnings Per Share	The following table sets forth the calculation of basic and diluted net income (loss) per share: Year Ended December 31, 2015 2014 2013 (in thousands, except per share amounts) Net income (loss) $ (487,771 ) $ 15,081 $ (192,733 ) Basic weighted-average common shares outstanding in period 48,303 48,011 47,497 Add dilutive effects of stock options and nonvested shares of common stock — 425 — Diluted weighted-average common shares outstanding in period 48,303 48,436 47,497 Basic net income (loss) per common share $ (10.10 ) $ 0.31 $ (4.06 ) Diluted net income (loss) per common share $ (10.10 ) $ 0.31 $ (4.06 )

Supplemental Disclosures of C26

Supplemental Disclosures of Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2015
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	Supplemental cash flow information is as follows: Year Ended December 31, 2015 2014 2013 (in thousands) Cash paid for interest, net of amount capitalized $ 61,047 $ 65,935 $ 94,205 Cash paid for income taxes 2 1 1,163 Supplemental disclosures of non-cash investing and financing activities: Accrued receivables - oil and gas properties (1) — 42,872 — Accrued liabilities - oil and gas properties 33,805 72,297 75,340 Change in asset retirement obligations, net of disposals (9,101 ) (22,740 ) (6,996 ) Retirement of treasury stock (1,173 ) (2,684 ) (1,778 ) Fair value of properties exchanged in non-cash transactions — 77,078 — Transfer of lease financing obligation — 36,075 45,190 (1) Includes a receivable of $42.9 million related to a settlement agreement with the U.S. Department of Interior resulting in the cancellation of certain Cottonwood Gulch natural gas leases in 2014.

Divestitures and Assets Held 27

Divestitures and Assets Held for Sale (Tables)	12 Months Ended
	Dec. 31, 2015
Discontinued Operations and Disposal Groups [Abstract]
Disposal Groups Excluding Discontinued Operations Disclosure	The carrying amounts by major asset class within the disposal group for the Piceance Divestiture are summarized below (in thousands): Assets: Proved properties $ 1,320,745 Furniture, equipment and other 4,907 Accumulated depreciation, depletion, amortization and impairment (688,864 ) Total assets $ 636,788 Liabilities: Asset retirement obligation $ 22,448 Lease financing obligation 36,075 Other liabilities 84 Total liabilities $ 58,607 Net assets $ 578,181

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Outstanding Debt	The Company's outstanding debt is summarized below: As of December 31, 2015 As of December 31, 2014 Maturity Date Principal Carrying Amount Principal Carrying Amount (in thousands) Amended Credit Facility April 9, 2020 $ — $ — $ — $ — Convertible Notes (1)(2) March 15, 2028 579 579 25,344 25,344 7.625% Senior Notes (3) October 1, 2019 400,000 400,000 400,000 400,000 7.0% Senior Notes (4) October 15, 2022 400,000 400,000 400,000 400,000 Lease Financing Obligation (5) August 10, 2020 3,222 3,222 3,648 3,648 Total Debt $ 803,801 $ 803,801 $ 828,992 $ 828,992 Less: Current Portion of Long-Term Debt (6)(7) 440 440 25,770 25,770 Total Long-Term Debt $ 803,361 $ 803,361 $ 803,222 $ 803,222 (1) The aggregate estimated fair value of the Convertible Notes was approximately $0.5 million and $25.1 million as of December 31, 2015 and 2014 , respectively, based on reported market trades of these instruments. On March 20, 2015, the holders put 98% of the Convertible Notes to the Company, leaving $0.6 million principal amount remaining. (2) The Company has the right at any time, with at least 30 days' notice, to call the Convertible Notes, and the holders have the right to require the Company to purchase the notes on each of March 20, 2018 and March 20, 2023. (3) The aggregate estimated fair value of the 7.625% Senior Notes was approximately $270.2 million and $359.8 million as of December 31, 2015 and 2014 , respectively, based on reported market trades of these instruments. (4) The aggregate estimated fair value of the 7.0% Senior Notes was approximately $272.0 million and $366.0 million as of December 31, 2015 and 2014 , respectively, based on reported market trades of these instruments. (5) The aggregate estimated fair value of the Lease Financing Obligation was approximately $3.1 million and $3.5 million as of December 31, 2015 and 2014 , respectively. As there is no active public market for the Lease Financing Obligation, the aggregate estimated fair value was based on market-based parameters of comparable term secured financing instruments. (6) The current portion of long-term debt as of December 31, 2015 includes the current portion of the Lease Financing Obligation. (7) The current portion of long-term debt as of December 31, 2014 includes the current portion of the Lease Financing Obligation and the principal amount of the Convertible Notes.
Cash and Non-Cash Portion of Interest Expense Related to Long Term Debt	The following table summarizes, for the periods indicated, the cash or accrued portion of interest expense related to the Amended Credit Facility, 9.875% Senior Notes that were redeemed in full on July 15, 2013, Convertible Notes, 7.625% Senior Notes, 7.0% Senior Notes and the Lease Financing Obligation along with the non-cash portion resulting from the amortization of the debt discount and transaction costs through interest expense: As of December 31, 2015 2014 2013 (in thousands) Amended Credit Facility (1) Cash interest $ 1,755 $ 4,837 $ 6,802 Non-cash interest (2) 2,704 2,342 2,342 9.875% Senior Notes (3) Cash interest $ — $ — $ 13,373 Non-cash interest — — 1,361 Convertible Notes (4) Cash interest $ 301 $ 1,264 $ 1,267 Non-cash interest 8 5 6 7.625% Senior Notes (5) Cash interest $ 30,500 $ 30,500 $ 30,500 Non-cash interest 1,082 1,090 1,070 7.0% Senior Notes (6) Cash interest $ 28,000 $ 28,000 $ 28,000 Non-cash interest 806 814 795 Lease Financing Obligation (7) Cash interest $ 110 $ 638 $ 2,852 Non-cash interest 24 12 30 (1) Cash interest includes amounts related to interest and commitment fees paid on the Amended Credit Facility and participation and fronting fees paid on the letter of credit. (2) For the year ended December 31, 2015, amount includes $1.6 million related to amending the Amended Credit Facility. (3) The stated interest rate for the 9.875% Senior Notes was 9.875% per annum with an effective interest rate of 11.2% per annum. The Company redeemed the 9.875% Senior Notes in full on July 15, 2013. (4) The stated interest rate for the Convertible Notes is 5% per annum. The effective interest rate of the Convertible Notes includes amortization of the debt discount, which represented the fair value of the equity conversion feature at the time of issue. The stated interest rate of 5% on the Convertible Notes is the effective interest rate of the $0.6 million remaining principal balance, as the related debt discount was fully amortized as of March 31, 2012. (5) The stated interest rate for the 7.625% Senior Notes is 7.625% per annum with an effective interest rate of 8.0% per annum. (6) The stated interest rate for the 7.0% Senior Notes is 7.0% per annum with an effective interest rate of 7.2% per annum. (7) The effective interest rate for the Lease Financing Obligation is 3.3% per annum. The decrease in cash interest for the year ended December 31, 2015 and 2014, respectively, is due to the Piceance Divestiture in 2014 and West Tavaputs Divestiture in 2013.

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2015
Asset Retirement Obligation Disclosure [Abstract]
Schedule of Asset Retirement Obligations	A reconciliation of the Company's asset retirement obligations for the year ended December 31, 2015 , 2014 and 2013 is as follows: Year Ended December 31, 2015 2014 2013 (in thousands) Beginning of period $ 22,852 $ 43,005 $ 47,616 Liabilities incurred 781 4,027 2,359 Liabilities settled (739 ) (6,283 ) (1,096 ) Disposition of properties (9,056 ) (23,722 ) (13,543 ) Accretion expense 1,425 2,587 3,481 Revisions to estimate (87 ) 3,238 4,188 End of period $ 15,176 $ 22,852 $ 43,005 Less: Liabilities associated with properties held for sale — 146 — Less: Current asset retirement obligations 1,110 1,114 3,805 Long-term asset retirement obligations $ 14,066 $ 21,592 $ 39,200

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value, Balance Sheet Grouping	The following tables set forth by level within the fair value hierarchy the Company's financial assets and financial liabilities that were measured at fair value on a recurring basis. Assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company's assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the valuation of assets and liabilities and their placement within the fair value hierarchy levels. As of December 31, 2015 Level 1 Level 2 Level 3 Total (in thousands) Assets Deferred Compensation Plan $ 1,231 $ — $ — $ 1,231 Cash Equivalents 60,065 — — 60,065 Commodity Derivatives — 119,471 — 119,471 Liabilities Commodity Derivatives $ — $ — $ — $ — As of December 31, 2014 Level 1 Level 2 Level 3 Total (in thousands) Assets Deferred Compensation Plan $ 1,069 $ — $ — $ 1,069 Cash Equivalents 75,066 — — 75,066 Commodity Derivatives — 195,176 — 195,176 Liabilities Commodity Derivatives $ — $ 200 $ — $ 200
Schedule of Assets and Liabilities Measured on Non-recurring Basis	The following table sets forth by level within the fair value hierarchy the Company's non-financial assets and liabilities that were measured at fair value on a nonrecurring basis as of December 31, 2015 . Net Carrying Value as of December 31, 2015 Fair Value Measurements Using Level 1 Level 2 Level 3 Impairment (in thousands) Proved property (1) $ 178,221 $ — $ — $ 178,221 $ 559,282 Unproved property (1) 5,539 — — 5,539 13,156 (1) See Note 2 for additional details on impairment expense recognized. During the year ended December 31, 2014 , the Company recognized impairment on proved and unproved property of $39.8 million . Included in the total impairment charges of $39.8 million was $21.1 million of impairment charges related to the remaining Powder River Basin assets for which the Company utilized third party purchase offers as the basis for determining fair value. This property was classified as held for sale as of December 31, 2014. The following table sets forth by level within the fair value hierarchy the Company's non-financial assets and liabilities that were measured at fair value on a nonrecurring basis as of December 31, 2014 . Net Carrying Value as of December 31, 2014 Fair Value Measurements Using Level 1 Level 2 Level 3 Impairment (in thousands) Proved property (1)(2) $ 6,700 $ — $ — $ 6,700 $ 15,761 Unproved property (1)(2) 44,900 — — 44,900 24,082 (1) See Note 2 for additional details on impairment expense recognized. (2) In its Annual Report on Form 10K for the year ended December 31, 2014, the Company inadvertently disclosed the total net carrying value of proved and unproved properties rather than the amount that was subject to fair value measurement.

Derivative Instruments (Tables)

Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value Amounts of Derivative Instruments	The following table summarizes the location, as well as the gross and net fair value amounts of all derivative instruments presented on the Consolidated Balance Sheets as of the dates indicated. As of December 31, 2015 Balance Sheet Gross Amounts of Recognized Assets Gross Amounts Offset in the Balance Sheet Net Amounts of Assets Presented in the Balance Sheet (in thousands) Derivative assets (current) $ 99,809 $ — $ 99,809 Derivative assets (noncurrent) 19,662 — 19,662 Total derivative assets $ 119,471 $ — $ 119,471 As of December 31, 2014 Balance Sheet Gross Amounts of Recognized Assets Gross Amounts Offset in the Balance Sheet Net Amounts of Assets Presented in the Balance Sheet (in thousands) Derivative assets (current) $ 145,426 $ (200 ) (1) $ 145,226 Derivative assets (noncurrent) 49,750 — 49,750 Total derivative assets $ 195,176 $ (200 ) $ 194,976 Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Balance Sheet Net Amounts of Liabilities Presented in the Balance Sheet (in thousands) Derivative liabilities $ (200 ) $ 200 (2) $ — Derivatives and other noncurrent liabilities — — — Total derivative liabilities $ (200 ) $ 200 $ — (1) Amounts are netted against derivative asset balances with the same counterparty and are therefore presented as a net asset on the Consolidated Balance Sheets. (2) Amounts are netted against derivative liability balances with the same counterparty and are therefore presented as a net liability on the Consolidated Balance Sheets.
Cash Flow Hedge Gains and Losses	The following table summarizes the cash flow hedge gains, net of tax, and their locations on the Consolidated Balance Sheets and Consolidated Statements of Operations for the periods indicated: Derivatives Qualifying as Cash Flow Hedges Year Ended December 31, 2015 2014 2013 (in thousands) Amount of Gain (Loss) Recognized in AOCI Commodity Hedges $ — $ — $ — Amount of Gain (Loss) Reclassified from AOCI into Income (net of tax) (1)(2) Commodity Hedges $ — $ 669 $ 4,663 Amount of Gain (Loss) Recognized in Income on Ineffective Hedges Commodity Hedges $ — $ — $ — (1) Presented net of income tax expense of $0.4 million and $2.8 million for the years ended December 31, 2014 and 2013, respectively. (2) Gains reclassified from AOCI into income are included in the oil, gas and NGL production revenues in the Consolidated Statements of Operations.
Financial Instruments for Hedging Volumes	As of December 31, 2015 , the Company had financial instruments in place to hedge the following volumes for the periods indicated: For the Year 2016 For the Year 2017 Derivative Volumes Weighted Average Price Derivative Volumes Weighted Average Price Oil (Bbls) 2,478,600 $ 80.47 683,250 $ 75.61 Natural Gas (MMbtu) 1,830,000 4.10 — —
Realized and Unrealized Gains and Losses on Commodity Derivative Instruments	The table below summarizes the commodity derivative gains and losses the Company recognized related to its oil, gas and NGL derivative instruments for the periods indicated: Year Ended December 31, 2015 2014 2013 (in thousands) Commodity derivative settlements on derivatives designated as cash flow hedges (1) $ — $ 1,070 $ 7,463 Total commodity derivative gain (loss) (2) 104,147 197,447 (23,068 ) (1) Included in oil, gas and NGL production revenues in the Consolidated Statements of Operations. (2) Included in commodity derivative gain (loss) in the Consolidated Statements of Operations.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
(Expense) Benefit for Income Taxes	The (expense) benefit for income taxes consisted of the following for the periods indicated: Year Ended December 31, 2015 2014 2013 (in thousands) Current: Federal $ — $ (1,220 ) $ 1,233 State — (44 ) 352 Foreign — (1 ) (2 ) Deferred: Federal 158,757 (10,246 ) 107,300 State 18,328 (6,398 ) 9,750 Total $ 177,085 $ (17,909 ) $ 118,633
Reconciliation of Actual Income Tax (Expense) Benefit	Income tax (expense) benefit differed from the amounts computed by applying the U.S. federal income tax rate of 35% to pretax income from continuing operations as a result of the following: Year Ended December 31, 2015 2014 2013 (in thousands) Income tax (expense) benefit at the federal statutory rate $ 232,700 $ (11,546 ) $ 108,978 State income taxes, net of federal tax effect 19,399 (932 ) 6,702 Incentive stock compensation (69 ) (199 ) (678 ) Nondeductible political contributions and lobbying costs (11 ) (108 ) (96 ) Nondeductible officer compensation (110 ) (229 ) (138 ) Other permanent items (89 ) (89 ) (52 ) Valuation allowance (74,978 ) — — Deferred tax related to the changes in overall state tax rates (74 ) (5,230 ) 3,851 Other, net 317 424 66 Income tax (expense) benefit $ 177,085 $ (17,909 ) $ 118,633
Components of Deferred Tax Assets and Deferred Tax Liabilities	The tax effects of temporary differences that give rise to significant components of the deferred tax assets and deferred tax liabilities at December 31, 2015 and 2014 are presented below: As of December 31, 2015 2014 (in thousands) Current: Deferred tax assets (liabilities): Derivative instruments $ (37,846 ) $ (54,933 ) Accrued expenses 230 229 Bad debt expense 5 5 Prepaid expenses (615 ) (702 ) Other 7 (17 ) Total current deferred tax assets (liabilities) $ (38,219 ) $ (55,418 ) Long-term: Deferred tax assets: Net operating loss carryforward $ 124,828 $ 56,529 Deferred offering costs — 1,182 Stock-based compensation 17,123 15,767 Deferred rent 622 787 Minimum tax credit carryforward 1,402 1,690 Deferred compensation 915 1,062 State tax credit carryforwards 5,641 5,110 Financing obligation 1,428 1,586 Other 269 250 Less: Valuation allowance (80,088 ) (5,110 ) Total long-term deferred tax assets 72,140 78,853 Deferred tax liabilities: Oil and gas properties (26,466 ) (182,385 ) Long-term derivative instruments (7,455 ) (18,818 ) Total long-term deferred tax assets (liabilities) (33,921 ) (201,203 ) Net long-term deferred tax assets (liabilities) $ 38,219 $ (122,350 )

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2015
Text Block [Abstract]
Schedule of Stockholders Equity	The following table reflects the activity in the Company's common and treasury stock for the periods indicated: Year Ended December 31, 2015 2014 2013 Common Stock Outstanding: Shares at beginning of period 49,526,637 49,152,448 48,150,475 Exercise of common stock options — 7,926 259,699 Shares issued for 401(k) plan 31,699 36,533 47,235 Shares issued for directors' fees 44,892 44,551 52,081 Shares issued for nonvested shares of common stock 673,087 857,870 1,081,259 Shares retired or forfeited (411,803 ) (572,691 ) (438,301 ) Shares at end of period 49,864,512 49,526,637 49,152,448 Treasury Stock: Shares at beginning of period — — — Treasury stock acquired 109,473 116,813 96,880 Treasury stock retired (109,473 ) (116,813 ) (96,880 ) Shares at end of period — — —
Schedule of Accumulated Other Comprehensive Income	The components of accumulated other comprehensive income and related tax effects for the years ended December 31, 2013 and 2014 are as follows: Gross Tax Effect Net of Tax (in thousands) Accumulated other comprehensive income — December 31, 2012 $ 8,544 $ (3,212 ) $ 5,332 Reclassification adjustment for realized gains on hedges included in net income (7,465 ) 2,802 (4,663 ) Accumulated other comprehensive income — December 31, 2013 $ 1,079 $ (410 ) $ 669 Reclassification adjustment for realized gains on hedges included in net income (1,079 ) 410 (669 ) Accumulated other comprehensive income — December 31, 2014 (1) $ — $ — $ — (1) All cash flow hedged transactions were completed by December 31, 2014 resulting in a zero balance for AOCI.

Equity Incentive Compensation34

Equity Incentive Compensation Plans and Other Employee Benefits (Tables)	12 Months Ended
	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-Cash Stock-Based Compensation Cost Related to Equity Awards	The following table presents the non-cash stock-based compensation related to equity awards for the periods indicated: Year Ended December 31, 2015 2014 2013 (in thousands) Common stock options $ 652 $ 2,073 $ 4,696 Nonvested common stock 6,721 6,845 7,492 Nonvested common stock units (1) 1,115 1,065 1,272 Nonvested performance-based equity 1,652 990 2,174 Total $ 10,140 $ 10,973 $ 15,634 (1) Includes non-cash stock-based compensation related to director fees of $0.1 million , $0.1 million and $0.4 million for the years ended December 31, 2015 , 2014 and 2013 , respectively.
Summary of Share-Based Option Activity	A summary of share-based option activity under all the Company's plans as of December 31, 2015 , and changes during the year then ended, is presented below: Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Outstanding at January 1, 2015 1,339,365 $ 32.47 Granted — $ — Exercised — $ — Forfeited or expired (421,544 ) $ 39.50 Outstanding at December 31, 2015 917,821 $ 29.25 1.32 $ — Vested and expected to vest, at December 31, 2015 through the life of the options 917,318 $ 28.17 1.51 $ — Vested and exercisable at December 31, 2015 862,646 $ 29.37 1.40 $ —
Summary of Nonvested Equity Shares of Common Stock	A summary of the Company's nonvested shares of common stock as of December 31, 2015 , 2014 and 2013 , and changes during the years then ended, is presented below: Year Ended December 31, 2015 2014 2013 Shares Weighted Average Grant Date Fair Value Shares Weighted Average Grant Date Fair Value Shares Weighted Average Grant Date Fair Value Outstanding at January 1, 793,064 $ 21.47 756,118 $ 22.17 579,188 $ 31.02 Granted 673,087 $ 11.85 542,209 $ 22.00 630,715 $ 17.98 Vested (294,957 ) $ 21.69 (292,168 ) $ 24.05 (270,482 ) $ 29.82 Forfeited or expired (168,247 ) $ 17.63 (213,095 ) $ 21.99 (183,303 ) $ 24.87 Outstanding at December 31, 1,002,947 $ 15.53 793,064 $ 21.47 756,118 $ 22.17
Summary of Nonvested Performance-Based Equity Shares of Common Stock	A summary of the Company's non-vested performance-based shares of common stock as of December 31, 2015 , 2014 and 2013 , and changes during the years then ended, is presented below: Year Ended December 31, 2015 2014 2013 Shares Weighted Average Fair Shares Weighted Average Fair Shares Weighted Average Fair Outstanding at January 1, 614,077 $ 19.62 584,032 $ 19.80 291,606 $ 26.85 Granted — $ — 315,661 $ 23.86 450,544 $ 19.99 Modified, performance goals revised (1) — $ — — $ — (108,933 ) $ 27.75 Modified, performance goals revised (1) — $ — — $ — 108,933 $ 18.18 Vested (2) (11,623 ) $ 23.07 (42,833 ) $ 19.51 — $ — Forfeited or expired (133,893 ) $ 25.46 (242,783 ) $ 22.13 (158,118 ) $ 22.52 Outstanding at December 31, 468,561 $ 18.46 614,077 $ 19.62 584,032 $ 19.80 (1) As the Compensation Committee approved new performance metrics for the vesting of performance shares in the upcoming year, a new grant date was then created for any unvested awards that were granted in previous years, and a new fair value was established for financial reporting purposes. (2) The Compensation Committee approved a special retention award on July 18, 2013. A debt performance gate was required to be met as of December 31, 2013 in which the shares would vest on July 18, 2014, 2015 and 2016. The vested shares are included in the vested line item for the years ended December 31, 2015 and 2014.
Directors Fees	A summary of the Company's directors' fees and equity-based compensation for the years ended December 31, 2015 , 2014 and 2013 is presented below: Year Ended December 31, 2015 2014 2013 Director fees (shares) 14,892 3,928 16,151 Stock-based compensation (in thousands) $ 75 $ 75 $ 351
Deferred Compensation Liability	The table below summarizes the activity in the plan during the years ended December 31, 2015 and 2014 , and the Company's ending deferred compensation liability as of December 31, 2015 and 2014 : Year Ended December 31, 2015 2014 (in thousands) Beginning deferred compensation liability balance $ 1,069 $ 941 Employee contributions 410 441 Company matching contributions 119 160 Distributions (346 ) (503 ) Participant earnings (losses) (21 ) 30 Ending deferred compensation liability balance $ 1,231 $ 1,069 Amount to be paid within one year $ 206 $ 220 Remaining balance to be paid beyond one year $ 1,025 $ 849
Deferred Compensation Investment Assets	The following table represents the Company's activity in the investment assets held in the rabbi trust during the years ended December 31, 2015 and 2014 : Year Ended December 31, 2015 2014 (in thousands) Beginning investment balance $ 1,069 $ 941 Investment purchases 529 601 Distributions (346 ) (503 ) Earnings (losses) (21 ) 30 Ending investment balance $ 1,231 $ 1,069
Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Summary of Nonvested Equity Shares of Common Stock	A summary of the Company's nonvested share units of common stock as of December 31, 2015 , 2014 and 2013 , and changes during the years then ended, is presented in the table below: Year Ended December 31, 2015 2014 2013 Shares Weighted Average Fair Shares Weighted Average Shares Weighted Average Outstanding at January 1, 54,945 $ 23.84 55,778 $ 19.35 49,185 $ 18.50 Granted 135,439 $ 8.31 45,928 $ 24.49 56,464 $ 22.33 Vested (44,892 ) $ 18.38 (46,761 ) $ 22.25 (49,871 ) $ 18.96 Forfeited or expired — $ — — $ — — $ — Outstanding at December 31, 145,492 $ 11.07 54,945 $ 23.84 55,778 $ 19.35

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Schedule of Aggregate Undiscounted Minimum Future Lease Payments	Lease Financing Obligation. The Company has a Lease Financing Obligation with Bank of America Leasing & Capital, LLC as the lead bank as discussed in Note 5 . The aggregate undiscounted minimum future lease payments, including both principal and interest components, are presented below: As of December 31, 2015 (in thousands) 2016 $ 537 2017 537 2018 537 2019 1,825 2020 — Thereafter — Total $ 3,436
Gross Future Minimum Transportation Demand and Firm Processing Charges	The amounts in the table below represent the Company's future minimum transportation charges. As of December 31, 2015 (in thousands) 2016 $ 18,692 2017 18,692 2018 18,692 2019 18,692 2020 18,692 Thereafter 10,902 Total $ 104,362
Future Minimum Annual Payments Under Drilling, Lease and Other Agreements	Future minimum annual payments under lease and other agreements are as follows: As of December 31, 2015 (in thousands) 2016 (1) $ 6,676 2017 2,892 2018 2,591 2019 633 2020 — Thereafter — Total $ 12,792 (1) Includes a contractual obligation of $3.2 million related to certain drilling commitments on sold properties.

Guarantor Subsidiaries (Tables)

Guarantor Subsidiaries (Tables)	12 Months Ended
	Dec. 31, 2015
Text Block [Abstract]
Schedule of Condensed Consolidating Balance Sheets	Condensed Consolidating Balance Sheets As of December 31, 2015 Parent Guarantor Intercompany Consolidated (in thousands) Assets: Current assets $ 274,115 $ 202 $ — $ 274,317 Property and equipment, net 1,164,086 6,598 — 1,170,684 Intercompany receivable (payable) 21,412 (21,412 ) — — Investment in subsidiaries (14,664 ) — 14,664 — Noncurrent assets 70,228 — — 70,228 Total assets $ 1,515,177 $ (14,612 ) $ 14,664 $ 1,515,229 Liabilities and Stockholders' Equity: Current liabilities $ 145,231 $ — $ — $ 145,231 Long-term debt 803,361 — — 803,361 Deferred income taxes — — — — Other noncurrent liabilities 17,169 52 — 17,221 Stockholders' equity 549,416 (14,664 ) 14,664 549,416 Total liabilities and stockholders' equity $ 1,515,177 $ (14,612 ) $ 14,664 $ 1,515,229 As of December 31, 2014 Parent Guarantor Intercompany Consolidated (in thousands) Assets: Current assets $ 426,103 $ 2 $ — $ 426,105 Property and equipment, net 1,730,074 23,047 — 1,753,121 Intercompany receivable (payable) 22,840 (22,840 ) — — Investment in subsidiaries 163 — (163 ) — Noncurrent assets 65,258 — — 65,258 Total assets $ 2,244,438 $ 209 $ (163 ) $ 2,244,484 Liabilities and Stockholders' Equity: Current liabilities $ 264,687 $ — $ — $ 264,687 Long-term debt 803,222 — — 803,222 Deferred income taxes 122,350 — — 122,350 Other noncurrent liabilities 24,691 46 — 24,737 Stockholders' equity 1,029,488 163 (163 ) 1,029,488 Total liabilities and stockholders' equity $ 2,244,438 $ 209 $ (163 ) $ 2,244,484
Schedule of Condensed Consolidating Statements of Operations	Condensed Consolidating Statements of Operations Year Ended December 31, 2015 Parent Guarantor Intercompany Consolidated (in thousands) Operating and other revenues $ 207,282 $ 610 $ — $ 207,892 Operating expenses (844,577 ) (15,437 ) — (860,014 ) General and administrative (53,890 ) — — (53,890 ) Interest income and other income (expense) 41,156 — — 41,156 Income (loss) before income taxes and equity in earnings (loss) of subsidiaries (650,029 ) (14,827 ) — (664,856 ) (Provision for) Benefit from income taxes 177,085 — — 177,085 Equity in earnings (loss) of subsidiaries (14,827 ) — 14,827 — Net income (loss) $ (487,771 ) $ (14,827 ) $ 14,827 $ (487,771 ) Year Ended December 31, 2014 Parent Guarantor Intercompany Consolidated (in thousands) Operating and other revenues $ 472,288 $ 3 $ — $ 472,291 Operating expenses (514,721 ) (337 ) — (515,058 ) General and administrative (53,361 ) — — (53,361 ) Interest income and other income (expense) 129,118 — — 129,118 Income (loss) before income taxes and equity in earnings (loss) of subsidiaries 33,324 (334 ) — 32,990 (Provision for) Benefit from income taxes (17,909 ) — — (17,909 ) Equity in earnings (loss) of subsidiaries (334 ) — 334 — Net income (loss) $ 15,081 $ (334 ) $ 334 $ 15,081 Year Ended December 31, 2013 Parent Guarantor Intercompany Consolidated (in thousands) Operating and other revenues $ 568,055 $ 38 $ — $ 568,093 Operating expenses (682,898 ) (270 ) — (683,168 ) General and administrative (64,902 ) — — (64,902 ) Interest and other income (expense) (131,389 ) — — (131,389 ) Income (loss) before income taxes and equity in earnings (loss) of subsidiaries (311,134 ) (232 ) — (311,366 ) (Provision for) Benefit from income taxes 118,633 — — 118,633 Equity in earnings (loss) of subsidiaries (232 ) — 232 — Net income (loss) $ (192,733 ) $ (232 ) $ 232 $ (192,733 )
Schedule of Condensed Consolidating Statements of Comprehensive Income	Condensed Consolidating Statements of Comprehensive Income (Loss) Year Ended December 31, 2015 Parent Guarantor Intercompany Consolidated (in thousands) Net Income (Loss) $ (487,771 ) $ (14,827 ) $ 14,827 $ (487,771 ) Other Comprehensive Income (Loss), net of tax: Effect of derivative financial instruments — — — — Other comprehensive income (loss) — — — — Comprehensive Income (Loss) $ (487,771 ) $ (14,827 ) $ 14,827 $ (487,771 ) Year Ended December 31, 2014 Parent Guarantor Intercompany Consolidated (in thousands) Net Income (Loss) $ 15,081 $ (334 ) $ 334 $ 15,081 Other Comprehensive Income (Loss), net of tax: Effect of derivative financial instruments (669 ) — — (669 ) Other comprehensive income (loss) (669 ) — — (669 ) Comprehensive Income (Loss) $ 14,412 $ (334 ) $ 334 $ 14,412 Year Ended December 31, 2013 Parent Issuer Guarantor Subsidiaries Intercompany Eliminations Consolidated (in thousands) Net Income (Loss) $ (192,733 ) $ (232 ) $ 232 $ (192,733 ) Other Comprehensive Income (Loss), net of tax: Effect of derivative financial instruments (4,663 ) — — (4,663 ) Other comprehensive income (loss) (4,663 ) — — (4,663 ) Comprehensive Income (Loss) $ (197,396 ) $ (232 ) $ 232 $ (197,396 )
Schedule of Condensed Consolidating Statements of Cash Flows	Condensed Consolidating Statements of Cash Flows Year Ended December 31, 2015 Parent Guarantor Intercompany Consolidated (in thousands) Cash flows from operating activities $ 193,329 $ 349 $ — $ 193,678 Cash flows from investing activities: Additions to oil and gas properties, including acquisitions (325,613 ) 1,079 — (324,534 ) Additions to furniture, fixtures and other (1,223 ) — — (1,223 ) Proceeds from sale of properties and other investing activities 123,122 — — 123,122 Cash paid for short-term investments (114,883 ) — — (114,883 ) Proceeds from sale of short-term investments 115,000 — — 115,000 Intercompany transfers 1,428 — (1,428 ) — Cash flows from financing activities: Proceeds from debt — — — — Principal and redemption premium payments on debt (25,191 ) — — (25,191 ) Intercompany transfers — (1,428 ) 1,428 — Other financing activities (3,037 ) — — (3,037 ) Change in cash and cash equivalents (37,068 ) — — (37,068 ) Beginning cash and cash equivalents 165,904 — — 165,904 Ending cash and cash equivalents $ 128,836 $ — $ — $ 128,836 Year Ended December 31, 2014 Parent Guarantor Intercompany Consolidated (in thousands) Cash flows from operating activities $ 261,704 $ 13 $ — $ 261,717 Cash flows from investing activities: Additions to oil and gas properties, including acquisitions (571,215 ) (9,728 ) — (580,943 ) Additions to furniture, fixtures and other (3,658 ) — — (3,658 ) Proceeds from sale of properties and other investing activities 553,477 1,819 — 555,296 Intercompany transfers (7,896 ) — 7,896 — Cash flows from financing activities: Proceeds from debt 165,000 — — 165,000 Principal and redemption premium payments on debt (283,546 ) — — (283,546 ) Intercompany transfers — 7,896 (7,896 ) — Other financing activities (2,557 ) — — (2,557 ) Change in cash and cash equivalents 111,309 — — 111,309 Beginning cash and cash equivalents 54,595 — — 54,595 Ending cash and cash equivalents $ 165,904 $ — $ — $ 165,904 Year Ended December 31, 2013 Parent Guarantor Intercompany Consolidated (in thousands) Cash flows from operating activities $ 265,323 $ (58 ) $ — $ 265,265 Cash flows from investing activities: Additions to oil and gas properties, including acquisitions (439,785 ) (5,694 ) — (445,479 ) Additions to furniture, fixtures and other (2,254 ) — — (2,254 ) Proceeds from sale of properties and other investing activities 310,704 — — 310,704 Cash flows from financing activities: Proceeds from debt 420,000 — — 420,000 Principal and redemption premium payments on debt (576,422 ) — — (576,422 ) Intercompany transfers (5,752 ) 5,752 — — Other financing activities 3,336 — — 3,336 Change in cash and cash equivalents (24,850 ) — — (24,850 ) Beginning cash and cash equivalents 79,445 — — 79,445 Ending cash and cash equivalents $ 54,595 $ — $ — $ 54,595

Summary of Significant Accoun37

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Summary Of Significant Accounting Policies [Line Items]
Non-cash impairment of oil and gas properties	$ 572,400	$ 39,800
Anti Dilutive Securities Excluded From Computation of Earnings Per Share Amount		1,406,938
5% Convertible Senior Notes Due 2028 [Member]
Summary Of Significant Accounting Policies [Line Items]
Debt, stated interest rate	5.00%
Debt maturity date	2,028
Less Receivable Due to Industry Partner
Summary Of Significant Accounting Policies [Line Items]
Accounts Receivable, Gross		$ 4,700
Receivable from Department of Interior, Gross
Summary Of Significant Accounting Policies [Line Items]
Accounts Receivable, Gross		47,600
West Tavaputs, Unproved [Member]
Summary Of Significant Accounting Policies [Line Items]
Non-cash impairment of oil and gas properties			$ 2,500
Powder River Oil [Member]
Summary Of Significant Accounting Policies [Line Items]
Non-cash impairment of oil and gas properties		14,800
Other, Unproved [Member]
Summary Of Significant Accounting Policies [Line Items]
Non-cash impairment of oil and gas properties			17,100
West Tavaputs, Proved [Member]
Summary Of Significant Accounting Policies [Line Items]
Non-cash impairment of oil and gas properties		1,000
Paradox Basin, Unproved [Member]
Summary Of Significant Accounting Policies [Line Items]
Non-cash impairment of oil and gas properties		11,600
Uinta Basin, Unproved [Member]
Summary Of Significant Accounting Policies [Line Items]
Non-cash impairment of oil and gas properties		6,100
Powder River Oil, Unproved [Member]
Summary Of Significant Accounting Policies [Line Items]
Non-cash impairment of oil and gas properties		6,400
Proved Oil And Gas Properties [Member]
Summary Of Significant Accounting Policies [Line Items]
Non-cash impairment of oil and gas properties	$ 559,282	15,761	206,953
Unproved Oil And Gas Properties [Member]
Summary Of Significant Accounting Policies [Line Items]
Non-cash impairment of oil and gas properties	$ 13,156	$ 24,082	$ 19,598

Summary of Significant Accoun38

Summary of Significant Accounting Policies - Summary of Accounts Receivable (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for doubtful accounts	$ (14)	$ (14)
Total accounts receivable	43,461	112,209
Accrued oil, gas and NGL sales [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable gross	33,594	35,099
Due from joint interest owners [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable gross	8,373	27,937
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable gross	$ 1,508	$ 49,187

Summary of Significant Accoun39

Summary of Significant Accounting Policies - Net Capitalized Costs and Associated Accumulated Depreciation, Depletion & Amortization and Non Cash Impairments (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Accounting Policies [Abstract]
Proved properties	$ 320,538	$ 390,482
Wells and related equipment and facilities	1,592,716	1,537,370
Support equipment and facilities	77,785	68,371
Materials and supplies	9,171	13,069
Total proved oil and gas properties	2,000,210	2,009,292
Unproved properties	33,336	78,898
Wells and facilities in progress	45,862	69,936
Total unproved oil and gas properties, excluded from amortization	79,198	148,834
Assets held for sale	0	9,234
Accumulated depreciation, depletion, amortization and impairment	(918,510)	(427,954)
Total oil and gas properties, net	$ 1,160,898	$ 1,739,406

Summary of Significant Accoun40

Summary of Significant Accounting Policies - Non-Cash Impairment Charges, Included within Impairment, Dry Hole Costs and Abandonment Expense in Consolidated Statements of Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Summary Of Significant Accounting Policies [Line Items]
Non-cash impairment of oil and gas properties	$ 572,400	$ 39,800
Dry hole costs	123	101	$ 1,124
Abandonment expense	2,749	6,597	10,723
Total non-cash impairment, dry hole costs and abandonment expense	575,310	46,881	238,398
Unproved Oil And Gas Properties [Member]
Summary Of Significant Accounting Policies [Line Items]
Non-cash impairment of oil and gas properties	13,156	24,082	19,598
Non Cash Impairment Of Inventory [Member]
Summary Of Significant Accounting Policies [Line Items]
Non-cash impairment of inventory	$ 0	$ 340	$ 0

Summary of Significant Accoun41

Summary of Significant Accounting Policies - Accounts Payable and Accrued Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Accounting Policies [Abstract]
Accrued drilling, completion and facility costs	$ 32,895	$ 68,124
Accrued lease operating, gathering, transportation and processing expenses	4,930	12,526
Accrued general and administrative expenses	10,962	8,482
Accrued interest payable	13,918	14,284
Accrued payables for property sales	167	16,296
Trade payables and other	1,465	6,540
Total accounts payable and accrued liabilities	$ 64,337	$ 126,252

Summary of Significant Accoun42

Summary of Significant Accounting Policies - Calculation of Basic and Diluted Earnings (Loss) Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounting Policies [Abstract]
Net Income (Loss)	$ (487,771)	$ 15,081	$ (192,733)
Basic weighted-average common shares outstanding in period (in shares)	48,303,276	48,010,730	47,496,857
Add dilutive effects of stock options and nonvested equity shares of common stock (in shares)	0	425,000	0
Diluted weighted-average common shares outstanding in period (in shares)	48,303,276	48,435,725	47,496,857
Basic net income (loss) per common share (in dollars per share)	$ (10.10)	$ 0.31	$ (4.06)
Diluted net income (loss) per common share (in dollars per share)	$ (10.10)	$ 0.31	$ (4.06)

Supplemental Disclosures of C43

Supplemental Disclosures of Cash Flow Information - Supplemental Cash Flow Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Supplemental Cash Flow Information [Abstract]
Cash paid for interest, net of amount capitalized	$ 61,047	$ 65,935	$ 94,205
Cash paid for income taxes	2	1	1,163
Supplemental disclosures of non-cash investing and financing activities:
Accrued receivables - oil and gas properties (1)	0	42,872	0
Accrued liabilities - oil and gas properties	33,805	72,297	75,340
Change in asset retirement obligations, net of disposals	(9,101)	(22,740)	(6,996)
Retirement of treasury stock	(1,173)	(2,684)	(1,778)
Fair value of properties exchanged in non-cash transactions	0	77,078	0
Transfer of lease financing obligation	$ 0	$ 36,075	$ 45,190

Divestitures and Assets Held 44

Divestitures and Assets Held for Sale - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)a	Dec. 31, 2014USD ($)a	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)
Proceeds from Divestiture of Businesses				$ 325,300
Non-cash impairment of oil and gas properties	$ 572,400	$ 39,800
Accumulated Depreciation Depletion Amortization And Impairment Property Plant And Equipment	$ 934,745	454,202
Cash proceeds and recognized pre-tax loss				$ (4,500)
Percent of Acreage Sold that is Proved Developed	76.00%
Assets, Fair Value Disclosure, Nonrecurring	$ 180,000
Gain (Loss) on Disposition of Oil and Gas Property	(1,745)	(100,407)	$ 0
Transfer of lease financing obligation	0	36,075	45,190
Wind River Basin [Member]
Percentage Of Assets Sold				100.00%
Cash proceeds and recognized pre-tax loss			(3,100)
Powder River Basin [Member]
Percentage Of Assets Sold				100.00%
Piceance [Member]
Proceeds from Divestiture of Businesses		498,700
Gain (Loss) on Disposition of Oil and Gas Property		(79,500)
Proved properties		1,320,745
Furniture, equipment and other		4,907
Accumulated depreciation, depletion, amortization and impairment		(688,864)
Total assets		636,788
Asset retirement obligation		22,448
Transfer of lease financing obligation		36,075
Other liabilities		84
Total liabilities		58,607
Net assets		578,181
West Tavaputs [Member]
Proceeds from Divestiture of Businesses			308,700
Non-cash impairment of inventory		1,000	$ 209,500
Powder River Oil [Member]
Proceeds from Divestiture of Businesses	$ 9,300	30,000
Unproved Oil and Gas Assets Sold		40,600
Accumulated Depreciation Depletion Amortization And Impairment Property Plant And Equipment		$ 33,100
Net Mineral Acres Sold | a	19,492	17,497
Net Mineral Acres Exchanged Relinquished | a		29,015
Net Mineral Acres Exchanged Received | a		7,856
Assets, Fair Value Disclosure, Nonrecurring		$ 71,000
Gain (Loss) on Disposition of Oil and Gas Property		(24,400)
Proved properties		86,200
Asset retirement obligation		1,300
DJ Basin, non-core [Member]
Proceeds from Divestiture of Businesses	$ 30,700
Net Mineral Acres Sold | a	23,000
Uinta Basin, non-core [Member]
Proceeds from Divestiture of Businesses	$ 26,000
Net Mineral Acres Sold | a	17,600
Powder River Oil, Proved [Member]
Non-cash impairment of oil and gas properties		14,800
Powder River Oil, Unproved [Member]
Non-cash impairment of oil and gas properties		$ 6,400

Divestitures and Assets Held 45

Divestitures and Assets Held for Sale - Asset Held for Sale (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Long Lived Assets Held-for-sale [Line Items]
Non-cash impairment of oil and gas properties	$ 572.4	$ 39.8
Powder River Oil, Proved [Member]
Long Lived Assets Held-for-sale [Line Items]
Non-cash impairment of oil and gas properties		14.8
Powder River Oil, Unproved [Member]
Long Lived Assets Held-for-sale [Line Items]
Non-cash impairment of oil and gas properties		$ 6.4

Long-Term Debt - Outstanding De

Long-Term Debt - Outstanding Debt (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Principal	$ 803,361	$ 803,222
Carrying Amount	803,361	803,222
Debt, fair value	$ 542,200	725,800
Amended Credit Facility [Member]
Debt Instrument [Line Items]
Maturity Date	Apr. 9, 2020
Principal	$ 0	0
Carrying Amount	$ 0	0
9.875% Senior Notes [Member]
Debt Instrument [Line Items]
Debt, stated interest rate	9.875%
Convertible Notes [Member]
Debt Instrument [Line Items]
Maturity Date	Mar. 15, 2028
Principal	$ 579	25,344
Carrying Amount	579	25,344
Debt, fair value	500	25,100
Convertible Debt, Fair Value Disclosures	$ 500	25,100
7.625% Senior Notes [Member]
Debt Instrument [Line Items]
Maturity Date	Oct. 1, 2019
Principal	$ 400,000	400,000
Carrying Amount	$ 400,000	$ 400,000
Debt, stated interest rate	7.625%	7.625%
Debt, fair value	$ 270,200	$ 359,800
7.0% Senior Notes [Member]
Debt Instrument [Line Items]
Maturity Date	Oct. 15, 2022
Principal	$ 400,000	400,000
Carrying Amount	$ 400,000	$ 400,000
Debt, stated interest rate	7.00%	7.00%
Debt, fair value	$ 272,000	$ 366,000
Lease Financing Obligation [Member]
Debt Instrument [Line Items]
Maturity Date	Aug. 10, 2020
Principal	$ 3,222	3,648
Carrying Amount	3,222	3,648
Debt, fair value	3,100	3,500
Total Debt [Member]
Debt Instrument [Line Items]
Principal	803,801	828,992
Carrying Amount	803,801	828,992
Current Portion of Long-Term Debt [Member]
Debt Instrument [Line Items]
Principal	440	25,770
Carrying Amount	$ 440	$ 25,770

Long-Term Debt - Additional Inf

Long-Term Debt - Additional Information (Detail)	Mar. 20, 2015	Mar. 20, 2012USD ($)	Dec. 31, 2015USD ($)Lenders	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Mar. 12, 2012USD ($)	Sep. 27, 2011USD ($)	Mar. 12, 2008USD ($)
Debt Instrument [Line Items]
Number of Lenders, Credit Facility | Lenders			13
Line of credit facility, maximum borrowing capacity			$ 375,000,000
Average annual interest rates incurred on Amended Credit Facility				1.90%
Line of credit facility, reduced borrowing capacity			349,000,000
Principal amount			803,361,000	$ 803,222,000
(Gain) loss on extinguishment of debt			(1,749,000)	0	$ 21,460,000
Purchase of equipment			$ 1,800,000
Minimum [Member]
Debt Instrument [Line Items]
Revolving credit facility, interest rate above London Interbank Offered Rate			1.50%
Revolving credit facility interest rate percent above LIBOR alternate interest rate			0.50%
Commitment fee percentage			0.375%
Maximum [Member]
Debt Instrument [Line Items]
Revolving credit facility, interest rate above London Interbank Offered Rate			2.50%
Revolving credit facility interest rate percent above LIBOR alternate interest rate			1.50%
Commitment fee percentage			0.50%
Convertible Notes [Member]
Debt Instrument [Line Items]
Convertible Debt, Fair Value Disclosures			$ 500,000	25,100,000
Debt instrument, maturity date			Mar. 15, 2028
Principal amount			$ 579,000	25,344,000
5% Convertible Senior Notes Due 2028 [Member]
Debt Instrument [Line Items]
Principal amount								$ 172,500,000
Face Amount of Outstanding Convertible Notes Repaid		$ 147,200,000
Percentage of notes put to company	98.00%	85.00%
Debt, stated interest rate			5.00%
Convertible Debt [Member]
Debt Instrument [Line Items]
(Gain) loss on extinguishment of debt			$ (2,600,000)
Five Percentage Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Face Amount of Outstanding Convertible Notes Repaid			$ 24,800,000
Convertible Notes [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date			Mar. 15, 2028
Principal amount			$ 600,000
Debt, stated interest rate			5.00%
Debt instrument conversion price rate of redemption			100.00%
Minimum days notice to call Convertible Notes			30 days
Amended Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date			Apr. 9, 2020
Line of credit facility, maximum amount outstanding during period			$ 0
Letters of credit issued amount			26,000,000
Principal amount			$ 0	0
9.875% Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage			11.20%
Debt, stated interest rate			9.875%
7.625% Senior Notes Due 2019 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date			Oct. 1, 2019
Principal amount							$ 400,000,000
Debt, stated interest rate			7.625%
7.0% Senior Notes Due 2022 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date			Oct. 15, 2022
Principal amount						$ 400,000,000
Par value of senior notes			103.50%
Lease Financing Obligation [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage			3.30%
Debt instrument, maturity date			Aug. 10, 2020
Principal amount			$ 3,222,000	3,648,000
Weighted average implicit rate based on interest expense			3.30%
7.625% Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage			8.00%
Debt instrument, maturity date			Oct. 1, 2019
Principal amount			$ 400,000,000	$ 400,000,000
Par value of senior notes			103.813%
Debt, stated interest rate			7.625%	7.625%
7.0% Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage			7.20%
Debt instrument, maturity date			Oct. 15, 2022
Principal amount			$ 400,000,000	$ 400,000,000
Debt, stated interest rate			7.00%	7.00%
Line of Credit [Member]
Debt Instrument [Line Items]
Interest Expense, Debt			$ 1,600,000
(Gain) loss on extinguishment of debt			$ 800,000

Long-Term Debt - Cash and Non-C

Long-Term Debt - Cash and Non-Cash Portion of Interest Expense Related to Long Term Debt (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Mar. 12, 2012
Debt Instrument [Line Items]
Principal	$ 803,361,000	$ 803,222,000
Cash interest [Member]
Debt Instrument [Line Items]
Amended Credit Facility interest	1,755,000	4,837,000	$ 6,802,000
Non-cash interest [Member]
Debt Instrument [Line Items]
Amended Credit Facility interest	$ 2,704,000	2,342,000	2,342,000
9.875% Senior Notes [Member]
Debt Instrument [Line Items]
Debt, stated interest rate	9.875%
Effective interest rate of debt instrument	11.20%
9.875% Senior Notes [Member] | Cash interest [Member]
Debt Instrument [Line Items]
Senior Notes interest	$ 0	0	13,373,000
9.875% Senior Notes [Member] | Non-cash interest [Member]
Debt Instrument [Line Items]
Senior Notes interest	$ 0	0	1,361,000
5% Convertible Notes [Member]
Debt Instrument [Line Items]
Debt, stated interest rate	5.00%
Convertible Notes [Member]
Debt Instrument [Line Items]
Debt, stated interest rate	5.00%
Principal	$ 600,000
Convertible Notes [Member]
Debt Instrument [Line Items]
Principal	579,000	25,344,000
Convertible Notes [Member] | Cash interest [Member]
Debt Instrument [Line Items]
Convertible Notes interest	301,000	1,264,000	1,267,000
Convertible Notes [Member] | Non-cash interest [Member]
Debt Instrument [Line Items]
Convertible Notes interest	$ 8,000	$ 5,000	6,000
7.625% Senior Notes [Member]
Debt Instrument [Line Items]
Debt, stated interest rate	7.625%	7.625%
Effective interest rate of debt instrument	8.00%
Principal	$ 400,000,000	$ 400,000,000
7.625% Senior Notes [Member] | Cash interest [Member]
Debt Instrument [Line Items]
Senior Notes interest	30,500,000	30,500,000	30,500,000
7.625% Senior Notes [Member] | Non-cash interest [Member]
Debt Instrument [Line Items]
Senior Notes interest	$ 1,082,000	$ 1,090,000	1,070,000
7.0% Senior Notes Due 2022 [Member]
Debt Instrument [Line Items]
Principal				$ 400,000,000
7.0% Senior Notes [Member]
Debt Instrument [Line Items]
Debt, stated interest rate	7.00%	7.00%
Effective interest rate of debt instrument	7.20%
Principal	$ 400,000,000	$ 400,000,000
7.0% Senior Notes [Member] | Cash interest [Member]
Debt Instrument [Line Items]
Senior Notes interest	28,000,000	28,000,000	28,000,000
7.0% Senior Notes [Member] | Non-cash interest [Member]
Debt Instrument [Line Items]
Senior Notes interest	$ 806,000	814,000	795,000
Lease Financing Obligation [Member]
Debt Instrument [Line Items]
Effective interest rate of debt instrument	3.30%
Principal	$ 3,222,000	3,648,000
Lease Financing Obligation [Member] | Cash interest [Member]
Debt Instrument [Line Items]
Financial Obligation interest	110,000	638,000	2,852,000
Lease Financing Obligation [Member] | Non-cash interest [Member]
Debt Instrument [Line Items]
Financial Obligation interest	$ 24,000	$ 12,000	$ 30,000

Asset Retirement Obligations -

Asset Retirement Obligations - Schedule of Asset Retirement Obligations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning of period	$ 22,852	$ 43,005	$ 47,616
Liabilities incurred	781	4,027	2,359
Liabilities settled	(739)	(6,283)	(1,096)
Disposition of properties	(9,056)	(23,722)	(13,543)
Accretion expense	1,425	2,587	3,481
Revisions to estimate	(87)	3,238	4,188
End of period	15,176	22,852	43,005
Less: Liabilities associated with properties held for sale	0	146	0
Less: Current asset retirement obligations	1,110	1,114	3,805
Long-term asset retirement obligations	$ 14,066	$ 21,592	$ 39,200

Fair Value Measurements - Balan

Fair Value Measurements - Balance Sheet Grouping (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Assets
Deferred Compensation Plan	$ 1,231	$ 1,069
Cash Equivalents	128,836	165,904	$ 54,595	$ 79,445
Cash Equivalents - Money Market Funds [Member]
Assets
Cash Equivalents	60,065	75,066
Commodity Derivatives [Member]
Assets
Commodity Derivatives	119,471	195,176
Liabilities
Commodity Derivatives	0	200
Level 1 [Member]
Assets
Deferred Compensation Plan	1,231	1,069
Level 1 [Member] | Cash Equivalents - Money Market Funds [Member]
Assets
Cash Equivalents	60,065	75,066
Level 1 [Member] | Commodity Derivatives [Member]
Assets
Commodity Derivatives	0	0
Liabilities
Commodity Derivatives	0	0
Level 2 [Member]
Assets
Deferred Compensation Plan	0	0
Level 2 [Member] | Cash Equivalents - Money Market Funds [Member]
Assets
Cash Equivalents	0	0
Level 2 [Member] | Commodity Derivatives [Member]
Assets
Commodity Derivatives	119,471	195,176
Liabilities
Commodity Derivatives	0	200
Level 3 [Member]
Assets
Deferred Compensation Plan	0	0
Level 3 [Member] | Cash Equivalents - Money Market Funds [Member]
Assets
Cash Equivalents	0	0
Level 3 [Member] | Commodity Derivatives [Member]
Assets
Commodity Derivatives	0	0
Liabilities
Commodity Derivatives	$ 0	$ 0

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value Measurements [Line Items]
Debt, fair value	$ 542.2	$ 725.8
Assets, Fair Value Disclosure, Nonrecurring	180
Non-cash impairment of oil and gas properties	$ 572.4	$ 39.8
9.875% Senior Notes [Member]
Fair Value Measurements [Line Items]
Debt, stated interest rate	9.875%
7.625% Senior Notes [Member]
Fair Value Measurements [Line Items]
Debt, stated interest rate	7.625%	7.625%
Debt, fair value	$ 270.2	$ 359.8
7.0% Senior Notes [Member]
Fair Value Measurements [Line Items]
Debt, stated interest rate	7.00%	7.00%
Debt, fair value	$ 272	$ 366
Convertible Notes [Member]
Fair Value Measurements [Line Items]
Debt, fair value	0.5	25.1
Lease Financing Obligation [Member]
Fair Value Measurements [Line Items]
Debt, fair value	$ 3.1	3.5
Powder River Basin [Member]
Fair Value Measurements [Line Items]
Non-cash impairment of oil and gas properties		$ 21.1

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured on a Non-recurring Basis (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Capitalized Costs, Oil and Gas Producing Activities, Net	$ 1,160,898	$ 1,739,406
Non-cash impairment of oil and gas properties	572,400	39,800
Proved Oil And Gas Properties [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Non-cash impairment of oil and gas properties	559,282	15,761	$ 206,953
Proved Oil And Gas Properties [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Capitalized Costs, Oil and Gas Producing Activities, Net	178,221	6,700
Proved Oil And Gas Properties [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Oil and Gas Property, Successful Effort Method, Net	0	0
Proved Oil And Gas Properties [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Oil and Gas Property, Successful Effort Method, Net	0	0
Proved Oil And Gas Properties [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Oil and Gas Property, Successful Effort Method, Net	178,221	6,700
Unproved Oil And Gas Properties [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Non-cash impairment of oil and gas properties	13,156	24,082	$ 19,598
Unproved Oil And Gas Properties [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Capitalized Costs, Oil and Gas Producing Activities, Net	5,539	44,900
Unproved Oil And Gas Properties [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Oil and Gas Property, Successful Effort Method, Net	0	0
Unproved Oil And Gas Properties [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Oil and Gas Property, Successful Effort Method, Net	0	0
Unproved Oil And Gas Properties [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Oil and Gas Property, Successful Effort Method, Net	$ 5,539	$ 44,900

Derivative Instruments - Fair V

Derivative Instruments - Fair Value Amounts of Derivative Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Gross Amounts of Recognized Assets	$ 119,471	$ 195,176
Gross Amounts Offset in the Balance Sheet	0	(200)
Net Amounts of Assets Presented in the Balance Sheet	119,471	194,976
Gross Amounts of Recognized Liabilities		(200)
Gross Amounts Offset in the Balance Sheet		200
Net Amounts of Liabilities Presented in the Balance Sheet		0
Derivative Assets [Member]
Derivatives, Fair Value [Line Items]
Gross Amounts of Recognized Assets	99,809	145,426
Gross Amounts Offset in the Balance Sheet	0	(200)
Net Amounts of Assets Presented in the Balance Sheet	99,809	145,226
Deferred Financing Costs, Derivative Assets and Other Non Current Assets [Member]
Derivatives, Fair Value [Line Items]
Gross Amounts of Recognized Assets	19,662	49,750
Gross Amounts Offset in the Balance Sheet	0	0
Net Amounts of Assets Presented in the Balance Sheet	$ 19,662	49,750
Derivative Liabilities [Member]
Derivatives, Fair Value [Line Items]
Gross Amounts of Recognized Liabilities		(200)
Gross Amounts Offset in the Balance Sheet		200
Net Amounts of Liabilities Presented in the Balance Sheet		0
Derivative and Other Non Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Gross Amounts of Recognized Liabilities		0
Gross Amounts Offset in the Balance Sheet		0
Net Amounts of Liabilities Presented in the Balance Sheet		$ 0

Derivative Instruments - Cash F

Derivative Instruments - Cash Flow Hedge Gain and Losses (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI	$ 0	$ 0	$ 0
Amount of Gain (Loss) Reclassified from AOCI into Income (net of tax)	$ 0	$ 0	$ 0
Derivatives Qualifying as Cash Flow Hedges	Commodity Hedges	Commodity Hedges	Commodity Hedges
Effect of derivative financial instruments, taxes		$ 410	$ 2,802
Commodity Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified from AOCI into Income (net of tax)	$ 0	$ 669	$ 4,663

Derivative Instruments - Financ

Derivative Instruments - Financial Instruments for Hedging Volume (Detail)	Dec. 31, 2015USD ($)MMBTUbbl
2016 [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Oil (Bbls) | bbl	2,478,600
Weighted Average Price, Hedge Backed Oil Volumes	$ 80.47
Natural Gas (MMbtu) | MMBTU	1,830,000
Weighted Average Price, Hedge Backed Gas Volumes	$ 4.10
2017 [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Oil (Bbls) | bbl	683,250
Weighted Average Price, Hedge Backed Oil Volumes	$ 75.61
Natural Gas (MMbtu) | MMBTU	0
Weighted Average Price, Hedge Backed Gas Volumes	$ 0

Derivative Instruments - Realiz

Derivative Instruments - Realized and Unrealized Gains and Losses on Commodity Derivative Instruments (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Operating and other revenues	$ 207,892	$ 472,291	$ 568,093
Oil and Natural Gas Derivative Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Operating and other revenues	0	1,070	7,463
Total commodity derivative gain (loss)	$ 104,147	$ 197,447	$ (23,068)

Derivative Instruments - Additi

Derivative Instruments - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015Counterparty
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Number of counterparties for hedges at period end	8

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Loss Carryforwards [Line Items]
U.S. federal income tax rate	35.00%
Federal tax net operating loss carryforwards	$ 333,800
Federal AMT credit carryforward	1,400
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	(74,978)	$ 0	$ 0
Deferred Tax Liabilities, Net	0	$ 177,768
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforward, Amount	$ 8,700

Income Taxes - Expense for Inco

Income Taxes - Expense for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Current Federal	$ 0	$ (1,220)	$ 1,233
Current State	0	(44)	352
Current Foreign	0	(1)	(2)
Deferred Federal	158,757	(10,246)	107,300
Deferred State	18,328	(6,398)	9,750
Income tax (expense) benefit	$ 177,085	$ (17,909)	$ 118,633

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Actual Income Tax Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Income tax (expense) benefit at the federal statutory rate	$ 232,700	$ (11,546)	$ 108,978
State income taxes, net of federal tax effect	19,399	(932)	6,702
Incentive stock compensation	(69)	(199)	(678)
Nondeductible political contributions and lobbying costs	(11)	(108)	(96)
Nondeductible officer compensation	(110)	(229)	(138)
Other permanent items	(89)	(89)	(52)
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	(74,978)	0	0
Deferred tax related to the changes in overall state tax rates	(74)	(5,230)	3,851
Other, net	317	424	66
Income tax (expense) benefit	$ 177,085	$ (17,909)	$ 118,633

Income Taxes - Components of De

Income Taxes - Components of Deferred Tax Assets and Deferred Tax Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Components of Deferred Tax Assets and Liabilities [Abstract]
Derivative instruments	$ (37,846)	$ (54,933)
Accrued expenses	230	229
Bad debt expense	5	5
Prepaid expenses	(615)	(702)
Other	7	(17)
Total current deferred tax assets (liabilities)	(38,219)	(55,418)
Net operating loss carryforward	124,828	56,529
Deferred offering costs	0	1,182
Stock-based compensation	17,123	15,767
Deferred rent	622	787
Minimum tax credit carryforward	1,402	1,690
Deferred compensation	915	1,062
State tax credit carryforwards	5,641	5,110
Financing obligation	1,428	1,586
Other	269	250
Less: Valuation allowance	(80,088)	(5,110)
Total long-term deferred tax assets	72,140	78,853
Oil and gas properties	(26,466)	(182,385)
Long-term derivative instruments	(7,455)	(18,818)
Total long-term deferred tax assets (liabilities)	(33,921)	(201,203)
Net long-term deferred tax assets (liabilities)	38,219	0
Net long-term deferred tax assets (liabilities)	$ 0	$ (122,350)

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - $ / shares	Dec. 31, 2015	Dec. 31, 2014
Class of Stock [Line Items]
Preferred Stock, Shares Issued	0
Preferred stock, shares authorized	75,000,000
Preferred stock, par value	$ 0.001
Common stock, shares authorized	150,000,000	150,000,000
Common stock, par value	$ 0.001	$ 0.001
Preferred stock, shares outstanding	0

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of Stockholders Equity (Detail) - shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares at beginning of period	49,526,637	49,152,448	48,150,475
Exercise of common stock options	0	7,926	259,699
Shares issued for 401(k) plan	31,699	36,533	47,235
Shares issued for directors' fees	44,892	44,551	52,081
Shares issued for nonvested shares of common stock	673,087	857,870	1,081,259
Shares retired or forfeited	(411,803)	(572,691)	(438,301)
Shares at end of period	49,864,512	49,526,637	49,152,448
Shares at beginning of period	0	0	0
Treasury stock acquired	109,473	116,813	96,880
Treasury stock retired	(109,473)	(116,813)	(96,880)
Shares at end of period	0	0	0

Stockholders Equity - Schedule

Stockholders Equity - Schedule of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss), before Tax [Roll Forward]
Accumulated other comprehensive income, Gross Beginning	$ 1,079	$ 8,544
Reclassification adjustment for realized gains on hedges included in net income, Gross	(1,079)	(7,465)
Accumulated other comprehensive income, Gross Ending	0	1,079
Accumulated Other Comprehensive Income (Loss), Tax [Roll Forward]
Accumulated other comprehensive income, Tax Effect Beginning	(410)	(3,212)
Reclassification adjustment for realized gains on hedges included in net income, Tax Effect	410	2,802
Accumulated other comprehensive income, Tax Effect Ending	0	(410)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated other comprehensive income, Net of Tax Beginning	(669)	(5,332)
Reclassification adjustment for realized gains on hedges included in net income, Net of Tax	(669)	(4,663)
Accumulated other comprehensive income, Net of Tax Ending	$ 0	$ 669

Equity Incentive Compensation65

Equity Incentive Compensation Plans and Other Employee Benefits - Additional Information (Detail)	1 Months Ended				12 Months Ended
	Feb. 28, 2014	Feb. 28, 2013	May. 31, 2012shares	Mar. 31, 2012	Dec. 31, 2015USD ($)unitageshares	Dec. 31, 2014USD ($)shares	Dec. 31, 2013USD ($)shares	Dec. 31, 2012shares	Dec. 31, 2011shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost					$ 10,800,000
Weighted-average period (years)					1 year 10 months 24 days
Expected dividend yield					0.00%
Weighted average expected terms range, minimum period					4 years 3 months 18 days
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Weighted Average Expected Term Maximum					4 years 7 months 6 days
Percentage of grant's vesting on anniversary date					25.00%
Annual compounded forfeiture rate, minimum					4.00%
Annual compounded forfeiture rate, maximum					10.00%
Fair value of performance-based shares vested in year					$ 300,000	$ 800,000
Total intrinsic value of options exercised					0	100,000	$ 500,000
Proceeds from stock option exercises					0	126,000	6,385,000
Fair value of equity awards					7,200,000	8,000,000	8,100,000
Non-cash stock based compensation					$ 10,140,000	10,973,000	15,634,000
Performance shares set as side at the end of plan | shares								179,987
Minimum age for employees to be eligible under employee directed savings plan | age					21
Percentage of employee's contribution matched by the company					100.00%
Percentage of employee's pretax income					6.00%
Percentage of common stock matched by company					50.00%
Cash and common stock contributions					$ 1,200,000	1,700,000	1,900,000
Percentage of employee's cash compensation reached under cash matching contributions					6.00%
Deferred Compensation Cash-based Arrangements, Liability, Current and Noncurrent					$ 1,231,000	$ 1,069,000	$ 941,000
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average expected term (in years)					1 month 2 days
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average expected term (in years)					6 years
2012 Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares granted | shares			2,051,402
Aggregate number of shares of common stock subject to options or stock appreciation granted | shares			500,000
Expiration period of option granted			10 years
Two Thousand And Fifteen Performance Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted percentage of stockholders return related to performance goals					60.00%
Performance goals percentage for change in discretionary cash flows					40.00%
Maximum Number Of Cash Units Vest As Percentage Of Performance Cash Units Granted					200.00%
Number Of Performance Cash Units Granted | unit					422,345
Deferred Compensation Cash-based Arrangements, Liability, Current and Noncurrent					$ 400,000
Deferred Compensation Arrangement with Individual, Compensation Expense					400,000
Performance Cash Unit Price					$ 3.95
Two Thousand And Fifteen Performance Program [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of performance-based awards allowed to vest within a year					25.00%
Two Thousand And Fifteen Performance Program [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of total grant that will vest for metrics met at stretch level					200.00%
Percentage of total grant that will vest for metrics met at target level					100.00%
Percentage of performance-based awards allowed to vest within a year					50.00%
Two Thousand And Fourteen Performance Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted percentage of stockholders return related to performance goals	60.00%
Performance goals percentage for change in discretionary cash flows	40.00%
Two Thousand And Fourteen Performance Program [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of total grant that will vest for metrics met at stretch level	200.00%			200.00%
Percentage of total grant that will vest for metrics met at target level	100.00%
Percentage of performance-based awards allowed to vest within a year	25.00%
2010 Performance Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of Performance Based Shares Vested						19.80%	0.00%	26.60%	25.90%
Total Percent of Performance Based Shares Vested						72.30%
Number of Performance Based Shares Vested | shares						21,968	0	57,944	59,582
Percent of Market Based Shares Vested						33.40%	0.00%	12.50%	37.50%
Total Percent of Market Based Shares Vested						83.40%
Number of Market Based Shares Vested | shares						9,242	0	6,801	21,574
2012 Performance Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted percentage of stockholders return related to performance goals				33.30%
Performance goals percentage for change in discretionary cash flows				33.30%
Performance goals percentage weight for change in proved properties				33.30%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period | shares					0
2013 Performance Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of total grant that will vest for metrics met at stretch level		200.00%
Weighted percentage of stockholders return related to performance goals		33.30%
Performance goals percentage for change in discretionary cash flows		33.30%
Performance goals percentage weight for change in proved properties		33.30%
Percentage of performance-based awards allowed to vest within a year		50.00%
Percentage of total grant that will vest for metrics met at target level		100.00%
Performance shares set as side at the end of plan | shares							450,544
Percentage of performance-based awards allowed to vest within a year		25.00%
Maximum number of common stock vest as percentage of performance shares granted		200.00%
Percent of Performance Based Shares Vested					29.60%
2013 Performance Program [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of total grant that will vest for metrics met at stretch level		200.00%
Percentage of total grant that will vest for metrics met at target level		100.00%
Nonvested Performance Based Equity Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period | shares					0	315,661	450,544
Non-cash stock based compensation					$ 1,652,000	$ 990,000	$ 2,174,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period | shares					11,623	42,833	0

Equity Incentive Compensation66

Equity Incentive Compensation Plans and Other Employee Benefits - Non-Cash Stock-Based Compensation Cost Related to Equity Awards (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stock Based Compensation [Line Items]
Non-cash stock based compensation	$ 10,140	$ 10,973	$ 15,634
Common Stock Options [Member]
Stock Based Compensation [Line Items]
Non-cash stock based compensation	652	2,073	4,696
Nonvested Equity Common Stock [Member]
Stock Based Compensation [Line Items]
Non-cash stock based compensation	6,721	6,845	7,492
Nonvested Equity Common Stock Units [Member]
Stock Based Compensation [Line Items]
Non-cash stock based compensation	1,115	1,065	1,272
Nonvested Performance-Based Equity [Member]
Stock Based Compensation [Line Items]
Non-cash stock based compensation	$ 1,652	$ 990	$ 2,174

Equity Incentive Compensation67

Equity Incentive Compensation Plans and Other Employee Benefits - Fair Value Assumptions and Methodology (Detail)	12 Months Ended
	Dec. 31, 2015
Disclosure Equity Incentive Compensation Plans And Other Employee Benefits Fair Value Assumptions And Methodology [Abstract]
Expected dividend yield	0.00%

Equity Incentive Compensation68

Equity Incentive Compensation Plans and Other Employee Benefits - Summary of Share-Based Option Activity (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at January 1, 2015	1,339,365
Granted	0
Exercised	0	(7,926)	(259,699)
Forfeited or expired	(421,544)
Outstanding at December 31, 2015	917,821	1,339,365
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding at January 1, 2015	$ 32.47
Granted	0
Exercised	0
Forfeited or expired	39.50
Outstanding at December 31, 2015	$ 29.25	$ 32.47
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Outstanding at December 31, 2015, Weighted-average remaining contractual term	1 year 3 months 25 days
Outstanding at December 31, 2015, Aggregate intrinsic value	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest [Abstract]
Vested and expected to vest, at December 31, 2015 through the life of the options	917,318
Vested and exercisable at December 31, 2015	862,646
Vested, or expected to vest, at December 31, 2015 through the life of the options, Weighted-average Exercise Price	$ 28.17
Vested and exercisable at December 31, 2015, Weighted-average Exercise Price	$ 29.37
Vested, or expected to vest, at December 31, 2015 through the life of the options, Weighted-average remaining contractual term	1 year 6 months 3 days
Vested and exercisable at December 31, 2015, Weighted-average remaining contractual term	1 year 4 months 25 days
Vested and expected to vest, at December 31, 2015 through the life of the options, Aggregate intrinsic value	$ 0
Vested and exercisable at December 31, 2015, Aggregate intrinsic value	$ 0

Equity Incentive Compensation69

Equity Incentive Compensation Plans and Other Employee Benefits - Summary of Nonvested Equity Shares of Common Stock (Detail) - Nonvested Equity Common Stock [Member] - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding Beginning, Shares	793,064	756,118	579,188
Granted, Shares	673,087	542,209	630,715
Vested, Shares	(294,957)	(292,168)	(270,482)
Forfeited or expired, Shares	(168,247)	(213,095)	(183,303)
Outstanding Ending, Shares	1,002,947	793,064	756,118
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Outstanding Beginning, Weighted-average Grant Date Fair-Value	$ 21.47	$ 22.17	$ 31.02
Granted, Weighted-average Grant Date Fair-Value	11.85	22	17.98
Vested, Weighted-average Grant Date Fair-Value	21.69	24.05	29.82
Forfeited or expired, Weighted-average Grant Date Fair-Value	17.63	21.99	24.87
Outstanding Ending, Weighted-average Grant Date Fair-Value	$ 15.53	$ 21.47	$ 22.17

Equity Incentive Compensation70

Equity Incentive Compensation Plans and Other Employee Benefits - Summary of Nonvested Equity Shares of Common Stock Issued for Payment of Director Fees (Detail) - Director [Member] - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Based Compensation Cost Related To Prior Performance Goal	$ 0.1	$ 0.1	$ 0.4
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding Beginning, Shares	54,945	55,778	49,185
Granted, Shares	135,439	45,928	56,464
Vested, Shares	(44,892)	(46,761)	(49,871)
Forfeited or expired, Shares	0	0	0
Outstanding Ending, Shares	145,492	54,945	55,778
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Outstanding Beginning, Weighted-average Grant Date Fair-Value	$ 23.84	$ 19.35	$ 18.50
Granted, Weighted-average Grant Date Fair-Value	8.31	24.49	22.33
Vested, Weighted-average Grant Date Fair-Value	18.38	22.25	18.96
Forfeited or expired, Weighted-average Grant Date Fair-Value	0	0	0
Outstanding Ending, Weighted-average Grant Date Fair-Value	$ 11.07	$ 23.84	$ 19.35

Equity Incentive Compensation71

Equity Incentive Compensation Plans and Other Employee Benefits - Summary of Nonvested Performance-Based Equity Shares of Common Stock (Detail) - Nonvested Performance-Based Equity [Member] - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding Beginning, Shares	614,077	584,032	291,606
Vested, Shares	(11,623)	(42,833)	0
Modified, performance goals revised, Shares	0	0	(108,933)
Modified, performance goals revised, Shares	0	0	108,933
Granted, Shares	0	315,661	450,544
Forfeited or expired, Shares	(133,893)	(242,783)	(158,118)
Outstanding Ending, Shares	468,561	614,077	584,032
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Outstanding Beginning, Weighted-average Grant Date Fair-Value	$ 19.62	$ 19.80	$ 26.85
Vested, Weighted-average Grant Date Fair-Value	23.07	19.51	0
Modified, performance goals revised, Weighted-average Grant Date Fair Value	0	0	27.75
Modified, performance goals revised, Weighted-average Grant Date Fair Value	0	0	18.18
Granted, Weighted-average Grant Date Fair-Value	0	23.86	19.99
Forfeited or expired, Weighted-average Grant Date Fair-Value	25.46	22.13	22.52
Outstanding Ending, Weighted-average Grant Date Fair-Value	$ 18.46	$ 19.62	$ 19.80

Equity Incentive Compensation72

Equity Incentive Compensation Plans and Other Employee Benefits - Director Fees (Detail) - Director [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Director fees (shares)	14,892	3,928	16,151
Stock-based compensation (in thousands)	$ 75	$ 75	$ 351

Equity Incentive Compensation73

Equity Incentive Compensation Plans and Other Employee Benefits - Deferred Compensation Liability (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Deferred Compensation Liability [Roll Forward]
Beginning deferred compensation liability balance	$ 1,069	$ 941
Employee contributions	410	441
Company matching contributions	119	160
Distributions	(346)	(503)
Participant earnings (losses)	(21)	30
Ending deferred compensation liability balance	1,231	1,069
Deferred Compensation Liability [Abstract]
Amount to be paid within one year	206	220
Remaining balance to be paid beyond one year	$ 1,025	$ 849

Equity Incentive Compensation74

Equity Incentive Compensation Plans and Other Employee Benefits - Deferred Compensation Investment Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Compensation Liability [Roll Forward]
Beginning investment balance	$ 1,069	$ 941
Investment purchases	529	601
Distributions	(346)	(503)
Earnings (losses)	(21)	30
Ending investment balance	$ 1,231	$ 1,069

Significant Customers and Oth75

Significant Customers and Other Concentrations - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015CounterpartyCustomer	Dec. 31, 2014Customer	Dec. 31, 2013Customer
Concentration Risk [Line Items]
Number of counterparties of which hedges are in place | Counterparty	8
Sales Revenue, Product Line [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Customers account for production revenues | Customer	4	2	1

Equity Distribution Agreement (

Equity Distribution Agreement (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)shares
Equity Distribution Agreement [Abstract]
Maximum Aggregate Offering Price | $	$ 100
Number of Shares Sold, Equity Distribution Agreement | shares	0

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)
Contingencies And Commitments [Line Items]
Drilling Commitment	$ 3.2
Number of Firm Transportation Contracts	2
Minimum [Member]
Contingencies And Commitments [Line Items]
Contract term, years	6 years

Commitments and Contingencies78

Commitments and Contingencies - Schedule of Aggregate Undiscounted Minimum Future Lease Payments (Detail) - Lease Financing Obligation [Member] $ in Thousands	Dec. 31, 2015USD ($)
Future Minimum Lease Payments Under Capital Leases And Operating Leases For Continuing Operations [Line Items]
2,016	$ 537
2,017	537
2,018	537
2,019	1,825
2,020	0
Thereafter	0
Total	$ 3,436

Commitments and Contingencies79

Commitments and Contingencies - Gross Future Minimum Transportation Demand and Firm Processing Charges (Detail) $ in Thousands	Dec. 31, 2015USD ($)
Commitments and Contingencies Disclosure [Abstract]
2,016	$ 18,692
2,017	18,692
2,018	18,692
2,019	18,692
2,020	18,692
Thereafter	10,902
Total	$ 104,362

Commitments and Contingencies80

Commitments and Contingencies - Future Minimum Annual Payments under Drilling, Lease and Other Agreements (Detail) - Office & Equipment Leases $ in Thousands	Dec. 31, 2015USD ($)
Operating Leased Assets [Line Items]
2,016	$ 6,676
2,017	2,892
2,018	2,591
2,019	633
2,020	0
Thereafter	0
Total	$ 12,792

Guarantor Subsidiaries - Additi

Guarantor Subsidiaries - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Guarantor Subsidiaries [Line Items]
Percentage of Guarantor Subsidiaries	100.00%
7.625% Senior Notes [Member]
Guarantor Subsidiaries [Line Items]
Debt, stated interest rate	7.625%	7.625%
7.0% Senior Notes [Member]
Guarantor Subsidiaries [Line Items]
Debt, stated interest rate	7.00%	7.00%

Guarantor Subsidiaries - Schedu

Guarantor Subsidiaries - Schedule of Condensed Consolidating Balance Sheets (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Assets:
Current assets	$ 274,317	$ 426,105
Property and equipment, net	1,170,684	1,753,121
Intercompany receivable (payable)	0	0
Investment in subsidiaries	0	0
Noncurrent assets	70,228	65,258
Total	1,515,229	2,244,484
Liabilities and Stockholders' Equity:
Current liabilities	145,231	264,687
Long-term debt	803,361	803,222
Deferred income taxes	0	122,350
Other noncurrent liabilities	17,221	24,737
Stockholders' equity	549,416	1,029,488	$ 1,005,718	$ 1,182,775
Total	1,515,229	2,244,484
Parent Issuer [Member]
Assets:
Current assets	274,115	426,103
Property and equipment, net	1,164,086	1,730,074
Intercompany receivable (payable)	21,412	22,840
Investment in subsidiaries	(14,664)	163
Noncurrent assets	70,228	65,258
Total	1,515,177	2,244,438
Liabilities and Stockholders' Equity:
Current liabilities	145,231	264,687
Long-term debt	803,361	803,222
Deferred income taxes	0	122,350
Other noncurrent liabilities	17,169	24,691
Stockholders' equity	549,416	1,029,488
Total	1,515,177	2,244,438
Guarantor Subsidiaries [Member]
Assets:
Current assets	202	2
Property and equipment, net	6,598	23,047
Intercompany receivable (payable)	(21,412)	(22,840)
Investment in subsidiaries	0	0
Noncurrent assets	0	0
Total	(14,612)	209
Liabilities and Stockholders' Equity:
Current liabilities	0	0
Long-term debt	0	0
Deferred income taxes	0	0
Other noncurrent liabilities	52	46
Stockholders' equity	(14,664)	163
Total	(14,612)	209
Intercompany Eliminations [Member]
Assets:
Current assets	0	0
Property and equipment, net	0	0
Intercompany receivable (payable)	0	0
Investment in subsidiaries	14,664	(163)
Noncurrent assets	0	0
Total	14,664	(163)
Liabilities and Stockholders' Equity:
Current liabilities	0	0
Long-term debt	0	0
Deferred income taxes	0	0
Other noncurrent liabilities	0	0
Stockholders' equity	14,664	(163)
Total	$ 14,664	$ (163)

Guarantor Subsidiaries - Sche83

Guarantor Subsidiaries - Schedule of Condensed Consolidating Statements of Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Operating and other revenues	$ 207,892	$ 472,291	$ 568,093
Operating expenses	(860,014)	(515,058)	(683,168)
General and administrative	(53,890)	(53,361)	(64,902)
Interest income and other income (expense)	41,156	129,118	(131,389)
Income (loss) before income taxes and equity in earnings (loss) of subsidiaries	(664,856)	32,990	(311,366)
(Provision for) Benefit from income taxes	177,085	(17,909)	118,633
Equity in earnings (loss) of subsidiaries	0	0	0
Net income (loss)	(487,771)	15,081	(192,733)
Parent Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Operating and other revenues	207,282	472,288	568,055
Operating expenses	(844,577)	(514,721)	(682,898)
General and administrative	(53,890)	(53,361)	(64,902)
Interest income and other income (expense)	41,156	129,118	(131,389)
Income (loss) before income taxes and equity in earnings (loss) of subsidiaries	(650,029)	33,324	(311,134)
(Provision for) Benefit from income taxes	177,085	(17,909)	118,633
Equity in earnings (loss) of subsidiaries	(14,827)	(334)	(232)
Net income (loss)	(487,771)	15,081	(192,733)
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Operating and other revenues	610	3	38
Operating expenses	(15,437)	(337)	(270)
General and administrative	0	0	0
Interest income and other income (expense)	0	0	0
Income (loss) before income taxes and equity in earnings (loss) of subsidiaries	(14,827)	(334)	(232)
(Provision for) Benefit from income taxes	0	0	0
Equity in earnings (loss) of subsidiaries	0	0	0
Net income (loss)	(14,827)	(334)	(232)
Intercompany Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Operating and other revenues	0	0	0
Operating expenses	0	0	0
General and administrative	0	0	0
Interest income and other income (expense)	0	0	0
Income (loss) before income taxes and equity in earnings (loss) of subsidiaries	0	0	0
(Provision for) Benefit from income taxes	0	0	0
Equity in earnings (loss) of subsidiaries	14,827	334	232
Net income (loss)	$ 14,827	$ 334	$ 232

Guarantor Subsidiaries - Sche84

Guarantor Subsidiaries - Schedule of Condensed Consolidating Statements of Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Net Income (Loss)	$ (487,771)	$ 15,081	$ (192,733)
Effect of derivative financial instruments	0	(669)	(4,663)
Other comprehensive income (loss)	0	(669)	(4,663)
Comprehensive Income (Loss)	(487,771)	14,412	(197,396)
Parent Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Net Income (Loss)	(487,771)	15,081	(192,733)
Effect of derivative financial instruments	0	(669)	(4,663)
Other comprehensive income (loss)	0	(669)	(4,663)
Comprehensive Income (Loss)	(487,771)	14,412	(197,396)
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net Income (Loss)	(14,827)	(334)	(232)
Effect of derivative financial instruments	0	0	0
Other comprehensive income (loss)	0	0	0
Comprehensive Income (Loss)	(14,827)	(334)	(232)
Intercompany Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net Income (Loss)	14,827	334	232
Effect of derivative financial instruments	0	0	0
Other comprehensive income (loss)	0	0	0
Comprehensive Income (Loss)	$ 14,827	$ 334	$ 232

Guarantor Subsidiaries - Sche85

Guarantor Subsidiaries - Schedule of Condensed Consolidating Statements of Cash Flows (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Cash flows from operating activities	$ 193,678	$ 261,717	$ 265,265
Cash flows from investing activities:
Additions to oil and gas properties, including acquisitions	(324,534)	(580,943)	(445,479)
Additions to furniture, fixtures and other	(1,223)	(3,658)	(2,254)
Proceeds from sale of properties and other investing activities	123,122	555,296	310,704
Cash paid for short-term investments	(114,883)	0	0
Proceeds from the sale of short-term investments	115,000	0	0
Intercompany Transfers Investing Activities	0	0
Cash flows from financing activities:
Proceeds from debt	0	165,000	420,000
Principal and redemption premium payments on debt	(25,191)	(283,546)	(576,422)
Intercompany transfers	0	0	0
Other financing activities	(3,037)	(2,557)	3,336
Increase (Decrease) in Cash and Cash Equivalents	(37,068)	111,309	(24,850)
Beginning Cash and Cash Equivalents	165,904	54,595	79,445
Ending Cash and Cash Equivalents	128,836	165,904	54,595
Parent Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Cash flows from operating activities	193,329	261,704	265,323
Cash flows from investing activities:
Additions to oil and gas properties, including acquisitions	(325,613)	(571,215)	(439,785)
Additions to furniture, fixtures and other	(1,223)	(3,658)	(2,254)
Proceeds from sale of properties and other investing activities	123,122	553,477	310,704
Cash paid for short-term investments	(114,883)
Proceeds from the sale of short-term investments	115,000
Intercompany Transfers Investing Activities	1,428	(7,896)
Cash flows from financing activities:
Proceeds from debt	0	165,000	420,000
Principal and redemption premium payments on debt	(25,191)	(283,546)	(576,422)
Intercompany transfers	0	0	(5,752)
Other financing activities	(3,037)	(2,557)	3,336
Increase (Decrease) in Cash and Cash Equivalents	(37,068)	111,309	(24,850)
Beginning Cash and Cash Equivalents	165,904	54,595	79,445
Ending Cash and Cash Equivalents	128,836	165,904	54,595
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Cash flows from operating activities	349	13	(58)
Cash flows from investing activities:
Additions to oil and gas properties, including acquisitions	1,079	(9,728)	(5,694)
Additions to furniture, fixtures and other	0	0	0
Proceeds from sale of properties and other investing activities	0	1,819	0
Cash paid for short-term investments	0
Proceeds from the sale of short-term investments	0
Intercompany Transfers Investing Activities	0	0
Cash flows from financing activities:
Proceeds from debt	0	0	0
Principal and redemption premium payments on debt	0	0	0
Intercompany transfers	(1,428)	7,896	5,752
Other financing activities	0	0	0
Increase (Decrease) in Cash and Cash Equivalents	0	0	0
Beginning Cash and Cash Equivalents	0	0	0
Ending Cash and Cash Equivalents	0	0	0
Intercompany Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Cash flows from operating activities	0	0	0
Cash flows from investing activities:
Additions to oil and gas properties, including acquisitions	0	0	0
Additions to furniture, fixtures and other	0	0	0
Proceeds from sale of properties and other investing activities	0	0	0
Cash paid for short-term investments	0
Proceeds from the sale of short-term investments	0
Intercompany Transfers Investing Activities	(1,428)	7,896
Cash flows from financing activities:
Proceeds from debt	0	0	0
Principal and redemption premium payments on debt	0	0	0
Intercompany transfers	1,428	(7,896)	0
Other financing activities	0	0	0
Increase (Decrease) in Cash and Cash Equivalents	0	0	0
Beginning Cash and Cash Equivalents	0	0	0
Ending Cash and Cash Equivalents	$ 0	$ 0	$ 0