SM Energy (SM) 10-Q 31 Jul 20 2020 Q2 Quarterly report Financial data

Cover page

Cover page - shares	6 Months Ended
	Jun. 30, 2020	Jul. 23, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2020
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	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		114,458,893
Entity Central Index Key	0000893538
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Amendment Flag	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) (in thousands, except share data) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 10	$ 10
Accounts receivable	127,173	184,732
Derivative assets	211,582	55,184
Prepaid expenses and other	16,704	12,708
Total current assets	355,469	252,634
Property and equipment (successful efforts method):
Proved oil and gas properties	8,134,461	8,934,020
Accumulated depletion, depreciation, and amortization	(4,536,537)	(4,177,876)
Unproved oil and gas properties	923,666	1,005,887
Wells in progress	266,957	118,769
Other property and equipment, net of accumulated depreciation of $65,447 and $64,032, respectively	37,278	72,848
Total property and equipment, net	4,825,825	5,953,648
Noncurrent assets:
Derivative assets	34,390	20,624
Other noncurrent assets	51,944	65,326
Total noncurrent assets	86,334	85,950
Total assets	5,267,628	6,292,232
Other property and equipment, accumulated depreciation	65,447	64,032
Current liabilities:
Accounts payable and accrued expenses	257,053	402,008
Derivative liabilities	38,250	50,846
Other current liabilities	12,597	19,189
Total current liabilities	307,900	472,043
Noncurrent liabilities:
Revolving credit facility	193,000	122,500
Senior Notes, net	2,263,119	2,610,298
Asset retirement obligations	86,628	84,134
Deferred income taxes	57,049	189,386
Derivative liabilities	24,028	3,444
Other noncurrent liabilities	55,072	61,433
Total noncurrent liabilities	2,678,896	3,071,195
Commitments and contingencies (note 6)
Stockholders’ equity:
Common stock, $0.01 par value - authorized: 200,000,000 shares; issued and outstanding: 113,553,271 and 112,987,952 shares, respectively	1,136	1,130
Additional paid-in capital	1,825,327	1,791,596
Retained earnings	465,310	967,587
Accumulated other comprehensive loss	(10,941)	(11,319)
Total stockholders' equity	2,280,832	2,748,994
Total liabilities and stockholders’ equity	$ 5,267,628	$ 6,292,232
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	200,000,000	200,000,000
Common Stock, Shares, Issued	113,553,271	112,987,952
Common Stock, Shares, Outstanding	113,553,271	112,987,952

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) (in thousands, except per share data) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Operating revenues and other income:
Oil, gas, and NGL production revenue		$ 169,790	$ 406,854	$ 524,023	$ 747,330
Net gain on divestiture activity		91	262	91	323
Other operating revenues		(249)	56	1,252	449
Total operating revenues and other income		169,632	407,172	525,366	748,102
Operating expenses:
Oil, gas, and NGL production expense		80,445	123,050	199,997	244,355
Depletion, depreciation, amortization, and asset retirement obligation liability accretion		180,856	206,330	414,345	384,076
Exploration		9,787	10,877	21,136	22,225
Impairment	[1]	8,750	12,417	998,513	18,755
General and administrative		27,227	30,920	54,674	63,006
Net derivative (gain) loss		167,200	(79,655)	(378,140)	97,426
Other operating (income) expense, net		8,046	(934)	8,612	(599)
Total operating expenses		482,311	303,005	1,319,137	829,244
Income (loss) from operations		(312,679)	104,167	(793,771)	(81,142)
Interest expense		(40,354)	(39,627)	(81,866)	(77,607)
Gain on extinguishment of debt		227,281	0	239,476	0
Other non-operating expense, net		(185)	(562)	(679)	(879)
Income (loss) before income taxes		(125,937)	63,978	(636,840)	(159,628)
Income tax (expense) benefit		36,685	(13,590)	135,693	32,448
Net income (loss)		$ (89,252)	$ 50,388	$ (501,147)	$ (127,180)
Basic weighted-average common shares outstanding		113,008	112,262	113,015	112,257
Diluted weighted-average common shares outstanding		113,008	112,932	113,015	112,257
Basic net income (loss) per common share		$ (0.79)	$ 0.45	$ (4.43)	$ (1.13)
Diluted net income (loss) per common share		(0.79)	0.45	(4.43)	(1.13)
Dividends per common share		$ 0	$ 0	$ 0.01	$ 0.05
[1]	(2) Amounts may not calculate due to rounding.

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (UNAUDITED) (in thousands) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (89,252)	$ 50,388	$ (501,147)	$ (127,180)
Other comprehensive income, net of tax:
Pension liability adjustment	188	119	378	382
Total other comprehensive income, net of tax	188	119	378	382
Total comprehensive income (loss)	$ (89,064)	$ 50,507	$ (500,769)	$ (126,798)

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	Accumulated Other Comprehensive Loss
Cash dividends declared per share	$ 0.05
Balances, Common Stock, Shares, Outstanding, Beginning at Dec. 31, 2018		112,241,966
Balances, Total Stockholders' Equity, Beginning at Dec. 31, 2018	$ 2,920,322	$ 1,122	$ 1,765,738	$ 1,165,842	$ (12,380)
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(177,568)			(177,568)
Other comprehensive income	263				263
Cash dividends declared, per share	(5,612)			(5,612)
Issuance of common stock upon vesting of RSUs, net of shares used for tax withholdings (Shares)		2,579
Issuance of common stock upon vesting of RSUs, net of shares used for tax withholdings (Amount)	(18)	$ 0	(18)
Stock-based compensation expense (Amount)	5,838		5,838
Balances, Common Stock, Shares, Outstanding, Ending at Mar. 31, 2019		112,244,545
Balances, Total Stockholders' Equity, Ending at Mar. 31, 2019	$ 2,743,225	$ 1,122	1,771,558	982,662	(12,117)
Cash dividends declared per share	$ 0.05
Balances, Common Stock, Shares, Outstanding, Beginning at Dec. 31, 2018		112,241,966
Balances, Total Stockholders' Equity, Beginning at Dec. 31, 2018	$ 2,920,322	$ 1,122	1,765,738	1,165,842	(12,380)
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(127,180)
Other comprehensive income	382
Balances, Common Stock, Shares, Outstanding, Ending at Jun. 30, 2019		112,525,633
Balances, Total Stockholders' Equity, Ending at Jun. 30, 2019	$ 2,801,843	$ 1,125	1,779,665	1,033,051	(11,998)
Cash dividends declared per share	$ 0
Balances, Common Stock, Shares, Outstanding, Beginning at Mar. 31, 2019		112,244,545
Balances, Total Stockholders' Equity, Beginning at Mar. 31, 2019	$ 2,743,225	$ 1,122	1,771,558	982,662	(12,117)
Increase (Decrease) in Stockholders' Equity
Net income (loss)	50,388			50,388
Other comprehensive income	119				119
Issuance of common stock upon vesting of RSUs, net of shares used for tax withholdings (Shares)		290
Issuance of common stock upon vesting of RSUs, net of shares used for tax withholdings (Amount)	(2)	$ 0	(2)
Stock-based compensation expense (Shares)		96,719
Stock-based compensation expense (Amount)	6,154	$ 1	6,153
Issuance of common stock under Employee Stock Purchase Plan (Shares)		184,079
Issuance of common stock under Employee Stock Purchase Plan (Amount)	1,959	$ 2	1,957
Other	0		(1)	1
Balances, Common Stock, Shares, Outstanding, Ending at Jun. 30, 2019		112,525,633
Balances, Total Stockholders' Equity, Ending at Jun. 30, 2019	$ 2,801,843	$ 1,125	1,779,665	1,033,051	(11,998)
Cash dividends declared per share	$ 0.01
Balances, Common Stock, Shares, Outstanding, Beginning at Dec. 31, 2019	112,987,952	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 declared, per share	(1,130)			(1,130)
Issuance of common stock upon vesting of RSUs, net of shares used for tax withholdings (Shares)		730
Issuance of common stock upon vesting of RSUs, net of shares used for tax withholdings (Amount)	(3)	$ 0	(3)
Stock-based compensation expense (Amount)	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	$ 0.01
Balances, Common Stock, Shares, Outstanding, Beginning at Dec. 31, 2019	112,987,952	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)	(501,147)
Other comprehensive income	378
Issuance of Warrants	$ 21,500
Balances, Common Stock, Shares, Outstanding, Ending at Jun. 30, 2020	113,553,271	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
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
Stock-based compensation expense (Shares)		267,576
Stock-based compensation expense (Amount)	5,712	$ 3	5,709
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
Issuance of Warrants	$ 21,520		21,520
Balances, Common Stock, Shares, Outstanding, Ending at Jun. 30, 2020	113,553,271	113,553,271
Balances, Total Stockholders' Equity, Ending at Jun. 30, 2020	$ 2,280,832	$ 1,136	$ 1,825,327	$ 465,310	$ (10,941)

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) (in thousands) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019		Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net income (loss)		$ (89,252)	$ 50,388		$ (501,147)	$ (127,180)
Adjustments to reconcile net loss to net cash provided by operating activities
Net gain on divestiture activity		(91)	(262)		(91)	(323)
Depletion, depreciation, amortization, and asset retirement obligation liability accretion		180,856	206,330		414,345	384,076
Impairment	[1]	8,750	12,417		998,513	18,755
Stock-based compensation expense					11,273	11,992
Net derivative (gain) loss		167,200	(79,655)		(378,140)	97,426
Derivative settlement gain (loss)					215,965	(879)
Amortization of debt discount and deferred financing costs					8,578	7,633
Gain on extinguishment of debt		(227,281)	0		(239,476)	0
Deferred income taxes		(36,921)	13,766		(136,268)	(33,237)
Other, net					(3,827)	(1,287)
Net change in working capital					(57,254)	21,454
Net cash provided by operating activities					332,471	378,430
Cash flows from investing activities:
Net proceeds from the sale of oil and gas properties					92	12,520	[2]
Capital expenditures					(310,209)	(576,127)
Other, net					0	319
Net cash used in investing activities					(310,117)	(563,288)
Cash flows from financing activities:
Proceeds from revolving credit facility					841,000	696,500
Repayment of revolving credit facility					(770,500)	(578,500)
Debt issuance costs related to 10.0% Senior Secured Notes due 2025					(10,491)	0
Cash paid to repurchase 6.125% Senior Notes due 2022					(28,318)	0
Repayment of 1.50% Senior Convertible Notes due 2021					(53,508)	0
Net proceeds from sale of common stock					947	1,959
Dividends paid					(1,130)	(5,612)
Other, net					(354)	(1,044)
Net cash provided by (used in) financing activities					(22,354)	113,303
Net change in cash, cash equivalents, and restricted cash					0	(71,555)
Cash, cash equivalents, and restricted cash at beginning of period					10	77,965
Cash, cash equivalents, and restricted cash at end of period		10	6,410		10	6,410
Supplemental Cash Flow Information - Operating activities:
Cash paid for interest, net of capitalized interest					(82,313)	(67,646)
Supplemental Cash Flow Information - Investing activities:
Decrease in capital expenditure accruals and other					(28,896)	(10,097)
Supplemental Cash Flow Information - Supplemental non-cash investing activities:
Carrying value of properties exchanged					0	66,588
Supplemental Cash Flow Information - Supplemental non-cash financing activities:
Non-cash gain on extinguishment of debt, net					292,984	0
Cash and cash equivalents		10	12		10	12
Restricted Cash		$ 0	$ 6,398	[2]	$ 0	$ 6,398	[2]
[1]	(2) Amounts may not calculate due to rounding.
[2]	(1) As of June 30, 2019, a portion of net proceeds from the sale of oil and gas properties was restricted for future property acquisitions. Restricted cash is included in the other noncurrent assets line item on the accompanying unaudited condensed consolidated balance sheets (“accompanying balance sheets”).

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2020
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 2019 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 June 30, 2020, 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 2019 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 2019 Form 10-K . Recently Issued Accounting Standards In December 2019, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (“ASU 2019-12”). ASU 2019-12 was issued to reduce the complexity of accounting for income taxes for those entities that fall within the scope of the accounting standard. The guidance is to be applied using a prospective method, excluding amendments related to franchise taxes, which should be applied on either a retrospective basis for all periods presented or a modified retrospective basis through a cumulative-effect adjustment to retained earnings as of the beginning of the fiscal year of adoption. ASU 2019-12 is effective for fiscal years beginning after December 15, 2020, with early adoption permitted. The Company early adopted ASU 2019-12 on January 1, 2020, and there was no material impact on the Company’s unaudited condensed consolidated financial statements or disclosures upon adoption. In March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting (“ASU 2020-04”). 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 is effective for all entities as of March 12, 2020 through December 31, 2022. The Company is evaluating the options provided by ASU 2020-04. 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. As disclosed in the 2019 Form 10-K , on January 1, 2020, the Company adopted ASU No. 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments , and ASU No. 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract . As expected, there was no material impact on the Company’s unaudited condensed consolidated financial statements or disclosures upon adoption of these ASUs. There are no 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 June 30, 2020, or through the filing of this report.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	6 Months Ended
	Jun. 30, 2020
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 regions for the three and six months ended June 30, 2020, and 2019: Midland Basin South Texas Total Three Months Ended Three Months Ended Three Months Ended 2020 2019 2020 2019 2020 2019 (in thousands) Oil production revenue $ 114,358 $ 288,447 $ 5,158 $ 15,697 $ 119,516 $ 304,144 Gas production revenue 11,921 16,449 22,942 48,775 34,863 65,224 NGL production revenue 45 (43) 15,366 37,529 15,411 37,486 Total $ 126,324 $ 304,853 $ 43,466 $ 102,001 $ 169,790 $ 406,854 Relative percentage 74 % 75 % 26 % 25 % 100 % 100 % ____________________________________________ Note: Amounts may not calculate due to rounding. Midland Basin South Texas Total Six Months Ended Six Months Ended Six Months Ended 2020 2019 2020 2019 2020 2019 (in thousands) Oil production revenue $ 390,494 $ 513,694 $ 20,715 $ 29,511 $ 411,209 $ 543,205 Gas production revenue 23,255 32,041 52,318 98,296 75,573 130,337 NGL production revenue 103 (22) 37,138 73,810 37,241 73,788 Total $ 413,852 $ 545,713 $ 110,171 $ 201,617 $ 524,023 $ 747,330 Relative percentage 79 % 73 % 21 % 27 % 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 2019 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 (“ASC”) 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; thus, there are no material unsatisfied or partially unsatisfied performance obligations at the end of the reporting period.

Divestitures, Assets Held for S

Divestitures, Assets Held for Sale, and Acquisitions	6 Months Ended
	Jun. 30, 2020
Divestitures, Assets Held for Sale, and Acquisitions [Abstract]
Divestitures, Assets Held for Sale, and Acquisitions	Note 3 - Divestitures, Assets Held for Sale, and Acquisitions Divestitures No material divestitures occurred during the first six months of 2020 and 2019, and there were no assets classified as held for sale as of June 30, 2020, or December 31, 2019. Acquisitions No material acquisitions or acreage trades of oil and gas properties occurred during the first half of 2020. During the first half of 2019, the Company completed several non-monetary acreage trades of primarily undeveloped properties located in Howard, Martin, and Midland Counties, Texas, resulting in the exchange of approximately 2,000 net acres, with $66.6 million of carrying value attributed to the properties transferred by the Company. These trades were recorded at carryover basis with no gain or loss recognized.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Note 4 - Income Taxes The provision for income taxes for the three and six months ended June 30, 2020, and 2019, consisted of the following: For the Three Months Ended For the Six Months Ended 2020 2019 2020 2019 (in thousands) Current portion of income tax (expense) benefit: Federal $ — $ — $ — $ — State (236) 176 (575) (789) Deferred portion of income tax (expense) benefit 36,921 (13,766) 136,268 33,237 Income tax (expense) benefit $ 36,685 $ (13,590) $ 135,693 $ 32,448 Effective tax rate 29.1 % 21.2 % 21.3 % 20.3 % Recorded income tax expense or benefit differs from the amounts 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, and the cumulative impact of other smaller permanent differences. The quarterly rate can also be affected by the proportional impacts of forecasted net income or loss for each period presented, as reflected in the table above. A change in the Company’s effective tax rate between reporting periods will generally reflect differences in estimating permanent differences compared to changes in forecasted net income or loss. Each quarter, the Company evaluates its deferred tax assets for potential realization, weighing both positive and negative evidence to determine, on a more likely than not basis, the future utilization by asset and jurisdiction. When the significance of negative evidence outweighs the Company’s positive support of realization, a valuation allowance is recorded. Subsequently, when the significance of positive evidence outweighs negative evidence that a deferred tax asset will be realized, the valuation allowance is released. During the second quarter of 2020, the Company executed certain debt exchange transactions that resulted in cancellation of debt income and supported the utilization of its deferred tax assets. As a result, the Company released the valuation allowance recorded in the previous quarter which increased the Company’s income tax benefit and tax benefit rate for the three months ended June 30, 2020. The Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”) was enacted on March 27, 2020. The primary feature of the CARES Act that the Company benefited from was the acceleration of its refundable Alternative Minimum Tax (“AMT”) credits. On April 1, 2020, the Company filed an election to accelerate its remaining refundable AMT credits of $7.6 million. The Company received the refund in July 2020.

Long-Term Debt

Long-Term Debt	6 Months Ended
	Jun. 30, 2020
Debt Disclosure [Abstract]
Long-Term Debt	Note 5 - Long-Term Debt During the second quarter of 2020, the Company initiated an offer to exchange its outstanding senior unsecured notes, as presented in the Senior Unsecured Notes section below (“Senior Unsecured Notes”), other than the 1.50% Senior Convertible Notes due 2021 (“2021 Senior Convertible Notes,” and together with the Senior Unsecured Notes, “Old Notes”), and a private exchange of its outstanding 2021 Senior Convertible Notes and portions of its outstanding Senior Unsecured Notes (“Private Exchange”), in each case for newly issued 10.0% Senior Secured Second Lien Notes due January 15, 2025 (“2025 Senior Secured Notes”), referred to together as “Exchange Offers.” In connection with the Exchange Offers, the Company and its lenders amended the Credit Agreement to increase the amount of permitted second lien indebtedness to an aggregate amount of $1.0 billion, inclusive of the 2021 Senior Convertible Notes (“Permitted Second Lien Debt”). Additionally, the Company amended the indenture governing its 2021 Senior Convertible Notes, by entering into the Third Supplemental Indenture, dated as of April 29, 2020, (“Third Supplemental Indenture”), to the original Indenture, dated as of May 21, 2015, as supplemented and amended by the Second Supplemental Indenture, dated as of August 12, 2016, collectively referred to as the “2021 Notes Indenture.” The Third Supplemental Indenture provides that the Company will satisfy any conversion obligation solely in cash. On June 17, 2020 (“Settlement Date”), 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 Convertible Notes for $446.7 million in aggregate principal amount of 2025 Senior Secured Notes, as well as, in connection with the Private Exchange, (a) $53.5 million in cash to certain holders of the 2021 Senior Convertible Notes and (b) warrants to acquire up to an aggregate of approximately 5.9 million shares, or approximately five percent of its outstanding common stock, exercisable upon the occurrence of certain future triggering events, to certain holders who exchanged Old Notes in the Private Exchange. Please refer to Note 11 - Fair Value Measurements for more information regarding the warrants issued by the Company. Pursuant to the 2021 Notes Indenture, upon the issuance of Permitted Second Lien Debt, the remaining outstanding 2021 Senior Convertible Notes became secured and are subsequently referred to as the “2021 Senior Secured Convertible Notes,” and together with the 2025 Senior Secured Notes, the “Senior Secured Notes.” The following table summarizes the principal amounts of the Old Notes tendered as of the Settlement Date: Title of Old Notes Tendered Principal Amount of Old Notes Tendered (in thousands) 1.50% Senior Convertible Notes due 2021 $ 107,015 6.125% Senior Notes due 2022 141,701 5.0% Senior Notes due 2024 155,339 5.625% Senior Notes due 2025 150,882 6.75% Senior Notes due 2026 80,765 6.625% Senior Notes due 2027 83,209 Total $ 718,911 Please refer to the Credit Agreement , Senior Secured Notes , and Senior Unsecured Notes sections below for additional information regarding the debt transactions conducted by the Company during the second quarter of 2020. Credit Agreement The Company’s Credit Agreement provides for a senior secured revolving credit facility with a maximum loan amount of $2.5 billion. During the second quarter of 2020, the Company and its lenders completed the semi-annual borrowing base redetermination, and entered into the Third Amendment and the Fourth Amendment to the Credit Agreement (collectively, “Amendments”). As a result of lower commodity prices and a corresponding decrease in the value of the Company’s proved reserves, the borrowing base and aggregate lender commitments were both reduced to $1.1 billion. The Amendments permitted the Company to incur second lien debt of up to $827.5 million prior to the next scheduled redetermination date of October 1, 2020, provided that all principal amounts of such debt are used to redeem unsecured senior debt of the Company for less than or equal to 80% of par value. The Amendments also permitted the Company to grant a second-priority security interest to the holders of the Company’s outstanding 2021 Senior Convertible Notes to secure the Company’s obligations under the 2021 Senior Convertible Notes. As a result, the Company may incur Permitted Second Lien Debt in an aggregate amount of up to $1.0 billion. As of June 30, 2020, the Company had $487.8 million of available Permitted Second Lien Debt capacity. Additionally, the Amendments reduced the amount of dividends that the Company may declare and pay on an annual basis from $50.0 million to $12.0 million. The Credit Agreement is scheduled to mature on September 28, 2023, except that, pursuant to the Amendments, newly issued Permitted Second Lien Debt used to redeem any portion of the remaining 6.125% Senior Notes due 2022 (“2022 Senior Notes”) must have maturities on or after 180 days after September 28, 2023; otherwise, the maturity date of the Credit Agreement will be July 2, 2023. Without regard to which maturity date is in effect, the maturity date could occur earlier on August 16, 2022, if the Company has not completed certain repurchase, redemption, or refinancing activities associated with its 2022 Senior Notes, and does not have certain unused availability for borrowing under the Credit Agreement, as outlined in the Credit Agreement. 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. The Third Amendment to the Credit Agreement amended the borrowing base utilization grid as presented in the table below. 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. Borrowing Base Utilization Percentage <25% ≥25% <50% ≥50% <75% ≥75% <90% ≥90% Eurodollar Loans (1) 1.750 % 2.000 % 2.500 % 2.750 % 3.000 % ABR Loans or Swingline Loans 0.750 % 1.000 % 1.500 % 1.750 % 2.000 % Commitment Fee Rate 0.375 % 0.375 % 0.500 % 0.500 % 0.500 % ____________________________________________ (1) 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, 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 July 23, 2020, June 30, 2020, and December 31, 2019: As of July 23, 2020 As of June 30, 2020 As of December 31, 2019 (in thousands) Revolving credit facility (1) $ 180,000 $ 193,000 $ 122,500 Letters of credit (2) 42,000 42,000 — Available borrowing capacity 878,000 865,000 1,077,500 Total aggregate lender commitment amount $ 1,100,000 $ 1,100,000 $ 1,200,000 ____________________________________________ (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 $5.0 million and $5.9 million as of June 30, 2020, and December 31, 2019, 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 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 June 30, 2020, consisted of the following: As of June 30, 2020 Principal Amount Unamortized Debt Discount Unamortized Deferred Financing Costs Principal Amount, Net (in thousands) 10.0% Senior Secured Notes due 2025 $ 446,675 $ (41,340) $ (11,596) $ 393,739 1.50% Senior Secured Convertible Notes due 2021 (1) 65,485 (3,592) (349) 61,544 Total $ 512,160 $ (44,932) $ (11,945) $ 455,283 ____________________________________________ (1) As discussed above, as required by the 2021 Notes Indenture and as permitted by the Credit Agreement, as the Company issued Permitted Second Lien Debt upon the closing of the Exchange Offers, its remaining 2021 Senior Convertible Notes contemporaneously became secured. 2025 Senior Secured Notes . On June 17, 2020, the Company issued $446.7 million in aggregate principal amount of 2025 Senior Secured Notes due January 15, 2025. The Company incurred fees of $11.7 million, which are being amortized as deferred financing costs over the life of the 2025 Senior Secured Notes. Upon the issuance of the 2025 Senior Secured Notes, the Company recorded $405.0 million as the initial carrying amount, which approximated their fair value at issuance. The excess of the principal amount of the 2025 Senior Secured Notes over its fair value was recorded as a debt discount. The debt discount and deferred financing costs are amortized to interest expense through the maturity date. In connection with the issuance of the 2025 Senior Secured Notes, the Company entered into an indenture dated as of June 17, 2020 with UMB Bank, N.A., as trustee, governing the 2025 Senior Secured Notes (“2025 Notes Indenture”). The Company may redeem some or all of its 2025 Senior Secured Notes prior to their maturity at redemption prices based on a premium, plus accrued and unpaid interest as described in the 2025 Notes Indenture. The 2025 Senior Secured Notes 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 with the 2021 Senior Secured Convertible Notes. The 2025 Senior Secured Notes rank senior in right of payment with all of the Company’s existing and any future unsecured senior or subordinated debt. 2021 Senior Secured Convertible Notes . Upon issuance of the 2025 Senior Secured Notes, which was Permitted Second Lien Debt, as required by the 2021 Notes Indenture, and as permitted by the Credit Agreement, the 2021 Senior Convertible Notes became secured senior obligations of the Company on a second-priority basis, ranking junior to the Company’s obligations under the Credit Agreement and equal in priority with the 2025 Senior Secured Notes. The 2021 Senior Secured Convertible Notes rank senior in right of payment to all of the Company’s existing and any future unsecured senior or subordinated debt. During the second quarter of 2020, pursuant to the Third Supplemental Indenture, the Company agreed to satisfy any conversion obligation solely in cash, resulting in reclassification of the fair value of the equity components out of additional paid-in capital. Please refer to Note 5 - Long-Term Debt in the 2019 Form 10-K for additional detail on the Company’s 2021 Senior Convertible Notes and associated capped call transactions. On June 17, 2020, the Company retired $107.0 million in aggregate principal amount of its 2021 Senior Convertible Notes that were exchanged in the Private Exchange. As a result, the Company paid $740,000 of accrued and unpaid interest and recognized $6.1 million and $593,000 of previously unamortized debt discount and deferred financing costs, respectively, associated with the retired 2021 Senior Convertible Notes. The 2021 Senior Secured Convertible Notes were not convertible at the option of holders as of June 30, 2020, or through the filing of this report. Notwithstanding the inability to convert, the if-converted value of the 2021 Senior Secured Convertible Notes did not exceed the principal amount. The remaining debt discount and debt-related issuance costs are being amortized to the principal value of the 2021 Senior Secured Convertible Notes as interest expense through the maturity date of July 1, 2021. Interest expense recognized on the 2021 Senior Secured Convertible Notes related to the stated interest rate and amortization of the debt discount totaled $2.6 million and $2.7 million for the three months ended June 30, 2020, and 2019, respectively, and totaled $5.4 million for each of the six months ended June 30, 2020, and 2019. 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 June 30, 2020, and December 31, 2019, consisted of the following: As of June 30, 2020 As of December 31, 2019 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 $ 294,346 $ 1,494 $ 292,852 $ 476,796 $ 2,920 $ 473,876 5.0% Senior Notes due 2024 344,661 2,278 342,383 500,000 3,766 496,234 5.625% Senior Notes due 2025 349,118 3,108 346,010 500,000 4,903 495,097 6.75% Senior Notes due 2026 419,235 4,321 414,914 500,000 5,571 494,429 6.625% Senior Notes due 2027 416,791 5,114 411,677 500,000 6,601 493,399 1.50% Senior Convertible Notes due 2021 (1)(2) — — — 172,500 15,237 157,263 Total $ 1,824,151 $ 16,315 $ 1,807,836 $ 2,649,296 $ 38,998 $ 2,610,298 ____________________________________________ (1) Unamortized deferred financing costs attributable to the 2021 Senior Convertible Notes include $13.9 million related to the unamortized debt discount as of December 31, 2019. (2) As discussed above, as required by the 2021 Notes Indenture and as permitted by the Credit Agreement, as the Company issued Permitted Second Lien Debt upon the closing of the Exchange Offers, its remaining 2021 Senior Convertible Notes contemporaneously became secured. The senior unsecured notes listed above (collectively referred to as “Senior Unsecured Notes,” and together with the Senior Secured Notes, “Senior Notes”) 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. Please refer to Note 5 - Long-Term Debt in the 2019 Form 10-K for additional detail on the Company’s Senior Unsecured Notes. On June 17, 2020, the Company retired $611.9 million in aggregate principal amount of its Senior Unsecured Notes that were exchanged in the Exchange Offers. As a result, the Company paid $8.1 million of accrued and unpaid interest and recognized $5.0 million of previously unamortized deferred financing costs associated with the retired Senior Unsecured Notes. The Company cancelled all retired Senior Unsecured Notes upon closing of the Exchange Offers. During the first quarter of 2020, the Company repurchased a total of $40.7 million in aggregate principal amount of its 2022 Senior Notes in open market transactions for a total settlement amount, excluding accrued interest, of $28.3 million. In connection with the repurchase, the Company recorded a gain on extinguishment of debt of $12.2 million for the three months ended March 31, 2020. This amount included discounts realized upon repurchase of $12.4 million partially offset by approximately $235,000 of accelerated unamortized deferred financing costs. The Company canceled all repurchased 2022 Senior Notes upon cash settlement. Covenants The Company is subject to certain covenants under the Credit Agreement and the indentures governing the Senior Secured Notes and the Senior Unsecured Notes that, among other terms, limit the Company’s ability to incur additional indebtedness, make restricted payments including dividends, sell assets, 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, create liens that secure debt, enter into transactions with affiliates, and merge or consolidate with another company. The Company was in compliance with all such covenants as of June 30, 2020, and through the filing of this report. Capitalized Interest Capitalized interest costs for the three months ended June 30, 2020, and 2019, totaled $4.1 million and $5.0 million, respectively, and totaled $6.8 million and $9.9 million for the six months ended June 30, 2020, and 2019, respectively. The amount of interest the Company capitalizes generally fluctuates based on the amount borrowed, the Company’s capital program, and the timing and amount of costs associated with capital projects that are considered in progress. Capitalized interest costs are included in total costs incurred.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2020
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 2019 Form 10-K . Please refer to Note 6 - Commitments and Contingencies in the 2019 Form 10-K for additional discussion of the Company’s commitments. Drilling Rig Service Contracts . During the first half of 2020, and through the filing of this report, the Company amended certain of its drilling rig contracts resulting in the reduction of day rates and potential early termination fees and the extension of contract terms. As of the filing of this report, the Company’s drilling rig commitments totaled $17.6 million under contract terms extending through the second quarter of 2021. If all of these contracts were terminated as of the filing of this report, the Company would avoid a portion of the contractual service commitments; however, the Company would be required to pay $9.0 million in early termination fees. The Company does not expect to incur material penalties with regard to its drilling rig contracts. Drilling and Completion Commitments . During the first half of 2020, the Company entered into an agreement that includes minimum drilling and completion footage requirements on certain existing leases. If these minimum requirements are not satisfied by March 31, 2021, 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 June 30, 2020, the liquidated damages could range from zero to a maximum of $39.5 million, with the maximum exposure assuming no additional development activity occurred prior to March 31, 2021. The Company also entered into an agreement that includes a minimum number of wells drilled and completed on certain existing leases. If these minimum requirements are not satisfied by December 31, 2021, the Company will be required to pay liquidated damages based on the difference between the actual number of wells drilled and completed and the minimum requirements. As of June 30, 2020, the liquidated damages could range from zero to a maximum of $11.5 million, with the maximum exposure assuming no additional development activity occurred prior to December 31, 2021. As of the filing of this report, the Company expects to meet its obligations under both agreements. 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	6 Months Ended
	Jun. 30, 2020
Share-based Payment Arrangement [Abstract]
Compensation Plans	Note 7 - Compensation Plans Equity Incentive Compensation Plan As of June 30, 2020, 4.2 million shares of common stock were available for grant under the Company’s Equity Incentive Compensation Plan (“Equity Plan”). Performance Share Units The Company grants 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-year performance period. PSUs generally vest on the third anniversary of the date of the grant or upon other triggering events as set forth in the Equity Plan. For PSUs granted in 2017, which the Company determined to be equity awards, the settlement criteria included a combination of the Company’s Total Shareholder Return (“TSR”) on an absolute basis, and the Company’s TSR relative to the TSR of certain peer companies over the associated three-year performance period. The fair value of the PSUs granted in 2017 was measured on the grant date using a stochastic Monte Carlo simulation using geometric Brownian motion (“GBM Model”). As these awards depend entirely on market-based settlement criteria, the associated compensation expense is recognized on a straight-line basis within general and administrative expense and exploration expense over the vesting periods of the respective awards. For PSUs granted in 2018 and 2019, the settlement criteria include a combination of the Company’s 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 value of the PSUs granted in 2018 and 2019 was 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 $2.8 million and $2.9 million for the three months ended June 30, 2020, and 2019, respectively, and $5.4 million and $5.7 million for the six months ended June 30, 2020, and 2019, respectively. As of June 30, 2020, there was $10.0 million of total unrecognized compensation expense related to non-vested PSU awards, which is being amortized through 2022. There were no material changes to the outstanding and non-vested PSUs during the six months ended June 30, 2020. Subsequent to June 30, 2020, the Company settled all PSUs that were granted in 2017, which earned a 0.9 times multiplier, by issuing 485,060 net shares of the Company’s common stock in accordance with the terms of the applicable PSU awards. The Company and the majority of grant participants 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. As a result, 215,451 shares were withheld to satisfy income and payroll tax withholding obligations that occurred upon delivery of the shares underlying those PSUs. Employee Restricted Stock Units The Company grants restricted stock units (“RSUs”) to eligible persons as part of its Equity Plan. Each RSU 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 a three-year 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 RSU is equal to the closing price of the Company’s common stock on the day 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 $2.7 million and $2.8 million for the three months ended June 30, 2020, and 2019, respectively and $5.3 million and $5.5 million for the six months ended June 30, 2020, and 2019, respectively. As of June 30, 2020, there was $10.8 million of total unrecognized compensation expense related to non-vested RSU awards, which is being amortized through 2022. There were no material changes to the outstanding and non-vested RSUs during the six months ended June 30, 2020. Subsequent to June 30, 2020, the Company settled 587,088 RSUs that related to awards granted in previous years. The Company and the majority of grant participants 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. As a result, the Company issued 420,562 net shares of common stock upon settlement of the awards. The remaining 166,526 shares were withheld to satisfy income and payroll tax withholding obligations that occurred upon delivery of the shares underlying those RSUs. Director Shares During the second quarters of 2020, and 2019, the Company issued 267,576 and 96,719 shares, respectively, of its common stock to its non-employee directors under the Equity Plan. Shares issued during the second quarter of 2020 will fully vest on December 31, 2020. Shares issued during the second quarter of 2019 fully vested on December 31, 2019. 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, without accruing in excess of $25,000 in value from purchases for each calendar year. The purchase price of the stock is 85 percent of the lower of the fair market value of the stock on either the first or last day of the purchase period. The ESPP is intended to qualify under Section 423 of the Internal Revenue Code. There were 297,013 and 184,079 shares issued under the ESPP during the second quarters of 2020, and 2019, respectively. Total proceeds to the Company for the issuance of these shares was $947,000 and $2.0 million for the six months ended June 30, 2020, and 2019, respectively. The fair value of ESPP grants is measured at the date of grant using the Black-Scholes option-pricing model.

Pension Benefits

Pension Benefits	6 Months Ended
	Jun. 30, 2020
Defined Benefit Plan [Abstract]
Pension Benefits	Note 8 - Pension Benefits Pension Plans The Company has a non-contributory defined benefit pension plan covering employees who meet age and service requirements and who began employment with the Company prior to January 1, 2016 (“Qualified Pension Plan”). The Company also has a supplemental non-contributory pension plan covering certain management employees (“Nonqualified Pension Plan” and together with the Qualified Pension Plan, “Pension Plans”). The Company froze the Pension Plans to new participants, effective as of January 1, 2016. Employees participating in the Pension Plans prior to the plans being frozen will continue to earn benefits. Components of Net Periodic Benefit Cost for the Pension Plans For the Three Months Ended For the Six Months Ended 2020 2019 2020 2019 (in thousands) Components of net periodic benefit cost: Service cost $ 863 $ 1,108 $ 2,258 $ 2,791 Interest cost 480 739 1,178 1,395 Expected return on plan assets that reduces periodic pension benefit cost (474) (321) (867) (787) Amortization of prior service cost 5 5 9 9 Amortization of net actuarial loss 235 147 475 479 Net periodic benefit cost $ 1,109 $ 1,678 $ 3,053 $ 3,887 Prior service costs are amortized on a straight-line basis over the average remaining service period of active participants. Gains and losses in excess of 10 percent of the greater of the benefit obligation or the market-related value of assets are amortized over the average remaining service period of active participants. The service cost component of net periodic benefit cost for the Pension Plans is presented as an operating expense within the general and administrative and exploration expense line items on the accompanying statements of operations while the other components of net periodic benefit cost for the Pension Plans are presented as non-operating expenses within the other non-operating expense, net line item on the accompanying statements of operations. Contributions As of the filing of this report, the Company has contributed $4.6 million to the Qualified Pension Plan in 2020.

Earnings per Share

Earnings per Share	6 Months Ended
	Jun. 30, 2020
Earnings Per Share [Abstract]
Earnings per Share	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. As of June 30, 2019, potentially dilutive securities for this calculation consisted primarily of non-vested RSUs, contingent PSUs, and shares into which the 2021 Senior Convertible Notes were convertible, which were measured using the treasury stock method. Shares of the Company’s common stock traded at an average closing price below the $40.50 conversion price applicable to the 2021 Senior Convertible Notes for the three and six months ended June 30, 2019, therefore, the 2021 Senior Convertible Notes had no dilutive impact. On April 29, 2020, pursuant to the Third Supplemental Indenture, the Company agreed that it will satisfy any conversion obligation with respect to the 2021 Senior Convertible Notes solely in cash. As a result, the Company’s 2021 Senior Secured Convertible Notes are no longer convertible into shares of the Company’s common stock and thus, were not considered to be a potentially dilutive instrument as of June 30, 2020. On June 17, 2020, the Company issued warrants to purchase up to an aggregate of approximately 5.9 million shares, or approximately five percent of its outstanding common stock, at an exercise price of $0.01 per share, as discussed in Note 5 - Long-Term Debt . The Warrant Agreement dated as of June 17, 2020 (“Warrant Agreement”), states that the warrants are only exercisable upon the Triggering Date, as defined in Note 11 - Fair Value Measurements. The warrants were not exercisable during the six months ended June 30, 2020, and therefore had no dilutive impact. Please refer to Note 11 - Fair Value Measurements for additional detail regarding the terms of the warrants. As of June 30, 2020, potentially dilutive securities for this calculation consist primarily of non-vested RSUs, contingent PSUs, and warrants, which are measured using the treasury stock method. Please refer to Note 7 - Compensation Plans and Note 11 - Fair Value Measurements in this report, and Note 9 - Earnings Per Share in the 2019 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 anti-dilutive securities for the periods presented: For the Three Months Ended For the Six Months Ended 2020 2019 2020 2019 (in thousands) Anti-dilutive 701 — 877 715 The following table sets forth the calculations of basic and diluted net income (loss) per common share: For the Three Months Ended For the Six Months Ended 2020 2019 2020 2019 (in thousands, except per share data) Net income (loss) $ (89,252) $ 50,388 $ (501,147) $ (127,180) Basic weighted-average common shares outstanding 113,008 112,262 113,015 112,257 Dilutive effect of non-vested RSUs and contingent PSUs — 670 — — Diluted weighted-average common shares outstanding 113,008 112,932 113,015 112,257 Basic net income (loss) per common share $ (0.79) $ 0.45 $ (4.43) $ (1.13) Diluted net income (loss) per common share $ (0.79) $ 0.45 $ (4.43) $ (1.13)

Derivative Financial Instrument

Derivative Financial Instruments	6 Months Ended
	Jun. 30, 2020
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 has entered into various 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 June 30, 2020, 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 production, and swap arrangements for 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 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 New York Mercantile Exchange (“NYMEX”) WTI and WTI Midland for a portion of its Midland Basin production with sales contracts that settle at WTI Midland prices, and basis swap contracts with fixed price differentials between 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. 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 June 30, 2020, the Company had commodity derivative contracts outstanding through the fourth quarter of 2022 as summarized in the tables below. Oil Swaps Contract Period NYMEX WTI Volumes Weighted-Average Contract Price (MBbl) (per Bbl) Third quarter 2020 3,361 $ 56.43 Fourth quarter 2020 4,397 $ 57.03 2021 13,467 $ 39.65 2022 1,276 $ 41.75 Total 22,501 Oil Collars Contract Period NYMEX WTI Volumes Weighted-Average Floor Price Weighted-Average Ceiling Price (MBbl) (per Bbl) (per Bbl) Third quarter 2020 1,252 $ 55.00 $ 62.90 Fourth quarter 2020 610 $ 55.00 $ 61.90 2021 329 $ 55.00 $ 56.70 Total 2,191 Oil Basis Swaps Contract Period WTI Midland-NYMEX WTI Volumes Weighted-Average Contract Price (1) NYMEX WTI-ICE Brent Volumes Weighted-Average Contract Price (2) (MBbl) (per Bbl) (MBbl) (per Bbl) Third quarter 2020 3,607 $ (0.62) 920 $ (8.01) Fourth quarter 2020 4,087 $ (0.38) 920 $ (8.01) 2021 11,527 $ 0.87 3,650 $ (7.86) 2022 9,500 $ 1.15 3,650 $ (7.78) Total 28,721 9,140 ____________________________________________ (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). Oil Roll Differential Swaps Contract Period NYMEX WTI Volumes Weighted-Average (MBbl) (per Bbl) Third quarter 2020 3,077 $ (1.34) Fourth quarter 2020 2,503 $ (1.18) 2021 4,002 $ (0.52) Total 9,582 Gas Swaps Contract Period IF HSC Volumes Weighted-Average WAHA Volumes Weighted-Average Contract Price (BBtu) (per MMBtu) (BBtu) (per MMBtu) Third quarter 2020 4,493 $ 2.41 4,628 $ 1.08 Fourth quarter 2020 9,327 $ 2.39 4,872 $ 1.21 2021 41,736 $ 2.38 20,676 $ 1.52 2022 6,104 $ 2.23 2,681 $ 1.90 Total (1) 61,660 32,857 ____________________________________________ (1) The Company has natural gas swaps in place that settle against Inside FERC Houston Ship Channel (“IF HSC”), Inside FERC West Texas (“IF WAHA”), and Platt’s Gas Daily West Texas (“GD WAHA”). As of June 30, 2020, WAHA volumes were comprised of 71 percent IF WAHA and 29 percent GD WAHA. NGL Swaps OPIS Propane Mont Belvieu Non-TET Contract Period Volumes Weighted-Average Contract Price (MBbl) (per Bbl) Third quarter 2020 409 $ 22.33 Fourth quarter 2020 466 $ 22.29 Total 875 Commodity Derivative Contracts Entered Into Subsequent to June 30, 2020 Subsequent to June 30, 2020, the Company entered into the following commodity derivative contracts: • fixed price NYMEX WTI oil swap contracts for 2021 through the fourth quarter of 2022 for a total of 3.7 MMBbl of oil production at a weighted-average contract price of $43.29 per Bbl; • fixed price WTI Midland-NYMEX WTI oil basis swap contracts for 2021 for a total of 2.3 MMBbl of oil production at a weighted-average contract price of $0.21 per Bbl; • a fixed price GD WAHA gas swap contract for the fourth quarter of 2021 for a total of 920 BBtu of gas production at a contract price of $1.99 per MMBtu; and • a fixed price OPIS Propane Mont Belvieu Non-TET swap contract for 2021 for a total of 0.4 MMBbl of propane production at a contract price of $19.74 per Bbl. 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 derivative commodity contracts as hedging instruments. The fair value of the commodity derivative contracts was a net asset of $183.7 million and $21.5 million as of June 30, 2020, and December 31, 2019, respectively. The following table details the fair value of commodity derivative contracts recorded in the accompanying balance sheets, by category: As of June 30, 2020 As of December 31, 2019 (in thousands) Derivative assets: Current assets $ 211,582 $ 55,184 Noncurrent assets 34,390 20,624 Total derivative assets $ 245,972 $ 75,808 Derivative liabilities: Current liabilities $ 38,250 $ 50,846 Noncurrent liabilities 24,028 3,444 Total derivative liabilities $ 62,278 $ 54,290 Offsetting of Derivative Assets and Liabilities As of June 30, 2020, and December 31, 2019, 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 June 30, 2020 December 31, 2019 June 30, 2020 December 31, 2019 (in thousands) Gross amounts presented in the accompanying balance sheets $ 245,972 $ 75,808 $ (62,278) $ (54,290) Amounts not offset in the accompanying balance sheets (62,278) (35,075) 62,278 35,075 Net amounts $ 183,694 $ 40,733 $ — $ (19,215) The following table summarizes the commodity components of the derivative settlement (gain) loss, as well as the components of the net derivative (gain) loss line item presented in the accompanying statements of operations: For the Three Months Ended For the Six Months Ended 2020 2019 2020 2019 (in thousands) Derivative settlement (gain) loss: Oil contracts $ (138,606) $ 10,689 $ (192,188) $ 12,058 Gas contracts (1,054) (5,668) (15,679) (1,534) NGL contracts (2,868) (9,111) (8,098) (9,645) Total derivative settlement (gain) loss $ (142,528) $ (4,090) $ (215,965) $ 879 Net derivative (gain) loss: Oil contracts $ 151,250 $ (34,552) $ (391,290) $ 151,245 Gas contracts 8,261 (25,996) 14,989 (32,109) NGL contracts 7,689 (19,107) (1,839) (21,710) Total net derivative (gain) loss $ 167,200 $ (79,655) $ (378,140) $ 97,426 Credit Related Contingent Features As of June 30, 2020, 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	6 Months Ended
	Jun. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value Disclosures	Note 11 - 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 June 30, 2020: Level 1 Level 2 Level 3 (in thousands) Assets: Derivatives (1) $ — $ 245,972 $ — Liabilities: Derivatives (1) $ — $ 62,278 $ — __________________________________________ (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, 2019: Level 1 Level 2 Level 3 (in thousands) Assets: Derivatives (1) $ — $ 75,808 $ — Liabilities: Derivatives (1) $ — $ 54,290 $ — ____________________________________________ (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 , and to Note 11 - Fair Value Measurements in the 2019 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 assets included in total property and equipment, net, measured at fair value as of June 30, 2020, or December 31, 2019. Proved oil and gas properties . Proved oil and gas property costs are evaluated for impairment and reduced to fair value when there is an indication that associated carrying costs may not be recoverable. The Company uses an income valuation technique, which converts future cash flows to a single present value amount, to measure the fair value of proved properties using a discount rate, price and cost forecasts, and certain reserve risk-adjustment factors, as selected by the Company’s management. The Company uses a discount rate that represents a current market-based weighted average cost of capital. The prices for oil and gas are forecast based on NYMEX strip pricing, adjusted for basis differentials, for the first five years, after which a flat terminal price is used for each commodity stream. The prices for NGLs are forecasted using Oil Price Information Service (“OPIS”) Mont Belvieu pricing, for as long as the market is actively trading, after which a flat terminal price is used. Future operating costs are also adjusted as deemed appropriate for these estimates. Certain undeveloped reserve estimates are also risk-adjusted given the risk to related projected cash flows due to performance and exploitation uncertainties. Other Property and Equipment. Other property and equipment costs are evaluated for impairment and reduced to fair value when there is an indication the carrying costs may not be recoverable. To measure the fair value of other property and equipment, the Company uses an income valuation technique or market approach depending on the quality of information available to support management’s assumptions and the circumstances. The valuation includes consideration of the proved and unproved assets supported by the property and equipment, future cash flows associated with the assets, and fixed costs necessary to operate and maintain the assets. No proved property impairment expense was recorded during the three months ended June 30, 2020. For the six months ended June 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 due to 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 cash flows based on the prevailing market-based weighed average cost of capital as of March 31, 2020. No proved property impairment expense was recorded during the three or six months ended June 30, 2019. The following table presents impairment of oil and gas properties expense and abandonment and impairment of unproved properties expense recorded during the periods presented: For the Three Months Ended For the Six Months Ended 2020 2019 2020 2019 (in millions) Impairment of proved oil and gas properties and related support equipment $ — $ — $ 956.7 $ — Abandonment and impairment of unproved properties (1) 8.8 12.4 41.9 18.8 Impairment (2) $ 8.8 $ 12.4 $ 998.5 $ 18.8 ____________________________________________ (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 June 30, 2020, and December 31, 2019, are recorded at carrying value. (2) Amounts may not calculate due to rounding. Please refer to Note 1 - Summary of Significant Accounting Policies and Note 11 - Fair Value Measurements in the 2019 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 Note 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 June 30, 2020, or December 31, 2019, 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 June 30, 2020 As of December 31, 2019 Principal Amount Fair Value Principal Amount Fair Value (in thousands) 6.125% Senior Unsecured Notes due 2022 $ 294,346 $ 214,873 $ 476,796 $ 481,564 5.0% Senior Unsecured Notes due 2024 $ 344,661 $ 190,477 $ 500,000 $ 479,815 5.625% Senior Unsecured Notes due 2025 $ 349,118 $ 185,033 $ 500,000 $ 475,835 6.75% Senior Unsecured Notes due 2026 $ 419,235 $ 213,286 $ 500,000 $ 494,860 6.625% Senior Unsecured Notes due 2027 $ 416,791 $ 206,566 $ 500,000 $ 493,750 10.0% Senior Secured Notes due 2025 $ 446,675 $ 424,064 $ — $ — 1.5% Senior Convertible Notes due 2021 (1) $ — $ — $ 172,500 $ 164,430 1.5% Senior Secured Convertible Notes due 2021 (1) $ 65,485 $ 60,246 $ — $ — ____________________________________________ (1) The Company’s 2021 Senior Convertible Notes became secured in the second quarter of 2020 upon closing of the Exchange Offers. Please refer to Note 5 - Long-Term Debt for additional information. The carrying value of the Company’s revolving credit facility approximates its fair value, as the applicable interest rates are floating, based on prevailing market rates. Warrants As discussed 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 outstanding common stock, at an exercise price of $0.01 per share. The warrants are exercisable any time from and after the Triggering Date, as subsequently defined, until June 30, 2023. The Triggering Date 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 issued are indexed to the Company’s common stock and are required to be settled through physical settlement or net share settlement if exercised. The warrants were not exercisable during the six months ended June 30, 2020, or through the filing of this report. The fair value of the warrants on the issuance date was determined using a stochastic Monte Carlo simulation using the GBM Model. The Company evaluated the warrants under authoritative accounting guidance and determined that they should be classified as

Leases

Leases	6 Months Ended
	Jun. 30, 2020
Lessee Disclosure [Abstract]
Leases	Note 12 - Leases ASC Topic 842 - Leases (“Topic 842”), requires lessees to recognize operating and finance leases with terms greater than 12 months on the balance sheet. As of June 30, 2020, the Company did not have any agreements in place that were classified as finance leases under Topic 842. Arrangements classified as operating leases are included on the accompanying balance sheets within the other noncurrent assets, other current liabilities, and other noncurrent liabilities line items. As outlined in Topic 842, an ROU asset represents a lessee’s right to use an underlying asset for the lease term, while the associated lease liability represents the lessee’s obligations to make lease payments. At the commencement date, which is the date on which a lessor makes an underlying asset available for use by a lessee, a lease ROU asset and corresponding lease liability is recognized based on the present value of the future lease payments. Excluded from the initial measurement are certain variable lease payments, which for the Company’s drilling rigs, completion crews, and midstream agreements, may be a significant component of the total lease costs. Subsequent to initial measurement, costs associated with the Company’s operating leases are either expensed on the accompanying statements of operations or capitalized on the accompanying balance sheets depending on the nature and use of the underlying ROU asset and in accordance with GAAP requirements. Please refer to Note 12 - Leases in the 2019 Form 10-K for more information regarding the Company's policy on leases, and assumptions and judgments made in the initial and subsequent measurement of lease ROU assets and corresponding liabilities. Currently, the Company has operating leases for asset classes that include office space, office equipment, drilling rigs, midstream agreements, vehicles, and equipment rentals used in field operations. For those operating leases included on the accompanying balance sheets, which only includes leases with terms greater than 12 months at commencement, remaining lease terms range from less than one year to approximately six years. The weighted-average lease term remaining for these leases is approximately three years. Certain leases also contain optional extension periods that allow for terms to be extended for up to an additional 10 years. An early termination option also exists for certain leases, some of which allow for the Company to terminate a lease within one year. Exercising an early termination option may also result in an early termination penalty depending on the terms of the underlying agreement. Based on expectations for those agreements with early termination options, there are no leases in which material early termination options are reasonably certain to be exercised by the Company. For the three months ended June 30, 2020, and 2019, total costs related to operating leases, including short-term leases, and variable lease payments made for leases with initial lease terms greater than 12 months, were $62.2 million and $139.8 million, respectively. For the six months ended June 30, 2020, and 2019, total lease costs were $135.0 million and $315.1 million, respectively. These totals do not reflect amounts that may be reimbursed by other third parties in the normal course of business, such as non-operating working interest owners. Components of the Company’s total lease cost, whether capitalized or expensed, for the three and six months ended June 30, 2020, and 2019, consisted of the following: For the Three Months Ended June 30, For the Six Months Ended June 30, 2020 2019 2020 2019 (in thousands) Operating lease cost $ 4,453 $ 11,479 $ 11,287 $ 20,458 Short-term lease cost (1) 36,630 102,085 80,202 237,002 Variable lease cost (2) 21,136 26,198 43,470 57,606 Total lease cost $ 62,219 $ 139,762 $ 134,959 $ 315,066 ____________________________________________ (1) Costs associated with short-term lease agreements relate primarily to operational activities where underlying lease terms are less than one year. This amount is significant as it includes drilling and completion activities and field equipment rentals, most of which are contracted for 12 months or less. It is expected that this amount will fluctuate primarily with the number of drilling rigs and completion crews the Company is operating under short-term agreements. (2) Variable lease payments include additional payments made that were not included in the initial measurement of the ROU asset and corresponding liability for lease agreements with terms longer than 12 months. Variable lease payments relate to the actual volumes transported under certain midstream agreements, actual usage associated with drilling rigs, completion crews, and vehicles, and variable utility costs associated with the Company’s leased office space. Fluctuations in variable lease payments are driven by actual volumes delivered and the number of drilling rigs and completion crews operating under long-term agreements. Right-of-use assets obtained in exchange for new operating lease liabilities totaled $745,000 for the three and six months ended June 30, 2020, and $10.5 million and $22.7 million for the three and six months ended June 30, 2019, respectively. Cash paid for amounts included in the measurement of lease liabilities for the six months ended June 30, 2020, and 2019, was as follows: For the Six Months Ended June 30, 2020 2019 (in thousands) Operating cash flows from operating leases $ 6,065 $ 5,966 Investing cash flows from operating leases $ 6,188 $ 14,808 Maturities for the Company’s operating lease liabilities included on the accompanying balance sheets as of June 30, 2020, were as follows: As of June 30, 2020 (in thousands) 2020 (remaining after June 30, 2020) $ 7,161 2021 12,938 2022 5,948 2023 3,602 2024 2,081 Thereafter 1,640 Total Lease payments $ 33,370 Less: Imputed interest (1) (3,340) Total $ 30,030 ____________________________________________ (1) The weighted-average discount rate used to determine the operating lease liability as of June 30, 2020, was 6.9 percent. Amounts recorded on the accompanying balance sheets for operating leases as of June 30, 2020, and December 31, 2019, were as follows: As of June 30, 2020 As of December 31, 2019 (in thousands) Other noncurrent assets $ 27,778 $ 39,717 Other current liabilities $ 12,597 $ 19,189 Other noncurrent liabilities $ 17,433 $ 23,137 As of June 30, 2020, and through the filing of this report, the Company has no material lease arrangements which are scheduled to commence in the future.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2020
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 2019 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 June 30, 2020, 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 December 2019, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (“ASU 2019-12”). ASU 2019-12 was issued to reduce the complexity of accounting for income taxes for those entities that fall within the scope of the accounting standard. The guidance is to be applied using a prospective method, excluding amendments related to franchise taxes, which should be applied on either a retrospective basis for all periods presented or a modified retrospective basis through a cumulative-effect adjustment to retained earnings as of the beginning of the fiscal year of adoption. ASU 2019-12 is effective for fiscal years beginning after December 15, 2020, with early adoption permitted. The Company early adopted ASU 2019-12 on January 1, 2020, and there was no material impact on the Company’s unaudited condensed consolidated financial statements or disclosures upon adoption. In March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting (“ASU 2020-04”). 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 is effective for all entities as of March 12, 2020 through December 31, 2022. The Company is evaluating the options provided by ASU 2020-04. 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. As disclosed in the 2019 Form 10-K , on January 1, 2020, the Company adopted ASU No. 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments , and ASU No. 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract . As expected, there was no material impact on the Company’s unaudited condensed consolidated financial statements or disclosures upon adoption of these ASUs. There are no 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 June 30, 2020, 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 , and to Note 11 - Fair Value Measurements in the 2019 Form 10-K for more information regarding the Company’s derivative instruments.
Property, Plant and Equipment, Impairment, Policy [Policy Text Block]	Oil and Gas Properties and Other Property and Equipment The Company had no assets included in total property and equipment, net, measured at fair value as of June 30, 2020, or December 31, 2019. Proved oil and gas properties . Proved oil and gas property costs are evaluated for impairment and reduced to fair value when there is an indication that associated carrying costs may not be recoverable. The Company uses an income valuation technique, which converts future cash flows to a single present value amount, to measure the fair value of proved properties using a discount rate, price and cost forecasts, and certain reserve risk-adjustment factors, as selected by the Company’s management. The Company uses a discount rate that represents a current market-based weighted average cost of capital. The prices for oil and gas are forecast based on NYMEX strip pricing, adjusted for basis differentials, for the first five years, after which a flat terminal price is used for each commodity stream. The prices for NGLs are forecasted using Oil Price Information Service (“OPIS”) Mont Belvieu pricing, for as long as the market is actively trading, after which a flat terminal price is used. Future operating costs are also adjusted as deemed appropriate for these estimates. Certain undeveloped reserve estimates are also risk-adjusted given the risk to related projected cash flows due to performance and exploitation uncertainties. Other Property and Equipment. Other property and equipment costs are evaluated for impairment and reduced to fair value when there is an indication the carrying costs may not be recoverable. To measure the fair value of other property and equipment, the Company uses an income valuation technique or market approach depending on the quality of information available to support management’s assumptions and the circumstances. The valuation includes consideration of the proved and unproved assets supported by the property and equipment, future cash flows associated with the assets, and fixed costs necessary to operate and maintain the assets. No proved property impairment expense was recorded during the three months ended June 30, 2020. For the six months ended June 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 due to 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 cash flows based on the prevailing market-based weighed average cost of capital as of March 31, 2020. No proved property impairment expense was recorded during the three or six months ended June 30, 2019.
Leases, Policy [Policy Text Block]	Arrangements classified as operating leases are included on the accompanying balance sheets within the other noncurrent assets, other current liabilities, and other noncurrent liabilities line items. As outlined in Topic 842, an ROU asset represents a lessee’s right to use an underlying asset for the lease term, while the associated lease liability represents the lessee’s obligations to make lease payments. At the commencement date, which is the date on which a lessor makes an underlying asset available for use by a lessee, a lease ROU asset and corresponding lease liability is recognized based on the present value of the future lease payments. Excluded from the initial measurement are certain variable lease payments, which for the Company’s drilling rigs, completion crews, and midstream agreements, may be a significant component of the total lease costs. Subsequent to initial measurement, costs associated with the Company’s operating leases are either expensed on the accompanying statements of operations or capitalized on the accompanying balance sheets depending on the nature and use of the underlying ROU asset and in accordance with GAAP requirements. Please refer to Note 12 - Leases in the 2019 Form 10-K for more information regarding the Company's policy on leases, and assumptions and judgments made in the initial and subsequent measurement of lease ROU assets and corresponding liabilities.

Fair Value Measures and Disclos

Fair Value Measures and Disclosures (Policies)	6 Months Ended
	Jun. 30, 2020
Fair Value Disclosures [Abstract]
Property, Plant and Equipment, Impairment, Policy [Policy Text Block]	Oil and Gas Properties and Other Property and Equipment The Company had no assets included in total property and equipment, net, measured at fair value as of June 30, 2020, or December 31, 2019. Proved oil and gas properties . Proved oil and gas property costs are evaluated for impairment and reduced to fair value when there is an indication that associated carrying costs may not be recoverable. The Company uses an income valuation technique, which converts future cash flows to a single present value amount, to measure the fair value of proved properties using a discount rate, price and cost forecasts, and certain reserve risk-adjustment factors, as selected by the Company’s management. The Company uses a discount rate that represents a current market-based weighted average cost of capital. The prices for oil and gas are forecast based on NYMEX strip pricing, adjusted for basis differentials, for the first five years, after which a flat terminal price is used for each commodity stream. The prices for NGLs are forecasted using Oil Price Information Service (“OPIS”) Mont Belvieu pricing, for as long as the market is actively trading, after which a flat terminal price is used. Future operating costs are also adjusted as deemed appropriate for these estimates. Certain undeveloped reserve estimates are also risk-adjusted given the risk to related projected cash flows due to performance and exploitation uncertainties. Other Property and Equipment. Other property and equipment costs are evaluated for impairment and reduced to fair value when there is an indication the carrying costs may not be recoverable. To measure the fair value of other property and equipment, the Company uses an income valuation technique or market approach depending on the quality of information available to support management’s assumptions and the circumstances. The valuation includes consideration of the proved and unproved assets supported by the property and equipment, future cash flows associated with the assets, and fixed costs necessary to operate and maintain the assets. No proved property impairment expense was recorded during the three months ended June 30, 2020. For the six months ended June 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 due to 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 cash flows based on the prevailing market-based weighed average cost of capital as of March 31, 2020. No proved property impairment expense was recorded during the three or six months ended June 30, 2019.
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 , and to Note 11 - Fair Value Measurements in the 2019 Form 10-K for more information regarding the Company’s derivative instruments.

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	6 Months Ended
	Jun. 30, 2020
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 regions for the three and six months ended June 30, 2020, and 2019: Midland Basin South Texas Total Three Months Ended Three Months Ended Three Months Ended 2020 2019 2020 2019 2020 2019 (in thousands) Oil production revenue $ 114,358 $ 288,447 $ 5,158 $ 15,697 $ 119,516 $ 304,144 Gas production revenue 11,921 16,449 22,942 48,775 34,863 65,224 NGL production revenue 45 (43) 15,366 37,529 15,411 37,486 Total $ 126,324 $ 304,853 $ 43,466 $ 102,001 $ 169,790 $ 406,854 Relative percentage 74 % 75 % 26 % 25 % 100 % 100 % ____________________________________________ Note: Amounts may not calculate due to rounding. Midland Basin South Texas Total Six Months Ended Six Months Ended Six Months Ended 2020 2019 2020 2019 2020 2019 (in thousands) Oil production revenue $ 390,494 $ 513,694 $ 20,715 $ 29,511 $ 411,209 $ 543,205 Gas production revenue 23,255 32,041 52,318 98,296 75,573 130,337 NGL production revenue 103 (22) 37,138 73,810 37,241 73,788 Total $ 413,852 $ 545,713 $ 110,171 $ 201,617 $ 524,023 $ 747,330 Relative percentage 79 % 73 % 21 % 27 % 100 % 100 % ____________________________________________ Note: Amounts may not calculate due to rounding.

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 30, 2020
Income Tax Disclosure [Abstract]
Schedule of provision for income taxes [Table Text Block]	The provision for income taxes for the three and six months ended June 30, 2020, and 2019, consisted of the following: For the Three Months Ended For the Six Months Ended 2020 2019 2020 2019 (in thousands) Current portion of income tax (expense) benefit: Federal $ — $ — $ — $ — State (236) 176 (575) (789) Deferred portion of income tax (expense) benefit 36,921 (13,766) 136,268 33,237 Income tax (expense) benefit $ 36,685 $ (13,590) $ 135,693 $ 32,448 Effective tax rate 29.1 % 21.2 % 21.3 % 20.3 %

Long-Term Debt (Tables)

Long-Term Debt (Tables)	Jun. 30, 2020	Jun. 17, 2020	Jun. 30, 2020
Debt Disclosure [Abstract]
Schedule of Long-Term Debt Instruments, Senior Notes Tendered		The following table summarizes the principal amounts of the Old Notes tendered as of the Settlement Date: Title of Old Notes Tendered Principal Amount of Old Notes Tendered (in thousands) 1.50% Senior Convertible Notes due 2021 $ 107,015 6.125% Senior Notes due 2022 141,701 5.0% Senior Notes due 2024 155,339 5.625% Senior Notes due 2025 150,882 6.75% Senior Notes due 2026 80,765 6.625% Senior Notes due 2027 83,209 Total $ 718,911
Schedule of Borrowing Base Utilization [Table Text Block]	Borrowing Base Utilization Percentage <25% ≥25% <50% ≥50% <75% ≥75% <90% ≥90% Eurodollar Loans (1) 1.750 % 2.000 % 2.500 % 2.750 % 3.000 % ABR Loans or Swingline Loans 0.750 % 1.000 % 1.500 % 1.750 % 2.000 % Commitment Fee Rate 0.375 % 0.375 % 0.500 % 0.500 % 0.500 % ____________________________________________ (1) 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, which provides guidance related to reference rate reform .
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 July 23, 2020, June 30, 2020, and December 31, 2019: As of July 23, 2020 As of June 30, 2020 As of December 31, 2019 (in thousands) Revolving credit facility (1) $ 180,000 $ 193,000 $ 122,500 Letters of credit (2) 42,000 42,000 — Available borrowing capacity 878,000 865,000 1,077,500 Total aggregate lender commitment amount $ 1,100,000 $ 1,100,000 $ 1,200,000 ____________________________________________ (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 $5.0 million and $5.9 million as of June 30, 2020, and December 31, 2019, 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 credit facility on a dollar-for-dollar basis.
Schedule Of Long-term Debt Instruments, Secured			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 June 30, 2020, consisted of the following: As of June 30, 2020 Principal Amount Unamortized Debt Discount Unamortized Deferred Financing Costs Principal Amount, Net (in thousands) 10.0% Senior Secured Notes due 2025 $ 446,675 $ (41,340) $ (11,596) $ 393,739 1.50% Senior Secured Convertible Notes due 2021 (1) 65,485 (3,592) (349) 61,544 Total $ 512,160 $ (44,932) $ (11,945) $ 455,283 ____________________________________________ (1) As discussed above, as required by the 2021 Notes Indenture and as permitted by the Credit Agreement, as the Company issued Permitted Second Lien Debt upon the closing of the Exchange Offers, its remaining 2021 Senior Convertible Notes contemporaneously became secured.
Schedule Of Long-term Debt Instruments, Unsecured			Senior Unsecured Notes, net of unamortized deferred financing costs, included within the Senior Notes, net line item on the accompanying balance sheets as of June 30, 2020, and December 31, 2019, consisted of the following: As of June 30, 2020 As of December 31, 2019 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 $ 294,346 $ 1,494 $ 292,852 $ 476,796 $ 2,920 $ 473,876 5.0% Senior Notes due 2024 344,661 2,278 342,383 500,000 3,766 496,234 5.625% Senior Notes due 2025 349,118 3,108 346,010 500,000 4,903 495,097 6.75% Senior Notes due 2026 419,235 4,321 414,914 500,000 5,571 494,429 6.625% Senior Notes due 2027 416,791 5,114 411,677 500,000 6,601 493,399 1.50% Senior Convertible Notes due 2021 (1)(2) — — — 172,500 15,237 157,263 Total $ 1,824,151 $ 16,315 $ 1,807,836 $ 2,649,296 $ 38,998 $ 2,610,298 ____________________________________________ (1) Unamortized deferred financing costs attributable to the 2021 Senior Convertible Notes include $13.9 million related to the unamortized debt discount as of December 31, 2019. (2) As discussed above, as required by the 2021 Notes Indenture and as permitted by the Credit Agreement, as the Company issued Permitted Second Lien Debt upon the closing of the Exchange Offers, its remaining 2021 Senior Convertible Notes contemporaneously became secured.

Pension Benefits (Tables)

Pension Benefits (Tables)	6 Months Ended
	Jun. 30, 2020
Defined Benefit Plan [Abstract]
Components of the net periodic benefit cost for the pension plans [Table Text Block]	Components of Net Periodic Benefit Cost for the Pension Plans For the Three Months Ended For the Six Months Ended 2020 2019 2020 2019 (in thousands) Components of net periodic benefit cost: Service cost $ 863 $ 1,108 $ 2,258 $ 2,791 Interest cost 480 739 1,178 1,395 Expected return on plan assets that reduces periodic pension benefit cost (474) (321) (867) (787) Amortization of prior service cost 5 5 9 9 Amortization of net actuarial loss 235 147 475 479 Net periodic benefit cost $ 1,109 $ 1,678 $ 3,053 $ 3,887

Earnings per Share (Tables)

Earnings per Share (Tables)	6 Months Ended
	Jun. 30, 2020
Earnings Per Share [Abstract]
Schedule of anti-dilutive securities excluded from computation of earnings per share [Table Text Block]	The following table details the weighted-average anti-dilutive securities for the periods presented: For the Three Months Ended For the Six Months Ended 2020 2019 2020 2019 (in thousands) Anti-dilutive 701 — 877 715
Schedule of calculations of basic and diluted net income (loss) per common share [Table Text Block]	The following table sets forth the calculations of basic and diluted net income (loss) per common share: For the Three Months Ended For the Six Months Ended 2020 2019 2020 2019 (in thousands, except per share data) Net income (loss) $ (89,252) $ 50,388 $ (501,147) $ (127,180) Basic weighted-average common shares outstanding 113,008 112,262 113,015 112,257 Dilutive effect of non-vested RSUs and contingent PSUs — 670 — — Diluted weighted-average common shares outstanding 113,008 112,932 113,015 112,257 Basic net income (loss) per common share $ (0.79) $ 0.45 $ (4.43) $ (1.13) Diluted net income (loss) per common share $ (0.79) $ 0.45 $ (4.43) $ (1.13)

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2020
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Schedule of notional amounts of outstanding derivative positions [Table Text Block]	As of June 30, 2020, the Company had commodity derivative contracts outstanding through the fourth quarter of 2022 as summarized in the tables below. Oil Swaps Contract Period NYMEX WTI Volumes Weighted-Average Contract Price (MBbl) (per Bbl) Third quarter 2020 3,361 $ 56.43 Fourth quarter 2020 4,397 $ 57.03 2021 13,467 $ 39.65 2022 1,276 $ 41.75 Total 22,501 Oil Collars Contract Period NYMEX WTI Volumes Weighted-Average Floor Price Weighted-Average Ceiling Price (MBbl) (per Bbl) (per Bbl) Third quarter 2020 1,252 $ 55.00 $ 62.90 Fourth quarter 2020 610 $ 55.00 $ 61.90 2021 329 $ 55.00 $ 56.70 Total 2,191 Oil Basis Swaps Contract Period WTI Midland-NYMEX WTI Volumes Weighted-Average Contract Price (1) NYMEX WTI-ICE Brent Volumes Weighted-Average Contract Price (2) (MBbl) (per Bbl) (MBbl) (per Bbl) Third quarter 2020 3,607 $ (0.62) 920 $ (8.01) Fourth quarter 2020 4,087 $ (0.38) 920 $ (8.01) 2021 11,527 $ 0.87 3,650 $ (7.86) 2022 9,500 $ 1.15 3,650 $ (7.78) Total 28,721 9,140 ____________________________________________ (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). Oil Roll Differential Swaps Contract Period NYMEX WTI Volumes Weighted-Average (MBbl) (per Bbl) Third quarter 2020 3,077 $ (1.34) Fourth quarter 2020 2,503 $ (1.18) 2021 4,002 $ (0.52) Total 9,582 Gas Swaps Contract Period IF HSC Volumes Weighted-Average WAHA Volumes Weighted-Average Contract Price (BBtu) (per MMBtu) (BBtu) (per MMBtu) Third quarter 2020 4,493 $ 2.41 4,628 $ 1.08 Fourth quarter 2020 9,327 $ 2.39 4,872 $ 1.21 2021 41,736 $ 2.38 20,676 $ 1.52 2022 6,104 $ 2.23 2,681 $ 1.90 Total (1) 61,660 32,857 ____________________________________________ (1) The Company has natural gas swaps in place that settle against Inside FERC Houston Ship Channel (“IF HSC”), Inside FERC West Texas (“IF WAHA”), and Platt’s Gas Daily West Texas (“GD WAHA”). As of June 30, 2020, WAHA volumes were comprised of 71 percent IF WAHA and 29 percent GD WAHA. NGL Swaps OPIS Propane Mont Belvieu Non-TET Contract Period Volumes Weighted-Average Contract Price (MBbl) (per Bbl) Third quarter 2020 409 $ 22.33 Fourth quarter 2020 466 $ 22.29 Total 875
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 June 30, 2020 As of December 31, 2019 (in thousands) Derivative assets: Current assets $ 211,582 $ 55,184 Noncurrent assets 34,390 20,624 Total derivative assets $ 245,972 $ 75,808 Derivative liabilities: Current liabilities $ 38,250 $ 50,846 Noncurrent liabilities 24,028 3,444 Total derivative liabilities $ 62,278 $ 54,290
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 June 30, 2020 December 31, 2019 June 30, 2020 December 31, 2019 (in thousands) Gross amounts presented in the accompanying balance sheets $ 245,972 $ 75,808 $ (62,278) $ (54,290) Amounts not offset in the accompanying balance sheets (62,278) (35,075) 62,278 35,075 Net amounts $ 183,694 $ 40,733 $ — $ (19,215)
Schedule of the components of the derivative settlement (gain) loss and of the net derivative (gain) loss [Table Text Block]	The following table summarizes the commodity components of the derivative settlement (gain) loss, as well as the components of the net derivative (gain) loss line item presented in the accompanying statements of operations: For the Three Months Ended For the Six Months Ended 2020 2019 2020 2019 (in thousands) Derivative settlement (gain) loss: Oil contracts $ (138,606) $ 10,689 $ (192,188) $ 12,058 Gas contracts (1,054) (5,668) (15,679) (1,534) NGL contracts (2,868) (9,111) (8,098) (9,645) Total derivative settlement (gain) loss $ (142,528) $ (4,090) $ (215,965) $ 879 Net derivative (gain) loss: Oil contracts $ 151,250 $ (34,552) $ (391,290) $ 151,245 Gas contracts 8,261 (25,996) 14,989 (32,109) NGL contracts 7,689 (19,107) (1,839) (21,710) Total net derivative (gain) loss $ 167,200 $ (79,655) $ (378,140) $ 97,426

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2020
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 June 30, 2020: Level 1 Level 2 Level 3 (in thousands) Assets: Derivatives (1) $ — $ 245,972 $ — Liabilities: Derivatives (1) $ — $ 62,278 $ — __________________________________________ (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, 2019: Level 1 Level 2 Level 3 (in thousands) Assets: Derivatives (1) $ — $ 75,808 $ — Liabilities: Derivatives (1) $ — $ 54,290 $ — ____________________________________________ (1) This represents a financial asset or liability that is measured at fair value on a recurring basis.
Impairment of oil and gas properties [Table Text Block]	The following table presents impairment of oil and gas properties expense and abandonment and impairment of unproved properties expense recorded during the periods presented: For the Three Months Ended For the Six Months Ended 2020 2019 2020 2019 (in millions) Impairment of proved oil and gas properties and related support equipment $ — $ — $ 956.7 $ — Abandonment and impairment of unproved properties (1) 8.8 12.4 41.9 18.8 Impairment (2) $ 8.8 $ 12.4 $ 998.5 $ 18.8 ____________________________________________ (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 June 30, 2020, and December 31, 2019, are recorded at carrying value. (2) Amounts may not calculate due to rounding.
Long Term Debt Fair Value [Table Text Block]	Long-Term Debt The following table reflects the fair value of the Company’s Senior Note 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 June 30, 2020, or December 31, 2019, 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 June 30, 2020 As of December 31, 2019 Principal Amount Fair Value Principal Amount Fair Value (in thousands) 6.125% Senior Unsecured Notes due 2022 $ 294,346 $ 214,873 $ 476,796 $ 481,564 5.0% Senior Unsecured Notes due 2024 $ 344,661 $ 190,477 $ 500,000 $ 479,815 5.625% Senior Unsecured Notes due 2025 $ 349,118 $ 185,033 $ 500,000 $ 475,835 6.75% Senior Unsecured Notes due 2026 $ 419,235 $ 213,286 $ 500,000 $ 494,860 6.625% Senior Unsecured Notes due 2027 $ 416,791 $ 206,566 $ 500,000 $ 493,750 10.0% Senior Secured Notes due 2025 $ 446,675 $ 424,064 $ — $ — 1.5% Senior Convertible Notes due 2021 (1) $ — $ — $ 172,500 $ 164,430 1.5% Senior Secured Convertible Notes due 2021 (1) $ 65,485 $ 60,246 $ — $ — ____________________________________________ (1) The Company’s 2021 Senior Convertible Notes became secured in the second quarter of 2020 upon closing of the Exchange Offers. Please refer to Note 5 - Long-Term Debt for additional information.

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2020
Lessee Disclosure [Abstract]
Components of total lease cost [Table Text Block]	Components of the Company’s total lease cost, whether capitalized or expensed, for the three and six months ended June 30, 2020, and 2019, consisted of the following: For the Three Months Ended June 30, For the Six Months Ended June 30, 2020 2019 2020 2019 (in thousands) Operating lease cost $ 4,453 $ 11,479 $ 11,287 $ 20,458 Short-term lease cost (1) 36,630 102,085 80,202 237,002 Variable lease cost (2) 21,136 26,198 43,470 57,606 Total lease cost $ 62,219 $ 139,762 $ 134,959 $ 315,066 ____________________________________________ (1) Costs associated with short-term lease agreements relate primarily to operational activities where underlying lease terms are less than one year. This amount is significant as it includes drilling and completion activities and field equipment rentals, most of which are contracted for 12 months or less. It is expected that this amount will fluctuate primarily with the number of drilling rigs and completion crews the Company is operating under short-term agreements. (2) Variable lease payments include additional payments made that were not included in the initial measurement of the ROU asset and corresponding liability for lease agreements with terms longer than 12 months. Variable lease payments relate to the actual volumes transported under certain midstream agreements, actual usage associated with drilling rigs, completion crews, and vehicles, and variable utility costs associated with the Company’s leased office space. Fluctuations in variable lease payments are driven by actual volumes delivered and the number of drilling rigs and completion crews operating under long-term agreements. Right-of-use assets obtained in exchange for new operating lease liabilities totaled $745,000 for the three and six months ended June 30, 2020, and $10.5 million and $22.7 million for the three and six months ended June 30, 2019, respectively. Cash paid for amounts included in the measurement of lease liabilities for the six months ended June 30, 2020, and 2019, was as follows: For the Six Months Ended June 30, 2020 2019 (in thousands) Operating cash flows from operating leases $ 6,065 $ 5,966 Investing cash flows from operating leases $ 6,188 $ 14,808
Operating lease liability maturities [Table Text Block]	Maturities for the Company’s operating lease liabilities included on the accompanying balance sheets as of June 30, 2020, were as follows: As of June 30, 2020 (in thousands) 2020 (remaining after June 30, 2020) $ 7,161 2021 12,938 2022 5,948 2023 3,602 2024 2,081 Thereafter 1,640 Total Lease payments $ 33,370 Less: Imputed interest (1) (3,340) Total $ 30,030 ____________________________________________ (1) The weighted-average discount rate used to determine the operating lease liability as of June 30, 2020, was 6.9 percent.
Balance Sheet information related to operating leases [Table Text Block]	Amounts recorded on the accompanying balance sheets for operating leases as of June 30, 2020, and December 31, 2019, were as follows: As of June 30, 2020 As of December 31, 2019 (in thousands) Other noncurrent assets $ 27,778 $ 39,717 Other current liabilities $ 12,597 $ 19,189 Other noncurrent liabilities $ 17,433 $ 23,137

Disaggregation of oil, gas, and

Disaggregation of oil, gas, and NGL production revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 169,790	$ 406,854	$ 524,023	$ 747,330
Revenue, Remaining Performance Obligation, Amount	0		0
Oil production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	119,516	304,144	411,209	543,205
Gas production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	34,863	65,224	75,573	130,337
NGL production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	15,411	37,486	37,241	73,788
Midland Basin [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	126,324	304,853	413,852	545,713
Midland Basin [Member] | Oil production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	114,358	288,447	390,494	513,694
Midland Basin [Member] | Gas production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	11,921	16,449	23,255	32,041
Midland Basin [Member] | NGL production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	45	(43)	103	(22)
South Texas [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	43,466	102,001	110,171	201,617
South Texas [Member] | Oil production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	5,158	15,697	20,715	29,511
South Texas [Member] | Gas production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	22,942	48,775	52,318	98,296
South Texas [Member] | NGL production revenue [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 15,366	$ 37,529	$ 37,138	$ 73,810
Revenue Benchmark [Member] | Geographic Concentration Risk [Member]
Segment Reporting Information [Line Items]
Relative percentage	100.00%	100.00%	100.00%	100.00%
Revenue Benchmark [Member] | Geographic Concentration Risk [Member] | Midland Basin [Member]
Segment Reporting Information [Line Items]
Relative percentage	74.00%	75.00%	79.00%	73.00%
Revenue Benchmark [Member] | Geographic Concentration Risk [Member] | South Texas [Member]
Segment Reporting Information [Line Items]
Relative percentage	26.00%	25.00%	21.00%	27.00%

Accounts Receivable from Custom

Accounts Receivable from Customers (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Accounts Receivable [Line Items]
Accounts receivable from contracts with customers	$ 127,173	$ 184,732
Accrued Income Receivable [Member]
Accounts Receivable [Line Items]
Accounts receivable from contracts with customers	$ 60,900	$ 146,300
Minimum [Member]
Accounts Receivable [Line Items]
Revenue receipt, days after sale	30
Maximum [Member]
Accounts Receivable [Line Items]
Revenue receipt, days after sale	90

Divestitures and Assets Held fo

Divestitures and Assets Held for Sale (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Divestitures, Assets Held for Sale, and Acquisitions [Abstract]
Properties held for sale, net	$ 0	$ 0

Nonmonetary Transactions (Detai

Nonmonetary Transactions (Details)	6 Months Ended
	Jun. 30, 2020USD ($)	Jun. 30, 2019USD ($)a
Nonmonetary Transactions [Abstract]
Net acres exchanged | a		2,000
Carrying value of properties exchanged	$ 0	$ 66,588,000
Basis of accounting for assets exchanged		carryover
Gain (loss) recognized on trade		$ 0

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Jul. 30, 2020
Components of the provision for income taxes
Federal	$ 0	$ 0	$ 0	$ 0
State	(236)	176	(575)	(789)
Deferred portion of income tax (expense) benefit	36,921	(13,766)	136,268	33,237
Income tax (expense) benefit	$ 36,685	$ (13,590)	$ 135,693	$ 32,448
Effective tax rate	29.10%	21.20%	21.30%	20.30%
Subsequent Event [Member]
Proceeds from income tax refunds					$ 7,600

Revolving Credit Facility (Deta

Revolving Credit Facility (Details) - USD ($) $ in Thousands		Jun. 30, 2020		Mar. 31, 2020	Jul. 23, 2020	Dec. 31, 2019
Line of Credit Facility [Line Items]
Revolving credit facility		$ 193,000				$ 122,500
Revolving Credit Facility [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Revolving credit facility, maximum loan amount		2,500,000
Revolving credit facility, current borrowing base		1,100,000
Revolving credit facility, aggregate lender commitments		1,100,000				1,200,000
Revolving credit facility, dividend restrictions, amount		12,000		$ 50,000
Revolving credit facility	[1]	193,000				122,500
Letters of credit		42,000	[2]			0
Available borrowing capacity		865,000				1,077,500
Revolving Credit Facility, unamortized deferred financing costs		$ 5,000				$ 5,900
Revolving Credit Facility [Member] | Revolving Credit Facility [Member] | Subsequent Event [Member]
Line of Credit Facility [Line Items]
Revolving credit facility, aggregate lender commitments					$ 1,100,000
Revolving credit facility					180,000
Letters of credit	[2]				42,000
Available borrowing capacity					$ 878,000
Borrowing Base Utilization Of Less Than 25 Percent [Member] | Revolving Credit Facility [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Revolving credit facility, unused capacity, commitment fee rate		0.375%
Borrowing Base Utilization Of 25 Percent Or More But Less Than 50 Percent [Member] | Revolving Credit Facility [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Revolving credit facility, unused capacity, commitment fee rate		0.375%
Borrowing Base Utilization Of 50 Percent Or More But Less Than 75 Percent [Member] | Revolving Credit Facility [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Revolving credit facility, unused capacity, commitment fee rate		0.50%
Borrowing Base Utilization Of 75 Percent Or More But Less Than 90 Percent [Member] | Revolving Credit Facility [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Revolving credit facility, unused capacity, commitment fee rate		0.50%
Borrowing Base Utilization Of 90 Percent Or More [Member] | Revolving Credit Facility [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Revolving credit facility, unused capacity, commitment fee rate		0.50%
Eurodollar [Member] | Borrowing Base Utilization Of Less Than 25 Percent [Member] | Revolving Credit Facility [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Revolving credit facility, basis spread on variable rate	[3]	1.75%
Eurodollar [Member] | Borrowing Base Utilization Of 25 Percent Or More But Less Than 50 Percent [Member] | Revolving Credit Facility [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Revolving credit facility, basis spread on variable rate	[3]	2.00%
Eurodollar [Member] | Borrowing Base Utilization Of 50 Percent Or More But Less Than 75 Percent [Member] | Revolving Credit Facility [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Revolving credit facility, basis spread on variable rate	[3]	2.50%
Eurodollar [Member] | Borrowing Base Utilization Of 75 Percent Or More But Less Than 90 Percent [Member] | Revolving Credit Facility [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Revolving credit facility, basis spread on variable rate	[3]	2.75%
Eurodollar [Member] | Borrowing Base Utilization Of 90 Percent Or More [Member] | Revolving Credit Facility [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Revolving credit facility, basis spread on variable rate	[3]	3.00%
Prime Rate [Member] | Borrowing Base Utilization Of Less Than 25 Percent [Member] | Revolving Credit Facility [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Revolving credit facility, basis spread on variable rate		0.75%
Prime Rate [Member] | Borrowing Base Utilization Of 25 Percent Or More But Less Than 50 Percent [Member] | Revolving Credit Facility [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Revolving credit facility, basis spread on variable rate		1.00%
Prime Rate [Member] | Borrowing Base Utilization Of 50 Percent Or More But Less Than 75 Percent [Member] | Revolving Credit Facility [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Revolving credit facility, basis spread on variable rate		1.50%
Prime Rate [Member] | Borrowing Base Utilization Of 75 Percent Or More But Less Than 90 Percent [Member] | Revolving Credit Facility [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Revolving credit facility, basis spread on variable rate		1.75%
Prime Rate [Member] | Borrowing Base Utilization Of 90 Percent Or More [Member] | Revolving Credit Facility [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Revolving credit facility, basis spread on variable rate		2.00%
[1]	(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 $5.0 million and $5.9 million as of June 30, 2020, and December 31, 2019, respectively. These costs are being amortized over the term of the revolving credit facility on a straight-line basis.
[2]	2) Letters of credit outstanding reduce the amount available under the credit facility on a dollar-for-dollar basis.
[3]	(1) 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, which provides guidance related to reference rate reform .

Senior Secured Notes (Details)

Senior Secured Notes (Details) - USD ($) shares in Thousands		3 Months Ended			6 Months Ended
		Jun. 30, 2020		Jun. 30, 2019	Jun. 30, 2020		Jun. 30, 2019	Jun. 17, 2020	May 05, 2020	Dec. 31, 2019
Senior Secured Notes [Line Items]
Increase to Permitted Second Lien Debt									$ 827,500,000
Permitted Second Lien Debt		$ 1,000,000,000			$ 1,000,000,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights								5,900
Warrants Percent of Outstanding Stock								5.00%
Available Permitted Second Lien Debt Capacity [Member]
Senior Secured Notes [Line Items]
Permitted Second Lien Debt		$ 487,800,000			$ 487,800,000
10.0% Senior Secured Notes due 2025
Senior Secured Notes [Line Items]
Senior Notes, interest rate, stated percentage		10.00%			10.00%
Senior Notes, Principal amount		$ 446,675,000			$ 446,675,000			$ 446,700,000		$ 0
Senior Secured Notes, Unamortized Debt Discount		(41,340,000)			(41,340,000)
Senior Secured Notes, unamortized deferred financing costs		(11,596,000)			(11,596,000)
Senior Secured Notes, Principal Amount, Net		$ 393,739,000			$ 393,739,000
Senior Secured Notes, Debt Issuance Costs, Gross								11,700,000
Debt Instrument, Senior Notes, Initial Fair Value								$ 405,000,000
1.50% Senior Secured Convertible Notes Due 2021 [Member]
Senior Secured Notes [Line Items]
Senior Notes, interest rate, stated percentage		1.50%			1.50%
Senior Notes, Principal amount	[2]	$ 65,485,000	[1]		$ 65,485,000	[1]				$ 0
Senior Secured Notes, Unamortized Debt Discount	[1]	(3,592,000)			(3,592,000)
Senior Secured Notes, unamortized deferred financing costs	[1]	(349,000)			(349,000)
Senior Secured Notes, Principal Amount, Net	[1]	61,544,000			61,544,000
Interest Expense, Debt		2,600,000		$ 2,700,000	5,400,000		$ 5,400,000
Senior Secured Notes
Senior Secured Notes [Line Items]
Senior Notes, Principal amount		512,160,000			512,160,000
Senior Secured Notes, Unamortized Debt Discount		(44,932,000)			(44,932,000)
Senior Secured Notes, unamortized deferred financing costs		(11,945,000)			(11,945,000)
Senior Secured Notes, Principal Amount, Net		$ 455,283,000			$ 455,283,000
[1]	(1) As discussed above, as required by the 2021 Notes Indenture and as permitted by the Credit Agreement, as the Company issued Permitted Second Lien Debt upon the closing of the Exchange Offers, its remaining 2021 Senior Convertible Notes contemporaneously became secured
[2]	(1) The Company’s 2021 Senior Convertible Notes became secured in the second quarter of 2020 upon closing of the Exchange Offers. Please refer to Note 5 - Long-Term Debt for additional information.

Senior Unsecured Notes (Details

Senior Unsecured Notes (Details) - USD ($) $ in Thousands		Jun. 30, 2020	Jun. 17, 2020	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Senior Unsecured Notes [Line Items]
Repayment of 1.50% Senior Convertible Notes due 2021							$ 53,508	$ 0
Gain on Extinguishment of Debt, Non Cash Portion							292,984	0
Gain on extinguishment of debt				$ 227,281		$ 0	239,476	$ 0
Senior Unsecured Notes [Member]
Senior Unsecured Notes [Line Items]
Senior Unsecured Notes, exchanged or repurchased face amount			$ 611,900
Debt Instrument, Redemption Price, Percentage		80.00%
Senior Notes, Principal amount		$ 1,824,151		1,824,151			1,824,151		$ 2,649,296
Senior Unsecured Notes, unamortized deferred financing costs		16,315		16,315			16,315		38,998
Senior Unsecured Notes, Principal Amount, Net		$ 1,807,836		$ 1,807,836			$ 1,807,836		2,610,298
Interest Paid, Senior Unsecured Notes, Accrued and Unpaid			8,100
Senior Unsecured Notes [Member] | Accelerated unamortized deferred financing costs [Member]
Senior Unsecured Notes [Line Items]
Gain on Extinguishment of Debt, Non Cash Portion			5,000
6.125% Senior Unsecured Notes due 2022 [Member]
Senior Unsecured Notes [Line Items]
Senior Notes, interest rate, stated percentage		6.125%		6.125%			6.125%
Senior Unsecured Notes, exchanged or repurchased face amount			141,701		$ 40,700
Senior Notes, Principal amount		$ 294,346		$ 294,346			$ 294,346		476,796
Senior Unsecured Notes, unamortized deferred financing costs		1,494		1,494			1,494		2,920
Senior Unsecured Notes, Principal Amount, Net		$ 292,852		$ 292,852			$ 292,852		473,876
Senior Unsecured Notes, repurchased settlement amount					28,300
Gain on extinguishment of debt					12,200
Discount realized on extinguishment of debt					12,400
6.125% Senior Unsecured Notes due 2022 [Member] | Accelerated unamortized deferred financing costs [Member]
Senior Unsecured Notes [Line Items]
Gain on Extinguishment of Debt, Non Cash Portion					$ 235
5.0% Senior Unsecured Notes due 2024 [Member]
Senior Unsecured Notes [Line Items]
Senior Notes, interest rate, stated percentage		5.00%		5.00%			5.00%
Senior Unsecured Notes, exchanged or repurchased face amount			155,339
Senior Notes, Principal amount		$ 344,661		$ 344,661			$ 344,661		500,000
Senior Unsecured Notes, unamortized deferred financing costs		2,278		2,278			2,278		3,766
Senior Unsecured Notes, Principal Amount, Net		$ 342,383		$ 342,383			$ 342,383		496,234
5.625% Senior Unsecured Notes due 2025 [Member]
Senior Unsecured Notes [Line Items]
Senior Notes, interest rate, stated percentage		5.625%		5.625%			5.625%
Senior Unsecured Notes, exchanged or repurchased face amount			150,882
Senior Notes, Principal amount		$ 349,118		$ 349,118			$ 349,118		500,000
Senior Unsecured Notes, unamortized deferred financing costs		3,108		3,108			3,108		4,903
Senior Unsecured Notes, Principal Amount, Net		$ 346,010		$ 346,010			$ 346,010		495,097
6.75% Senior Unsecured Notes due 2026 [Member]
Senior Unsecured Notes [Line Items]
Senior Notes, interest rate, stated percentage		6.75%		6.75%			6.75%
Senior Unsecured Notes, exchanged or repurchased face amount			80,765
Senior Notes, Principal amount		$ 419,235		$ 419,235			$ 419,235		500,000
Senior Unsecured Notes, unamortized deferred financing costs		4,321		4,321			4,321		5,571
Senior Unsecured Notes, Principal Amount, Net		$ 414,914		$ 414,914			$ 414,914		494,429
6.625% Senior Unsecured Notes due 2027 [Member]
Senior Unsecured Notes [Line Items]
Senior Notes, interest rate, stated percentage		6.625%		6.625%			6.625%
Senior Unsecured Notes, exchanged or repurchased face amount			$ 83,209
Senior Notes, Principal amount		$ 416,791		$ 416,791			$ 416,791		500,000
Senior Unsecured Notes, unamortized deferred financing costs		5,114		5,114			5,114		6,601
Senior Unsecured Notes, Principal Amount, Net		$ 411,677		$ 411,677			$ 411,677		493,399
1.50% Senior Unsecured Convertible Notes Due 2021 [Member]
Senior Unsecured Notes [Line Items]
Senior Notes, interest rate, stated percentage		1.50%	1.50%	1.50%			1.50%
Senior Unsecured Notes, exchanged or repurchased face amount			$ 107,015
Repayment of 1.50% Senior Convertible Notes due 2021			53,500
Senior Notes, Principal amount	[1],[2]	$ 0		$ 0			$ 0		172,500
Senior Unsecured Notes, unamortized deferred financing costs	[2]	0		0			0		15,237	[3]
1.50% Senior Unsecured Convertible Notes due 2021, Unamortized Debt Discount									(13,900)
Senior Unsecured Notes, Principal Amount, Net	[2]	$ 0		$ 0			$ 0		$ 157,263
Interest Paid, Senior Unsecured Notes, Accrued and Unpaid			740
1.50% Senior Unsecured Convertible Notes Due 2021 [Member] | Accelerated unamortized deferred financing costs [Member]
Senior Unsecured Notes [Line Items]
Gain on Extinguishment of Debt, Non Cash Portion			593
1.50% Senior Unsecured Convertible Notes Due 2021 [Member] | Accelerated unamortized debt discount [Member]
Senior Unsecured Notes [Line Items]
Gain on Extinguishment of Debt, Non Cash Portion			6,100
Senior Unsecured Notes and 1.50% Senior Unsecured Convertible Notes due 2021
Senior Unsecured Notes [Line Items]
Senior Unsecured Notes, exchanged or repurchased face amount			$ 718,911
[1]	(1) The Company’s 2021 Senior Convertible Notes became secured in the second quarter of 2020 upon closing of the Exchange Offers. Please refer to Note 5 - Long-Term Debt for additional information.
[2]	(2) As discussed above, as required by the 2021 Notes Indenture and as permitted by the Credit Agreement, as the Company issued Permitted Second Lien Debt upon the closing of the Exchange Offers, its remaining 2021 Senior Convertible Notes contemporaneously became secured.
[3]	(1) Unamortized deferred financing costs attributable to the 2021 Senior Convertible Notes include $13.9 million related to the unamortized debt discount as of December 31, 2019.

Capitalized Interest (Details)

Capitalized Interest (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Debt Disclosure [Abstract]
Capitalized interest costs	$ 4.1	$ 5	$ 6.8	$ 9.9

Commitments (Details)

Commitments (Details) - USD ($) $ in Millions	Jul. 30, 2020	Jun. 30, 2020
Minimum [Member]
Commitments and Contingencies [Line Items]
Potential penalty for not meeting minimum drilling and completion requirements		$ 0
Potential Penalty for not Meeting Minimum Drilling and Completion Counts		0
Maximum [Member]
Commitments and Contingencies [Line Items]
Potential penalty for not meeting minimum drilling and completion requirements		39.5
Potential Penalty for not Meeting Minimum Drilling and Completion Counts		$ 11.5
Drilling Rig Leasing Contracts [Member] | Subsequent Event [Member]
Commitments and Contingencies [Line Items]
Contractual Obligation	$ 17.6
Early Termination Penalty for Rig Contract Cancellation	$ 9

Compensation Plans_ Stock Based

Compensation Plans: Stock Based (Details) $ in Millions	Jul. 01, 2020shares	Jun. 30, 2020USD ($)shares	Jun. 30, 2020USD ($)shares	Jun. 30, 2019USD ($)shares	Jun. 30, 2020USD ($)shares	Jun. 30, 2019USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant		4,200,000	4,200,000		4,200,000
Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued to directors			267,576	96,719
Performance Shares (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award Vesting Period (on non-printing section)		3 years
Stock-based compensation expense | $			$ 2.8	$ 2.9	$ 5.4	$ 5.7
Unrecognized stock based compensation expense | $		$ 10	$ 10		$ 10
Performance Shares (PSUs) | Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Issued in Period	485,060
Shares Withheld for Tax Withholding Obligation	215,451
Multiplier Applied to PSU Awards at Settlement Sub Event	0.9
Performance Shares (PSUs) | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Multiplier applied to PSU awards at settlement		0	0		0
Performance Shares (PSUs) | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Multiplier applied to PSU awards at settlement		2	2		2
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award Vesting Period (on non-printing section)		3 years
Stock-based compensation expense | $			$ 2.7	$ 2.8	$ 5.3	$ 5.5
Unrecognized stock based compensation expense | $		$ 10.8	$ 10.8		$ 10.8
Number of shares represented by each RSU		1	1		1
Restricted Stock Units (RSUs) | Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSUs settled, awards granted in previous years	587,088
Shares Issued in Period	420,562
Shares Withheld for Tax Withholding Obligation	166,526

Employee Stock Purchase Plan (D

Employee Stock Purchase Plan (Details) - Employee Stock Purchase Plan [Member] - USD ($)	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum Employee Subscription Rate	15.00%
Maximum Employee Subscription	$ 25,000
Purchase Price of Common Stock, Percent	85.00%
Issuance of common stock under Employee Stock Purchase Plan (Shares)	297,013	184,079
Proceeds, Issuance of Shares, Share-based Payment Arrangement, Excluding Option Exercised	$ 947,000	$ 2,000,000

Pension Benefits (Details)

Pension Benefits (Details) - USD ($) $ in Thousands	Jul. 30, 2020	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Components of Net Periodic Benefit Costs for the Pension Plans
Service cost		$ 863	$ 1,108	$ 2,258	$ 2,791
Interest cost		480	739	1,178	1,395
Expected return on plan assets that reduces periodic pension benefit cost		(474)	(321)	(867)	(787)
Amortization of prior service cost		5	5	9	9
Amortization of net actuarial loss		235	147	475	479
Net periodic benefit cost		$ 1,109	$ 1,678	$ 3,053	$ 3,887
Pension plans, net gain (loss) amortization threshold		10.00%		10.00%
Subsequent Event [Member]
Components of Net Periodic Benefit Costs for the Pension Plans
Employer contributions	$ 4,600

Earnings per Share (Details)

Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Jun. 17, 2020
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Anti-dilutive securities excluded from earnings per share	701,000		0		877,000	715,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights							5,900,000
Exercise Price of Warrants							$ 0.01
Incremental Common Shares Attributable to Dilutive Effect of Warrants					0
Warrants Percent of Outstanding Stock							5.00%
Calculation of basic and diluted earnings per share
Net income (loss)	$ (89,252)	$ (411,895)	$ 50,388	$ (177,568)	$ (501,147)	$ (127,180)
Basic weighted-average common shares outstanding	113,008,000		112,262,000		113,015,000	112,257,000
Dilutive effect of non-vested RSUs and contingent PSUs	0		670,000		0	0
Diluted weighted-average common shares outstanding	113,008,000		112,932,000		113,015,000	112,257,000
Basic net income (loss) per common share	$ (0.79)		$ 0.45		$ (4.43)	$ (1.13)
Diluted net income (loss) per common share	$ (0.79)		0.45		$ (4.43)	(1.13)
1.50% Senior Unsecured Convertible Notes Due 2021 [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Senior Convertible Notes, conversion price			$ 40.50			$ 40.50

Derivative Financial Instrume_3

Derivative Financial Instruments (Details) bbl in Thousands, BTU in Billions		Jul. 30, 2020BTU$ / Barrels$ / EnergyContentbbl	Jun. 30, 2020BTU$ / Barrels$ / EnergyContentbbl
NYMEX Oil Swap Contract Third Quarter, 2020 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			3,361
Derivative, Swap Type, Weighted-Average Contract Price | $ / Barrels			56.43
NYMEX Oil Swap Contract Fourth Quarter, 2020 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			4,397
Derivative, Swap Type, Weighted-Average Contract Price | $ / Barrels			57.03
NYMEX Oil Swap Contract, 2021 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			13,467
Derivative, Swap Type, Weighted-Average Contract Price | $ / Barrels			39.65
NYMEX Oil Swap Contract, 2022
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			1,276
Derivative, Swap Type, Weighted-Average Contract Price | $ / Barrels			41.75
NYMEX Oil Swap Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			22,501
NYMEX Oil Collar Contract Third Quarter, 2020 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			1,252
Derivative, Weighted-Average Floor Price | $ / Barrels			55
Derivative, Weighted-Average Ceiling Price | $ / Barrels			62.90
NYMEX Oil Collar Contract Fourth Quarter, 2020 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			610
Derivative, Weighted-Average Floor Price | $ / Barrels			55
Derivative, Weighted-Average Ceiling Price | $ / Barrels			61.90
NYMEX Oil Collar Contract, 2021 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			329
Derivative, Weighted-Average Floor Price | $ / Barrels			55
Derivative, Weighted-Average Ceiling Price | $ / Barrels			56.70
NYMEX Oil Collar Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			2,191
NYMEX Oil Calendar Month Average Roll Differential Contract Third Quarter, 2020
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			3,077
Derivative, Roll Differential Swap Type, Weighted-Average Contract Price | $ / Barrels			(1.34)
NYMEX Oil Calendar Month Average Roll Differential Fourth Quarter, 2020
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			2,503
Derivative, Roll Differential Swap Type, Weighted-Average Contract Price | $ / Barrels			(1.18)
NYMEX Oil Calendar Month Average Roll Differential Contract, 2021
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			4,002
Derivative, Roll Differential Swap Type, Weighted-Average Contract Price | $ / Barrels			(0.52)
NYMEX Oil Calendar Month Average Roll Differential Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			9,582
WTI Midland NYMEX WTI [Member] | Oil Basis Swap Contract Third Quarter, 2020 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			3,607
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price | $ / Barrels	[1]		(0.62)
WTI Midland NYMEX WTI [Member] | Oil Basis Swap Contract Fourth Quarter, 2020 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			4,087
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price | $ / Barrels	[1]		(0.38)
WTI Midland NYMEX WTI [Member] | Oil Basis Swap Contract, 2021 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			11,527
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price | $ / Barrels	[1]		0.87
WTI Midland NYMEX WTI [Member] | Oil Basis Swap Contract, 2022 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			9,500
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price | $ / Barrels	[1]		1.15
WTI Midland NYMEX WTI [Member] | Oil Basis Swap [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			28,721
NYMEX WTI ICE Brent [Member] | Oil Basis Swap Contract Third Quarter, 2020 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			920
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price | $ / Barrels	[2]		(8.01)
NYMEX WTI ICE Brent [Member] | Oil Basis Swap Contract Fourth Quarter, 2020 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			920
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price | $ / Barrels	[2]		(8.01)
NYMEX WTI ICE Brent [Member] | Oil Basis Swap Contract, 2021 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			3,650
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price | $ / Barrels	[2]		(7.86)
NYMEX WTI ICE Brent [Member] | Oil Basis Swap Contract, 2022 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			3,650
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price | $ / Barrels	[2]		(7.78)
NYMEX WTI ICE Brent [Member] | Oil Basis Swap [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			9,140
IF HSC [Member] | Gas Swaps Contract Third Quarter, 2020 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent			2.41
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU			4,493
IF HSC [Member] | Gas Swaps Contract Fourth Quarter, 2020 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent			2.39
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU			9,327
IF HSC [Member] | Gas Swaps Contract, 2021 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent			2.38
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU			41,736
IF HSC [Member] | Gas Swaps Contract, 2022 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent			2.23
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU			6,104
IF HSC [Member] | Gas Swaps Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU	[3]		61,660
WAHA [Member] | Gas Swaps Contract Third Quarter, 2020 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent			1.08
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU			4,628
WAHA [Member] | Gas Swaps Contract Fourth Quarter, 2020 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent			1.21
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU			4,872
WAHA [Member] | Gas Swaps Contract, 2021 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent			1.52
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU			20,676
WAHA [Member] | Gas Swaps Contract, 2022 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent			1.90
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU			2,681
WAHA [Member] | Gas Swaps Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU	[3]		32,857
IF WAHA [Member]
Derivative Financial Instruments
Index percent of natural gas fixed swaps			71.00%
GD WAHA [Member]
Derivative Financial Instruments
Index percent of natural gas fixed swaps			29.00%
OPIS Propane Mont Belvieu Non-TET [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			875
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Third Quarter, 2020 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			409
Derivative, Swap Type, Weighted-Average Contract Price | $ / Barrels			22.33
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Fourth Quarter, 2020 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			466
Derivative, Swap Type, Weighted-Average Contract Price | $ / Barrels			22.29
Subsequent Event [Member] | NYMEX Oil Swap Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		3,700
Derivative, Swap Type, Weighted-Average Contract Price | $ / Barrels		43.29
Subsequent Event [Member] | WTI Midland NYMEX WTI [Member]
Derivative Financial Instruments
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price | $ / Barrels		0.21
Subsequent Event [Member] | WTI Midland NYMEX WTI [Member] | Oil Basis Swap [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		2,300
Subsequent Event [Member] | GD WAHA [Member] | Gas Swaps Contracts [Member]
Derivative Financial Instruments
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent		1.99
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		920
Subsequent Event [Member] | OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		400
Derivative, Swap Type, Weighted-Average Contract Price | $ / Barrels		19.74
[1]	(1) Represents the price differential between WTI Midland (Midland, Texas) and NYMEX WTI (Cushing, Oklahoma).
[2]	(2) Represents the price differential between NYMEX WTI (Cushing, Oklahoma) and ICE Brent (North Sea).
[3]	(1) The Company has natural gas swaps in place that settle against Inside FERC Houston Ship Channel (“IF HSC”), Inside FERC West Texas (“IF WAHA”), and Platt’s Gas Daily West Texas (“GD WAHA”). As of June 30, 2020, WAHA volumes were comprised of 71 percent IF WAHA and 29 percent GD WAHA.

Derivative Financial Instrume_4

Derivative Financial Instruments Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2020		Dec. 31, 2019
Fair value of derivative assets and liabilities
Derivative, fair value, net	$ 183,700		$ 21,500
Derivative assets, current	211,582		55,184
Derivative assets, noncurrent	34,390		20,624
Total derivative assets	245,972		75,808
Derivative liabilities, current	38,250		50,846
Derivatives liabilities, noncurrent	24,028		3,444
Total derivative liabilities	(62,278)		(54,290)
Derivative asset, amounts not offset in the accompanying balance sheets	(62,278)		(35,075)
Derivative liabilities, amounts not offset in the accompanying balance sheets	62,278		35,075
Derivative asset, fair value, net amounts	183,694		40,733
Derivative liabilities, fair value, net amounts	0		(19,215)
Not Designated as Hedging Instrument [Member]
Fair value of derivative assets and liabilities
Derivative assets, current	211,582		55,184
Derivative assets, noncurrent	34,390		20,624
Derivative liabilities, current	38,250		50,846
Derivatives liabilities, noncurrent	24,028		3,444
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Not Designated as Hedging Instrument [Member]
Fair value of derivative assets and liabilities
Total derivative assets	245,972	[1]	75,808	[2]
Total derivative liabilities	$ 62,278	[1]	$ 54,290	[2]
[1]	(1) This represents a financial asset or liability that is measured at fair value on a recurring basis.
[2]	(1) This represents a financial asset or liability that is measured at fair value on a recurring basis.

Derivative Financial Instrume_5

Derivative Financial Instruments Gains and Losses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Derivative Instruments, (Gain) Loss [Line Items]
Derivative settlement (gain) loss	$ (142,528)	$ (4,090)	$ (215,965)	$ 879
Net derivative (gain) loss	167,200	(79,655)	(378,140)	97,426
Oil Contracts [Member]
Derivative Instruments, (Gain) Loss [Line Items]
Derivative settlement (gain) loss	(138,606)	10,689	(192,188)	12,058
Net derivative (gain) loss	151,250	(34,552)	(391,290)	151,245
Gas Contracts [Member]
Derivative Instruments, (Gain) Loss [Line Items]
Derivative settlement (gain) loss	(1,054)	(5,668)	(15,679)	(1,534)
Net derivative (gain) loss	8,261	(25,996)	14,989	(32,109)
NGL Contracts [Member]
Derivative Instruments, (Gain) Loss [Line Items]
Derivative settlement (gain) loss	(2,868)	(9,111)	(8,098)	(9,645)
Net derivative (gain) loss	$ 7,689	$ (19,107)	$ (1,839)	$ (21,710)

Credit Facility and Derivative

Credit Facility and Derivative Counterparties (Details)	Jun. 30, 2020
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) - USD ($) $ / shares in Units, shares in Thousands		Jun. 17, 2020	Jun. 30, 2020		Jun. 30, 2019	Jun. 30, 2020		Jun. 30, 2019	Mar. 31, 2020	Dec. 31, 2019
Assets
Derivative Assets, Fair Value, Gross Asset			$ 245,972,000			$ 245,972,000				$ 75,808,000
Total property and equipment, net, recorded at fair value			0			0				0
Liabilities
Derivative Liability, Fair Value, Gross Liability			62,278,000			62,278,000				54,290,000
Oil and Gas Property [Abstract]
Impairment of proved oil and gas properties and related support equipment			0		$ 0	956,700,000		$ 0
Abandonment and impairment of unproved properties	[1]		8,800,000		12,400,000	41,900,000		18,800,000
Impairment	[2]		8,750,000		$ 12,417,000	998,513,000		$ 18,755,000
Debt Instrument, Fair Value Disclosure [Abstract]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		5,900
Warrants Percent of Outstanding Stock		5.00%
Exercise Price of Warrants		$ 0.01
Warrant Triggering Date - Amount		$ 1,000,000,000
Issuance of Warrants			$ 21,520,000			$ 21,500,000
6.125% Senior Unsecured Notes due 2022 [Member]
Debt Instrument, Fair Value Disclosure [Abstract]
Senior Notes, interest rate, stated percentage			6.125%			6.125%
Senior Notes, Principal amount			$ 294,346,000			$ 294,346,000				476,796,000
Long-term Debt, Fair Value			$ 214,873,000			$ 214,873,000				481,564,000
5.0% Senior Unsecured Notes due 2024 [Member]
Debt Instrument, Fair Value Disclosure [Abstract]
Senior Notes, interest rate, stated percentage			5.00%			5.00%
Senior Notes, Principal amount			$ 344,661,000			$ 344,661,000				500,000,000
Long-term Debt, Fair Value			$ 190,477,000			$ 190,477,000				479,815,000
5.625% Senior Unsecured Notes due 2025 [Member]
Debt Instrument, Fair Value Disclosure [Abstract]
Senior Notes, interest rate, stated percentage			5.625%			5.625%
Senior Notes, Principal amount			$ 349,118,000			$ 349,118,000				500,000,000
Long-term Debt, Fair Value			$ 185,033,000			$ 185,033,000				475,835,000
6.75% Senior Unsecured Notes due 2026 [Member]
Debt Instrument, Fair Value Disclosure [Abstract]
Senior Notes, interest rate, stated percentage			6.75%			6.75%
Senior Notes, Principal amount			$ 419,235,000			$ 419,235,000				500,000,000
Long-term Debt, Fair Value			$ 213,286,000			$ 213,286,000				494,860,000
6.625% Senior Unsecured Notes due 2027 [Member]
Debt Instrument, Fair Value Disclosure [Abstract]
Senior Notes, interest rate, stated percentage			6.625%			6.625%
Senior Notes, Principal amount			$ 416,791,000			$ 416,791,000				500,000,000
Long-term Debt, Fair Value			$ 206,566,000			$ 206,566,000				493,750,000
10.0% Senior Secured Notes due 2025
Debt Instrument, Fair Value Disclosure [Abstract]
Senior Notes, interest rate, stated percentage			10.00%			10.00%
Senior Notes, Principal amount		$ 446,700,000	$ 446,675,000			$ 446,675,000				0
Long-term Debt, Fair Value			$ 424,064,000			$ 424,064,000				0
1.50% Senior Unsecured Convertible Notes Due 2021 [Member]
Debt Instrument, Fair Value Disclosure [Abstract]
Senior Notes, interest rate, stated percentage		1.50%	1.50%			1.50%
Senior Notes, Principal amount	[3],[4]		$ 0			$ 0				172,500,000
Long-term Debt, Fair Value	[3]		$ 0			$ 0				164,430,000
1.50% Senior Secured Convertible Notes Due 2021 [Member]
Debt Instrument, Fair Value Disclosure [Abstract]
Senior Notes, interest rate, stated percentage			1.50%			1.50%
Senior Notes, Principal amount	[3]		$ 65,485,000	[5]		$ 65,485,000	[5]			0
Long-term Debt, Fair Value	[3]		60,246,000			60,246,000				0
Not Designated as Hedging Instrument [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets
Derivative Assets, Fair Value, Gross Asset			0	[6]		0	[6]			0	[7]
Liabilities
Derivative Liability, Fair Value, Gross Liability			0	[6]		0	[6]			0	[7]
Not Designated as Hedging Instrument [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets
Derivative Assets, Fair Value, Gross Asset			245,972,000	[6]		245,972,000	[6]			75,808,000	[7]
Liabilities
Derivative Liability, Fair Value, Gross Liability			(62,278,000)	[6]		(62,278,000)	[6]			(54,290,000)	[7]
Not Designated as Hedging Instrument [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets
Derivative Assets, Fair Value, Gross Asset			0	[6]		0	[6]			0	[7]
Liabilities
Derivative Liability, Fair Value, Gross Liability			$ 0	[6]		$ 0	[6]			$ 0	[7]
Measurement Input, Discount Rate [Member] | Fair Value, Nonrecurring [Member]
Oil and Gas Property [Abstract]
Present value calculation discount rate									11.00%
[1]	(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 June 30, 2020, and December 31, 2019, are recorded at carrying value.
[2]	(2) Amounts may not calculate due to rounding.
[3]	(1) The Company’s 2021 Senior Convertible Notes became secured in the second quarter of 2020 upon closing of the Exchange Offers. Please refer to Note 5 - Long-Term Debt for additional information.
[4]	(2) As discussed above, as required by the 2021 Notes Indenture and as permitted by the Credit Agreement, as the Company issued Permitted Second Lien Debt upon the closing of the Exchange Offers, its remaining 2021 Senior Convertible Notes contemporaneously became secured.
[5]	(1) As discussed above, as required by the 2021 Notes Indenture and as permitted by the Credit Agreement, as the Company issued Permitted Second Lien Debt upon the closing of the Exchange Offers, its remaining 2021 Senior Convertible Notes contemporaneously became secured
[6]	(1) This represents a financial asset or liability that is measured at fair value on a recurring basis.
[7]	(1) This represents a financial asset or liability that is measured at fair value on a recurring basis.

Lease Parameter (Details)

Lease Parameter (Details)	6 Months Ended
	Jun. 30, 2020
Lessee, Lease, Description [Line Items]
Weighted-average remaining lease term	3 years
Optional extension period	10 years
Minimum [Member]
Lessee, Lease, Description [Line Items]
Remaining lease term	1 year
Maximum [Member]
Lessee, Lease, Description [Line Items]
Remaining lease term	6 years

Components of total lease cost

Components of total lease cost (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Lessee Disclosure [Abstract]
Total lease cost		$ 62,219	$ 139,762	$ 134,959	$ 315,066
Operating lease cost		4,453	11,479	11,287	20,458
Short-term lease cost	[1]	36,630	102,085	80,202	237,002
Variable lease cost	[2]	21,136	26,198	43,470	57,606
Operating cash flows from operating leases				6,065	5,966
Investing cash flows from operating leases				6,188	14,808
Right-of-use assets obtained in exchange for new operating lease liabilities		$ 745	$ 10,500	$ 745	$ 22,700
[1]	(1) Costs associated with short-term lease agreements relate primarily to operational activities where underlying lease terms are less than one year. This amount is significant as it includes drilling and completion activities and field equipment rentals, most of which are contracted for 12 months or less. It is expected that this amount will fluctuate primarily with the number of drilling rigs and completion crews the Company is operating under short-term agreements.
[2]	(2) Variable lease payments include additional payments made that were not included in the initial measurement of the ROU asset and corresponding liability for lease agreements with terms longer than 12 months. Variable lease payments relate to the actual volumes transported under certain midstream agreements, actual usage associated with drilling rigs, completion crews, and vehicles, and variable utility costs associated with the Company’s leased office space. Fluctuations in variable lease payments are driven by actual volumes delivered and the number of drilling rigs and completion crews operating under long-term agreements.

Operating lease liability matur

Operating lease liability maturities (Details) $ in Thousands	Jun. 30, 2020USD ($)
Lessee Disclosure [Abstract]
Operating lease liability payments, due 2020 (remaining after June 30, 2020)	$ 7,161
Operating lease liability payments, due 2021	12,938
Operating lease liability payments, due 2022	5,948
Operating lease liability payments, due 2023	3,602
Operating lease liability payments, due 2024	2,081
Operating lease liability payments, due thereafter	1,640
Total lease payments	33,370
Imputed interest	(3,340)	[1]
Total operating lease liability	$ 30,030
Weighted-average discount rate	6.90%
[1]	(1) The weighted-average discount rate used to determine the operating lease liability as of June 30, 2020, was 6.9 percent.

Balance Sheet information relat

Balance Sheet information related to operating leases (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Lessee Disclosure [Abstract]
Other noncurrent assets	$ 27,778	$ 39,717
Other current liabilities	12,597	19,189
Other noncurrent liabilities	$ 17,433	$ 23,137