SM Energy (SM) 10-Q 29 Oct 21 2021 Q3 Quarterly report Financial data

Cover page

Cover page - shares	9 Months Ended
	Sep. 30, 2021	Oct. 21, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	001-31539
Entity Registrant Name	SM ENERGY CO
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	41-0518430
Entity Address, Address Line One	1775 Sherman Street, Suite 1200
Entity Address, City or Town	Denver
Entity Address, State or Province	CO
Entity Address, Postal Zip Code	80203
City Area Code	(303)
Local Phone Number	861-8140
Title of 12(b) Security	Common stock, $0.01 par value
Trading Symbol	SM
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		121,473,790
Entity Central Index Key	0000893538
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Amendment Flag	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) (in thousands, except share data) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 29,800	$ 10
Accounts receivable	272,248	162,455
Derivative assets	24,514	31,203
Prepaid expenses and other	9,708	10,001
Total current assets	336,270	203,669
Property and equipment (successful efforts method):
Proved oil and gas properties	9,271,463	8,608,522
Accumulated depletion, depreciation, and amortization	(5,439,387)	(4,886,973)
Unproved oil and gas properties	654,513	714,602
Wells in progress	142,259	233,498
Other property and equipment, net of accumulated depreciation of $65,462 and $63,662, respectively	36,635	32,217
Total property and equipment, net	4,665,483	4,701,866
Noncurrent assets:
Derivative assets	6,096	23,150
Other noncurrent assets	54,111	47,746
Total noncurrent assets	60,207	70,896
Total assets	5,061,960	4,976,431
Other property and equipment, accumulated depreciation	65,462	63,662
Current liabilities:
Accounts payable and accrued expenses	542,474	371,670
Derivative liabilities	552,044	200,189
Other current liabilities	9,049	11,880
Total current liabilities	1,103,567	583,739
Noncurrent liabilities:
Revolving credit facility	0	93,000
Senior Notes, net	2,077,630	2,121,319
Asset retirement obligations	85,514	83,325
Derivative liabilities	90,655	22,331
Other noncurrent liabilities	67,695	56,557
Total noncurrent liabilities	2,321,494	2,376,532
Commitments and contingencies (note 6)
Stockholders’ equity:
Common stock, $0.01 par value - authorized: 200,000,000 shares; issued and outstanding: 121,473,790 and 114,742,304 shares, respectively	1,215	1,147
Additional paid-in capital	1,838,620	1,827,914
Retained earnings (deficit)	(190,367)	200,697
Accumulated other comprehensive loss	(12,569)	(13,598)
Total stockholders’ equity	1,636,899	2,016,160
Total liabilities and stockholders’ equity	$ 5,061,960	$ 4,976,431
Common Stock, Par Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	200,000,000	200,000,000
Common Stock, Shares, Issued	121,473,790	114,742,304
Common Stock, Shares, Outstanding	121,473,790	114,742,304

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) (in thousands, except per share data) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Operating revenues and other income:
Oil, gas, and NGL production revenue	$ 759,813	$ 282,012	$ 1,745,547	$ 806,035
Other operating income (loss)	426	(997)	22,387	346
Total operating revenues and other income	760,239	281,015	1,767,934	806,381
Operating expenses:
Oil, gas, and NGL production expense	135,745	95,257	362,131	295,254
Depletion, depreciation, amortization, and asset retirement obligation liability accretion	202,701	181,708	574,375	596,053
Exploration	8,709	8,547	26,746	29,683
Impairment	8,750	8,750	26,250	1,007,263
General and administrative	25,530	24,452	74,883	79,126
Net derivative (gain) loss	209,146	63,871	924,183	(314,269)
Other operating expense, net	43,401	1,562	44,654	10,174
Total operating expenses	633,982	384,147	2,033,222	1,703,284
Income (loss) from operations	126,257	(103,132)	(265,288)	(896,903)
Interest expense	(40,861)	(41,519)	(120,268)	(123,385)
Gain (loss) on extinguishment of debt	5	25,070	(2,139)	264,546
Other non-operating income (expense), net	153	(1,680)	(1,071)	(2,359)
Income (loss) before income taxes	85,554	(121,261)	(388,766)	(758,101)
Income tax benefit	39	22,969	95	158,662
Net income (loss)	$ 85,593	$ (98,292)	$ (388,671)	$ (599,439)
Basic weighted-average common shares outstanding	121,457	114,371	118,224	113,462
Diluted weighted-average common shares outstanding	123,851	114,371	118,224	113,462
Basic net income (loss) per common share	$ 0.70	$ (0.86)	$ (3.29)	$ (5.28)
Diluted net income (loss) per common share	0.69	(0.86)	(3.29)	(5.28)
Dividends per common share	$ 0.01	$ 0.01	$ 0.02	$ 0.02

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (UNAUDITED) (in thousands) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 85,593	$ (98,292)	$ (388,671)	$ (599,439)
Other comprehensive income, net of tax:
Pension liability adjustment	246	1,195	1,029	1,573
Total other comprehensive income, net of tax	246	1,195	1,029	1,573
Total comprehensive income (loss)	$ 85,839	$ (97,097)	$ (387,642)	$ (597,866)

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY (UNAUDITED) (in thousands, except share data and dividends per share) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings (Deficit)	Accumulated Other Comprehensive Loss
Cash dividends declared per share	$ 0.01
Balances, Common Stock, Shares, Outstanding, Beginning at Dec. 31, 2019		112,987,952
Balances, Total Stockholders' Equity, Beginning at Dec. 31, 2019	$ 2,748,994	$ 1,130	$ 1,791,596	$ 967,587	$ (11,319)
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(411,895)			(411,895)
Other comprehensive income	190				190
Cash dividends	(1,130)			(1,130)
Issuance of common stock upon vesting of RSUs and settlement of PSUs, net of shares used for tax withholdings (Shares)		730
Issuance of common stock upon vesting of RSUs and settlement of PSUs, net of shares used for tax withholdings (Amount)	(3)	$ 0	(3)
Stock-based compensation expense	5,561		5,561
Balances, Common Stock, Shares, Outstanding, Ending at Mar. 31, 2020		112,988,682
Balances, Total Stockholders' Equity, Ending at Mar. 31, 2020	$ 2,341,717	$ 1,130	1,797,154	554,562	(11,129)
Cash dividends declared per share	$ 0.02
Balances, Common Stock, Shares, Outstanding, Beginning at Dec. 31, 2019		112,987,952
Balances, Total Stockholders' Equity, Beginning at Dec. 31, 2019	$ 2,748,994	$ 1,130	1,791,596	967,587	(11,319)
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(599,439)
Other comprehensive income	1,573
Balances, Common Stock, Shares, Outstanding, Ending at Sep. 30, 2020		114,572,800
Balances, Total Stockholders' Equity, Ending at Sep. 30, 2020	2,185,108	$ 1,146	1,827,836	365,872	(9,746)
Balances, Common Stock, Shares, Outstanding, Beginning at Mar. 31, 2020		112,988,682
Balances, Total Stockholders' Equity, Beginning at Mar. 31, 2020	2,341,717	$ 1,130	1,797,154	554,562	(11,129)
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(89,252)			(89,252)
Other comprehensive income	188				188
Issuance of common stock under Employee Stock Purchase Plan (Shares)		297,013
Issuance of common stock under Employee Stock Purchase Plan (Amount)	947	$ 3	944
Stock-based compensation expense (shares)		267,576
Stock-based compensation expense	5,712	$ 3	5,709
Issuance of Warrants	21,520		21,520
Balances, Common Stock, Shares, Outstanding, Ending at Jun. 30, 2020		113,553,271
Balances, Total Stockholders' Equity, Ending at Jun. 30, 2020	$ 2,280,832	$ 1,136	1,825,327	465,310	(10,941)
Cash dividends declared per share	$ 0.01
Increase (Decrease) in Stockholders' Equity
Net income (loss)	$ (98,292)			(98,292)
Other comprehensive income	1,195				1,195
Cash dividends	(1,146)			(1,146)
Issuance of common stock upon vesting of RSUs and settlement of PSUs, net of shares used for tax withholdings (Shares)		1,019,529
Issuance of common stock upon vesting of RSUs and settlement of PSUs, net of shares used for tax withholdings (Amount)	(1,557)	$ 10	(1,567)
Stock-based compensation expense	4,164		4,164
Other	(88)		(88)
Balances, Common Stock, Shares, Outstanding, Ending at Sep. 30, 2020		114,572,800
Balances, Total Stockholders' Equity, Ending at Sep. 30, 2020	$ 2,185,108	$ 1,146	1,827,836	365,872	(9,746)
Cash dividends declared per share	$ 0.01
Balances, Common Stock, Shares, Outstanding, Beginning at Dec. 31, 2020	114,742,304	114,742,304
Balances, Total Stockholders' Equity, Beginning at Dec. 31, 2020	$ 2,016,160	$ 1,147	1,827,914	200,697	(13,598)
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(251,269)			(251,269)
Other comprehensive income	191				191
Cash dividends	(1,147)			(1,147)
Stock-based compensation expense	5,737		5,737
Balances, Common Stock, Shares, Outstanding, Ending at Mar. 31, 2021		114,742,304
Balances, Total Stockholders' Equity, Ending at Mar. 31, 2021	$ 1,769,672	$ 1,147	1,833,651	(51,719)	(13,407)
Cash dividends declared per share	$ 0.02
Balances, Common Stock, Shares, Outstanding, Beginning at Dec. 31, 2020	114,742,304	114,742,304
Balances, Total Stockholders' Equity, Beginning at Dec. 31, 2020	$ 2,016,160	$ 1,147	1,827,914	200,697	(13,598)
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(388,671)
Other comprehensive income	$ 1,029
Balances, Common Stock, Shares, Outstanding, Ending at Sep. 30, 2021	121,473,790	121,473,790
Balances, Total Stockholders' Equity, Ending at Sep. 30, 2021	$ 1,636,899	$ 1,215	1,838,620	(190,367)	(12,569)
Cash dividends paid per share	$ 0.01
Balances, Common Stock, Shares, Outstanding, Beginning at Mar. 31, 2021		114,742,304
Balances, Total Stockholders' Equity, Beginning at Mar. 31, 2021	$ 1,769,672	$ 1,147	1,833,651	(51,719)	(13,407)
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(222,995)			(222,995)
Other comprehensive income	592				592
Cash dividends	(31)			(31)
Issuance of common stock under Employee Stock Purchase Plan (Shares)		252,665
Issuance of common stock under Employee Stock Purchase Plan (Amount)	1,315	$ 3	1,312
Stock-based compensation expense (shares)		57,795
Stock-based compensation expense	3,956	$ 1	3,955
Issuance of common stock through cashless exercise of warrants (Shares)		5,918,089
Issuance of common stock through cashless exercise of warrants (Amount)	0	$ 59	(59)
Balances, Common Stock, Shares, Outstanding, Ending at Jun. 30, 2021		120,970,853
Balances, Total Stockholders' Equity, Ending at Jun. 30, 2021	$ 1,552,509	$ 1,210	1,838,859	(274,745)	(12,815)
Cash dividends declared per share	$ 0.01
Increase (Decrease) in Stockholders' Equity
Net income (loss)	$ 85,593			85,593
Other comprehensive income	246				246
Cash dividends	(1,215)			(1,215)
Issuance of common stock upon vesting of RSUs and settlement of PSUs, net of shares used for tax withholdings (Shares)		502,937
Issuance of common stock upon vesting of RSUs and settlement of PSUs, net of shares used for tax withholdings (Amount)	(4,732)	$ 5	(4,737)
Stock-based compensation expense	$ 4,498		4,498
Balances, Common Stock, Shares, Outstanding, Ending at Sep. 30, 2021	121,473,790	121,473,790
Balances, Total Stockholders' Equity, Ending at Sep. 30, 2021	$ 1,636,899	$ 1,215	$ 1,838,620	$ (190,367)	$ (12,569)

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) (in thousands) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net loss		$ 85,593	$ (98,292)	$ (388,671)	$ (599,439)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depletion, depreciation, amortization, and asset retirement obligation liability accretion		202,701	181,708	574,375	596,053
Impairment		8,750	8,750	26,250	1,007,263
Stock-based compensation expense				14,191	15,437
Net derivative (gain) loss		209,146	63,871	924,183	(314,269)
Derivative settlement gain (loss)				(480,262)	286,270
Amortization of debt discount and deferred financing costs				13,350	13,084
(Gain) loss on extinguishment of debt		(5)	(25,070)	2,139	(264,546)
Deferred income taxes		(68)	(22,796)	(282)	(159,064)
Other, net				(7,301)	(6,294)
Net change in working capital				52,170	(40,411)
Net cash provided by operating activities				730,142	534,084
Cash flows from investing activities:
Net proceeds from the sale of oil and gas properties				8,835	92
Capital expenditures				(550,265)	(419,777)
Acquisition of proved and unproved oil and gas properties				(3,321)	(7,075)
Net cash used in investing activities				(544,751)	(426,760)
Cash flows from financing activities:
Proceeds from revolving credit facility				1,649,500	1,165,500
Repayment of revolving credit facility				(1,742,500)	(1,110,000)
Net proceeds from Senior Notes				392,771	0
Cash paid to repurchase Senior Notes				(450,776)	(147,770)
Debt issuance costs related to 10.0% Senior Secured Notes due 2025				0	(12,886)
Net proceeds from sale of common stock				1,315	947
Dividends paid				(1,178)	(1,130)
Other, net				(4,733)	(1,985)
Net cash used in financing activities				(155,601)	(107,324)
Net change in cash, cash equivalents, and restricted cash				29,790	0
Cash, cash equivalents, and restricted cash at beginning of period				10	10
Cash, cash equivalents, and restricted cash at end of period		$ 29,800	$ 10	29,800	10
Supplemental Cash Flow Information - Operating activities:
Cash paid for interest, net of capitalized interest				(126,228)	(122,174)
Supplemental Cash Flow Information - Investing activities:
Increase (decrease) in capital expenditure accruals and other				8,885	(17,405)
Supplemental Cash Flow Information - Investing activities:
Non-cash financing activities (1)	[1]
[1]	(1) Please refer to Note 5 - Long-Term Debt for discussion of the debt transactions completed during the nine months ended September 30, 2021, and 2020.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 1 - Summary of Significant Accounting Policies Description of Operations SM Energy Company, together with its consolidated subsidiaries (“SM Energy” or the “Company”), is an independent energy company engaged in the acquisition, exploration, development, and production of oil, gas, and NGLs in the state of Texas. Basis of Presentation The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial information, the instructions to Quarterly Report on Form 10-Q, and Regulation S-X. These financial statements do not include all information and notes required by GAAP for annual financial statements. However, except as disclosed herein, there has been no material change in the information disclosed in the notes to the consolidated financial statements included in the 2020 Form 10-K . In the opinion of management, all adjustments, consisting of normal recurring adjustments considered necessary for a fair presentation of interim financial information, have been included. Operating results for the periods presented are not necessarily indicative of expected results for the full year. In connection with the preparation of the Company’s unaudited condensed consolidated financial statements, the Company evaluated events subsequent to the balance sheet date of September 30, 2021, and through the filing of this report. Additionally, certain prior period amounts have been reclassified to conform to current period presentation in the accompanying unaudited condensed consolidated financial statements. Significant Accounting Policies The significant accounting policies followed by the Company are set forth in Note 1 - Summary of Significant Accounting Policies in the 2020 Form 10-K and are supplemented by the notes to the unaudited condensed consolidated financial statements included in this report. These unaudited condensed consolidated financial statements should be read in conjunction with the 2020 Form 10-K . Recently Issued Accounting Standards In March 2020, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting (“ASU 2020-04”), and in January 2021, issued ASU No. 2021-01, Reference Rate Reform (Topic 848): Scope (“ASU 2021-01”), to provide clarifying guidance regarding the scope of Topic 848. ASU 2020-04 was issued to provide optional guidance for a limited period of time to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform on financial reporting. Generally, the guidance is to be applied as of any date from the beginning of an interim period that includes or is subsequent to March 12, 2020, or prospectively from a date within an interim period that includes or is subsequent to March 12, 2020, up to the date that the financial statements are available to be issued. ASU 2020-04 and ASU 2021-01 are effective for all entities through December 31, 2022. As of September 30, 2021, the Company has not elected to use the optional guidance and continues to evaluate the options provided by ASU 2020-04 and ASU 2021-01. Please refer to Note 5 - Long-Term Debt for discussion of the use of the London Interbank Offered Rate (“LIBOR”) in connection with borrowings under the Credit Agreement. There are no other ASUs that would have a material effect on the Company’s unaudited condensed consolidated financial statements and related disclosures that have been issued but not yet adopted by the Company as of September 30, 2021, or through the filing of this report.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	9 Months Ended
	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	Note 2 - Revenue from Contracts with Customers The Company recognizes its share of revenue from the sale of produced oil, gas, and NGLs from its Midland Basin and South Texas assets. Oil, gas, and NGL production revenue presented within the accompanying unaudited condensed consolidated statements of operations (“accompanying statements of operations”) is reflective of the revenue generated from contracts with customers. The tables below present oil, gas, and NGL production revenue by product type for each of the Company’s operating areas for the three and nine months ended September 30, 2021, and 2020: Midland Basin South Texas Total Three Months Ended Three Months Ended Three Months Ended 2021 2020 2021 2020 2021 2020 (in thousands) Oil production revenue $ 501,071 $ 194,547 $ 57,323 $ 13,100 $ 558,394 $ 207,647 Gas production revenue 96,082 23,304 52,878 26,251 148,960 49,555 NGL production revenue 103 115 52,356 24,695 52,459 24,810 Total $ 597,256 $ 217,966 $ 162,557 $ 64,046 $ 759,813 $ 282,012 Relative percentage 79 % 77 % 21 % 23 % 100 % 100 % ____________________________________________ Note: Amounts may not calculate due to rounding. Midland Basin South Texas Total Nine Months Ended Nine Months Ended Nine Months Ended 2021 2020 2021 2020 2021 2020 (in thousands) Oil production revenue $ 1,191,668 $ 585,041 $ 108,871 $ 33,815 $ 1,300,539 $ 618,856 Gas production revenue 205,323 46,559 121,630 78,569 326,953 125,128 NGL production revenue 315 218 117,740 61,833 118,055 62,051 Total $ 1,397,306 $ 631,818 $ 348,241 $ 174,217 $ 1,745,547 $ 806,035 Relative percentage 80 % 78 % 20 % 22 % 100 % 100 % ____________________________________________ Note: Amounts may not calculate due to rounding. The Company recognizes oil, gas, and NGL production revenue at the point in time when custody and title (“control”) of the product transfers to the purchaser, which differs depending on the applicable contractual terms. Transfer of control drives the presentation of transportation, gathering, processing, and other post-production expenses (“fees and other deductions”) within the accompanying statements of operations. Fees and other deductions incurred by the Company prior to control transfer are recorded within the oil, gas, and NGL production expense line item on the accompanying statements of operations. When control is transferred at or near the wellhead, sales are based on a wellhead market price that is impacted by fees and other deductions incurred by the purchaser subsequent to the transfer of control. Please refer to Note 2 - Revenue from Contracts with Customers in the 2020 Form 10-K for more information regarding the types of contracts under which oil, gas, and NGL production revenue is generated. Significant judgments made in applying the guidance in Accounting Standards Codification Topic 606, Revenue from Contracts with Customers, relate to the point in time when control transfers to purchasers in gas processing arrangements with midstream processors. The Company does not believe that significant judgments are required with respect to the determination of the transaction price, including amounts that represent variable consideration, as volume and price carry a low level of estimation uncertainty given the precision of volumetric measurements and the use of index pricing with generally predictable differentials. Accordingly, the Company does not consider estimates of variable consideration to be constrained. The Company’s performance obligations arise upon the production of hydrocarbons from wells in which the Company has an ownership interest. The performance obligations are considered satisfied upon control transferring to a purchaser at the wellhead, inlet, or tailgate of the midstream processor’s processing facility, or other contractually specified delivery point. The time period between production and satisfaction of performance obligations is generally less than one day, therefore there are no material unsatisfied or partially unsatisfied performance obligations at the end of the reporting period. Revenue is recorded in the month when performance obligations are satisfied. However, settlement statements from the purchasers of hydrocarbons and the related cash consideration are received 30 to 90 days after production has occurred. As a result, the Company must estimate the amount of production delivered to the customer and the consideration that will ultimately be received for sale of the product. Estimated revenue due to the Company is recorded within the accounts receivable line item on the accompanying unaudited condensed consolidated balance sheets (“accompanying balance sheets”) until payment is received. The accounts receivable balances from contracts with customers within the accompanying balance sheets as of September 30, 2021, and December 31, 2020, were $227.5 million and $108.9 million, respectively. To estimate accounts receivable from contracts with

Equity Equity

Equity Equity	9 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Stockholders' Equity Note Disclosure	Note 3 - Equity On June 17, 2020, in connection with the Exchange Offers described below in Note 5 - Long-Term Debt , the Company issued warrants to purchase up to an aggregate of approximately 5.9 million shares, or approximately five percent of its then outstanding common stock, at an exercise price of $0.01 per share (“Warrants”). Upon issuance, the $21.5 million fair value of the Warrants was recorded in additional paid-in capital on the accompanying balance sheets, and was determined using a stochastic Monte Carlo simulation using geometric Brownian motion (“GBM Model”). The Company evaluated the Warrants under authoritative accounting guidance and determined that they should be classified as equity instruments, with no recurring fair value measurement required. There have been no changes to the initial carrying amount of the Warrants since issuance. The Warrant Agreement, dated as of June 17, 2020 (“Warrant Agreement”), provides that the Warrants are exercisable any time from and after the Triggering Date, as subsequently defined, until June 30, 2023. The Triggering Date, which occurred on January 15, 2021, is defined by the Warrant Agreement as the first trading day following five consecutive trading days on which the product of the number of shares of common stock issued and outstanding on four of the five trading days multiplied by the closing price per share of common stock for each such trading day exceeds $1.0 billion (“Triggering Date”). The Warrants are indexed to the Company’s common stock and are required to be settled through physical settlement or net share settlement, if exercised. During the second quarter of 2021, the Company issued 5,918,089 shares of common stock as a result of the cashless exercise of 5,922,260 Warrants at a weighted-average share price of $15.45 per share, as determined under the terms of the Warrant Agreement. At the request of stockholders and pursuant to the Company’s obligations under the Warrant Agreement, a registration statement covering the resale of a majority of these shares was filed with the U.S. Securities and Exchange Commission on June 11, 2021. No Warrants were exercised during the third quarter of 2021. The unexercised Warrants will remain exercisable at the election of the holders until their expiration on June 30, 2023.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Note 4 - Income Taxes The provision for income taxes for the three and nine months ended September 30, 2021, and 2020, consisted of the following: For the Three Months Ended For the Nine Months Ended 2021 2020 2021 2020 (in thousands) Current portion of income tax (expense) benefit: Federal $ — $ — $ — $ — State (29) 173 (187) (402) Deferred portion of income tax benefit 68 22,796 282 159,064 Income tax benefit $ 39 $ 22,969 $ 95 $ 158,662 Effective tax rate — % 18.9 % — % 20.9 % Recorded income tax expense or benefit differs from the amount that would be provided by applying the statutory United States federal income tax rate to income or loss before income taxes. These differences primarily relate to the effect of state income taxes, excess tax benefits and deficiencies from stock-based compensation awards, tax limitations on the compensation of covered individuals, changes in valuation allowances, the cumulative impact of other smaller permanent differences, and can also reflect the cumulative effect of an enacted tax rate change, in the period of enactment, on the Company’s net deferred tax asset and liability balance. The quarterly rate and the resulting income tax benefit can also be affected by the proportional impacts of forecasted net income or loss and the correlative effect on the valuation allowance for each period presented, as reflected in the table above. For all years before 2017, the Company is generally no longer subject to United States federal or state income tax examinations by tax authorities.

Long-Term Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Long-Term Debt	Note 5 - Long-Term Debt The following table summarizes the Company’s total outstanding balance on its revolving credit facility, Senior Secured Notes net of unamortized discount and deferred financing costs, and Senior Unsecured Notes net of unamortized deferred financing costs, as of September 30, 2021, and December 31, 2020: As of September 30, 2021 As of December 31, 2020 (in thousands) Revolving credit facility $ — $ 93,000 Senior Secured Notes (1) 405,007 460,656 Senior Unsecured Notes (1) 1,672,623 1,660,663 Total $ 2,077,630 $ 2,214,319 ____________________________________________ (1) Senior Secured Notes and Senior Unsecured Notes are defined below. Credit Agreement The Company’s Credit Agreement, which is scheduled to mature on September 28, 2023, provides for a senior secured revolving credit facility with a maximum loan amount of $2.5 billion. On June 8, 2021, the Company entered into a sixth amendment to the Credit Agreement to amend certain definitions and covenants relating to the Company's ability to issue permitted refinancing debt and to repurchase or redeem outstanding indebtedness to facilitate the Tender Offer and the 2022 Senior Notes Redemption, each as defined below. As of September 30, 2021, the borrowing base and aggregate lender commitments under the Credit Agreement were $1.1 billion. Subsequent to September 30, 2021, the fall semi-annual borrowing base redetermination was completed, which reaffirmed both the Company’s borrowing base and aggregate lender commitments at $1.1 billion. The next scheduled borrowing base redetermination date is April 1, 2022. Interest and commitment fees associated with the revolving credit facility are accrued based on a borrowing base utilization grid set forth in the Credit Agreement as presented in Note 5 - Long-Term Debt in the 2020 Form 10-K . At the Company’s election, borrowings under the Credit Agreement may be in the form of Eurodollar, Alternate Base Rate (“ABR”), or Swingline loans. Eurodollar loans accrue interest at LIBOR, plus the applicable margin from the utilization grid, and ABR and Swingline loans accrue interest at a market-based floating rate, plus the applicable margin from the utilization grid. Commitment fees are accrued on the unused portion of the aggregate lender commitment amount at rates from the utilization grid and are included in the interest expense line item on the accompanying statements of operations. The Credit Agreement specifies that if LIBOR is no longer a widely used benchmark rate, or if it is no longer used for determining interest rates for loans in the United States, a replacement interest rate that fairly reflects the cost to the lenders of funding loans shall be established by the Administrative Agent, as defined in the Credit Agreement, in consultation with the Company. Please refer to Note 1 - Summary of Significant Accounting Policies for discussion of FASB ASU 2020-04 and ASU 2021-01, which provides guidance related to reference rate reform . The following table presents the outstanding balance, total amount of letters of credit outstanding, and available borrowing capacity under the Credit Agreement as of October 21, 2021, September 30, 2021, and December 31, 2020: As of October 21, 2021 As of September 30, 2021 As of December 31, 2020 (in thousands) Revolving credit facility (1) $ — $ — $ 93,000 Letters of credit (2) 2,500 2,500 42,000 Available borrowing capacity 1,097,500 1,097,500 965,000 Total aggregate lender commitment amount $ 1,100,000 $ 1,100,000 $ 1,100,000 ____________________________________________ (1) Unamortized deferred financing costs attributable to the revolving credit facility are presented as a component of the other noncurrent assets line item on the accompanying balance sheets and totaled $3.1 million and $4.3 million as of September 30, 2021, and December 31, 2020, respectively. These costs are being amortized over the term of the revolving credit facility on a straight-line basis. (2) Letters of credit outstanding reduce the amount available under the revolving credit facility on a dollar-for-dollar basis. Senior Notes Senior Secured Notes . Senior Secured Notes, net of unamortized discount and deferred financing costs, included within the Senior Notes, net line item on the accompanying balance sheets as of September 30, 2021, and December 31, 2020, consisted of the following (collectively referred to as “Senior Secured Notes”): As of September 30, 2021 Principal Amount Unamortized Debt Discount Unamortized Deferred Financing Costs Net (in thousands) 10.0% Senior Secured Notes due 2025 $ 446,675 $ 32,232 $ 9,436 $ 405,007 As of December 31, 2020 Principal Amount Unamortized Debt Discount Unamortized Deferred Financing Costs Net (in thousands) 1.50% Senior Secured Convertible Notes due 2021 $ 65,485 $ 1,828 $ 175 $ 63,482 10.0% Senior Secured Notes due 2025 446,675 37,943 11,558 397,174 Total $ 512,160 $ 39,771 $ 11,733 $ 460,656 The Senior Secured Notes listed above are senior obligations of the Company, secured on a second-priority basis, ranking junior to the Company’s obligations under the Credit Agreement and equal in priority to one another. The Senior Secured Notes rank senior in right of payment with all of the Company’s existing and any future unsecured senior or subordinated debt. The 1.50% Senior Secured Convertible Notes due 2021 (“2021 Senior Secured Convertible Notes”) matured on July 1, 2021, and on that day, the Company used borrowings under its revolving credit facility to retire at par the outstanding principal amount of $65.5 million. Interest expense recognized on the 2021 Senior Secured Convertible Notes related to the stated interest rate and amortization of the debt discount. No interest expense was recognized for the three months ended September 30, 2021, $1.1 million was recognized for the three months ended September 30, 2020, and $2.3 million and $6.6 million was recognized for the nine months ended September 30, 2021, and 2020, respectively. The Company may redeem some or all of its 10.0% Senior Secured Notes due 2025 (“2025 Senior Secured Notes”) prior to their maturity at redemption prices based on a premium, plus accrued and unpaid interest, as described in the indenture governing the 2025 Senior Secured Notes. Senior Unsecured Notes . Senior Unsecured Notes, net of unamortized deferred financing costs, included within the Senior Notes, net line item on the accompanying balance sheets as of September 30, 2021, and December 31, 2020, consisted of the following (collectively referred to as “Senior Unsecured Notes,” and together with the Senior Secured Notes, “Senior Notes”): As of September 30, 2021 As of December 31, 2020 Principal Amount Unamortized Deferred Financing Costs Principal Amount, Net Principal Amount Unamortized Deferred Financing Costs Principal Amount, Net (in thousands) 6.125% Senior Notes due 2022 $ — $ — $ — $ 212,403 $ 855 $ 211,548 5.0% Senior Notes due 2024 104,769 451 104,318 277,034 1,576 275,458 5.625% Senior Notes due 2025 349,118 2,318 346,800 349,118 2,792 346,326 6.75% Senior Notes due 2026 419,235 3,445 415,790 419,235 3,970 415,265 6.625% Senior Notes due 2027 416,791 4,143 412,648 416,791 4,725 412,066 6.5% Senior Notes due 2028 400,000 6,933 393,067 — — — Total $ 1,689,913 $ 17,290 $ 1,672,623 $ 1,674,581 $ 13,918 $ 1,660,663 The Senior Unsecured Notes listed above are unsecured senior obligations and rank equal in right of payment with all of the Company’s existing and any future unsecured senior debt and are senior in right of payment to any future subordinated debt. The Company may redeem some or all of its Senior Unsecured Notes prior to their maturity at redemption prices based on a premium, plus accrued and unpaid interest as described in the indentures governing the Senior Unsecured Notes. Senior Notes Activity Second Quarter 2021 Senior Notes Transactions. On June 23, 2021, the Company issued $400.0 million in aggregate principal amount of its 6.5% Senior Notes at par with a maturity date of July 15, 2028 (“2028 Senior Notes”). The Company received net proceeds of $392.8 million after deducting fees of $7.2 million, which are being amortized as deferred financing costs over the life of the 2028 Senior Notes. The net proceeds were used to repurchase $193.1 million and $172.3 million of outstanding principal amount of the Company’s 6.125% Senior Notes due 2022 (“2022 Senior Notes”) and 5.0% Senior Notes due 2024 (“2024 Senior Notes”), respectively, through a cash tender offer (“Tender Offer”), and to redeem the remaining $19.3 million of 2022 Senior Notes not repurchased as part of the Tender Offer (“2022 Senior Notes Redemption”). The Company paid total consideration, excluding accrued interest, of $385.3 million, and recorded a net loss on extinguishment of debt of $2.1 million for the three months ended June 30, 2021, which included $1.5 million of accelerated unamortized deferred financing costs and $0.6 million of net premiums. The Company canceled all repurchased and redeemed 2022 Senior Notes and 2024 Senior Notes upon settlement. Second Quarter 2020 Senior Notes Transactions. During the second quarter of 2020, the Company initiated an offer to exchange certain of its then outstanding Senior Unsecured Notes, other than its 1.50% Senior Unsecured Convertible Notes due 2021 (“2021 Senior Unsecured Convertible Notes,” and together with the Senior Unsecured Notes, “Old Notes”), and entered into a private exchange of certain of its then outstanding 2021 Senior Unsecured Convertible Notes and portions of its then outstanding Senior Unsecured Notes (“Private Exchange”), in each case, for newly issued 2025 Senior Secured Notes, referred to together as “Exchange Offers.” On June 17, 2020, the Company exchanged $611.9 million in aggregate principal amount of Senior Unsecured Notes and $107.0 million in aggregate principal amount of 2021 Senior Unsecured Convertible Notes for $446.7 million in aggregate principal amount of 2025 Senior Secured Notes. Further, in connection with the Private Exchange, the Company tendered $53.5 million in cash to certain holders of the 2021 Senior Unsecured Convertible Notes and issued the Warrants. Please refer to Note 3 - Equity for more information regarding the Warrants. Upon the closing of the Exchange Offers, the Company recorded a net gain on extinguishment of debt of $227.3 million which included the recognition of $6.1 million and $5.6 million of previously unamortized debt discount and deferred financing costs, respectively. The Company canceled all Senior Unsecured Notes and 2021 Senior Unsecured Convertible Notes that were retired upon closing of the Exchange Offers. Pursuant to the indenture governing its 2021 Senior Unsecured Convertible Notes, the Company’s remaining outstanding 2021 Senior Unsecured Convertible Notes became secured. Please refer to Note 5 - Long-Term Debt in the 2020 Form 10-K for additional information regarding the debt transactions that occurred during the second quarter of 2020. First Quarter and Third Quarter 2020 Senior Notes Transactions. During the nine months ended September 30, 2020, the Company repurchased $103.2 million in aggregate principal amount of its 2022 Senior Notes and $29.0 million in aggregate principal amount of its 2024 Senior Notes in open market transactions at a discount, for a total settlement amount, excluding accrued interest, of $94.2 million. In connection with the repurchases, the Company recorded a net gain on extinguishment of debt of $25.1 million and $37.3 million for the three and nine months ended September 30, 2020, respectively. The net gain on extinguishment of debt includes discounts realized upon repurchase of $25.5 million and $37.9 million for the three and nine months ended September 30, 2020, respectively, partially offset by accelerated unamortized deferred financing costs of $0.5 million and $0.7 million for the three and nine months ended September 30, 2020, respectively. The Company canceled all repurchased 2022 Senior Notes and 2024 Senior Notes upon settlement. Please refer to Note 5 - Long-Term Debt in the 2020 Form 10-K for additional detail on the Company’s Senior Notes. Covenants The Company is subject to certain financial and non-financial covenants under the Credit Agreement and the indentures governing the Senior Notes that, among other terms, limit the Company’s ability to incur additional indebtedness, make restricted payments including dividends, sell assets, create liens that secure debt, enter into transactions with affiliates, merge or consolidate with another company, and with respect to the Company’s restricted subsidiaries, permit the consensual restriction on the ability of such restricted subsidiaries to pay dividends or indebtedness owing to the Company or to any other restricted subsidiaries. The Company was in compliance with all covenants under the Credit Agreement and the indentures governing the Senior Notes as of September 30, 2021, and through the filing of this report. Please refer to Note 5 - Long-Term Debt in the 2020 Form 10-K for additional detail on the Company’s covenants under the Credit Agreement and indentures governing the Senior Notes. Capitalized Interest Capitalized interest costs for the three months ended September 30, 2021, and 2020, totaled $3.5 million and $4.8 million, respectively, and totaled $12.5 million and $11.6 million for the nine months ended September 30, 2021, and 2020, respectively. The amount of interest the Company capitalizes generally fluctuates based on the amount borrowed, the Company’s capital program, and

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 6 - Commitments and Contingencies Commitments Other than those items discussed below, there have been no changes in commitments through the filing of this report that differ materially from those disclosed in the 2020 Form 10-K . Please refer to Note 6 - Commitments and Contingencies in the 2020 Form 10-K for additional discussion of the Company’s commitments. Drilling Rig Service Contracts . During the nine months ended September 30, 2021, the Company amended certain of its drilling rig contracts resulting in the extension of contract terms. As of September 30, 2021, the Company’s drilling rig commitments totaled $8.6 million under contract terms extending through the second quarter of 2022. If all of these contracts were terminated as of September 30, 2021, the Company would avoid a portion of the contractual service commitments; however, the Company would be required to pay $5.1 million in early termination fees. No material expenses related to early termination or standby fees were incurred by the Company during the nine months ended September 30, 2021, and the Company does not expect to incur material penalties with regard to its drilling rig contracts during the remainder of 2021. Drilling and Completion Commitments . During the first quarter of 2021, the Company amended an agreement that includes minimum drilling and completion footage requirements on certain existing leases. If these minimum requirements are not satisfied by March 31, 2022, the Company will be required to pay liquidated damages based on the difference between the actual footage drilled and completed and the minimum requirements. As of September 30, 2021, the liquidated damages could range from zero to a maximum of $25.9 million, with the maximum exposure assuming no additional development activity occurred prior to March 31, 2022. As of the filing of this report, the Company expects to meet its obligations under this agreement. Other Contracts. During the second quarter of 2021, the Company entered into an operating lease with a total estimated obligation of $25.8 million and an initial term extending through the second quarter of 2033. As of the filing of this report, the Company expects to meet this commitment. Contingencies The Company is subject to litigation and claims arising in the ordinary course of business. The Company accrues for such items when a liability is both probable and the amount can be reasonably estimated. In the opinion of management, the anticipated results of any pending litigation and claims are not expected to have a material effect on the results of operations, the financial position, or the cash flows of the Company.

Compensation Plans

Compensation Plans	9 Months Ended
	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Compensation Plans	Note 7 - Compensation Plans As of September 30, 2021, 4.2 million shares of common stock were available for grant under the Company’s Equity Incentive Compensation Plan (“Equity Plan”). The Company may also grant other types of long-term incentive-based awards, such as cash awards and performance-based cash awards, to eligible employees under its compensation plan. Performance Share Units The Company has granted performance share units (“PSUs”) to eligible employees as part of its Equity Plan. The number of shares of the Company’s common stock issued to settle PSUs ranges from zero to two times the number of PSUs awarded and is determined based on certain criteria over a three For PSUs granted in 2018 and 2019, the settlement criteria include a combination of the Company’s Total Shareholder Return (“TSR”) relative to the TSR of certain peer companies and the Company’s cash return on total capital invested (“CRTCI”) relative to the CRTCI of certain peer companies over the associated three-year performance period. In addition to these performance criteria, the award agreements for these grants also stipulate that if the Company’s absolute TSR is negative over the three-year performance period, the maximum number of shares of common stock that can be issued to settle outstanding PSUs is capped at one times the number of PSUs granted on the award date, regardless of the Company’s TSR and CRTCI performance relative to its peer group. The fair values of the PSUs granted in 2018 and 2019 were measured on the applicable grant dates using the GBM Model, with the assumption that the associated CRTCI performance condition will be met at the target amount at the end of the respective performance periods. Compensation expense for PSUs is recognized within general and administrative expense and exploration expense over the vesting periods of the respective awards. As these awards depend on a combination of performance-based settlement criteria and market-based settlement criteria, compensation expense may be adjusted in future periods as the number of units expected to vest increases or decreases based on the Company’s expected CRTCI performance relative to the applicable peer companies. The Company records compensation expense associated with the issuance of PSUs based on the fair value of the awards as of the date of grant. Total compensation expense recorded for PSUs was $0.8 million and $1.6 million for the three months ended September 30, 2021, and 2020, respectively, and $5.3 million and $7.0 million for the nine months ended September 30, 2021, and 2020, respectively. As of September 30, 2021, there was $2.2 million of total unrecognized compensation expense related to non-vested PSUs, which is being amortized through 2022. A summary of activity during the nine months ended September 30, 2021, is presented in the following table: PSUs (1) Weighted-Average Grant-Date Fair Value Non-vested at beginning of year 830,464 $ 17.52 Granted — $ — Vested (352,395) $ 23.81 Forfeited (12,222) $ 15.76 Non-vested at end of quarter 465,847 $ 12.80 ____________________________________________ (1) The number of shares of common stock assumes a multiplier of one. The actual final number of shares of common stock to be issued will range from zero to two times the number of PSUs awarded depending on the three-year performance multiplier. During the nine months ended September 30, 2021, the Company settled PSUs that were granted in 2018, which earned a 1.0 times multiplier. The Company and all eligible recipients mutually agreed to net share settle a portion of the awards to cover income and payroll tax withholdings, as provided for in the Equity Plan and applicable award agreements. After withholding 112,919 shares to satisfy income and payroll tax withholding obligations, 234,823 shares of the Company’s common stock were issued in accordance with the terms of the applicable award agreement. Employee Restricted Stock Units The Company grants restricted stock units (“RSUs”) to eligible persons as part of its Equity Plan. Each of the RSUs granted represents a right to receive one share of the Company’s common stock upon settlement of the award at the end of the specified vesting period. RSUs generally vest one-third of the total grant on each anniversary date of the grant over the applicable vesting period or upon other triggering events as set forth in the Equity Plan. The Company records compensation expense associated with the issuance of RSUs based on the fair value of the awards as of the date of grant. The fair value of an individual RSU is equal to the closing price of the Company’s common stock on the date of the grant. Compensation expense for RSUs is recognized within general and administrative expense and exploration expense over the vesting periods of the respective awards. Total compensation expense recorded for employee RSUs was $2.9 million and $1.8 million for the three months ended September 30, 2021, and 2020, respectively, and $7.2 million and $7.1 million for the nine months ended September 30, 2021, and 2020, respectively. As of September 30, 2021, there was $23.7 million of total unrecognized compensation expense related to non-vested RSUs, which is being amortized through 2024. A summary of activity during the nine months ended September 30, 2021, is presented in the following table: RSUs Weighted-Average Grant-Date Fair Value Non-vested at beginning of year 2,097,860 $ 8.83 Granted 661,402 $ 25.47 Vested (394,930) $ 16.69 Forfeited (67,619) $ 10.25 Non-vested at end of quarter 2,296,713 $ 12.23 During the nine months ended September 30, 2021, the Company settled RSUs upon the vesting of awards granted in previous years. The Company and all eligible recipients mutually agreed to net share settle a portion of the awards to cover income and payroll tax withholdings, as provided for in the Equity Plan and applicable award agreements. After withholding 106,543 shares to satisfy income and payroll tax withholding obligations, 268,114 shares of the Company’s common stock were issued in accordance with the terms of the applicable award agreements. Director Shares During the second quarters of 2021, and 2020, the Company issued 57,795 and 267,576 shares, respectively, of its common stock to its non-employee directors under the Equity Plan. Shares issued during the second quarter of 2021 will fully vest on December 31, 2021. Shares issued during the second quarter of 2020 fully vested on December 31, 2020. Employee Stock Purchase Plan Under the Company’s Employee Stock Purchase Plan (“ESPP”), eligible employees may purchase shares of the Company’s common stock through payroll deductions of up to 15 percent of eligible compensation, subject to a maximum of 2,500 shares per offering period and a maximum of $25,000 in value related to purchases for each calendar year. The purchase price of the stock is 85 percent of the lower of the trading price of the stock on either the first or last day of the purchase period. The ESPP is intended to qualify as an “employee stock purchase plan” under Section 423 of the Internal Revenue Code. There were 252,665 and 297,013 shares issued under the ESPP during the nine months ended September 30, 2021, and 2020, respectively. Total proceeds to the Company for the issuance of these shares was $1.3 million and $0.9 million for the nine months ended September 30, 2021, and 2020, respectively. The fair value of ESPP grants is measured at the date of grant using the Black-Scholes option-pricing model. Please refer to Note 7 - Compensation Plans in the 2020 Form 10-K for additional detail on the Company’s Equity Plan.

Earnings per Share

Earnings per Share	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Earnings Per Share [Text Block]	Note 9 - Earnings Per Share Basic net income or loss per common share is calculated by dividing net income or loss available to common stockholders by the basic weighted-average number of common shares outstanding for the respective period. Diluted net income or loss per common share is calculated by dividing net income or loss available to common stockholders by the diluted weighted-average number of common shares outstanding, which includes the effect of potentially dilutive securities. Potentially dilutive securities for this calculation consist primarily of non-vested RSUs, contingent PSUs, and Warrants, all of which were measured using the treasury stock method. The Warrants became exercisable at the election of the holders on January 15, 2021, and as a result, they were included as potentially dilutive securities on an adjusted weighted-average basis for the portion of the three and nine months ended September 30, 2021, for which they were outstanding. Please refer to Note 3 - Equity and Note 7 - Compensation Plans in this report, and Note 9 - Earnings Per Share in the 2020 Form 10-K for additional detail on these potentially dilutive securities. When the Company recognizes a net loss from continuing operations, all potentially dilutive shares are anti-dilutive and are consequently excluded from the calculation of diluted net loss per common share. The following table details the weighted-average number of anti-dilutive securities for the periods presented: For the Three Months Ended For the Nine Months Ended 2021 2020 2021 2020 (in thousands) Anti-dilutive — 158 5,200 450 The following table sets forth the calculations of basic and diluted net income (loss) per common share: For the Three Months Ended For the Nine Months Ended 2021 2020 2021 2020 (in thousands, except per share data) Net income (loss) $ 85,593 $ (98,292) $ (388,671) $ (599,439) Basic weighted-average common shares outstanding 121,457 114,371 118,224 113,462 Dilutive effect of non-vested RSUs and contingent PSUs 2,375 — — — Dilutive effect of warrants 19 — — — Diluted weighted-average common shares outstanding 123,851 114,371 118,224 113,462 Basic net income (loss) per common share $ 0.70 $ (0.86) $ (3.29) $ (5.28) Diluted net income (loss) per common share $ 0.69 $ (0.86) $ (3.29) $ (5.28)

Derivative Financial Instrument

Derivative Financial Instruments	9 Months Ended
	Sep. 30, 2021
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Derivative Financial Instruments	Note 10 - Derivative Financial Instruments Summary of Oil, Gas, and NGL Derivative Contracts in Place The Company regularly enters into commodity derivative contracts to mitigate a portion of its exposure to potentially adverse market changes in commodity prices and the associated impact on cash flows. As of September 30, 2021, all derivative counterparties were members of the Company’s Credit Agreement lender group and all contracts were entered into for other-than-trading purposes. The Company’s commodity derivative contracts consist of swap and collar arrangements for oil, natural gas, and NGL production. In a typical commodity swap agreement, if the agreed upon published third-party index price (“index price”) is lower than the swap fixed price, the Company receives the difference between the index price and the agreed upon swap fixed price. If the index price is higher than the swap fixed price, the Company pays the difference. For collar arrangements, the Company receives the difference between an agreed upon index price and the floor price if the index price is below the floor price. The Company pays the difference between the agreed upon ceiling price and the index price if the index price is above the ceiling price. No amounts are paid or received if the index price is between the floor and ceiling prices. The Company has entered into fixed price oil and natural gas basis swaps in order to mitigate exposure to adverse pricing differentials between certain industry benchmark prices and the actual physical pricing points where the Company’s production volumes are sold. Currently, the Company has basis swap contracts with fixed price differentials between: • NYMEX WTI and WTI Midland for a portion of its Midland Basin oil production with sales contracts that settle at WTI Midland prices, • NYMEX WTI and Intercontinental Exchange Brent Crude (“ICE Brent”) for a portion of its Midland Basin oil production with sales contracts that settle at ICE Brent prices, • NYMEX WTI and Argus WTI Houston Magellan East Houston Terminal (“MEH”) for a portion of its South Texas oil production with sales contracts that settle at Argus WTI Houston MEH prices, and • NYMEX Henry Hub (“HH”) and Inside FERC Tennessee Texas, Zone 0 (“IF Tenn TX Z0”) for a portion of its South Texas gas production with sales contracts that settle at IF Tenn TX Z0 prices. The Company has also entered into crude oil swap contracts to fix the differential in pricing between the NYMEX calendar month average and the physical crude oil delivery month (“Roll Differential”) in which the Company pays the periodic variable Roll Differential and receives a weighted-average fixed price differential. The weighted-average fixed price differential represents the amount of net addition (reduction) to delivery month prices for the notional volumes covered by the swap contracts. As of September 30, 2021, the Company had commodity derivative contracts outstanding through the fourth quarter of 2023 as summarized in the table below. Contract Period Fourth Quarter 2021 2022 2023 Oil Derivatives (volumes in MBbl and prices in $ per Bbl): Swaps NYMEX WTI Volumes 5,052 7,823 1,190 Weighted-Average Contract Price $ 41.70 $ 44.69 $ 45.20 Collars NYMEX WTI Volumes — 2,342 — Weighted-Average Floor Price $ — $ 54.00 $ — Weighted-Average Ceiling Price $ — $ 61.39 $ — Basis Swaps WTI Midland-NYMEX WTI Volumes 3,824 9,500 — Weighted-Average Contract Price (1) $ 0.71 $ 1.15 $ — NYMEX WTI-ICE Brent Volumes 920 3,650 — Weighted-Average Contract Price (2) $ (7.86) $ (7.78) $ — WTI Houston MEH-NYMEX WTI Volumes 466 1,329 — Weighted-Average Contract Price (3) $ 0.60 $ 1.25 $ — Roll Differential Swaps NYMEX WTI Volumes 3,831 11,278 1,832 Weighted-Average Contract Price $ (0.16) $ 0.11 $ 0.39 Gas Derivatives (volumes in BBtu and prices in $ per MMBtu): Swaps (4) IF HSC Volumes 12,412 28,932 — Weighted-Average Contract Price $ 2.41 $ 2.52 $ — WAHA Volumes 7,627 14,087 — Weighted-Average Contract Price $ 1.82 $ 2.32 $ — IF Tenn TX Z0 — 513 — Weighted-Average Contract Price $ — $ 3.22 $ — Collars NYMEX HH Volumes — 2,129 — Weighted-Average Floor Price $ — $ 3.40 $ — Weighted-Average Ceiling Price $ — $ 5.91 $ — Basis Swaps IF Tenn TX Z0-NYMEX HH Volumes — 1,254 — Weighted-Average Contract Price (5) $ — $ 0.04 $ — NGL Derivatives (volumes in MBbl and prices in $ per Bbl): Swaps OPIS Propane Mont Belvieu Non-TET Volumes 917 580 — Weighted-Average Contract Price $ 24.58 $ 29.71 $ — OPIS Normal Butane Mont Belvieu Non-TET Volumes 36 — — Weighted-Average Contract Price $ 30.87 $ — $ — Collars OPIS Propane Mont Belvieu Non-TET Volumes — 770 — Weighted-Average Floor Price $ — $ 25.78 $ — Weighted-Average Ceiling Price $ — $ 31.60 $ — ____________________________________________ (1) Represents the price differential between WTI Midland (Midland, Texas) and NYMEX WTI (Cushing, Oklahoma). (2) Represents the price differential between NYMEX WTI (Cushing, Oklahoma) and ICE Brent (North Sea). (3) Represents the price differential between Argus WTI Houston MEH (Houston, Texas) and NYMEX WTI (Cushing, Oklahoma). (4) The Company has natural gas swaps in place that settle against Inside FERC Houston Ship Channel (“IF HSC”), Inside FERC West Texas, and Platt’s Gas Daily West Texas (“IF WAHA” and “GD WAHA”, respectively, and together “WAHA”), and IF Tenn TX Z0. As of September 30, 2021, WAHA volumes were comprised of 81 percent IF WAHA and 19 percent GD WAHA. (5) Represents the price differential between IF Tenn TX Z0 (Corpus Christi, Texas) and NYMEX HH (Erath, Louisiana). Commodity Derivative Contracts Entered Into Subsequent to September 30, 2021 Subsequent to September 30, 2021, the Company entered into the following commodity derivative contracts: • NYMEX WTI oil collar contracts for the third quarter of 2022 for a total of 0.3 MMBbl of oil production at a floor price of $70.00 per Bbl and a weighted-average ceiling price of $73.52 per Bbl, and for the first quarter of 2023 for a total of 0.3 MMBbl of oil production at a floor price of $60.00 per Bbl and a ceiling price of $75.20 per Bbl; and • an IF HSC gas collar contract for the first quarter of 2023 for a total of 900 BBtu of gas production at a floor price of $3.38 per MMBtu and a ceiling price of $7.75 per MMBtu. Derivative Assets and Liabilities Fair Value The Company’s commodity derivatives are measured at fair value and are included in the accompanying balance sheets as derivative assets and liabilities, with the exception of derivative instruments that meet the “normal purchase normal sale” exclusion. The Company does not designate its commodity derivative contracts as hedging instruments. The fair value of the commodity derivative contracts was a net liability of $612.1 million and $168.2 million as of September 30, 2021, and December 31, 2020, respectively. The following table details the fair value of commodity derivative contracts recorded in the accompanying balance sheets, by category: As of September 30, 2021 As of December 31, 2020 (in thousands) Derivative assets: Current assets $ 24,514 $ 31,203 Noncurrent assets 6,096 23,150 Total derivative assets $ 30,610 $ 54,353 Derivative liabilities: Current liabilities $ 552,044 $ 200,189 Noncurrent liabilities 90,655 22,331 Total derivative liabilities $ 642,699 $ 222,520 Offsetting of Derivative Assets and Liabilities As of September 30, 2021, and December 31, 2020, all derivative instruments held by the Company were subject to master netting arrangements with various financial institutions. In general, the terms of the Company’s agreements provide for offsetting of amounts payable or receivable between it and the counterparty, at the election of both parties, for transactions that settle on the same date and in the same currency. The Company’s agreements also provide that in the event of an early termination, the counterparties have the right to offset amounts owed or owing under that and any other agreement with the same counterparty. The Company’s accounting policy is to not offset these positions in its accompanying balance sheets. The following table provides a reconciliation between the gross assets and liabilities reflected on the accompanying balance sheets and the potential effects of master netting arrangements on the fair value of the Company’s commodity derivative contracts: Derivative Assets as of Derivative Liabilities as of September 30, 2021 December 31, 2020 September 30, 2021 December 31, 2020 (in thousands) Gross amounts presented in the accompanying balance sheets $ 30,610 $ 54,353 $ (642,699) $ (222,520) Amounts not offset in the accompanying balance sheets (30,610) (53,598) 30,610 53,598 Net amounts $ — $ 755 $ (612,089) $ (168,922) The following table summarizes the commodity components of the derivative settlement (gain) loss, and the net derivative (gain) loss line items presented within the accompanying unaudited condensed consolidated statements of cash flows (“accompanying statements of cash flows”) and within the accompanying statements of operations, respectively: For the Three Months Ended For the Nine Months Ended 2021 2020 2021 2020 (in thousands) Derivative settlement (gain) loss: Oil contracts $ 154,113 $ (68,907) $ 344,740 $ (261,095) Gas contracts 35,757 (896) 88,437 (16,575) NGL contracts 23,685 (502) 47,085 (8,600) Total net derivative settlement (gain) loss $ 213,555 $ (70,305) $ 480,262 $ (286,270) Net derivative (gain) loss: Oil contracts $ 68,194 $ 30,641 $ 611,224 $ (360,649) Gas contracts 109,802 31,548 220,088 46,537 NGL contracts 31,150 1,682 92,871 (157) Total net derivative (gain) loss $ 209,146 $ 63,871 $ 924,183 $ (314,269) Credit Related Contingent Features As of September 30, 2021, and through the filing of this report, all of the Company’s derivative counterparties were members of the Company’s Credit Agreement lender group. Under the Credit Agreement, the Company is required to provide mortgage liens on assets having a value equal to at least 85 percent of the total PV-9, as defined in the Credit Agreement, of the Company’s proved oil and gas properties evaluated in the most recent reserve report. Collateral securing indebtedness under the Credit Agreement also secures the Company’s derivative agreement obligations.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Disclosures	Note 8 - Fair Value Measurements The Company follows fair value measurement accounting guidance for all assets and liabilities measured at fair value. This guidance defines fair value as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the measurement date. Market or observable inputs are the preferred sources of values, followed by assumptions based on hypothetical transactions in the absence of market inputs. The fair value hierarchy for grouping these assets and liabilities is based on the significance level of the following inputs: • Level 1 – quoted prices in active markets for identical assets or liabilities • Level 2 – quoted prices in active markets for similar assets or liabilities, quoted prices for identical or similar instruments in markets that are not active, and model-derived valuations whose inputs are observable or whose significant value drivers are observable • Level 3 – significant inputs to the valuation model are unobservable The following table is a listing of the Company’s assets and liabilities that are measured at fair value in the accompanying balance sheets and where they are classified within the fair value hierarchy as of September 30, 2021: Level 1 Level 2 Level 3 (in thousands) Assets: Derivatives (1) $ — $ 30,610 $ — Liabilities: Derivatives (1) $ — $ 642,699 $ — __________________________________________ (1) This represents a financial asset or liability that is measured at fair value on a recurring basis. The following table is a listing of the Company’s assets and liabilities that are measured at fair value in the accompanying balance sheets and where they are classified within the fair value hierarchy as of December 31, 2020: Level 1 Level 2 Level 3 (in thousands) Assets: Derivatives (1) $ — $ 54,353 $ — Liabilities: Derivatives (1) $ — $ 222,520 $ — ____________________________________________ (1) This represents a financial asset or liability that is measured at fair value on a recurring basis. Both financial and non-financial assets and liabilities are categorized within the above fair value hierarchy based on the lowest level of input that is significant to the fair value measurement. The following is a description of the valuation methodologies used by the Company as well as the general classification of such instruments pursuant to the above fair value hierarchy. Derivatives The Company uses Level 2 inputs to measure the fair value of oil, gas, and NGL commodity derivatives. Fair values are based upon interpolated data. The Company derives internal valuation estimates taking into consideration forward commodity price curves, counterparties’ credit ratings, the Company’s credit rating, and the time value of money. These valuations are then compared to the respective counterparties’ mark-to-market statements. The considered factors result in an estimated exit price that management believes provides a reasonable and consistent methodology for valuing derivative instruments. The commodity derivative instruments utilized by the Company are not considered by management to be complex, structured, or illiquid. The oil, gas, and NGL commodity derivative markets are highly active. Please refer to Note 10 - Derivative Financial Instruments in this report, and to Note 10 - Derivative Financial Instruments and Note 11 - Fair Value Measurements in the 2020 Form 10-K for more information regarding the Company’s derivative instruments. Oil and Gas Properties and Other Property and Equipment The Company had no material assets included in total property and equipment, net, measured at fair value as of September 30, 2021, or December 31, 2020. The following table presents impairment of proved properties expense and abandonment and impairment of unproved properties expense recorded for the periods presented: For the Three Months Ended September 30, For the Nine Months Ended September 30, 2021 2020 2021 2020 (in thousands) Impairment of proved oil and gas properties and related support equipment $ — $ — $ — $ 956,650 Abandonment and impairment of unproved properties (1) 8,750 8,750 26,250 50,613 Impairment $ 8,750 $ 8,750 $ 26,250 $ 1,007,263 ____________________________________________ (1) These impairments related to actual and anticipated lease expirations, as well as actual and anticipated losses on acreage due to title defects, changes in development plans, and other inherent acreage risks. The balances in the unproved oil and gas properties line item on the accompanying balance sheets as of September 30, 2021, and December 31, 2020, are recorded at carrying value. For the nine months ended September 30, 2020, the Company recorded impairment expense of $956.7 million related to its South Texas proved oil and gas properties and related support facilities as a result of the decrease in commodity price forecasts at the end of the first quarter of 2020, specifically decreases in oil and NGL prices. The Company used a discount rate of 11 percent in its calculation of the present value of expected future net cash flows based on the prevailing market-based weighted average cost of capital as of March 31, 2020. Please refer to Note 1 - Summary of Significant Accounting Policies and Note 11 - Fair Value Measurements in the 2020 Form 10-K for more information regarding the Company’s approach in determining the fair value of its properties. Long-Term Debt The following table reflects the fair value of the Company’s Senior Notes obligations measured using Level 1 inputs based on quoted secondary market trading prices. These notes were not presented at fair value on the accompanying balance sheets as of September 30, 2021, or December 31, 2020, as they were recorded at carrying value, net of any unamortized discounts and deferred financing costs. Please refer to Note 5 - Long-Term Debt for additional discussion. As of September 30, 2021 As of December 31, 2020 Principal Amount Fair Value Principal Amount Fair Value (in thousands) 1.50% Senior Secured Convertible Notes due 2021 $ — $ — $ 65,485 $ 61,449 10.0% Senior Secured Notes due 2025 $ 446,675 $ 498,212 $ 446,675 $ 482,887 6.125% Senior Notes due 2022 $ — $ — $ 212,403 $ 205,379 5.0% Senior Notes due 2024 $ 104,769 $ 104,392 $ 277,034 $ 240,072 5.625% Senior Notes due 2025 $ 349,118 $ 351,935 $ 349,118 $ 289,401 6.75% Senior Notes due 2026 $ 419,235 $ 428,773 $ 419,235 $ 342,385 6.625% Senior Notes due 2027 $ 416,791 $ 426,952 $ 416,791 $ 331,220 6.5% Senior Notes due 2028 $ 400,000 $ 414,352 $ — $ — As of December 31, 2020, the carrying value of the Company’s revolving credit facility approximated its fair value, as the applicable interest rates are floating, based on prevailing market rates.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation, Policy [Policy Text Block]	Basis of Presentation The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial information, the instructions to Quarterly Report on Form 10-Q, and Regulation S-X. These financial statements do not include all information and notes required by GAAP for annual financial statements. However, except as disclosed herein, there has been no material change in the information disclosed in the notes to the consolidated financial statements included in the 2020 Form 10-K . In the opinion of management, all adjustments, consisting of normal recurring adjustments considered necessary for a fair presentation of interim financial information, have been included. Operating results for the periods presented are not necessarily indicative of expected results for the full year. In connection with the preparation of the Company’s unaudited condensed consolidated financial statements, the Company evaluated events subsequent to the balance sheet date of September 30, 2021, and through the filing of this report. Additionally, certain prior period amounts have been reclassified to conform to current period presentation in the accompanying unaudited condensed consolidated financial statements.
Recently Issued Accounting Standards, Policy [Policy Text Block]	Recently Issued Accounting Standards In March 2020, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting (“ASU 2020-04”), and in January 2021, issued ASU No. 2021-01, Reference Rate Reform (Topic 848): Scope (“ASU 2021-01”), to provide clarifying guidance regarding the scope of Topic 848. ASU 2020-04 was issued to provide optional guidance for a limited period of time to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform on financial reporting. Generally, the guidance is to be applied as of any date from the beginning of an interim period that includes or is subsequent to March 12, 2020, or prospectively from a date within an interim period that includes or is subsequent to March 12, 2020, up to the date that the financial statements are available to be issued. ASU 2020-04 and ASU 2021-01 are effective for all entities through December 31, 2022. As of September 30, 2021, the Company has not elected to use the optional guidance and continues to evaluate the options provided by ASU 2020-04 and ASU 2021-01. Please refer to Note 5 - Long-Term Debt for discussion of the use of the London Interbank Offered Rate (“LIBOR”) in connection with borrowings under the Credit Agreement. There are no other ASUs that would have a material effect on the Company’s unaudited condensed consolidated financial statements and related disclosures that have been issued but not yet adopted by the Company as of September 30, 2021, or through the filing of this report.
Fair Value of Financial Instruments, Policy [Policy Text Block]	Derivatives The Company uses Level 2 inputs to measure the fair value of oil, gas, and NGL commodity derivatives. Fair values are based upon interpolated data. The Company derives internal valuation estimates taking into consideration forward commodity price curves, counterparties’ credit ratings, the Company’s credit rating, and the time value of money. These valuations are then compared to the respective counterparties’ mark-to-market statements. The considered factors result in an estimated exit price that management believes provides a reasonable and consistent methodology for valuing derivative instruments. The commodity derivative instruments utilized by the Company are not considered by management to be complex, structured, or illiquid. The oil, gas, and NGL commodity derivative markets are highly active. Please refer to Note 10 - Derivative Financial Instruments in this report, and to Note 10 - Derivative Financial Instruments and Note 11 - Fair Value Measurements in the 2020 Form 10-K for more information regarding the Company’s derivative instruments.

Fair Value Measures and Disclos

Fair Value Measures and Disclosures (Policies)	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments, Policy [Policy Text Block]	Derivatives The Company uses Level 2 inputs to measure the fair value of oil, gas, and NGL commodity derivatives. Fair values are based upon interpolated data. The Company derives internal valuation estimates taking into consideration forward commodity price curves, counterparties’ credit ratings, the Company’s credit rating, and the time value of money. These valuations are then compared to the respective counterparties’ mark-to-market statements. The considered factors result in an estimated exit price that management believes provides a reasonable and consistent methodology for valuing derivative instruments. The commodity derivative instruments utilized by the Company are not considered by management to be complex, structured, or illiquid. The oil, gas, and NGL commodity derivative markets are highly active. Please refer to Note 10 - Derivative Financial Instruments in this report, and to Note 10 - Derivative Financial Instruments and Note 11 - Fair Value Measurements in the 2020 Form 10-K for more information regarding the Company’s derivative instruments.

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	9 Months Ended
	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Disaggregation of oil, gas, and NGL production revenue [Table Text Block]	The tables below present oil, gas, and NGL production revenue by product type for each of the Company’s operating areas for the three and nine months ended September 30, 2021, and 2020: Midland Basin South Texas Total Three Months Ended Three Months Ended Three Months Ended 2021 2020 2021 2020 2021 2020 (in thousands) Oil production revenue $ 501,071 $ 194,547 $ 57,323 $ 13,100 $ 558,394 $ 207,647 Gas production revenue 96,082 23,304 52,878 26,251 148,960 49,555 NGL production revenue 103 115 52,356 24,695 52,459 24,810 Total $ 597,256 $ 217,966 $ 162,557 $ 64,046 $ 759,813 $ 282,012 Relative percentage 79 % 77 % 21 % 23 % 100 % 100 % ____________________________________________ Note: Amounts may not calculate due to rounding. Midland Basin South Texas Total Nine Months Ended Nine Months Ended Nine Months Ended 2021 2020 2021 2020 2021 2020 (in thousands) Oil production revenue $ 1,191,668 $ 585,041 $ 108,871 $ 33,815 $ 1,300,539 $ 618,856 Gas production revenue 205,323 46,559 121,630 78,569 326,953 125,128 NGL production revenue 315 218 117,740 61,833 118,055 62,051 Total $ 1,397,306 $ 631,818 $ 348,241 $ 174,217 $ 1,745,547 $ 806,035 Relative percentage 80 % 78 % 20 % 22 % 100 % 100 % ____________________________________________ Note: Amounts may not calculate due to rounding.

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Schedule of provision for income taxes [Table Text Block]	The provision for income taxes for the three and nine months ended September 30, 2021, and 2020, consisted of the following: For the Three Months Ended For the Nine Months Ended 2021 2020 2021 2020 (in thousands) Current portion of income tax (expense) benefit: Federal $ — $ — $ — $ — State (29) 173 (187) (402) Deferred portion of income tax benefit 68 22,796 282 159,064 Income tax benefit $ 39 $ 22,969 $ 95 $ 158,662 Effective tax rate — % 18.9 % — % 20.9 %

Long-Term Debt (Tables)

Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments [Table Text Block]	The following table summarizes the Company’s total outstanding balance on its revolving credit facility, Senior Secured Notes net of unamortized discount and deferred financing costs, and Senior Unsecured Notes net of unamortized deferred financing costs, as of September 30, 2021, and December 31, 2020: As of September 30, 2021 As of December 31, 2020 (in thousands) Revolving credit facility $ — $ 93,000 Senior Secured Notes (1) 405,007 460,656 Senior Unsecured Notes (1) 1,672,623 1,660,663 Total $ 2,077,630 $ 2,214,319 ____________________________________________ (1) Senior Secured Notes and Senior Unsecured Notes are defined below.
Schedule of Line of Credit Facilities [Table Text Block]	The following table presents the outstanding balance, total amount of letters of credit outstanding, and available borrowing capacity under the Credit Agreement as of October 21, 2021, September 30, 2021, and December 31, 2020: As of October 21, 2021 As of September 30, 2021 As of December 31, 2020 (in thousands) Revolving credit facility (1) $ — $ — $ 93,000 Letters of credit (2) 2,500 2,500 42,000 Available borrowing capacity 1,097,500 1,097,500 965,000 Total aggregate lender commitment amount $ 1,100,000 $ 1,100,000 $ 1,100,000 ____________________________________________ (1) Unamortized deferred financing costs attributable to the revolving credit facility are presented as a component of the other noncurrent assets line item on the accompanying balance sheets and totaled $3.1 million and $4.3 million as of September 30, 2021, and December 31, 2020, respectively. These costs are being amortized over the term of the revolving credit facility on a straight-line basis. (2) Letters of credit outstanding reduce the amount available under the revolving credit facility on a dollar-for-dollar basis.
Schedule Of Long-term Debt Instruments, Senior Secured Notes [Table Text Block]	Senior Secured Notes, net of unamortized discount and deferred financing costs, included within the Senior Notes, net line item on the accompanying balance sheets as of September 30, 2021, and December 31, 2020, consisted of the following (collectively referred to as “Senior Secured Notes”): As of September 30, 2021 Principal Amount Unamortized Debt Discount Unamortized Deferred Financing Costs Net (in thousands) 10.0% Senior Secured Notes due 2025 $ 446,675 $ 32,232 $ 9,436 $ 405,007 As of December 31, 2020 Principal Amount Unamortized Debt Discount Unamortized Deferred Financing Costs Net (in thousands) 1.50% Senior Secured Convertible Notes due 2021 $ 65,485 $ 1,828 $ 175 $ 63,482 10.0% Senior Secured Notes due 2025 446,675 37,943 11,558 397,174 Total $ 512,160 $ 39,771 $ 11,733 $ 460,656
Schedule Of Long-term Debt Instruments, Senior Unsecured Notes [Table Text Block]	Senior Unsecured Notes, net of unamortized deferred financing costs, included within the Senior Notes, net line item on the accompanying balance sheets as of September 30, 2021, and December 31, 2020, consisted of the following (collectively referred to as “Senior Unsecured Notes,” and together with the Senior Secured Notes, “Senior Notes”): As of September 30, 2021 As of December 31, 2020 Principal Amount Unamortized Deferred Financing Costs Principal Amount, Net Principal Amount Unamortized Deferred Financing Costs Principal Amount, Net (in thousands) 6.125% Senior Notes due 2022 $ — $ — $ — $ 212,403 $ 855 $ 211,548 5.0% Senior Notes due 2024 104,769 451 104,318 277,034 1,576 275,458 5.625% Senior Notes due 2025 349,118 2,318 346,800 349,118 2,792 346,326 6.75% Senior Notes due 2026 419,235 3,445 415,790 419,235 3,970 415,265 6.625% Senior Notes due 2027 416,791 4,143 412,648 416,791 4,725 412,066 6.5% Senior Notes due 2028 400,000 6,933 393,067 — — — Total $ 1,689,913 $ 17,290 $ 1,672,623 $ 1,674,581 $ 13,918 $ 1,660,663

Compensation Plans (Tables)

Compensation Plans (Tables)	9 Months Ended
	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Schedule of non-vested PSUs	A summary of activity during the nine months ended September 30, 2021, is presented in the following table: PSUs (1) Weighted-Average Grant-Date Fair Value Non-vested at beginning of year 830,464 $ 17.52 Granted — $ — Vested (352,395) $ 23.81 Forfeited (12,222) $ 15.76 Non-vested at end of quarter 465,847 $ 12.80 ____________________________________________ (1) The number of shares of common stock assumes a multiplier of one. The actual final number of shares of common stock to be issued will range from zero to two times the number of PSUs awarded depending on the three-year performance multiplier.
Schedule of non-vested RSUs	A summary of activity during the nine months ended September 30, 2021, is presented in the following table: RSUs Weighted-Average Grant-Date Fair Value Non-vested at beginning of year 2,097,860 $ 8.83 Granted 661,402 $ 25.47 Vested (394,930) $ 16.69 Forfeited (67,619) $ 10.25 Non-vested at end of quarter 2,296,713 $ 12.23

Earnings per Share (Tables)

Earnings per Share (Tables)	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Schedule of weighted-average anti-dilutive securities	The following table details the weighted-average number of anti-dilutive securities for the periods presented: For the Three Months Ended For the Nine Months Ended 2021 2020 2021 2020 (in thousands) Anti-dilutive — 158 5,200 450
Schedule of calculations of basic and diluted net loss per common share	The following table sets forth the calculations of basic and diluted net income (loss) per common share: For the Three Months Ended For the Nine Months Ended 2021 2020 2021 2020 (in thousands, except per share data) Net income (loss) $ 85,593 $ (98,292) $ (388,671) $ (599,439) Basic weighted-average common shares outstanding 121,457 114,371 118,224 113,462 Dilutive effect of non-vested RSUs and contingent PSUs 2,375 — — — Dilutive effect of warrants 19 — — — Diluted weighted-average common shares outstanding 123,851 114,371 118,224 113,462 Basic net income (loss) per common share $ 0.70 $ (0.86) $ (3.29) $ (5.28) Diluted net income (loss) per common share $ 0.69 $ (0.86) $ (3.29) $ (5.28)

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2021
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Schedule of notional amounts of outstanding derivative positions [Table Text Block]	As of September 30, 2021, the Company had commodity derivative contracts outstanding through the fourth quarter of 2023 as summarized in the table below. Contract Period Fourth Quarter 2021 2022 2023 Oil Derivatives (volumes in MBbl and prices in $ per Bbl): Swaps NYMEX WTI Volumes 5,052 7,823 1,190 Weighted-Average Contract Price $ 41.70 $ 44.69 $ 45.20 Collars NYMEX WTI Volumes — 2,342 — Weighted-Average Floor Price $ — $ 54.00 $ — Weighted-Average Ceiling Price $ — $ 61.39 $ — Basis Swaps WTI Midland-NYMEX WTI Volumes 3,824 9,500 — Weighted-Average Contract Price (1) $ 0.71 $ 1.15 $ — NYMEX WTI-ICE Brent Volumes 920 3,650 — Weighted-Average Contract Price (2) $ (7.86) $ (7.78) $ — WTI Houston MEH-NYMEX WTI Volumes 466 1,329 — Weighted-Average Contract Price (3) $ 0.60 $ 1.25 $ — Roll Differential Swaps NYMEX WTI Volumes 3,831 11,278 1,832 Weighted-Average Contract Price $ (0.16) $ 0.11 $ 0.39 Gas Derivatives (volumes in BBtu and prices in $ per MMBtu): Swaps (4) IF HSC Volumes 12,412 28,932 — Weighted-Average Contract Price $ 2.41 $ 2.52 $ — WAHA Volumes 7,627 14,087 — Weighted-Average Contract Price $ 1.82 $ 2.32 $ — IF Tenn TX Z0 — 513 — Weighted-Average Contract Price $ — $ 3.22 $ — Collars NYMEX HH Volumes — 2,129 — Weighted-Average Floor Price $ — $ 3.40 $ — Weighted-Average Ceiling Price $ — $ 5.91 $ — Basis Swaps IF Tenn TX Z0-NYMEX HH Volumes — 1,254 — Weighted-Average Contract Price (5) $ — $ 0.04 $ — NGL Derivatives (volumes in MBbl and prices in $ per Bbl): Swaps OPIS Propane Mont Belvieu Non-TET Volumes 917 580 — Weighted-Average Contract Price $ 24.58 $ 29.71 $ — OPIS Normal Butane Mont Belvieu Non-TET Volumes 36 — — Weighted-Average Contract Price $ 30.87 $ — $ — Collars OPIS Propane Mont Belvieu Non-TET Volumes — 770 — Weighted-Average Floor Price $ — $ 25.78 $ — Weighted-Average Ceiling Price $ — $ 31.60 $ — ____________________________________________ (1) Represents the price differential between WTI Midland (Midland, Texas) and NYMEX WTI (Cushing, Oklahoma). (2) Represents the price differential between NYMEX WTI (Cushing, Oklahoma) and ICE Brent (North Sea). (3) Represents the price differential between Argus WTI Houston MEH (Houston, Texas) and NYMEX WTI (Cushing, Oklahoma). (4) The Company has natural gas swaps in place that settle against Inside FERC Houston Ship Channel (“IF HSC”), Inside FERC West Texas, and Platt’s Gas Daily West Texas (“IF WAHA” and “GD WAHA”, respectively, and together “WAHA”), and IF Tenn TX Z0. As of September 30, 2021, WAHA volumes were comprised of 81 percent IF WAHA and 19 percent GD WAHA. (5) Represents the price differential between IF Tenn TX Z0 (Corpus Christi, Texas) and NYMEX HH (Erath, Louisiana).
Schedule of fair value of derivatives in accompanying balance sheets [Table Text Block]	The following table details the fair value of commodity derivative contracts recorded in the accompanying balance sheets, by category: As of September 30, 2021 As of December 31, 2020 (in thousands) Derivative assets: Current assets $ 24,514 $ 31,203 Noncurrent assets 6,096 23,150 Total derivative assets $ 30,610 $ 54,353 Derivative liabilities: Current liabilities $ 552,044 $ 200,189 Noncurrent liabilities 90,655 22,331 Total derivative liabilities $ 642,699 $ 222,520
Schedule of the potential effects of master netting arrangements [Table Text Block]	The following table provides a reconciliation between the gross assets and liabilities reflected on the accompanying balance sheets and the potential effects of master netting arrangements on the fair value of the Company’s commodity derivative contracts: Derivative Assets as of Derivative Liabilities as of September 30, 2021 December 31, 2020 September 30, 2021 December 31, 2020 (in thousands) Gross amounts presented in the accompanying balance sheets $ 30,610 $ 54,353 $ (642,699) $ (222,520) Amounts not offset in the accompanying balance sheets (30,610) (53,598) 30,610 53,598 Net amounts $ — $ 755 $ (612,089) $ (168,922)
Schedule of the components of the derivative settlement (gain) loss and the net derivative (gain) loss [Table Text Block]	The following table summarizes the commodity components of the derivative settlement (gain) loss, and the net derivative (gain) loss line items presented within the accompanying unaudited condensed consolidated statements of cash flows (“accompanying statements of cash flows”) and within the accompanying statements of operations, respectively: For the Three Months Ended For the Nine Months Ended 2021 2020 2021 2020 (in thousands) Derivative settlement (gain) loss: Oil contracts $ 154,113 $ (68,907) $ 344,740 $ (261,095) Gas contracts 35,757 (896) 88,437 (16,575) NGL contracts 23,685 (502) 47,085 (8,600) Total net derivative settlement (gain) loss $ 213,555 $ (70,305) $ 480,262 $ (286,270) Net derivative (gain) loss: Oil contracts $ 68,194 $ 30,641 $ 611,224 $ (360,649) Gas contracts 109,802 31,548 220,088 46,537 NGL contracts 31,150 1,682 92,871 (157) Total net derivative (gain) loss $ 209,146 $ 63,871 $ 924,183 $ (314,269)

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]	The following table is a listing of the Company’s assets and liabilities that are measured at fair value in the accompanying balance sheets and where they are classified within the fair value hierarchy as of September 30, 2021: Level 1 Level 2 Level 3 (in thousands) Assets: Derivatives (1) $ — $ 30,610 $ — Liabilities: Derivatives (1) $ — $ 642,699 $ — __________________________________________ (1) This represents a financial asset or liability that is measured at fair value on a recurring basis. The following table is a listing of the Company’s assets and liabilities that are measured at fair value in the accompanying balance sheets and where they are classified within the fair value hierarchy as of December 31, 2020: Level 1 Level 2 Level 3 (in thousands) Assets: Derivatives (1) $ — $ 54,353 $ — Liabilities: Derivatives (1) $ — $ 222,520 $ — ____________________________________________ (1) This represents a financial asset or liability that is measured at fair value on a recurring basis.
Impairments of oil and gas properties	The following table presents impairment of proved properties expense and abandonment and impairment of unproved properties expense recorded for the periods presented: For the Three Months Ended September 30, For the Nine Months Ended September 30, 2021 2020 2021 2020 (in thousands) Impairment of proved oil and gas properties and related support equipment $ — $ — $ — $ 956,650 Abandonment and impairment of unproved properties (1) 8,750 8,750 26,250 50,613 Impairment $ 8,750 $ 8,750 $ 26,250 $ 1,007,263 ____________________________________________ (1) These impairments related to actual and anticipated lease expirations, as well as actual and anticipated losses on acreage due to title defects, changes in development plans, and other inherent acreage risks. The balances in the unproved oil and gas properties line item on the accompanying balance sheets as of September 30, 2021, and December 31, 2020, are recorded at carrying value.
Long Term Debt Fair Value [Table Text Block]	Long-Term Debt The following table reflects the fair value of the Company’s Senior Notes obligations measured using Level 1 inputs based on quoted secondary market trading prices. These notes were not presented at fair value on the accompanying balance sheets as of September 30, 2021, or December 31, 2020, as they were recorded at carrying value, net of any unamortized discounts and deferred financing costs. Please refer to Note 5 - Long-Term Debt for additional discussion. As of September 30, 2021 As of December 31, 2020 Principal Amount Fair Value Principal Amount Fair Value (in thousands) 1.50% Senior Secured Convertible Notes due 2021 $ — $ — $ 65,485 $ 61,449 10.0% Senior Secured Notes due 2025 $ 446,675 $ 498,212 $ 446,675 $ 482,887 6.125% Senior Notes due 2022 $ — $ — $ 212,403 $ 205,379 5.0% Senior Notes due 2024 $ 104,769 $ 104,392 $ 277,034 $ 240,072 5.625% Senior Notes due 2025 $ 349,118 $ 351,935 $ 349,118 $ 289,401 6.75% Senior Notes due 2026 $ 419,235 $ 428,773 $ 419,235 $ 342,385 6.625% Senior Notes due 2027 $ 416,791 $ 426,952 $ 416,791 $ 331,220 6.5% Senior Notes due 2028 $ 400,000 $ 414,352 $ — $ —

Disaggregation of oil, gas, and

Disaggregation of oil, gas, and NGL production revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 759,813	$ 282,012	$ 1,745,547	$ 806,035
Revenue, Remaining Performance Obligation, Amount	0		0
Midland Basin
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	597,256	217,966	1,397,306	631,818
South Texas
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 162,557	$ 64,046	$ 348,241	$ 174,217
Revenue Benchmark | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Relative percentage	100.00%	100.00%	100.00%	100.00%
Revenue Benchmark | Geographic Concentration Risk | Midland Basin
Segment Reporting Information [Line Items]
Relative percentage	79.00%	77.00%	80.00%	78.00%
Revenue Benchmark | Geographic Concentration Risk | South Texas
Segment Reporting Information [Line Items]
Relative percentage	21.00%	23.00%	20.00%	22.00%
Oil production revenue
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 558,394	$ 207,647	$ 1,300,539	$ 618,856
Oil production revenue | Midland Basin
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	501,071	194,547	1,191,668	585,041
Oil production revenue | South Texas
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	57,323	13,100	108,871	33,815
Gas production revenue
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	148,960	49,555	326,953	125,128
Gas production revenue | Midland Basin
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	96,082	23,304	205,323	46,559
Gas production revenue | South Texas
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	52,878	26,251	121,630	78,569
NGL production revenue
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	52,459	24,810	118,055	62,051
NGL production revenue | Midland Basin
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	103	115	315	218
NGL production revenue | South Texas
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 52,356	$ 24,695	$ 117,740	$ 61,833

Accounts Receivable from Custom

Accounts Receivable from Customers (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Accrued Income Receivable
Accounts Receivable [Line Items]
Accounts receivable from contracts with customers	$ 227.5	$ 108.9
Minimum
Accounts Receivable [Line Items]
Revenue receipt, days after sale	30
Maximum
Accounts Receivable [Line Items]
Revenue receipt, days after sale	90

Equity (Details)

Equity (Details) - USD ($) $ / shares in Units, $ in Thousands	Jan. 15, 2021	Jun. 17, 2020	Jun. 30, 2021	Jun. 30, 2020	Sep. 30, 2021
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		5,900,000
Warrants Percent of Outstanding Stock		5.00%
Exercise Price of Warrants		$ 0.01
Issuance of Warrants		$ 21,500		$ 21,520
Class of Warrant or Right, Date from which Warrants or Rights Exercisable	Jan. 15, 2021
Warrant Triggering Date - Amount		$ 1,000,000
WarrantsExercised			5,922,260
Warrants and Rights Outstanding, Maturity Date					Jun. 30, 2023
Common Stock
Class of Warrant or Right [Line Items]
Issuance of common stock through cashless exercise of warrants (Shares)			5,918,089
Weighted Average
Class of Warrant or Right [Line Items]
Shares Issued, Price Per Share			$ 15.45

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Components of the provision for income taxes
Federal	$ 0	$ 0	$ 0	$ 0
State	(29)	173	(187)	(402)
Deferred portion of income tax benefit	68	22,796	282	159,064
Income tax benefit	$ 39	$ 22,969	$ 95	$ 158,662
Effective tax rate	0.00%	18.90%	0.00%	20.90%

Credit Agreement (Details)

Credit Agreement (Details) - USD ($) $ in Thousands	Oct. 28, 2021	Oct. 21, 2021	Sep. 30, 2021	Dec. 31, 2020
Line of Credit Facility [Line Items]
Revolving credit facility			$ 0	$ 93,000
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Revolving credit facility			0	93,000
Letters of credit			2,500	42,000
Available borrowing capacity			1,097,500	965,000
Revolving credit facility, aggregate lender commitments			1,100,000	1,100,000
Revolving credit facility, maximum loan amount			2,500,000
Revolving credit facility, current borrowing base			1,100,000
Revolving Credit Facility, unamortized deferred financing costs			$ 3,100	$ 4,300
Revolving Credit Facility [Member] | Subsequent Event
Line of Credit Facility [Line Items]
Revolving credit facility		$ 0
Letters of credit		2,500
Available borrowing capacity		1,097,500
Revolving credit facility, aggregate lender commitments	$ 1,100,000	$ 1,100,000
Revolving credit facility, current borrowing base	$ 1,100,000

Senior Secured Notes (Details)

Senior Secured Notes (Details) - USD ($) $ in Thousands	Jul. 01, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Jun. 17, 2020
Senior Notes [Line Items]
Secured Long-term Debt, Noncurrent		$ 405,007		$ 405,007		$ 460,656
10.0% Senior Secured Notes due 2025
Senior Notes [Line Items]
Senior Notes, interest rate, stated percentage		10.00%		10.00%		10.00%
Senior Notes, Principal amount		$ 446,675		$ 446,675		$ 446,675	$ 446,700
Senior Secured Notes, Unamortized Debt Discount		32,232		32,232		37,943
Senior Notes, unamortized deferred financing costs		9,436		9,436		11,558
Secured Long-term Debt, Noncurrent		$ 405,007		$ 405,007		$ 397,174
1.50% Senior Secured Convertible Notes Due 2021
Senior Notes [Line Items]
Senior Notes, interest rate, stated percentage		1.50%		1.50%		1.50%
Senior Notes, Principal amount		$ 0		$ 0		$ 65,485
Senior Secured Notes, Unamortized Debt Discount						1,828
Senior Notes, unamortized deferred financing costs						175
Secured Long-term Debt, Noncurrent						63,482
Repayment of 1.50% Senior Convertible Notes due 2021	$ 65,500
Interest Expense, Debt		$ 0	$ 1,100	$ 2,300	$ 6,600
Senior Secured Notes [Member]
Senior Notes [Line Items]
Senior Notes, Principal amount						512,160
Senior Secured Notes, Unamortized Debt Discount						39,771
Senior Notes, unamortized deferred financing costs						$ 11,733

Senior Unsecured Notes (Details

Senior Unsecured Notes (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Jun. 23, 2021	Dec. 31, 2020	Sep. 30, 2020
Senior Notes [Line Items]
Unsecured Long-term Debt, Noncurrent	$ 1,672,623		$ 1,660,663
6.125% Senior Unsecured Notes due 2022
Senior Notes [Line Items]
Senior Notes, interest rate, stated percentage	6.125%		6.125%
Senior Notes, Principal amount	$ 0		$ 212,403
Senior Notes, unamortized deferred financing costs	0		855
Unsecured Long-term Debt, Noncurrent	$ 0		$ 211,548
5.0% Senior Unsecured Notes due 2024
Senior Notes [Line Items]
Senior Notes, interest rate, stated percentage	5.00%		5.00%
Senior Notes, Principal amount	$ 104,769		$ 277,034
Senior Notes, unamortized deferred financing costs	451		1,576
Unsecured Long-term Debt, Noncurrent	$ 104,318		$ 275,458
5.625% Senior Unsecured Notes due 2025
Senior Notes [Line Items]
Senior Notes, interest rate, stated percentage	5.625%		5.625%
Senior Notes, Principal amount	$ 349,118		$ 349,118
Senior Notes, unamortized deferred financing costs	2,318		2,792
Unsecured Long-term Debt, Noncurrent	$ 346,800		$ 346,326
6.75% Senior Unsecured Notes due 2026
Senior Notes [Line Items]
Senior Notes, interest rate, stated percentage	6.75%		6.75%
Senior Notes, Principal amount	$ 419,235		$ 419,235
Senior Notes, unamortized deferred financing costs	3,445		3,970
Unsecured Long-term Debt, Noncurrent	$ 415,790		$ 415,265
6.625% Senior Unsecured Notes due 2027
Senior Notes [Line Items]
Senior Notes, interest rate, stated percentage	6.625%		6.625%
Senior Notes, Principal amount	$ 416,791		$ 416,791
Senior Notes, unamortized deferred financing costs	4,143		4,725
Unsecured Long-term Debt, Noncurrent	$ 412,648		$ 412,066
6.5% Senior Unsecured Notes Due 2028
Senior Notes [Line Items]
Senior Notes, interest rate, stated percentage	6.50%	6.50%	6.50%
Senior Notes, Principal amount	$ 400,000	$ 400,000	$ 0
Senior Notes, unamortized deferred financing costs	6,933		0
Unsecured Long-term Debt, Noncurrent	393,067		0
Senior Unsecured Notes [Member]
Senior Notes [Line Items]
Senior Notes, Principal amount	1,689,913		1,674,581
Senior Notes, unamortized deferred financing costs	$ 17,290		$ 13,918
1.50% Senior Unsecured Convertible Notes Due 2021 [Member]
Senior Notes [Line Items]
Senior Notes, interest rate, stated percentage				1.50%

Long-Term Debt (Details)

Long-Term Debt (Details) - USD ($) $ in Thousands	Oct. 28, 2021	Jun. 23, 2021	Jun. 17, 2020	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Oct. 21, 2021	Dec. 31, 2020
Long-Term Debt [Line Items]
Revolving credit facility				$ 0				$ 0			$ 93,000
Secured Long-term Debt, Noncurrent				405,007				405,007			460,656
Unsecured Long-term Debt, Noncurrent				1,672,623				1,672,623			1,660,663
Total long-term debt, net				2,077,630				2,077,630			2,214,319
Gain (loss) on extinguishment of debt				5		$ 25,070		$ (2,139)	$ 264,546
Debt Instrument, Covenant Compliance								The Company was in compliance with all covenants under the Credit Agreement and the indentures governing the Senior Notes as of September 30, 2021, and through the filing of this report.
Capitalized interest costs				3,500		4,800		$ 12,500	11,600
6.5% Senior Unsecured Notes Due 2028
Long-Term Debt [Line Items]
Unsecured Long-term Debt, Noncurrent				393,067				393,067			0
Senior Notes, Principal amount		$ 400,000		$ 400,000				$ 400,000			$ 0
Senior Notes, interest rate, stated percentage		6.50%		6.50%				6.50%			6.50%
Debt Instrument, Maturity Date		Jul. 15, 2028
Proceeds from Debt, Net of Issuance Costs		$ 392,800
Senior Secured Notes, Debt Issuance Costs, Gross		7,200
6.125% Senior Unsecured Notes due 2022
Long-Term Debt [Line Items]
Unsecured Long-term Debt, Noncurrent				$ 0				$ 0			$ 211,548
Senior Notes, Principal amount				$ 0				$ 0			$ 212,403
Senior Notes, interest rate, stated percentage				6.125%				6.125%			6.125%
Senior Unsecured Notes, exchanged or repurchased face amount		193,100			$ 19,300	103,200			103,200
5.0% Senior Unsecured Notes due 2024
Long-Term Debt [Line Items]
Unsecured Long-term Debt, Noncurrent				$ 104,318				$ 104,318			$ 275,458
Senior Notes, Principal amount				$ 104,769				$ 104,769			$ 277,034
Senior Notes, interest rate, stated percentage				5.00%				5.00%			5.00%
Senior Unsecured Notes, exchanged or repurchased face amount		$ 172,300				29,000			29,000
6.125% Senior Unsecured Notes Due 2022 and 5.0% Senior Unsecured Notes Due 2024 [Member]
Long-Term Debt [Line Items]
Senior Unsecured Notes, repurchased settlement amount					385,300	94,200			94,200
Gain (loss) on extinguishment of debt					(2,100)	25,100			37,300
Debt Instrument, Repurchase Premium					600
Discount realized on extinguishment of debt						(25,500)			(37,900)
6.125% Senior Unsecured Notes Due 2022 and 5.0% Senior Unsecured Notes Due 2024 [Member] | Accelerated unamortized deferred financing costs [Member]
Long-Term Debt [Line Items]
Write off of Deferred Debt Issuance Cost					$ 1,500	$ 500			$ 700
1.50% Senior Unsecured Convertible Notes Due 2021 [Member]
Long-Term Debt [Line Items]
Senior Notes, interest rate, stated percentage						1.50%			1.50%
Senior Unsecured Notes, exchanged or repurchased face amount			$ 107,000
Repayment of 1.50% Senior Convertible Notes due 2021			53,500
10.0% Senior Secured Notes due 2025
Long-Term Debt [Line Items]
Secured Long-term Debt, Noncurrent				$ 405,007				$ 405,007			$ 397,174
Senior Notes, Principal amount			446,700	$ 446,675				$ 446,675			$ 446,675
Senior Notes, interest rate, stated percentage				10.00%				10.00%			10.00%
Senior Unsecured Notes [Member]
Long-Term Debt [Line Items]
Senior Notes, Principal amount				$ 1,689,913				$ 1,689,913			$ 1,674,581
Senior Unsecured Notes, exchanged or repurchased face amount			$ 611,900
Senior Secured Notes, Senior Unsecured Notes, and 1.50% Senior Unsecured Convertible Notes Due 2021
Long-Term Debt [Line Items]
Gain (loss) on extinguishment of debt							$ 227,300
Senior Secured Notes, Senior Unsecured Notes, and 1.50% Senior Unsecured Convertible Notes Due 2021 | Accelerated unamortized deferred financing costs [Member]
Long-Term Debt [Line Items]
Write off of Deferred Debt Issuance Cost							5,600
Senior Secured Notes, Senior Unsecured Notes, and 1.50% Senior Unsecured Convertible Notes Due 2021 | Accelerated Unamortized Debt Discount
Long-Term Debt [Line Items]
Write off of Deferred Debt Issuance Cost							$ 6,100
Subsequent Event
Long-Term Debt [Line Items]
Debt Instrument, Covenant Compliance	The Company was in compliance with all covenants under the Credit Agreement and the indentures governing the Senior Notes as of September 30, 2021, and through the filing of this report.
Revolving Credit Facility [Member]
Long-Term Debt [Line Items]
Revolving credit facility				$ 0				$ 0			$ 93,000
Revolving Credit Facility [Member] | Subsequent Event
Long-Term Debt [Line Items]
Revolving credit facility										$ 0

Commitments (Details)

Commitments (Details) $ in Millions	Sep. 30, 2021USD ($)
Drilling Rig Leasing Contracts
Commitments and Contingencies [Line Items]
Early Termination Penalty for Rig Contract Cancellation	$ 5.1
Contractual Obligation	8.6
Operating Lease
Commitments and Contingencies [Line Items]
Contractual Obligation	25.8
Minimum
Commitments and Contingencies [Line Items]
Potential penalty for not meeting minimum drilling and completion requirements	0
Maximum
Commitments and Contingencies [Line Items]
Potential penalty for not meeting minimum drilling and completion requirements	$ 25.9

Compensation Plans_ Stock Based

Compensation Plans: Stock Based (Details) $ / shares in Units, $ in Millions	Sep. 30, 2021USD ($)$ / sharesshares	Sep. 30, 2021USD ($)$ / sharesshares	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)$ / sharesshares	Sep. 30, 2020USD ($)	Dec. 31, 2020$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award
Shares available for grant	4,200,000	4,200,000		4,200,000
Performance Shares (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award
Multiplier applied to PSU awards at settlement	1	1		1
Award Vesting Period	3 years
Stock-based compensation expense | $		$ 0.8	$ 1.6	$ 5.3	$ 7
Unrecognized stock based compensation expense | $	$ 2.2	$ 2.2		$ 2.2
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Multiplier Assumed	1	1		1
Shares Issued in Period				234,823
Shares Withheld for Tax Withholding Obligation				112,919
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	465,847	465,847		465,847		830,464
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value | $ / shares	$ 12.80	$ 12.80		$ 12.80		$ 17.52
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period				0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ / shares				$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period				(352,395)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value | $ / shares				$ 23.81
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period				(12,222)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value | $ / shares				$ 15.76
Performance Shares (PSUs) | Minimum
Share-based Compensation Arrangement by Share-based Payment Award
Multiplier applied to PSU awards at settlement	0	0		0
Performance Shares (PSUs) | Maximum
Share-based Compensation Arrangement by Share-based Payment Award
Multiplier applied to PSU awards at settlement	2	2		2
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation expense | $		$ 2.9	$ 1.8	$ 7.2	$ 7.1
Unrecognized stock based compensation expense | $	$ 23.7	$ 23.7		$ 23.7
Number of shares represented by each RSU	1	1		1
Shares Issued in Period				268,114
Shares Withheld for Tax Withholding Obligation				106,543
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	2,296,713	2,296,713		2,296,713		2,097,860
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value | $ / shares	$ 12.23	$ 12.23		$ 12.23		$ 8.83
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period				661,402
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ / shares				$ 25.47
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period				(394,930)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value | $ / shares				$ 16.69
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period				(67,619)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value | $ / shares				$ 10.25

Director Shares (Details)

Director Shares (Details) - shares	3 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Director
Share-based Compensation Arrangement by Share-based Payment Award
Shares issued to directors	57,795	267,576

Employee Stock Purchase Plan (D

Employee Stock Purchase Plan (Details) - Employee Stock Purchase Plan - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award
Maximum Employee Subscription Rate	15.00%
Maximum Number of Shares Per Employee	2,500
Maximum Employee Subscription Value	$ 25
Purchase Price of Common Stock, Percent	85.00%
Issuance of common stock under Employee Stock Purchase Plan (Shares)	252,665	297,013
Proceeds, Issuance of Shares, Share-based Payment Arrangement, Excluding Option Exercised	$ 1,300	$ 900

Earnings per Share (Details)

Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	Jan. 15, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Class of Warrant or Right, Date from which Warrants or Rights Exercisable	Jan. 15, 2021
Anti-dilutive securities excluded from earnings per share		0			158			5,200	450
Earnings Per Share Reconciliation [Abstract]
Net income (loss)		$ 85,593	$ (222,995)	$ (251,269)	$ (98,292)	$ (89,252)	$ (411,895)	$ (388,671)	$ (599,439)
Basic weighted-average common shares outstanding		121,457			114,371			118,224	113,462
Dilutive effect of non-vested RSUs and contingent PSUs		2,375			0			0	0
Dilutive effect of warrants		19			0			0	0
Diluted weighted-average common shares outstanding		123,851			114,371			118,224	113,462
Basic net income (loss) per common share		$ 0.70			$ (0.86)			$ (3.29)	$ (5.28)
Diluted net income (loss) per common share		$ 0.69			$ (0.86)			$ (3.29)	$ (5.28)

Derivative Financial Instrume_3

Derivative Financial Instruments (Details) bbl in Thousands, BTU in Billions	Oct. 28, 2021BTU$ / Barrels$ / EnergyContentbbl	Sep. 30, 2021BTU$ / Barrels$ / EnergyContentbbl
NYMEX Oil Swap Contract Fourth Quarter, Year 1
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		5,052
Derivative, Swap Type, Weighted-Average Contract Price		41.70
NYMEX Oil Swap Contract, Year 2
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		7,823
Derivative, Swap Type, Weighted-Average Contract Price		44.69
NYMEX Oil Swap Contract, Year 3
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		1,190
Derivative, Swap Type, Weighted-Average Contract Price		45.20
NYMEX Oil Collar Contract, Fourth Quarter, Year 1
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		0
Derivative, Weighted-Average Floor Price		0
Derivative, Weighted-Average Ceiling Price		0
NYMEX Oil Collar Contract, Year 2
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		2,342
Derivative, Weighted-Average Floor Price		54
Derivative, Weighted-Average Ceiling Price		61.39
NYMEX Oil Collar Contract, Year 3
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		0
Derivative, Weighted-Average Floor Price		0
Derivative, Weighted-Average Ceiling Price		0
NYMEX Oil Calendar Month Average Roll Differential Fourth Quarter, Year 1
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		3,831
Derivative, Roll Differential Swap Type, Weighted-Average Contract Price		(0.16)
NYMEX Oil Calendar Month Average Roll Differential Contract, Year 2
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		11,278
Derivative, Roll Differential Swap Type, Weighted-Average Contract Price		0.11
NYMEX Oil Calendar Month Average Roll Differential Contract, Year 3
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		1,832
Derivative, Roll Differential Swap Type, Weighted-Average Contract Price		0.39
WTI Midland NYMEX WTI [Member] | Oil Basis Swap Contract Fourth Quarter, Year 1
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		3,824
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price		0.71
WTI Midland NYMEX WTI [Member] | Oil Basis Swap Contract, Year 2
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		9,500
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price		1.15
WTI Midland NYMEX WTI [Member] | Oil Basis Swap Contract, Year 3
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		0
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price		0
NYMEX WTI ICE Brent [Member] | Oil Basis Swap Contract Fourth Quarter, Year 1
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		920
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price		(7.86)
NYMEX WTI ICE Brent [Member] | Oil Basis Swap Contract, Year 2
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		3,650
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price		(7.78)
NYMEX WTI ICE Brent [Member] | Oil Basis Swap Contract, Year 3
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		0
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price		0
WTI Houston MEH NYMEX WTI | Oil Basis Swap Contract Fourth Quarter, Year 1
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		466
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price		0.60
WTI Houston MEH NYMEX WTI | Oil Basis Swap Contract, Year 2
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		1,329
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price		1.25
WTI Houston MEH NYMEX WTI | Oil Basis Swap Contract, Year 3
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		0
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price		0
IF HSC [Member] | Gas Swaps Contract Fourth Quarter, Year 1
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		12,412
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent		2.41
IF HSC [Member] | Gas Swaps Contract, Year 2
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		28,932
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent		2.52
IF HSC [Member] | Gas Swaps Contract, Year 3
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		0
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent		0
WAHA [Member] | Gas Swaps Contract Fourth Quarter, Year 1
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		7,627
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent		1.82
WAHA [Member] | Gas Swaps Contract, Year 2
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		14,087
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent		2.32
WAHA [Member] | Gas Swaps Contract, Year 3
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		0
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent		0
IF Tenn TX Z0 | Gas Swaps Contract Fourth Quarter, Year 1
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		0
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent		0
IF Tenn TX Z0 | Gas Swaps Contract, Year 2
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		513
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent		3.22
IF Tenn TX Z0 | Gas Swaps Contract, Year 3
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		0
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent		0
NYMEX HH | Gas Collar Contract, Fourth Quarter, Year 1
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		0
Derivative, Weighted-Average Floor Price | $ / EnergyContent		0
Derivative, Weighted-Average Ceiling Price | $ / EnergyContent		0
NYMEX HH | Gas Collar Contract, Year 2
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		2,129
Derivative, Weighted-Average Floor Price | $ / EnergyContent		3.40
Derivative, Weighted-Average Ceiling Price | $ / EnergyContent		5.91
NYMEX HH | Gas Collar Contract, Year 3
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		0
Derivative, Weighted-Average Floor Price | $ / EnergyContent		0
Derivative, Weighted-Average Ceiling Price | $ / EnergyContent		0
IF Tenn TX Z0 NYMEX HH | Gas Basis Swap Contract Fourth Quarter, Year 1
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		0
Derivative, Gas Basis Swap Type, Weighted-Average Contract Price | $ / EnergyContent		0
IF Tenn TX Z0 NYMEX HH | Gas Basis Swap Contract, Year 2
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		1,254
Derivative, Gas Basis Swap Type, Weighted-Average Contract Price | $ / EnergyContent		0.04
IF Tenn TX Z0 NYMEX HH | Gas Basis Swap Contract, Year 3
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		0
Derivative, Gas Basis Swap Type, Weighted-Average Contract Price | $ / EnergyContent		0
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Fourth Quarter, Year 1
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		917
Derivative, Swap Type, Weighted-Average Contract Price		24.58
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract, Year 2
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		580
Derivative, Swap Type, Weighted-Average Contract Price		29.71
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract, Year 3
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		0
Derivative, Swap Type, Weighted-Average Contract Price		0
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Collar Contract, Fourth Quarter, Year 1
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		0
Derivative, Weighted-Average Floor Price		0
Derivative, Weighted-Average Ceiling Price		0
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Collar Contract, Year 2
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		770
Derivative, Weighted-Average Floor Price		25.78
Derivative, Weighted-Average Ceiling Price		31.60
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Collar Contract, Year 3
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		0
Derivative, Weighted-Average Floor Price		0
Derivative, Weighted-Average Ceiling Price		0
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Fourth Quarter, Year 1
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		36
Derivative, Swap Type, Weighted-Average Contract Price		30.87
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract, Year 2
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		0
Derivative, Swap Type, Weighted-Average Contract Price		0
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract, Year 3
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl		0
Derivative, Swap Type, Weighted-Average Contract Price		0
IF WAHA [Member]
Derivative Financial Instruments
Index percent of natural gas fixed swaps		81.00%
GD WAHA [Member]
Derivative Financial Instruments
Index percent of natural gas fixed swaps		19.00%
Subsequent Event | NYMEX Oil Collar Contract Third Quarter, Year 2
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl	300
Derivative, Weighted-Average Floor Price	70
Derivative, Weighted-Average Ceiling Price	73.52
Subsequent Event | NYMEX Oil Collar Contract First Quarter, Year 3
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume | bbl	300
Derivative, Weighted-Average Floor Price	60
Derivative, Weighted-Average Ceiling Price	75.20
Subsequent Event | IF HSC [Member] | Gas Collar Contract, First Quarter, Year 3
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU	900
Derivative, Weighted-Average Floor Price | $ / EnergyContent	3.38
Derivative, Weighted-Average Ceiling Price | $ / EnergyContent	7.75

Derivative Financial Instrume_4

Derivative Financial Instruments Fair Value (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Fair value of derivative assets and liabilities
Derivative, fair value, net	$ (612,100,000)	$ (168,200,000)
Derivative assets, current	24,514,000	31,203,000
Derivative assets, noncurrent	6,096,000	23,150,000
Total derivative assets	30,610,000	54,353,000
Derivative liabilities, current	552,044,000	200,189,000
Derivatives liabilities, noncurrent	90,655,000	22,331,000
Total derivative liabilities	(642,699,000)	(222,520,000)
Derivative asset, amounts not offset in the accompanying balance sheets	(30,610,000)	(53,598,000)
Derivative liabilities, amounts not offset in the accompanying balance sheets	30,610,000	53,598,000
Derivative asset, fair value, net amounts	0	755,000
Derivative liabilities, fair value, net amounts	(612,089,000)	(168,922,000)
Not Designated as Hedging Instrument
Fair value of derivative assets and liabilities
Derivative assets, current	24,514,000	31,203,000
Derivative assets, noncurrent	6,096,000	23,150,000
Derivative liabilities, current	552,044,000	200,189,000
Derivatives liabilities, noncurrent	90,655,000	22,331,000
Fair Value, Recurring | Fair Value, Inputs, Level 2 | Not Designated as Hedging Instrument
Fair value of derivative assets and liabilities
Total derivative assets	30,610,000	54,353,000
Total derivative liabilities	$ 642,699,000	$ 222,520,000

Derivative Financial Instrume_5

Derivative Financial Instruments Gains and Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Derivative Instruments, (Gain) Loss [Line Items]
Derivative settlement (gain) loss	$ 213,555	$ (70,305)	$ 480,262	$ (286,270)
Net derivative (gain) loss	209,146	63,871	924,183	(314,269)
Oil Contracts [Member]
Derivative Instruments, (Gain) Loss [Line Items]
Derivative settlement (gain) loss	154,113	(68,907)	344,740	(261,095)
Net derivative (gain) loss	68,194	30,641	611,224	(360,649)
Gas Contracts [Member]
Derivative Instruments, (Gain) Loss [Line Items]
Derivative settlement (gain) loss	35,757	(896)	88,437	(16,575)
Net derivative (gain) loss	109,802	31,548	220,088	46,537
NGL Contracts [Member]
Derivative Instruments, (Gain) Loss [Line Items]
Derivative settlement (gain) loss	23,685	(502)	47,085	(8,600)
Net derivative (gain) loss	$ 31,150	$ 1,682	$ 92,871	$ (157)

Credit Facility and Derivative

Credit Facility and Derivative Counterparties (Details)	Sep. 30, 2021
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Percentage of proved property secured for credit facility borrowing	85.00%

Fair Value (Details)

Fair Value (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)	Jun. 23, 2021USD ($)	Dec. 31, 2020USD ($)	Jun. 17, 2020USD ($)
Assets
Derivative Assets, Fair Value, Gross Asset	$ 30,610		$ 30,610			$ 54,353
Liabilities
Derivative Liability, Fair Value, Gross Liability	(642,699)		(642,699)			(222,520)
Oil and Gas Property [Abstract]
Property, Plant, and Equipment, Fair Value Disclosure	0		0			$ 0
Impairment of Proved Oil and Gas Properties	0	$ 0	0	$ 956,650
Abandonment and impairment of unproved properties	8,750	8,750	26,250	50,613
Impairment of Oil and Gas Properties	$ 8,750	$ 8,750	$ 26,250	$ 1,007,263
1.50% Senior Secured Convertible Notes Due 2021
Debt Instrument, Fair Value Disclosure [Abstract]
Senior Notes, interest rate, stated percentage	1.50%		1.50%			1.50%
Senior Notes, Principal amount	$ 0		$ 0			$ 65,485
Long-term Debt, Fair Value	$ 0		$ 0			$ 61,449
10.0% Senior Secured Notes due 2025
Debt Instrument, Fair Value Disclosure [Abstract]
Senior Notes, interest rate, stated percentage	10.00%		10.00%			10.00%
Senior Notes, Principal amount	$ 446,675		$ 446,675			$ 446,675	$ 446,700
Long-term Debt, Fair Value	$ 498,212		$ 498,212			$ 482,887
6.125% Senior Unsecured Notes due 2022
Debt Instrument, Fair Value Disclosure [Abstract]
Senior Notes, interest rate, stated percentage	6.125%		6.125%			6.125%
Senior Notes, Principal amount	$ 0		$ 0			$ 212,403
Long-term Debt, Fair Value	$ 0		$ 0			$ 205,379
5.0% Senior Unsecured Notes due 2024
Debt Instrument, Fair Value Disclosure [Abstract]
Senior Notes, interest rate, stated percentage	5.00%		5.00%			5.00%
Senior Notes, Principal amount	$ 104,769		$ 104,769			$ 277,034
Long-term Debt, Fair Value	$ 104,392		$ 104,392			$ 240,072
5.625% Senior Unsecured Notes due 2025
Debt Instrument, Fair Value Disclosure [Abstract]
Senior Notes, interest rate, stated percentage	5.625%		5.625%			5.625%
Senior Notes, Principal amount	$ 349,118		$ 349,118			$ 349,118
Long-term Debt, Fair Value	$ 351,935		$ 351,935			$ 289,401
6.75% Senior Unsecured Notes due 2026
Debt Instrument, Fair Value Disclosure [Abstract]
Senior Notes, interest rate, stated percentage	6.75%		6.75%			6.75%
Senior Notes, Principal amount	$ 419,235		$ 419,235			$ 419,235
Long-term Debt, Fair Value	$ 428,773		$ 428,773			$ 342,385
6.625% Senior Unsecured Notes due 2027
Debt Instrument, Fair Value Disclosure [Abstract]
Senior Notes, interest rate, stated percentage	6.625%		6.625%			6.625%
Senior Notes, Principal amount	$ 416,791		$ 416,791			$ 416,791
Long-term Debt, Fair Value	$ 426,952		$ 426,952			$ 331,220
6.5% Senior Unsecured Notes Due 2028
Debt Instrument, Fair Value Disclosure [Abstract]
Senior Notes, interest rate, stated percentage	6.50%		6.50%		6.50%	6.50%
Senior Notes, Principal amount	$ 400,000		$ 400,000		$ 400,000	$ 0
Long-term Debt, Fair Value	414,352		414,352			0
Fair Value, Nonrecurring | Measurement Input, Discount Rate | Oil and Gas Properties
Oil and Gas Property [Abstract]
Fair Value Assumptions, Measurement Input		0.11		0.11
Not Designated as Hedging Instrument | Fair Value, Recurring | Fair Value, Inputs, Level 1
Assets
Derivative Assets, Fair Value, Gross Asset	0		0			0
Liabilities
Derivative Liability, Fair Value, Gross Liability	0		0			0
Not Designated as Hedging Instrument | Fair Value, Recurring | Fair Value, Inputs, Level 2
Assets
Derivative Assets, Fair Value, Gross Asset	30,610		30,610			54,353
Liabilities
Derivative Liability, Fair Value, Gross Liability	642,699		642,699			222,520
Not Designated as Hedging Instrument | Fair Value, Recurring | Fair Value, Inputs, Level 3
Assets
Derivative Assets, Fair Value, Gross Asset	0		0			0
Liabilities
Derivative Liability, Fair Value, Gross Liability	$ 0		$ 0			$ 0