Chord Energy (WLLBW) 10-K 25 Feb 21 2020 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 17, 2021	Jun. 30, 2020
Document and Entity Information
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	001-31899
Entity Registrant Name	WHITING PETROLEUM CORP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-0098515
Entity Address, Address Line One	1700 Lincoln Street, Suite 4700
Entity Address, City or Town	Denver
Entity Address, State or Province	CO
Entity Address, Postal Zip Code	80203-4547
City Area Code	303
Local Phone Number	837-1661
Title of 12(b) Security	Common Stock
Trading Symbol	WLL
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Bankruptcy Proceedings, Reporting Current	true
Entity Common Stock, Shares Outstanding		39,000,022
Entity Public Float			$ 102,673,000
Entity Central Index Key	0001255474
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 25,607	$ 8,652
Restricted cash	2,760
Accounts receivable trade, net	142,830	308,249
Prepaid expenses and other	19,224	14,082
Total current assets	190,421	330,983
Property and equipment:
Oil and gas properties, successful efforts method	1,812,601	12,812,007
Other property and equipment	74,064	178,689
Total property and equipment	1,886,665	12,990,696
Less accumulated depreciation, depletion and amortization	(73,869)	(5,735,239)
Total property and equipment, net	1,812,796	7,255,457
Other long-term assets	40,723	50,281
TOTAL ASSETS	2,043,940	7,636,721
Current liabilities:
Accounts payable trade	23,697	80,100
Revenues and royalties payable	151,196	202,010
Accrued capital expenditures	20,155	64,263
Accrued liabilities and other	476	53,928
Accrued lease operating expenses	23,457	38,262
Accrued interest	36,170	53,597
Taxes payable	11,997	26,844
Derivative liabilities	49,485	10,285
Accrued employee compensation and benefits	5,361	21,125
Total current liabilities	321,994	550,414
Long-term debt	360,000	2,799,885
Asset retirement obligations	91,864	131,208
Operating lease obligations	17,415	31,722
Deferred income taxes		73,593
Other long-term liabilities	23,863	24,928
Total liabilities	815,136	3,611,750
Commitments and contingencies
Equity (Deficit):
Common stock	38	92
Additional paid-in capital	1,189,693	6,409,991
Accumulated earnings (deficit)	39,073	(2,385,112)
Total equity	1,228,804	4,024,971
TOTAL LIABILITIES AND EQUITY	$ 2,043,940	$ 7,636,721

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
CONSOLIDATED BALANCE SHEETS [Abstract]
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	500,000,000	225,000,000
Common stock, shares issued	38,051,125	91,743,571
Common stock, shares outstanding	38,051,125	91,326,469

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2020	Aug. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
OPERATING REVENUES
Oil, NGL and natural gas sales	$ 273,358	$ 459,004	$ 1,572,245	$ 2,081,414
OPERATING EXPENSES
Lease operating expenses	73,981	158,228	328,427	311,895
Transportation, gathering, compression and other	8,038	22,266	42,438	48,105
Production and ad valorem taxes	24,150	41,204	138,212	171,823
Depreciation, depletion and amortization	77,502	338,757	816,488	781,329
Exploration and impairment	7,865	4,184,830	54,738	67,368
General and administrative	21,734	91,816	132,609	123,250
Derivative (gain) loss, net	24,714	(181,614)	53,769	17,170
Loss on sale of properties	395	927	1,964	1,949
Amortization of deferred gain on sale		(5,116)	(9,069)	(11,354)
Total operating expenses	238,379	4,651,298	1,559,576	1,511,535
INCOME (LOSS) FROM OPERATIONS	34,979	(4,192,294)	12,669	569,879
OTHER INCOME (EXPENSE)
Interest expense	(8,080)	(73,054)	(191,047)	(197,474)
Gain (loss) on extinguishment of debt		25,883	7,830	(31,968)
Interest income and other	136	211	1,602	3,430
Reorganization items, net		217,419
Total other income (expense)	(7,944)	170,459	(181,615)	(226,012)
INCOME (LOSS) BEFORE INCOME TAXES	27,035	(4,021,835)	(168,946)	343,867
INCOME TAX EXPENSE (BENEFIT)
Current	2,463	2,718
Deferred	(14,501)	(59,092)	72,220	1,373
Total income tax benefit	(12,038)	(56,374)	72,220	1,373
NET INCOME (LOSS)	$ 39,073	$ (3,965,461)	$ (241,166)	$ 342,494
INCOME (LOSS) PER COMMON SHARE
Basic (in dollars per share)	$ 1.03	$ (43.37)	$ (2.64)	$ 3.77
Diluted (in dollars per share)	$ 1.03	$ (43.37)	$ (2.64)	$ 3.73
WEIGHTED AVERAGE SHARES OUTSTANDING
Basic (in shares)	38,080	91,423	91,285	90,953
Diluted (in shares)	38,119	91,423	91,285	91,869

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2020	Aug. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)	$ 39,073	$ (3,965,461)	$ (241,166)	$ 342,494
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, depletion and amortization	77,502	338,757	816,488	781,329
Deferred income tax expense (benefit)	(14,501)	(59,092)	72,220	1,373
Amortization of debt issuance costs, debt discount and debt premium	1,258	13,535	28,340	30,700
Stock-based compensation	515	4,188	7,721	12,669
Amortization of deferred gain on sale		(5,116)	(9,069)	(11,354)
Loss on sale of properties	395	927	1,964	1,949
Oil and gas property impairments	3,233	4,161,885	17,866	45,288
(Gain) loss on extinguishment of debt		(25,883)	(7,830)	31,968
Non-cash derivative (gain) loss	20,772	(136,131)	78,626	(139,831)
Non-cash reorganization items, net		(274,588)
Payment for settlement of commodity derivative contract				(61,036)
Other, net	(1,761)	(223)	(1,352)	(6,706)
Changes in current assets and liabilities:
Accounts receivable trade, net	(7,100)	181,416	(24,343)	(11,571)
Prepaid expenses and other	1,989	(5,491)	7,165	4,026
Accounts payable trade and accrued liabilities	(42,922)	(46,734)	40,117	11,368
Revenues and royalties payable	5,690	(56,504)	(26,274)	56,751
Taxes payable	(1,975)	(12,872)	(4,513)	2,586
Net cash provided by operating activities	82,168	112,613	755,960	1,092,003
CASH FLOWS FROM INVESTING ACTIVITIES
Drilling and development capital expenditures	(33,987)	(238,456)	(793,365)	(813,981)
Acquisition of oil and gas properties	(166)	(493)	(6,031)	(142,723)
Other property and equipment	(2,486)	(1,072)	(6,451)	(1,096)
Proceeds from sale of properties	532	29,273	72,000	4,746
Net cash provided by (used in) investing activities	(36,107)	(210,748)	(733,847)	(953,054)
CASH FLOWS FROM FINANCING ACTIVITIES
Redemption of 5.0% Senior Notes due 2019				(990,023)
Repurchase of 1.25% Convertible Senior Notes due 2020		(52,890)	(297,000)
Repurchase of 5.75% Senior Notes due 2021			(95,279)
Debt issuance and extinguishment costs		(12,784)	(819)	(10,709)
Restricted stock used for tax withholdings		(307)	(3,830)	(4,744)
Proceeds from stock options exercised				755
Principal payments on finance lease obligations	(1,773)	(3,198)	(5,140)
Net cash provided by (used in) financing activities	(67,101)	138,890	(27,068)	(1,004,721)
NET CHANGE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(21,040)	40,755	(4,955)	(865,772)
CASH, CASH EQUIVALENTS AND RESTRICTED CASH
Beginning of period	49,407	8,652	13,607	879,379
End of period	28,367	49,407	8,652	13,607
SUPPLEMENTAL CASH FLOW DISCLOSURES
Income taxes paid (refunded), net	6,209	(1,028)	(7,508)	(32)
Interest paid, net of amounts capitalized	6,322	80,220	163,859	152,665
Cash paid for reorganization items	22,248	33,238
NONCASH INVESTING AND FINANCING ACTIVITIES
Accrued capital expenditures and accounts payable related to property additions	21,531	26,796	86,088	90,358
Leasehold improvements paid for by third party lessor under office lease agreement	99	49	10,422
Derivative termination settlement payments used to repay borrowings under Predecessor Credit Agreement		157,741
Predecessor Credit Agreement [Member]
CASH FLOWS FROM FINANCING ACTIVITIES
Borrowings under credit agreement		1,185,000	2,650,000	2,214,265
Repayments of borrowings under credit agreement		(1,402,259)	$ (2,275,000)	$ (2,214,265)
Exit Credit Agreement [Member]
CASH FLOWS FROM FINANCING ACTIVITIES
Borrowings under credit agreement	272,500	$ 425,328
Repayments of borrowings under credit agreement	$ (337,828)

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical)	Dec. 31, 2020	Aug. 31, 2020	Dec. 31, 2019	Jan. 31, 2018
5.0% Senior Notes due 2019 [Member]
Interest Rate (as a percent)			5.00%	5.00%
1.25% Convertible Senior Notes due 2020 [Member]
Interest Rate (as a percent)	1.25%	1.25%	1.25%
5.75% Senior Notes due 2021 [Member]
Interest Rate (as a percent)	5.75%	5.75%	5.75%

CONSOLIDATED STATEMENTS OF EQUI

CONSOLIDATED STATEMENTS OF EQUITY (DEFICIT) - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Total
BALANCES at Dec. 31, 2017	$ 92	$ 6,405,490	$ (2,486,440)	$ 3,919,142
BALANCES (in shares) at Dec. 31, 2017	92,095
Increase (Decrease) in Shareholders' Equity
Net income (loss)			342,494	342,494
Exercise of stock options		755		755
Exercise of stock options (in shares)	16
Restricted stock issued (in shares)	451
Restricted stock forfeited (in shares)	(351)
Restricted stock used for tax withholdings		(4,744)		(4,744)
Restricted stock used for tax withholdings (in shares)	(144)
Stock-based compensation		12,669		12,669
BALANCES at Dec. 31, 2018	$ 92	6,414,170	(2,143,946)	4,270,316
BALANCES (in shares) at Dec. 31, 2018	92,067
Increase (Decrease) in Shareholders' Equity
Net income (loss)			(241,166)	(241,166)
Adjustment to equity component of Convertible Senior Notes upon extinguishment		(8,070)		(8,070)
Restricted stock issued (in shares)	113
Restricted stock forfeited (in shares)	(286)
Restricted stock used for tax withholdings		(3,830)		(3,830)
Restricted stock used for tax withholdings (in shares)	(150)
Stock-based compensation		7,721		7,721
BALANCES at Dec. 31, 2019	$ 92	6,409,991	(2,385,112)	4,024,971
BALANCES (in shares) at Dec. 31, 2019	91,744
Increase (Decrease) in Shareholders' Equity
Net income (loss)			(3,965,461)	(3,965,461)
Adjustment to equity component of Convertible Senior Notes upon extinguishment		(3,461)		(3,461)
Restricted stock issued (in shares)	194
Restricted stock forfeited (in shares)	(238)
Restricted stock used for tax withholdings		(308)		(308)
Restricted stock used for tax withholdings (in shares)	(58)
Stock-based compensation		4,188		4,188
Cancellation of Predecessor stock	$ (92)	(6,410,410)	6,350,573	(59,929)
Cancellation of Predecessor stock (in shares)	(91,642)
BALANCES at Aug. 31, 2020
BALANCES (in shares) at Aug. 31, 2020
Increase (Decrease) in Shareholders' Equity
Issuance of Successor stock	$ 38	1,159,818		$ 1,159,856
Issuance of Successor stock (in shares)	38,051			38,051,125
Issuance of Successor warrants		29,360		$ 29,360
BALANCES at Aug. 31, 2020
BALANCES (in shares) at Aug. 31, 2020
Increase (Decrease) in Shareholders' Equity
Net income (loss)			39,073	39,073
Stock-based compensation		515		515
BALANCES at Dec. 31, 2020	$ 38	1,189,693	$ 39,073	1,228,804
BALANCES (in shares) at Dec. 31, 2020	38,051
Increase (Decrease) in Shareholders' Equity
Balance Successor	$ 38	$ 1,189,178		$ 1,189,216
Balance Successor, Shares	38,051

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2020
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Description of Operations Voluntary Reorganization under Chapter 11 of the Bankruptcy Code Upon emergence, the Company adopted fresh start accounting in accordance with FASB ASC Topic 852 – Reorganizations During the Current Predecessor YTD Period, the Company applied ASC 852 in preparing the consolidated financial statements, which requires distinguishing transactions associated with the reorganization separate from activities related to the ongoing operations of the business. Accordingly, pre-petition liabilities that could have been impacted by the chapter 11 proceedings were classified as liabilities subject to compromise. Additionally, certain expenses, realized gains and losses and provisions for losses that were realized or incurred during the Chapter 11 Cases, including adjustments to the carrying value of certain assets and indebtedness were recorded as reorganization items, net in the consolidated statements of operations for the relevant Predecessor periods. Ability to Continue as a Going Concern Basis of Presentation of Consolidated Financial Statements Reclassifications Use of Estimates — Cash, Cash Equivalents and Restricted Cash — The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheets and statements of cash flows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ ​ December 31, ​ ​ December 31, ​ ​ 2020 ​ ​ 2019 Cash and cash equivalents ​ $ 25,607 ​ ​ $ 8,652 Restricted cash ​ ​ 2,760 ​ ​ ​ - Total cash, cash equivalents and restricted cash ​ $ 28,367 ​ ​ $ 8,652 ​ Restricted cash as of December 31, 2020 shown in the table above consists of funds remaining in a professional fee escrow account that were reserved to pay certain professional fees upon emergence from the Chapter 11 Cases (the “Professional Fee Escrow Account”). Accounts Receivable Trade The Company routinely evaluates expected credit losses for all material trade and other receivables to determine if an allowance for credit losses is warranted. Expected credit losses are estimated based on (i) historic loss experience for pools of receivable balances with similar characteristics, (ii) the length of time balances have been outstanding and (iii) the economic status of each counterparty. These loss estimates are then adjusted for current and expected future economic conditions, which may include an assessment of the probability of non-payment, financial distress or expected future commodity prices and the impact that any current or future conditions could have on a counterparty’s credit quality and liquidity. As of December 31, 2020 (Successor), the Company had an immaterial allowance for credit losses due to the application of fresh start accounting. As of December 31, 2019 (Predecessor), the Company had an allowance for credit losses of $9 million. Inventories — Oil and Gas Properties Proved. The Company assesses its proved oil and gas properties for impairment whenever events or circumstances indicate that the carrying value of the assets may not be recoverable. Such events include, but are not limited to, declines in commodity prices, increases in operating costs, unfavorable reserve revisions, poor well performance, changes in development plans and potential property divestitures. The impairment test compares undiscounted future net cash flows to the assets’ net book value. These undiscounted cash flows are driven by significant assumptions, including the Company’s expected future development activity, reserve estimates, forecasted pricing, future operating costs, capital expenditures and severance taxes. If the net capitalized costs exceed undiscounted future net cash flows, then the cost of the property is written down to fair value utilizing a discounted future net cash flow analysis. Impairment expense for proved properties totaled $4 billion for the Current Predecessor YTD Period, which is reported in exploration and impairment expense in the consolidated statements of operations. Net carrying values of retired, sold or abandoned properties that constitute less than a complete unit of depreciable property are charged or credited, net of proceeds, to accumulated depreciation, depletion and amortization unless doing so significantly affects the unit-of-production amortization rate, in which case a gain or loss is recognized in income. Gains or losses from the disposal of complete units of depreciable property are recognized to earnings. Unproved. Exploratory. Costs of drilling exploratory wells are initially capitalized, pending determination of whether the well has found proved reserves. If an exploratory well has not found proved reserves, the costs of drilling the well and other associated costs are charged to expense. Costs incurred for exploratory wells that find reserves, which cannot yet be classified as proved, continue to be capitalized if (i) the well has found a sufficient quantity of reserves to justify completion as a producing well and (ii) the Company is making sufficient progress assessing the reserves and the economic and operating viability of the project. If either condition is not met, or if the Company obtains information that raises substantial doubt about the economic or operational viability of the project, the exploratory well costs, net of any salvage value, are expensed. Other Property and Equipment — buildings and leasehold improvements equipment Debt Issuance Costs Debt Discounts and Premiums Derivative Instruments Derivatives and Hedging Cash flows from derivatives used to manage commodity price risk are classified in operating activities along with the cash flows of the underlying hedged transactions. The Company does not enter into derivative instruments for speculative or trading purposes. Refer to the “Derivative Financial Instruments” footnote for further information. Asset Retirement Obligations and Environmental Costs Asset Retirement and Environmental Obligations Liabilities for environmental costs are recorded on an undiscounted basis when it is probable that obligations have been incurred and the amounts can be reasonably estimated. These liabilities are not reduced by possible recoveries from third parties. Deferred Gain on Sale Revenue Recognition Revenue from Contracts with Customers one Taxes collected and remitted to governmental agencies on behalf of customers are not included in revenues or costs and expenses. General and Administrative Expenses Stock-based Compensation Expense 401(k) Plan Acquisition Costs — Maintenance and Repairs Income Taxes Earnings Per Share Industry Segment and Geographic Information Concentration of Credit Risk ​ ​ ​ ​ ​ Year Ended December 31, 2020 Shell Trading (US) Company ​ 14 % Tesoro Crude Oil Co ​ 13 % ​ ​ ​ ​ ​ Year Ended December 31, 2019 Tesoro Crude Oil Co ​ 14 % Philips 66 Company ​ 12 % ​ ​ ​ ​ ​ Year Ended December 31, 2018 United Energy Trading, LLC ​ 17 % Tesoro Crude Oil Co ​ 14 % Philips 66 Company ​ 11 % ​ Commodity derivative contracts held by the Company are with six counterparties, all of which are participants in Whiting’s credit facility and all of which have investment-grade ratings from Moody’s and Standard & Poor’s. As of December 31, 2020, outstanding derivative contracts with Wells Fargo Bank, N.A., Bank of Oklahoma, JP Morgan Chase Bank, N.A. and Citibank, N.A. represented 31%, 23%, 19%, and 18% respectively, of total volumes hedged.

CHAPTER 11 EMERGENCE

CHAPTER 11 EMERGENCE	12 Months Ended
	Dec. 31, 2020
CHAPTER 11 EMERGENCE [Abstract]
CHAPTER 11 EMERGENCE	2. CHAPTER 11 EMERGENCE Plan of Reorganization under Chapter 11 of the Bankruptcy Code — On April 1, 2020, the Debtors commenced the Chapter 11 Cases as described in the “Summary of Significant Accounting Policies” footnote above. On April 23, 2020, the Debtors entered into the RSA with certain holders of the Company’s senior notes to support a restructuring in accordance with the terms set forth in the Plan. On August 14, 2020, the Bankruptcy Court confirmed the Plan. On September 1, 2020 the Debtors satisfied all conditions required for Plan effectiveness and emerged from the Chapter 11 Cases. On the Emergence Date and pursuant to the Plan: (1) The Company amended and restated its certificate of incorporation and bylaws. (2) The Company constituted a new Successor board of directors. (3) The Company appointed a new Chief Executive Officer and a new Chief Financial Officer. (4) The Company issued: ● 36,817,630 shares of the Successor’s common stock pro rata to holders of the Predecessor ’s senior notes, ● 1,233,495 shares of the Successor’s common stock pro rata to holders of the Predecessor’s common stock, ● 4,837,387 Series A Warrants to purchase the same number of shares of the Successor ’s common stock pro rata to holders of the Predecessor’s common stock and ● 2,418,840 Series B Warrants to purchase the same number of shares of the Successor’s common stock pro rata to holders of the Predecessor’s common stock. The Company also reserved 3,070,201 shares of the Successor’s common stock for potential future distribution to certain general unsecured claimants whose claim values were pending resolution in the Bankruptcy Court. In February 2021, the Company issued 948,897 shares out of this reserve to a general unsecured claimant in full settlement of such claimant’s claims pending before the Bankruptcy Court and for rejection damages relating to an executory contract. Refer to the “Subsequent Event” footnote for more information. Any remaining reserved shares that are not distributed to resolve pending claims will be cancelled. In addition, 4,035,885 shares have been reserved for distribution under the Company’s 2020 equity incentive plan, as further detailed in the “Stock-Based Compensation” footnote below. (5) Whiting Petroleum Corporation, as parent guarantor, and Whiting Oil and Gas, as borrower, entered into a reserves-based credit agreement with a syndicate of banks (the “Exit Credit Agreement”) with initial aggregate commitments in the amount of $750 million, with the ability to increase the aggregate commitments by up to an additional $750 million, subject to certain conditions. Refer to the “Long-Term Debt” footnote for more information on the Exit Credit Agreement. The Company utilized borrowings from the Exit Credit Agreement and cash on hand to repay all borrowings and accrued interest outstanding on its pre-emergence credit facility (the “Predecessor Credit Agreement”) as of the Emergence Date, which terminated on that date. (6) The holders of trade claims, administrative expense claims, other secured claims and other priority claims received payment in full in cash upon emergence or through the ordinary course of business after the Emergence Date. Executory Contracts Claims Resolution Process Interest Expense

FRESH START ACCOUNTING

FRESH START ACCOUNTING	12 Months Ended
	Dec. 31, 2020
FRESH START ACCOUNTING [Abstract]
FRESH START ACCOUNTING	3. FRESH START ACCOUNTING Fresh Start In accordance with ASC 852, with the application of fresh start accounting, the Company allocated its reorganization value to its individual assets based on their estimated fair values in conformity with FASB ASC Topic 820 – Fair Value Measurement Business Combinations Reorganization Value The Company’s principal assets are its oil and natural gas properties. The fair value of proved reserves was estimated using an income approach, which was based on the anticipated future cash flows associated with those proved reserves, risked by reserve category and discounted using a weighted average cost of capital rate of 14%. The proved reserve locations included in this analysis were limited to wells included in the Company's five-year development plan. Future prices for the income approach were based on forward strip price curves (adjusted for basis differentials). The fair value of the Company’s unproved reserves was estimated using a combination of income and market approaches. See further discussion below in “Fresh Start Accounting Adjustments.” The following table reconciles the Company’s enterprise value to the implied value of the Successor’s common stock as of September 1, 2020 (in thousands): ​ ​ ​ ​ Enterprise value ​ $ 1,591,887 Plus: Cash and cash equivalents ​ ​ 22,657 Less: Fair value of debt ​ ​ (425,328) Implied value of Successor common stock ​ $ 1,189,216 ​ The following table reconciles the Company’s enterprise value to its reorganization value as of September 1, 2020 (in thousands): ​ ​ ​ ​ Enterprise value ​ $ 1,591,887 Plus: ​ ​ ​ Cash and cash equivalents ​ ​ 22,657 Accounts payable trade ​ ​ 56,432 Revenues and royalties payable ​ ​ 145,506 Other current liabilities ​ ​ 143,790 Asset retirement obligations ​ ​ 121,343 Operating lease obligations ​ ​ 17,839 Deferred income taxes ​ ​ 14,501 Other long-term liabilities ​ ​ 28,773 Reorganization value ​ $ 2,142,728 ​ Although the Company believes the assumptions and estimates used to develop enterprise value and reorganization value are reasonable and appropriate, different assumptions and estimates could materially impact the analysis and resulting conclusions. The assumptions used in estimating these values are inherently uncertain and require judgment. See below under the caption “Fresh Start Adjustments” for additional information regarding assumptions used in the valuation of the Company’s significant assets and liabilities. Condensed Consolidated Balance Sheet at Emergence (in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of September 1, 2020 ​ ​ ​ ​ Reorganization ​ ​ Fresh Start ​ ​ ​ ​ ​ Predecessor ​ Adjustments ​ ​ Adjustments ​ ​ Successor ASSETS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Current assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash and cash equivalents ​ $ 547,354 ​ $ (524,697) (a) ​ $ - ​ ​ $ 22,657 Restricted cash ​ ​ 28,955 ​ ​ (2,205) (b) ​ ​ - ​ ​ ​ 26,750 Accounts receivable trade, net ​ ​ 136,881 ​ ​ - ​ ​ ​ 81 (o) ​ ​ 136,962 Prepaid expenses and other ​ ​ 18,722 ​ ​ 231 (c) ​ ​ 2,260 (p) ​ ​ 21,213 Total current assets ​ ​ 731,912 ​ ​ (526,671) ​ ​ ​ 2,341 ​ ​ ​ 207,582 Property and equipment: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Oil and gas properties, successful efforts method ​ ​ 4,885,013 ​ ​ - ​ ​ ​ (3,058,899) (q) ​ ​ 1,826,114 Other property and equipment ​ ​ 159,866 ​ ​ (909) (d) ​ ​ (87,642) (o)(r) ​ ​ 71,315 Total property and equipment ​ ​ 5,044,879 ​ ​ (909) ​ ​ ​ (3,146,541) ​ ​ ​ 1,897,429 Less accumulated depreciation, depletion and amortization ​ ​ (2,085,266) ​ ​ - ​ ​ ​ 2,085,266 (o)(q)(r) ​ ​ - Total property and equipment, net ​ ​ 2,959,613 ​ ​ (909) ​ ​ ​ (1,061,275) ​ ​ ​ 1,897,429 Debt issuance costs ​ ​ 1,834 ​ ​ 10,950 (e) ​ ​ - ​ ​ ​ 12,784 Other long-term assets ​ ​ 37,010 ​ ​ (8,760) (d) ​ ​ (3,317) (o)(s) ​ ​ 24,933 TOTAL ASSETS ​ $ 3,730,369 ​ $ (525,390) ​ ​ $ (1,062,251) ​ ​ $ 2,142,728 LIABILITIES AND EQUITY (DEFICIT) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Current liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Current portion of long-term debt ​ $ 912,259 ​ $ (912,259) (f) ​ $ - ​ ​ $ - Accounts payable trade ​ ​ 47,168 ​ ​ 9,264 (g)(h) ​ ​ - ​ ​ ​ 56,432 Revenues and royalties payable ​ ​ 145,506 ​ ​ - ​ ​ ​ - ​ ​ ​ 145,506 Accrued capital expenditures ​ ​ 14,037 ​ ​ 1,305 (g) ​ ​ - ​ ​ ​ 15,342 Accrued liabilities and other ​ ​ 46,327 ​ ​ 21,942 (g)(i) ​ ​ (6,529) (o)(t) ​ ​ 61,740 Accrued lease operating expenses ​ ​ 25,344 ​ ​ 1,394 (g) ​ ​ - ​ ​ ​ 26,738 Accrued interest ​ ​ 3,459 ​ ​ (3,332) (g)(j) ​ ​ (127) (o) ​ ​ - Taxes payable ​ ​ 13,972 ​ ​ - ​ ​ ​ - ​ ​ ​ 13,972 Derivative liabilities ​ ​ 25,998 ​ ​ - ​ ​ ​ - ​ ​ ​ 25,998 Total current liabilities ​ ​ 1,234,070 ​ ​ (881,686) ​ ​ ​ (6,656) ​ ​ ​ 345,728 Long-term debt ​ ​ - ​ ​ 425,328 (k) ​ ​ - ​ ​ ​ 425,328 Asset retirement obligations ​ ​ 150,925 ​ ​ - ​ ​ ​ (29,582) (u) ​ ​ 121,343 Operating lease obligations ​ ​ - ​ ​ 17,652 (d)(g) ​ ​ 187 (o) ​ ​ 17,839 Deferred income taxes ​ ​ 69,847 ​ ​ - ​ ​ ​ (55,346) (v) ​ ​ 14,501 Other long-term liabilities ​ ​ 18,160 ​ ​ 11,071 (g) ​ ​ (458) (o)(t) ​ ​ 28,773 Total liabilities not subject to compromise ​ ​ 1,473,002 ​ ​ (427,635) ​ ​ ​ (91,855) ​ ​ ​ 953,512 Liabilities subject to compromise ​ ​ 2,526,925 ​ ​ (2,526,925) (g) ​ ​ - ​ ​ ​ - Total liabilities ​ ​ 3,999,927 ​ ​ (2,954,560) ​ ​ ​ (91,855) ​ ​ ​ 953,512 Commitments and contingencies ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity (deficit): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Predecessor common stock ​ ​ 92 ​ ​ (92) (l) ​ ​ - ​ ​ ​ - Successor common stock ​ ​ - ​ ​ 38 (m) ​ ​ - ​ ​ ​ 38 Predecessor additional paid-in capital ​ ​ 6,410,410 ​ ​ (6,410,410) (l) ​ ​ - ​ ​ ​ - Successor additional paid-in capital ​ ​ - ​ ​ 1,189,178 (m) ​ ​ - ​ ​ ​ 1,189,178 Accumulated earnings (deficit) ​ ​ (6,680,060) ​ ​ 7,650,456 (n) ​ ​ (970,396) (w) ​ ​ - Total equity (deficit) ​ ​ (269,558) ​ ​ 2,429,170 ​ ​ ​ (970,396) ​ ​ ​ 1,189,216 TOTAL LIABILITIES AND EQUITY (DEFICIT) ​ $ 3,730,369 ​ $ (525,390) ​ ​ $ (1,062,251) ​ ​ $ 2,142,728 ​ Reorganization Adjustments (a) The table below reflects the sources and uses of cash on the Emergence Date pursuant to the terms of the Plan (in thousands): ​ ​ ​ ​ ​ Sources: ​ ​ ​ Release of restricted cash upon bankruptcy emergence ​ $ 28,205 Borrowings under the Exit Credit Agreement ​ ​ 425,328 Total sources of cash ​ ​ 453,533 Uses: ​ ​ ​ Payment of outstanding borrowings under the Predecessor Credit Agreement ​ ​ (912,259) Payment of accrued interest on the Predecessor Credit Agreement ​ ​ (3,437) Payment of debt issuance costs related to Exit Credit Agreement ​ ​ (10,950) Funding of the Professional Fee Escrow Account ​ ​ (26,000) Payment of professional fees upon emergence ​ ​ (14,470) Payment of contract cure amounts ​ ​ (11,114) Total uses of cash ​ ​ (978,230) ​ ​ ​ ​ Net uses of cash ​ $ (524,697) ​ (b) The table below reflects the net reclassification of cash balances to and from restricted cash on the Emergence Date pursuant to terms of the Plan (in thousands): ​ ​ ​ ​ ​ Funding of the Professional Fee Escrow Account ​ $ 26,000 Release of restricted cash upon bankruptcy emergence (1) ​ ​ (28,205) Net reclassifications from restricted cash ​ $ (2,205) (1) Includes $23 million of funds related to derivative termination settlements that were directed by the counterparty to be held in a segregated account until the Company emerged from bankruptcy, as well as $5 million of amounts set aside as adequate assurance for utility providers that were restricted until emergence. (c) Reflects the payment of professional fee retainers upon emergence. (d) The Company amended a corporate office lease agreement and terminated the lease of certain floors within that agreement, which amendment was effective upon emergence from the Chapter 11 Cases. As a result of the lease modification and terminations, the Company reduced the associated right-of-use assets and operating lease obligations by $10 million and $15 million, respectively, resulting in a $5 million gain on settlement of liabilities subject to compromise, which was recorded to reorganization items, net in the consolidated statements of operations. The corporate office lease was classified as an operating lease and the modification did not result in a change to the lease’s classification. Additionally, $18 million of long-term operating lease obligations in liabilities subject to compromise were reinstated to be satisfied in the ordinary course of business. (e) Represents $11 million of financing costs related to the Exit Credit Agreement which were capitalized as debt issuance costs and will be amortized to interest expense through the maturity date of April 1, 2024. (f) Reflects the payment in full of the borrowings outstanding under the Predecessor Credit Agreement on the Emergence Date. ​ (g) As part of the Plan, the Bankruptcy Court approved the settlement of certain claims reported within liabilities subject to compromise in the Company's consolidated balance sheet at their respective allowed claim amounts. The table below indicates the reinstatement or disposition of liabilities subject to compromise (in thousands): ​ ​ ​ ​ Liabilities subject to compromise pre-emergence ​ $ 2,526,925 Amounts reinstated on the Emergence Date: ​ ​ ​ Accounts payable trade ​ ​ (10,866) Accrued capital expenditures ​ ​ (1,305) Accrued lease operating expenses ​ ​ (1,394) Accrued liabilities and other ​ ​ (13,961) Accrued interest ​ ​ (105) Operating lease obligations ​ ​ (17,652) Other long-term liabilities ​ ​ (11,071) Total liabilities reinstated ​ ​ (56,354) Less: Amounts settled per the Plan ​ ​ ​ Issuance of common stock to general unsecured claim holders ​ ​ (1,125,062) Payment of contract cure amounts ​ ​ (10,836) Operating lease modification and terminations ​ ​ (9,669) Issuance of Successor common stock to holders of unvested cash-settled equity awards (1) ​ ​ (64) Total amounts settled ​ ​ (1,145,631) Gain on settlement of liabilities subject to compromise ​ $ 1,324,940 (1) Holders of unvested cash-settled restricted stock awards were included as existing equity interests in the Plan and thus received Successor common stock on a pro rata basis based on the amount of unvested awards held. This amount represents the gain on the liability related to those awards, which was included in liabilities subject to compromise prior to emergence. (h) Reflects the reinstatement of $11 million of accounts payable included in liabilities subject to compromise to be satisfied in the ordinary course of business, partially offset by $2 million of professional fees paid on the Emergence Date. (i) Represents the accrual of success fees payable upon emergence as well as certain other expenses, the payment of certain professional fees that were accrued for prior to emergence and the reinstatement of certain accrued liabilities included in liabilities subject to compromise to be satisfied in the ordinary course of business, as detailed in the following table (in thousands): ​ ​ ​ ​ ​ Reinstatement of accrued expenses from liabilities subject to compromise ​ $ 13,961 Recognition of success fee payable upon emergence ​ ​ 11,500 Other expenses accrued at emergence ​ ​ 3,315 Payment of certain professional fees accrued prior to emergence ​ ​ (6,834) Net impact to accrued liabilities and other ​ $ 21,942 ​ (j) Represents a $3 million payment of accrued interest on the Predecessor Credit Agreement and reinstated accrued interest that was included within liabilities subject to compromise to be satisfied in the ordinary course of business. (k) Reflects borrowings drawn under the Exit Credit Agreement upon emergence. Refer to the "Long-Term Debt" footnote for more information on the Exit Credit Agreement. (l) Pursuant to the terms of the Plan, on the Emergence Date, all Predecessor common stock interests were cancelled. As a result of the cancellation, the Company accelerated the recognition of $4 million in compensation expense related to the unrecognized portion of share-based compensation as of the Emergence Date, which was recorded to reorganization items, net in the consolidated statements of operations. (m) Reflects the issuance of Successor equity, including the issuance of 38,051,125 shares of common stock at a par value of $0.001 per share and warrants to purchase 7,256,227 shares of common stock in exchange for claims against or interests in the Debtors pursuant to the Plan. Equity issued to each class of claims is detailed in the table below (in thousands): ​ ​ ​ ​ ​ Issuance of common stock to general unsecured claim holders ​ $ 1,125,062 Issuance of common stock to Predecessor common stockholders and holders of unvested cash-settled equity awards ​ ​ 34,794 Issuance of warrants to Predecessor common stockholders and holders of unvested cash-settled equity awards ​ ​ 29,360 Fair value of Successor equity ​ $ 1,189,216 ​ (n) The table below reflects the cumulative impact of the reorganization adjustments discussed above (in thousands): ​ ​ ​ ​ ​ Gain on settlement of liabilities subject to compromise ​ $ 1,324,940 Cancellation of Predecessor equity (1) ​ ​ 6,414,541 Fair value of equity issued to Predecessor common stockholders and holders of unvested cash-settled equity awards ​ ​ (34,794) Fair value of warrants issued to Predecessor common stockholders and holders of unvested cash-settled equity awards ​ ​ (29,360) Success fees incurred upon emergence ​ ​ (17,303) Acceleration of unvested stock-based compensation awards ​ ​ (4,161) Other expenses incurred upon emergence ​ ​ (3,407) Net impact on accumulated earnings (deficit) ​ $ 7,650,456 (1) This value is reflective of Predecessor common stock, Predecessor additional paid in capital and the recognition of $4 million in compensation expense related to the unrecognized portion of share-based compensation. Fresh Start Adjustments (o) Reflects the adjustments to fair value made to operating and finance lease assets and liabilities. Upon adoption of fresh start accounting, the Company's remaining lease obligations were recalculated using the incremental borrowing rate applicable to the Company upon emergence and commensurate with the Successor's capital structure. The fair value adjustments related to leases are summarized in the table below (in thousands): ​ ​ ​ ​ ​ ​ Lease Asset/Liability ​ Balance Sheet Classification ​ Fair Value Adjustment Accounts receivable, net ​ Accounts receivable, net ​ $ 81 Operating lease assets, net ​ Other long-term assets ​ ​ (1,480) Finance lease assets ​ Other property and equipment ​ ​ (10,765) Accumulated depreciation - finance leases ​ Less accumulated depreciation, depletion and amortization ​ ​ 15,099 Accrued interest - finance leases ​ Accrued interest ​ ​ 127 Short-term finance lease obligation ​ Accrued liabilities and other ​ ​ (576) Short-term operating lease obligation ​ Accrued liabilities and other ​ ​ 319 Long-term finance lease obligation ​ Other long-term liabilities ​ ​ (1,174) Long-term operating lease obligation ​ Operating lease obligations ​ ​ (187) ​ ​ ​ ​ $ 1,444 (p) Reflects the adjustment to fair value of the Company's oil in tank inventory based on market prices as of the Emergence Date. (q) Reflects the adjustments to fair value of the Company's oil and natural gas properties and undeveloped properties, as well as the elimination of accumulated depletion, depreciation and amortization. For purposes of estimating the fair value of the Company's proved oil and gas properties, an income approach was used which estimated the fair value based on the anticipated future cash flows associated with the Company's proved reserves, risked by reserve category and discounted using a weighted average cost of capital rate of 14%. The proved reserve locations included in this analysis were limited to wells included in the Company's five-year development plan. Future prices for the income approach were based on forward strip price curves (adjusted for basis differentials) as of the Emergence Date. In estimating the fair value of the Company's unproved properties, a combination of income and market approaches were utilized. The income approach consistent with that utilized for proved properties was utilized for properties which had positive future cash flows associated with reserve locations that did not qualify as proved reserves. A market approach was used to value the remainder of the Company’s unproved properties. (r) Reflects the fair value adjustment to recognize the Company’s land, buildings and other property, plant and equipment as of the Emergence Date based on the fair values of such land, buildings and other property, plant and equipment as well as the elimination of related historical depletion, depreciation and amortization balances. Land and buildings were valued using a market approach. Other property, plant and equipment were valued using a cost approach based on the current replacement costs of the assets, less depreciation based on the estimated economic useful lives of the assets and the age of the assets. The fair value adjustments consisted of a decrease of $16 million in land and buildings, a decrease of $61 million in other property, plant and equipment and a corresponding write-off of $66 million in accumulated depletion, depreciation and amortization. (s) Reflects the adjustment to fair value of the Company's other long-term assets, including line fill and pipeline imbalances, based on the commodity market prices as of the Emergence Date, which resulted in a $2 million decrease to other long-term assets. (t) Represents the write-off of a deferred gain balance associated with the Predecessor. The deferred gain does not relate to the Successor and therefore the unamortized balance was written off in full in the Predecessor's consolidated statements of operations. Of the total $9 million write off, $7 million related to the short-term portion of the deferred gain (included in accrued liabilities and other in the consolidated balance sheets at emergence) and $2 million related to the long-term portion (included in other long-term liabilities in the consolidated balance sheets at emergence). (u) Reflects the adjustment to fair value of the Company's asset retirement obligations including using a credit-adjusted risk-free rate as of the Emergence Date. (v) Reflects the adjustment to fair value of the Company's deferred tax liability related to Whiting Canadian Holding Company ULC's outside basis difference in its ownership of a portion of Whiting's U.S. assets obtained through the acquisition of Kodiak Oil and Gas Corporation in 2014. (w) Reflects the cumulative impact of the fresh start adjustments discussed above. Reorganization Items, Net ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ ​ Four Months Ended December 31, 2020 ​ ​ Eight Months Ended August 31, 2020 Legal and professional advisory fees ​ $ - ​ ​ $ 57,170 Net gain on liabilities subject to compromise ​ ​ - ​ ​ ​ (1,324,940) Fresh start adjustments, net ​ ​ - ​ ​ ​ 1,025,742 Write-off of unamortized debt issuance costs and premium (1) ​ ​ - ​ ​ ​ 15,145 Other items, net ​ ​ - ​ ​ ​ 9,464 Total reorganization items, net ​ $ - ​ ​ $ (217,419) ​ (1) As a result of the Chapter 11 Cases and the adoption of ASC 852, the Company wrote off all unamortized premium and issuance cost balances related to its senior notes on the Petition Date .

OIL AND GAS PROPERTIES

OIL AND GAS PROPERTIES	12 Months Ended
	Dec. 31, 2020
OIL AND GAS PROPERTIES [Abstract]
OIL AND GAS PROPERTIES	4. OIL AND GAS PROPERTIES Net capitalized costs related to the Company’s oil and gas producing activities at December 31, 2020 and 2019 are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ ​ December 31, ​ ​ December 31, ​ 2020 ​ ​ 2019 Proved oil and gas properties ​ $ 1,701,163 ​ ​ $ 12,549,395 Unproved leasehold costs ​ ​ 105,073 ​ ​ ​ 103,278 Wells and facilities in progress ​ ​ 6,365 ​ ​ ​ 159,334 Total oil and gas properties, successful efforts method ​ ​ 1,812,601 ​ ​ ​ 12,812,007 Accumulated depletion ​ ​ (71,064) ​ ​ ​ (5,656,929) Oil and gas properties, net ​ $ 1,741,537 ​ ​ $ 7,155,078 ​

ACQUISITIONS AND DIVESTITURES

ACQUISITIONS AND DIVESTITURES	12 Months Ended
	Dec. 31, 2020
ACQUISITIONS AND DIVESTITURES [Abstract]
ACQUISITIONS AND DIVESTITURES	5. ACQUISITIONS AND DIVESTITURES 2020 Acquisitions and Divestitures On January 9, 2020, the Predecessor completed the divestiture of its interests in 30 non-operated, producing oil and gas wells and related undeveloped acreage located in McKenzie County, North Dakota for aggregate sales proceeds of $25 million (before closing adjustments). There were no significant acquisitions during the year ended December 31, 2020. 2019 Acquisitions and Divestitures On July 29, 2019, the Predecessor completed the divestiture of its interests in 137 non-operated, producing oil and gas wells located in the McKenzie, Mountrail and Williams counties of North Dakota for aggregate sales proceeds of $27 million (before closing adjustments). On August 15, 2019, the Predecessor completed the divestiture of its interests in 58 non-operated, producing oil and gas wells located in Richland County, Montana and Mountrail and Williams counties of North Dakota for aggregate sales proceeds of $26 million (before closing adjustments). There were no significant acquisitions during the year ended December 31, 2019. 2018 Acquisitions and Divestitures On July 31, 2018, the Predecessor completed the acquisition of certain oil and gas properties located in Richland County, Montana and McKenzie County, North Dakota for an aggregate purchase price of $130 million (before closing adjustments). The properties consist of approximately 54,800 net acres in the Williston Basin, including interests in 117 producing oil and gas wells and undeveloped acreage. The revenue and earnings from these properties since the acquisition date are included in the Predecessor’s consolidated financial statements for the year ended December 31, 2018 and are not material. Pro forma revenue and earnings for the acquired properties are not material to the Company’s consolidated financial statements and have not been presented accordingly. The acquisition was recorded using the acquisition method of accounting. The following table summarizes the allocation of the $123 million adjusted purchase price to the tangible assets acquired and liabilities assumed in this acquisition based on their relative fair values at the acquisition date, which did not result in the recognition of goodwill or a bargain purchase gain (in thousands): ​ ​ ​ ​ ​ Cash consideration ​ $ 122,861 ​ ​ ​ ​ Fair value of assets acquired: ​ ​ ​ Accounts receivable trade, net ​ $ 30 Prepaid expenses and other ​ ​ 43 Oil and gas properties, successful efforts method: ​ ​ ​ Proved oil and gas properties ​ ​ 106,860 Unproved oil and gas properties ​ ​ 21,769 Total fair value of assets acquired ​ ​ 128,702 ​ ​ ​ ​ Fair value of liabilities assumed: ​ ​ ​ Revenue and royalties payable ​ ​ 3,309 Asset retirement obligations ​ ​ 2,532 Total fair value of liabilities assumed ​ ​ 5,841 ​ ​ ​ ​ Total fair value of assets and liabilities acquired ​ $ 122,861 ​ There were no significant divestitures during the year ended December 31, 2018.

LEASES

LEASES	12 Months Ended
	Dec. 31, 2020
LEASES [Abstract]
LEASES	6. LEASES The Company accounts for leases in accordance with FASB ASC Topic 842 – Leases The Company has operating and finance leases for corporate and field offices, pipeline and midstream facilities and automobiles. Right-of-use (“ROU”) assets and liabilities associated with these leases are recognized at the lease commencement date based on the present value of the lease payments over the lease term. ROU assets represent the Company’s right to use an underlying asset for the lease term, and lease liabilities represent the Company’s obligation to make lease payments. Supplemental balance sheet information for the Company’s leases as of December 31, 2020 and December 31, 2019 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor Leases ​ Balance Sheet Classification ​ December 31, 2020 ​ ​ December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating leases ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating lease ROU assets ​ Other long-term assets ​ $ 21,962 ​ ​ $ 31,882 Accumulated depreciation ​ Other long-term assets ​ ​ (1,096) ​ ​ ​ (4,895) Operating lease ROU assets, net ​ ​ ​ $ 20,866 ​ ​ $ 26,987 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Short-term operating lease obligations ​ Accrued liabilities and other ​ $ 4,031 ​ ​ $ 7,346 Long-term operating lease obligations ​ Operating lease obligations ​ ​ 17,415 ​ ​ ​ 31,722 Total operating lease obligations ​ ​ ​ $ 21,446 ​ ​ $ 39,068 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Finance leases ​ ​ ​ ​ ​ ​ ​ ​ ​ Finance lease ROU assets ​ Other property and equipment ​ $ 19,706 ​ ​ $ 33,312 Accumulated depreciation ​ Accumulated depreciation, depletion and amortization ​ ​ (1,797) ​ ​ ​ (14,180) Finance lease ROU assets, net ​ ​ ​ $ 17,909 ​ ​ $ 19,132 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Short-term finance lease obligations ​ Accrued liabilities and other ​ $ 4,830 ​ ​ $ 4,974 Long-term finance lease obligations ​ Other long-term liabilities ​ ​ 13,138 ​ ​ ​ 16,638 Total finance lease obligations ​ ​ ​ $ 17,968 ​ ​ $ 21,612 The Company’s leases have remaining terms between less than one year to 10 years. Most of the Company’s leases do not state or imply a discount rate. Accordingly, the Company uses its incremental borrowing rate based on information available at lease commencement to determine the present value of the lease payments. Information regarding the Company’s lease terms and discount rates as of December 31, 2020 and December 31, 2019 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor Predecessor ​ ​ ​ ​ December 31, 2020 ​ ​ December 31, 2019 Weighted average remaining lease term ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating leases ​ ​ ​ ​ 7 years ​ ​ ​ 8 years Finance leases ​ ​ ​ ​ 4 years ​ ​ ​ 5 years ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average discount rate ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating leases ​ ​ ​ ​ 4.4% ​ ​ ​ 4.6% Finance leases ​ ​ ​ ​ 4.2% ​ ​ ​ 8.6% ​ Operating lease cost is recognized on a straight-line basis over the lease term. Finance lease cost is recognized based on the effective interest method for the lease liability and straight-line amortization of the ROU asset, resulting in more cost being recognized in earlier lease periods. All payments for short-term leases, including leases with a term of one month or less, are recognized in income or capitalized to the cost of oil and gas properties on a straight-line basis over the lease term. Additionally, any variable payments, which are generally related to the corresponding utilization of the asset, are recognized in the period in which the obligation was incurred. Lease cost for the periods presented consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor Predecessor ​ ​ Four Months Ended ​ ​ Eight Months Ended ​ Year Ended ​ ​ December 31, 2020 ​ ​ August 31, 2020 ​ December 31, 2019 Operating lease cost ​ $ 1,462 ​ ​ $ 4,691 ​ $ 11,512 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Finance lease cost: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortization of ROU assets ​ $ 1,842 ​ ​ $ 3,347 ​ $ 5,661 Interest on lease liabilities ​ ​ 260 ​ ​ ​ 1,131 ​ ​ 1,996 Total finance lease cost ​ $ 2,102 ​ ​ $ 4,478 ​ $ 7,657 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Short-term lease payments ​ $ 26,430 ​ ​ $ 164,815 ​ $ 676,850 Variable lease payments ​ $ 99 ​ ​ $ 23,307 ​ $ 31,812 ​ Total lease cost represents the total financial obligations of the Company, a portion of which has been or will be reimbursed by the Company’s working interest partners. Lease cost is included in various line items on the consolidated statements of operations or capitalized to oil and gas properties and is recorded at the Company’s net working interest. Supplemental cash flow information related to leases for the periods presented consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor Predecessor ​ ​ Four Months Ended ​ ​ Eight Months Ended ​ Year Ended ​ ​ December 31, 2020 ​ ​ August 31, 2020 ​ December 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating cash flows from operating leases ​ $ 2,174 ​ ​ $ 5,813 ​ $ 11,978 Operating cash flows from finance leases ​ $ 197 ​ ​ $ 1,156 ​ $ 2,006 Financing cash flows from finance leases ​ $ 1,773 ​ ​ $ 3,198 ​ $ 5,140 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ROU assets obtained in exchange for new operating lease obligations ​ $ 6,368 ​ ​ $ 3,252 ​ $ 18,658 ROU assets obtained in exchange for new finance lease obligations ​ $ - ​ ​ $ 170 ​ $ 4,158 ​ The Company’s lease obligations as of December 31, 2020 will mature as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ Year ending December 31, ​ Operating Leases ​ Finance Leases 2021 ​ $ 4,500 ​ $ 5,489 2022 ​ ​ 3,572 ​ ​ 4,693 2023 ​ ​ 3,255 ​ ​ 3,833 2024 ​ ​ 2,898 ​ ​ 3,214 2025 ​ ​ 1,903 ​ ​ 2,385 Remaining ​ ​ 9,349 ​ ​ — Total lease payments ​ ​ 25,477 ​ ​ 19,614 Less imputed interest ​ ​ (4,031) ​ ​ (1,646) Total discounted lease payments ​ $ 21,446 ​ $ 17,968 ​

LONG-TERM DEBT

LONG-TERM DEBT	12 Months Ended
	Dec. 31, 2020
LONG-TERM DEBT [Abstract]
LONG-TERM DEBT	7. LONG-TERM DEBT Long-term debt consisted of the following at December 31, 2020 and 2019 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ ​ December 31, ​ ​ December 31, ​ 2020 ​ ​ 2019 Exit Credit Agreement ​ $ 360,000 ​ ​ $ - Predecessor Credit Agreement ​ ​ - ​ ​ ​ 375,000 1.25% Convertible Senior Notes due 2020 ​ ​ - ​ ​ ​ 262,075 5.75% Senior Notes due 2021 ​ ​ - ​ ​ ​ 773,609 6.25% Senior Notes due 2023 ​ ​ - ​ ​ ​ 408,296 6.625% Senior Notes due 2026 ​ ​ - ​ ​ ​ 1,000,000 Total principal ​ ​ 360,000 ​ ​ ​ 2,818,980 Unamortized debt discounts and premiums ​ ​ - ​ ​ ​ (2,575) Unamortized debt issuance costs on notes ​ ​ - ​ ​ ​ (16,520) Total long-term debt ​ $ 360,000 ​ ​ $ 2,799,885 ​ Exit Credit Agreement (Successor) On the Emergence Date, Whiting Petroleum Corporation, as parent guarantor, and Whiting Oil and Gas, as borrower, entered into the Exit Credit Agreement, a reserves-based credit facility, with a syndicate of banks . As of December 31, 2020, the Exit Credit Agreement had a borrowing base and aggregate commitments of $750 million. As of December 31, 2020, the Company had $388 million of available borrowing capacity under the Exit Credit Agreement, which was net of $360 million of borrowings outstanding and $2 The borrowing base under the Exit Credit Agreement is determined at the discretion of the lenders, based on the collateral value of the Company’s proved reserves that have been mortgaged to such lenders, and is subject to initial redetermination on April 1, 2021, regular redeterminations on April 1 and October 1 of each year thereafter, as well as special redeterminations described in the Exit Credit Agreement, in each case which may increase or decrease the amount of the borrowing base. Additionally, the Company can increase the aggregate commitments by up to an additional $750 million, subject to certain conditions. A portion of the revolving credit facility in an aggregate amount not to exceed $50 million may be used to issue letters of credit for the account of Whiting Oil and Gas or other designated subsidiaries of the Company. As of December 31, 2020, $48 million was available for additional letters of credit under the Exit Credit Agreement. The Exit Credit Agreement provides for interest only payments until maturity on April 1, 2024, when the agreement terminates and all outstanding borrowings are due. In addition, the Exit Credit Agreement provides for certain mandatory prepayments, including if the Company’s cash balances are in excess of approximately $75 million during any given week, such excess must be utilized to repay borrowings under the Exit Credit Agreement. Interest under the Exit Credit Agreement accrues at the Company’s option at either (i) a base rate for a base rate loan plus a margin between 1.75% and 2.75% based on the ratio of outstanding borrowings and letters of credit to the lower of the current borrowing base or total commitments, where the base rate is defined as the greatest of the prime rate, the federal funds rate plus 0.5% per annum, or an adjusted LIBOR plus 1.0% per annum, or (ii) an adjusted LIBOR for a eurodollar loan plus a margin between 2.75% and 3.75% based on the ratio of outstanding borrowings and letters of credit to the lower of the current borrowing base or total commitments. Additionally, the Company incurs commitment fees of 0.5% on the unused portion of the aggregate commitments of the lenders under the Exit Credit Agreement, which are included as a component of interest expense. At December 31, 2020, the weighted average interest rate on the outstanding principal balance under the Exit Credit Agreement was 4.1%. The Exit Credit Agreement contains restrictive covenants that may limit the Company’s ability to, among other things, incur additional indebtedness, sell assets, make loans to others, make investments, enter into mergers, enter into hedging contracts, incur liens and engage in certain other transactions without the prior consent of its lenders. Except for limited exceptions, the Exit Credit Agreement also restricts the Company’s ability to make any dividend payments or distributions on its common stock prior to September 1, 2021, and thereafter only to the extent that the Company has distributable free cash flow and (i) at least 20% of available borrowing capacity, (ii) a consolidated net leverage ratio of less than or equal to 2.0 to 1.0, (iii) does not have a borrowing base deficiency and (iv) is not in default under the Exit Credit Agreement. These restrictions apply to all of the Company’s restricted subsidiaries (as defined in the Exit Credit Agreement). The Exit Credit Agreement requires the Company, as of the last day of any quarter to maintain commodity hedges covering a minimum of 65% of its projected production for the succeeding twelve months, and 35% of its projected production for the next succeeding twelve months, both as reflected in the Company’s most recent delivered proved reserves projection. The Company is also limited to hedging a maximum of 85% of its production from proved reserves. The Exit Credit Agreement requires the Company, as of the last day of any quarter beginning with the quarter ending December 31, 2020, to maintain the following ratios: (i) a consolidated current assets to consolidated current liabilities ratio of not less than 1.0 to 1.0 and (ii) a total debt to last four quarters’ EBITDAX ratio of not greater than 3.5 to 1.0. As of December 31, 2020, the Company was in compliance with the covenants under the Exit Credit Agreement. The obligations of Whiting Oil and Gas under the Exit Credit Agreement are secured by a first lien on substantially all of the Company’s and Whiting Oil and Gas’ properties. The Company has also guaranteed the obligations of Whiting Oil and Gas under the Exit Credit Agreement and has pledged the stock of its subsidiaries as security for its guarantee. Predecessor Credit Agreement Whiting Oil and Gas, the Company’s wholly owned subsidiary, had the Predecessor Credit Agreement that had a borrowing base of $2.05 billion and aggregate commitments of $1.75 billion prior to the Predecessor filing the Chapter 11 Cases. On the Emergence Date, the Predecessor Credit Agreement was terminated and the outstanding borrowings of $912 million and accrued interest of $3 million were paid in full. These payments were funded with cash on hand and proceeds from the Exit Credit Agreement. Predecessor Senior Notes and Convertible Senior Notes Prior to the Emergence Date, the Company had outstanding notes consisting of $774 million 5.75% Senior Notes due 2021 (the “2021 Senior Notes”), $408 million 6.25% Senior Notes due 2023 (the “2023 Senior Notes”) and $1.0 billion 6.625% Senior Notes due 2026 (the “2026 Senior Notes,” and collectively with the 2021 Senior Notes and 2023 Senior Notes, the “Senior Notes”) and $187 million of 1.25% Convertible Senior Notes due 2020 (the “Convertible Senior Notes”). These notes were unsecured obligations of Whiting Petroleum Corporation in the Chapter 11 Cases and were therefore included in liabilities subject to compromise on the consolidated balance sheets of the Predecessor as of August 31, 2020. On the Emergence Date, through implementation of the Plan, all outstanding obligations under the Senior Notes and the Convertible Senior Notes were cancelled and 36,817,630 shares of Successor common stock were issued to the holders of those outstanding notes. In addition, the remaining unamortized debt issuance costs and debt premium were written off to reorganization items, net in the consolidated statements of operations. Refer to the “Chapter 11 Emergence” and “Fresh Start Accounting” footnotes for more information. Convertible Senior Notes. Transaction costs related to the Convertible Senior Notes issuance were allocated to the liability and equity components based on their relative fair values. Issuance costs attributable to the liability component were recorded as a reduction to the carrying value of long-term debt on the consolidated balance sheet and were being amortized to interest expense over the term of the notes using the effective interest method. Issuance costs attributable to the equity component were recorded as a charge to additional paid-in capital within shareholders’ equity. The Convertible Senior Notes consisted of the following at December 31, 2019 (in thousands): ​ ​ ​ ​ Liability component ​ ​ ​ Principal ​ $ 262,075 Less: unamortized note discount ​ ​ (2,829) Less: unamortized debt issuance costs ​ ​ (220) Net carrying value ​ $ 259,026 Equity component (1) ​ $ 128,452 (1) Recorded in additional paid-in capital, net of $5 million of issuance costs and $50 million of deferred taxes as of December 31, 2019. Interest expense recognized on the Convertible Senior Notes related to the stated interest rate and amortization of the debt discount totaled $1 million, $26 million and $29 million for the Current Predecessor YTD Period, and the years ended December 31, 2019 and December 31, 2018, respectively. In September 2019, the Predecessor paid $299 million to complete a cash tender offer for $300 million aggregate principal amount of the Convertible Senior Notes, which payment consisted of the 99.0% purchase price plus all accrued and unpaid interest on the notes, which were allocated to the liability and equity components based on their relative fair values. The Company financed the tender offer with borrowings under the Predecessor Credit Agreement. As a result of the tender offer, the Company recognized a $4 million gain on extinguishment of debt, which was net of a $7 million charge for the non-cash write-off of unamortized debt issuance costs and debt discount and a $1 million charge for transaction costs. In addition, the Company recorded an $8 million reduction to the equity component of the Convertible Senior Notes. There was no deferred tax impact associated with this reduction due to the full valuation allowance in effect as of September 30, 2019. In March 2020, the Predecessor paid $53 million to repurchase $73 million aggregate principal amount of the Convertible Senior Notes, which payment consisted of the average 72.5% purchase price plus all accrued and unpaid interest on the notes, which were allocated to the liability and equity components based on their relative fair values. The Company financed the repurchases with borrowings under the Predecessor Credit Agreement. As a result of these repurchases, the Company recognized a $23 million gain on extinguishment of debt during the Current Predecessor YTD Period, which was net of a $0.2 million charge for the non-cash write-off of unamortized debt issuance costs and debt discount. In addition, the Company recorded a $3 million reduction to the equity component of the Convertible Senior Notes during the Current Predecessor YTD Period. There was no deferred tax impact associated with this reduction due to the full valuation allowance in effect as of March 31, 2020. Redemption of 2019 Senior Notes. Repurchases of 2021 Senior Notes.

ASSET RETIREMENT OBLIGATIONS

ASSET RETIREMENT OBLIGATIONS	12 Months Ended
	Dec. 31, 2020
ASSET RETIREMENT OBLIGATIONS [Abstract]
ASSET RETIREMENT OBLIGATIONS	8. ASSET RETIREMENT OBLIGATIONS The Company’s asset retirement obligations represent the present value of estimated future costs associated with the plugging and abandonment of oil and gas wells, removal of equipment and facilities from leased acreage, and land restoration in accordance with applicable local, state and federal laws and the terms of the Company’s lease agreements. The current portions as of December 31, 2020, September 1, 2020 and December 31, 2019 were $6 million, $5 million and $4 million, respectively, and have been included in accrued liabilities and other in the consolidated balance sheets. The following table provides a reconciliation of the Company’s asset retirement obligations for the periods presented (in thousands): ​ ​ ​ ​ Asset retirement obligation at January 1, 2019 (Predecessor) ​ $ 135,834 Additional liability incurred ​ ​ 2,097 Revisions to estimated cash flows ​ ​ (10,945) Accretion expense ​ ​ 11,602 Obligations on sold properties ​ ​ (2,078) Liabilities settled ​ ​ (1,617) Asset retirement obligation at December 31, 2019 (Predecessor) ​ ​ 134,893 Additional liability incurred ​ ​ 76 Revisions to estimated cash flows ​ ​ 56,702 Accretion expense ​ ​ 8,199 Obligations on sold properties ​ ​ (693) Liabilities settled (1) ​ ​ (42,854) Asset retirement obligation at August 31, 2020 (Predecessor) ​ ​ 156,323 ​ ​ ​ ​ Fresh start adjustment (2) ​ ​ (29,582) ​ ​ ​ ​ ​ ​ ​ ​ Asset retirement obligation at September 1, 2020 (Successor) ​ ​ 126,741 Additional liability incurred ​ ​ 20 Revisions to estimated cash flows ​ ​ (30,623) Accretion expense ​ ​ 3,801 Liabilities settled ​ ​ (1,809) Asset retirement obligation at December 31, 2020 (Successor) ​ $ 98,130 (1) A portion of the Predecessor’s asset retirement obligations related to a contractual obligation to remove certain offshore facilities in California. The Company included the related contract in its schedule of rejected contracts as part of the Plan, and the related amounts of the obligations were included in liabilities subject to compromise on the consolidated balance sheets of the Predecessor as of August 31, 2020. A final ruling from the Bankruptcy Court on the rejection of this contract has not yet been issued. Refer to the “Fresh Start Accounting” and “Commitments and Contingencies” footnotes for additional information. (2) Refer to the “Fresh Start Accounting” footnote for more information on fresh start adjustments .

DERIVATIVE FINANCIAL INSTRUMENT

DERIVATIVE FINANCIAL INSTRUMENTS	12 Months Ended
	Dec. 31, 2020
DERIVATIVE FINANCIAL INSTRUMENTS [Abstract]
DERIVATIVE FINANCIAL INSTRUMENTS	9. DERIVATIVE FINANCIAL INSTRUMENTS The Company is exposed to certain risks relating to its ongoing business operations, and it uses derivative instruments to manage its commodity price risk. In addition, the Company periodically enters into contracts that contain embedded features which are required to be bifurcated and accounted for separately as derivatives. Commodity Derivative Contracts — Crude Oil and Natural Gas Swaps and Collars. The table below details the Sucessor’s swap and collar derivatives entered into to hedge forecasted crude oil and natural gas production revenues as of December 31, 2020. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Average Settlement Period ​ Index ​ Derivative Instrument ​ Total Volumes (1) ​ Units ​ Swap Price ​ Floor ​ Ceiling Crude Oil ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ NYMEX WTI ​ Fixed Price Swaps ​ 4,386,000 ​ Bbl ​ $41.85 ​ - ​ - 2021 ​ NYMEX WTI ​ Two-way Collars ​ 6,956,000 ​ Bbl ​ - ​ $38.82 ​ $47.11 2022 ​ NYMEX WTI ​ Two-way Collars ​ 4,530,000 ​ Bbl ​ - ​ $38.41 ​ $48.75 ​ ​ ​ ​ Total ​ 15,872,000 ​ ​ ​ ​ ​ ​ ​ ​ Natural Gas ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ NYMEX Henry Hub ​ Fixed Price Swaps ​ 12,530,000 ​ MMBtu ​ $2.69 ​ - ​ - 2021 ​ NYMEX Henry Hub ​ Two-way Collars ​ 10,950,000 ​ MMBtu ​ - ​ $2.60 ​ $2.79 2022 ​ NYMEX Henry Hub ​ Fixed Price Swaps ​ 1,365,000 ​ MMBtu ​ $2.60 ​ - ​ - 2022 ​ NYMEX Henry Hub ​ Two-way Collars ​ 10,720,000 ​ MMBtu ​ - ​ $2.35 ​ $2.85 ​ ​ ​ ​ Total ​ 35,565,000 ​ ​ ​ ​ ​ ​ ​ ​ (1) Subsequent to December 31, 2020, the Successor entered into additional swaps for 1,447,000 Bbl of crude oil volumes and 6,120,000 MMBtu of natural gas volumes for the remainder of 2021 and 630,000 Bbl of crude oil volumes and 2,025,000 MMBtu of natural gas volumes for 2022. The Company also entered into additional two-way collars for 3,930,000 Bbl of crude oil volumes for 2022 and 1,980,000 Bbl of crude oil volumes and 1,800,000 MMBtu of natural gas volumes for the first three months of 2023. Finally, the Company entered into basis swaps for 6,120,000 MMBtu of natural gas volumes for the remainder of 2021 which are settled based on the difference between the Northern Natural Gas Ventura index price and NYMEX Henry Hub. Crude Oil Sales and Delivery Contract. Effect of Chapter 11 Cases Derivative Instrument Reporting — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (Gain) Loss Recognized in Income ​ ​ ​ ​ Successor ​ ​ Predecessor Not Designated as ASC 815 Hedges Statements of Operations Classification Four Months Ended December 31, 2020 Eight Months Ended August 31, 2020 Year Ended December 31, 2019 Year Ended December 31, 2018 Commodity contracts ​ Derivative (gain) loss, net ​ $ 24,714 ​ ​ $ (181,614) ​ $ 53,769 ​ $ 17,170 ​ Offsetting of Derivative Assets and Liabilities. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ ​ ​ December 31, 2020 (1) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net ​ ​ ​ ​ Gross ​ ​ ​ ​ Recognized ​ ​ ​ ​ Recognized ​ Gross ​ Fair Value Not Designated as ​ ​ ​ Assets/ ​ Amounts ​ Assets/ ASC 815 Hedges Balance Sheet Classification Liabilities Offset Liabilities Derivative assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commodity contracts - current ​ Prepaid expenses and other ​ $ 14,287 ​ $ (14,287) ​ $ - Commodity contracts - non-current ​ Other long-term assets ​ ​ 19,991 ​ ​ (19,991) ​ ​ - Total derivative assets ​ ​ ​ $ 34,278 ​ $ (34,278) ​ $ - Derivative liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commodity contracts - current ​ Derivative liabilities ​ $ 63,772 ​ $ (14,287) ​ $ 49,485 Commodity contracts - non-current ​ Other long-term liabilities ​ ​ 29,741 ​ ​ (19,991) ​ ​ 9,750 Total derivative liabilities ​ ​ ​ $ 93,513 ​ $ (34,278) ​ $ 59,235 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Predecessor ​ ​ ​ ​ December 31, 2019 (1) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net ​ ​ ​ ​ Gross ​ ​ ​ ​ Recognized ​ ​ ​ ​ Recognized ​ Gross ​ Fair Value Not Designated as ​ ​ ​ Assets/ ​ Amounts ​ Assets/ ASC 815 Hedges Balance Sheet Classification Liabilities Offset Liabilities Derivative assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commodity contracts - current ​ Prepaid expenses and other ​ $ 75,654 ​ $ (74,768) ​ $ 886 Commodity contracts - non-current ​ Other long-term assets ​ ​ 5,648 ​ ​ (5,648) ​ ​ - Total derivative assets ​ ​ ​ $ 81,302 ​ $ (80,416) ​ $ 886 Derivative liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commodity contracts - current ​ Derivative liabilities ​ $ 85,053 ​ $ (74,768) ​ $ 10,285 Commodity contracts - non-current ​ Other long-term liabilities ​ ​ 6,534 ​ ​ (5,648) ​ ​ 886 Total derivative liabilities ​ ​ ​ $ 91,587 ​ $ (80,416) ​ $ 11,171 (1) All of the counterparties to the Company’s financial derivative contracts subject to master netting arrangements are lenders under both the Exit Credit Agreement and the Predecessor Credit Agreement, which eliminates the need to post or receive collateral associated with its derivative positions. Therefore, columns for cash collateral pledged or received have not been presented in these tables. Contingent Features in Financial Derivative Instruments. ​

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	12 Months Ended
	Dec. 31, 2020
FAIR VALUE MEASUREMENTS [Abstract]
FAIR VALUE MEASUREMENTS	10. FAIR VALUE MEASUREMENTS The Company follows ASC 820 which establishes a three-level valuation hierarchy for disclosure of fair value measurements. The valuation hierarchy categorizes assets and liabilities measured at fair value into one of three different levels depending on the observability of the inputs employed in the measurement. The three levels are defined as follows: ● Level 1: Quoted Prices in Active Markets for Identical Assets – inputs to the valuation methodology are quoted prices (unadjusted) for identical assets or liabilities in active markets. ● Level 2: Significant Other Observable Inputs – inputs to the valuation methodology include quoted prices for similar assets and liabilities in active markets, and inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the financial instrument. ● Level 3: Significant Unobservable Inputs – inputs to the valuation methodology are unobservable and significant to the fair value measurement. A financial instrument’s categorization within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset or liability. Cash, cash equivalents, restricted cash, accounts receivable and accounts payable are carried at cost, which approximates their fair value because of the short-term maturity of these instruments. The Company’s Exit Credit Agreement and Predecessor Credit Agreement have a recorded value that approximates their fair value since their variable interest rates are tied to current market rates and the applicable margins represent market rates. The Predecessor’s Senior Notes were recorded at cost and the Predecessor’s Convertible Senior Notes were recorded at fair value at the date of issuance. The following table summarizes the fair values and carrying values of these instruments as of December 31, 2019 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Predecessor ​ ​ December 31, 2019 ​ ​ Fair ​ Carrying ​ Value (1) Value (2) 1.25% Convertible Senior Notes due 2020 ​ $ 260,214 ​ $ 259,026 5.75% Senior Notes due 2021 ​ ​ 732,995 ​ ​ 772,080 6.25% Senior Notes due 2023 ​ ​ 343,989 ​ ​ 405,392 6.625% Senior Notes due 2026 ​ ​ 681,250 ​ ​ 988,387 Total ​ $ 2,018,448 ​ $ 2,424,885 (1) Fair values are based on quoted market prices for these debt securities, and such fair values are therefore designated as Level 1 within the valuation hierarchy. (2) Carrying values are presented net of unamortized debt issuance costs and debt discounts or premiums. The Company’s derivative financial instruments are recorded at fair value and include a measure of the Company’s own nonperformance risk or that of its counterparty, as appropriate. The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis as of December 31, 2020 and 2019, and indicate the fair value hierarchy of the valuation techniques utilized by the Company to determine such fair values (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Fair Value ​ Level 1 Level 2 Level 3 December 31, 2020 Financial liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commodity derivatives – current ​ $ - ​ $ 49,485 ​ $ - ​ $ 49,485 Commodity derivatives – non-current ​ ​ - ​ ​ 9,750 ​ ​ - ​ ​ 9,750 Total financial liabilities ​ $ - ​ $ 59,235 ​ $ - ​ $ 59,235 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Predecessor ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Fair Value ​ Level 1 Level 2 Level 3 December 31, 2019 Financial assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commodity derivatives – current ​ $ - ​ $ 886 ​ $ - ​ $ 886 Total financial assets ​ $ - ​ $ 886 ​ $ - ​ $ 886 Financial liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commodity derivatives – current ​ $ - ​ $ 10,285 ​ $ - ​ $ 10,285 Commodity derivatives – non-current ​ ​ - ​ ​ 886 ​ ​ - ​ ​ 886 Total financial liabilities ​ $ - ​ $ 11,171 ​ $ - ​ $ 11,171 ​ The following methods and assumptions were used to estimate the fair values of the Company’s financial assets and liabilities that are measured on a recurring basis: Commodity Derivatives Non-recurring Fair Value Measurements — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Predecessor ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loss (Before ​ ​ Net Carrying ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tax) During the ​ ​ Value as of ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Current ​ ​ March 31, ​ Fair Value Measurements Using ​ Predecessor ​ 2020 Level 1 Level 2 Level 3 Period Proved property (1) ​ $ 816,234 ​ $ - ​ $ - ​ $ 816,234 ​ $ 3,732,096 (1) During the first quarter of 2020, certain proved oil and gas properties across the Company’s Williston Basin resource play with a previous carrying amount of $4.5 billion were written down to their fair value as of March 31, 2020 of $816 million, resulting in a non-cash impairment charge of $3.7 billion, which was recorded within exploration and impairment expense. These impaired properties were written down due to a reduction in anticipated future cash flows primarily driven by an expectation of sustained depressed oil prices and a resultant decline in future development plans for the properties. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Predecessor ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loss (Before ​ ​ Net Carrying ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tax) During the ​ ​ Value as of ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Current ​ ​ June 30, ​ Fair Value Measurements Using ​ Predecessor YTD ​ 2020 Level 1 Level 2 Level 3 Period Proved property (2) ​ $ 85,418 ​ $ - ​ $ - ​ $ 85,418 ​ $ 409,079 (2) During the second quarter of 2020, other proved oil and gas properties in the Company’s Williston Basin resource play with a previous carrying amount of $494 million were written down to their fair value as of June 30, 2020 of $85 million, resulting in a non-cash impairment charge of $409 million, which was recorded within exploration and impairment expense. These impaired properties were written down due to a reduction in anticipated future cash flows primarily driven by an expectation of sustained depressed oil prices and a resultant decline in future development plans for the properties assessed during the second quarter of 2020. Predecessor Proved Property Impairments Chapter 11 Emergence and Fresh Start Accounting.

REVENUE RECOGNITION

REVENUE RECOGNITION	12 Months Ended
	Dec. 31, 2020
REVENUE RECOGNITION [Abstract]
REVENUE RECOGNITION	11. REVENUE RECOGNITION The Company recognizes revenue in accordance with FASB ASC Topic 606 – Revenue from Contracts with Customers ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor OPERATING REVENUES ​ Four Months Ended December 31, 2020 ​ ​ Eight Months Ended August 31, 2020 ​ Year Ended December 31, 2019 ​ Year Ended December 31, 2018 Oil sales ​ $ 254,024 ​ ​ $ 440,820 ​ $ 1,492,218 ​ $ 1,850,052 NGL and natural gas sales ​ ​ 19,334 ​ ​ ​ 18,184 ​ ​ 80,027 ​ ​ 231,362 Oil, NGL and natural gas sales ​ $ 273,358 ​ ​ $ 459,004 ​ $ 1,572,245 ​ $ 2,081,414 ​ Whiting receives payment for product sales from one The Company has elected to utilize the practical expedient in ASC 606 that states the Company is not required to disclose the transaction price allocated to remaining performance obligations if the variable consideration is allocated entirely to a wholly unsatisfied performance obligation. Under the Company’s contracts, each monthly delivery of product represents a separate performance obligation, therefore, future volumes are wholly unsatisfied, and disclosure of the transaction price allocated to remaining performance obligations is not required.

SHAREHOLDERS' EQUITY

SHAREHOLDERS' EQUITY	12 Months Ended
	Dec. 31, 2020
SHAREHOLDERS' EQUITY
SHAREHOLDERS' EQUITY	12. SHAREHOLDERS’ EQUITY Common Stock — On the Emergence Date, upon emergence from the Chapter 11 Cases, all existing shares of the Predecessor’s common stock were cancelled and the Successor issued 38,051,125 shares of New Common Stock. Refer to the “Chapter 11 Emergence” and “Fresh Start Accounting” footnotes for more information. Warrants — The Series A Warrants are exercisable from the date of issuance until the fourth anniversary of the Emergence Date, at which time, all unexercised Series A Warrants will expire, and the rights of the holders of such warrants to purchase New Common Stock will terminate. The Series A Warrants are initially exercisable for one share of New Common Stock per Series A Warrant at an initial exercise price of $73.44 per Series A Warrant (the “Series A Exercise Price”). The Series B Warrants are exercisable from the date of issuance until the fifth anniversary of the Emergence Date, at which time, all unexercised Series B Warrants will expire, and the rights of the holders of such warrants to purchase New Common Stock will terminate. The Series B Warrants are initially exercisable for one share of New Common Stock per Series B Warrant at an initial exercise price of $83.45 per Series B Warrant (the “Series B Exercise Price” and together with the Series A Exercise Price, the “Exercise Prices”). Pursuant to the warrant agreements, no holder of a Warrant, by virtue of holding or having a beneficial interest in a Warrant, will have the right to vote, receive dividends, receive notice as stockholders with respect to any meeting of stockholders for the election of Whiting’s directors or any other matter, or exercise any rights whatsoever as a stockholder of Whiting unless, until and only to the extent such holders become holders of record of shares of New Common Stock issued upon settlement of the Warrants. The number of shares of New Common Stock for which a Warrant is exercisable, and the Exercise Prices, are subject to adjustment from time to time upon the occurrence of certain events, including stock splits, reverse stock splits or stock dividends to holders of New Common Stock or a reclassification in respect of New Common Stock.

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	12 Months Ended
	Dec. 31, 2020
STOCK-BASED COMPENSATION [Abstract]
STOCK-BASED COMPENSATION	13. STOCK-BASED COMPENSATION Equity Incentive Plan Historically, the Company has granted service-based restricted stock awards (“RSAs”) and restricted stock units (“RSUs”) to executive officers and employees, which generally vest ratably over a three-year service period. The Company has granted service-based RSAs and RSUs to directors, which generally vest over a one-year service period. In addition, the Company has granted performance share awards (“PSAs”) and performance share units (“PSUs”) to executive officers that are subject to market-based vesting criteria, which generally vest over a three-year service period. The Company accounts for forfeitures of awards granted under these plans as they occur in determining compensation expense. The Company recognizes compensation expense for all awards subject to market-based vesting conditions regardless of whether it becomes probable that these conditions will be achieved or not, and compensation expense for share-settled awards is not reversed if vesting does not actually occur. Successor Awards During the Successor Period, 89,021 shares of service-based RSUs were granted to executive officers and directors under the 2020 Equity Plan. The Company determines compensation expense for these share-settled awards using their fair value at the grant date based on the closing bid price of the Company’s common stock on such date. The weighted average grant date fair value of these RSUs was $17.47 per share. On September 29, 2020, 189,900 shares of market-based RSUs were granted to executive officers under the 2020 Equity Plan. The awards will vest upon the Successor’s common stock trading for 20 consecutive trading days above a certain daily volume weighted average price (“VWAP”) as follows: 50% will vest if the VWAP exceeds $32.57 per share, an additional 25% if the daily VWAP exceeds $48.86 per share and the final 25% if the daily VWAP exceeds $65.14 per share. The grant date fair value of these awards was estimated using a Monte Carlo valuation model (the “Monte Carlo Model”). ​ ​ ​ Number of simulations 100,000 Expected volatility 40% Risk-free interest rate 0.66% Dividend yield — The Company recognizes compensation expense based on the fair value as determined by the Monte Carlo Model over the expected vesting period, which is estimated to be between 1.8 and 3.8 years. The weighted average grant date fair value of these market-based RSUs was $6.54 per share. The Company recognized $1 million in stock-based compensation expense during the Successor Period. As of December 31, 2020, there was $2 million of unrecognized compensation cost related to unvested awards granted under the 2020 Equity Plan. That cost is expected to be recognized over a weighted average period of 2.7 years. Predecessor Awards During the eight months ended August 31, 2020 and the years ended December 31, 2019 and 2018, 53,198, 467,055 and 249,983 shares, respectively, of share-settled service-based RSAs and RSUs were granted to employees, executive officers and directors under the Predecessor Equity Plan. The Company determined compensation expense for these awards using their fair value at the grant date, which was based on the closing bid price of the Company’s common stock on such date. The weighted average grant date fair value of service-based RSAs and RSUs was $4.94 per share, $24.65 per share and $32.34 per share for the eight months ended August 31, 2020 and the years ended December 31, 2019 and 2018, respectively. On March 31, 2020, all of the RSAs issued to executive officers in 2020 were forfeited and concurrently replaced with cash incentives. Refer to “2020 Compensation Adjustments” below for more information. During the eight months ended August 31, 2020 and the years ended December 31, 2019 and 2018, 1,616,504, 774,665 and 308,432 shares, respectively, of cash-settled, service-based RSUs were granted to executive officers and employees under the Predecessor Equity Plan. The Company determined compensation expense for these awards using the fair value at the end of each reporting period, which was based on the closing bid price of the Company’s common stock on such date. On March 31, 2020, all of the RSUs issued to executive officers in 2020 were forfeited and concurrently replaced with cash incentives. Refer to “2020 Compensation Adjustments” below for more information. During the eight months ended August 31, 2020 and the years ended December 31, 2019 and 2018, 1,665,153, 347,493 and 230,932 shares, respectively, of PSAs and PSUs subject to certain market-based vesting criteria were granted to executive officers under the Predecessor Equity Plan. These market-based awards were to cliff vest on the third anniversary of the grant date, and the number of shares that would vest at the end of that three-year performance period were determined based on the rank of Whiting’s cumulative stockholder return compared to the stockholder return of a peer group of companies on each anniversary of the grant date over the three-year performance period. The number of awards earned could range from zero up to two times the number of shares initially granted. However, awards earned up to the target shares granted (or 100%) would have been settled in shares, while awards earned in excess of the target shares granted would have been settled in cash. The cash-settled component of such awards was recorded as a liability in the consolidated balance sheets and was remeasured at fair value using a Monte Carlo valuation model at the end of each reporting period. On March 31, 2020, all of the PSAs and PSUs issued to executive officers in 2020 were forfeited and concurrently replaced with cash incentives. Refer to “2020 Compensation Adjustments” below for more information. For the PSAs and PSUs subject to market conditions, the grant date fair value was estimated using the Monte Carlo Model. Expected volatility was calculated based on the historical volatility and implied volatility of Whiting’s common stock, and the risk-free interest rate was based on U.S. Treasury yield curve rates with maturities consistent with the three-year vesting period. The key assumptions used in valuing these market-based awards were as follows: ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 ​ 2018 Number of simulations 2,500,000 2,500,000 2,500,000 Expected volatility 76.52% ​ 72.95% ​ 72.80% Risk-free interest rate 1.51% ​ 2.60% ​ 2.12% Dividend yield — — — ​ The weighted average grant date fair value of the market-based awards that were to be settled in shares as determined by the Monte Carlo valuation model was $4.31 per share, $25.97 per share and $27.28 per share in the Current Predecessor YTD Period, 2019 and 2018, respectively. For the eight months ended August 31, 2020 and the years ended December 31, 2019 and 2018, the total fair value of the Company’s service-based and market-based awards vested was $1 million, $12 million and $16 million, respectively. Total stock-based compensation expense for Predecessor restricted stock awards for the eight months ended August 31, 2020 and the years ended December 31, 2019 and 2018 was $3 million, $8 million and $18 million, respectively. As a result of the implementation of the Plan, the Company accelerated $4 million of expense related to unvested awards, which was recorded to reorganization items, net in the consolidated statements of operations during the Current Predecessor YTD Period. Refer to the “Fresh Start Accounting” footnote for more information. 2020 Compensation Adjustments. Stock Options For the year ended December 31, 2018, the aggregate intrinsic value of stock options exercised was $0.1 million. There were no stock options exercised during the eight months ended August 31, 2020 or the year ended December 31, 2019. ​

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2020
INCOME TAXES [Abstract]
INCOME TAXES	14. INCOME TAXES Income tax expense (benefit) consists of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ Four Months Ended December 31, 2020 ​ ​ Eight Months Ended August 31, 2020 ​ Year Ended December 31, 2019 ​ Year Ended December 31, 2018 Current income tax expense (benefit) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Federal ​ $ - ​ ​ $ (1,028) ​ $ - ​ $ - Foreign ​ ​ 2,463 ​ ​ ​ 3,746 ​ ​ - ​ ​ - Total current income tax benefit ​ ​ 2,463 ​ ​ ​ 2,718 ​ ​ - ​ ​ - Deferred income tax expense (benefit) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Federal ​ ​ - ​ ​ ​ - ​ ​ 2,140 ​ ​ (10,960) State ​ ​ - ​ ​ ​ - ​ ​ (3,513) ​ ​ 12,333 Foreign ​ ​ (14,501) ​ ​ ​ (59,092) ​ ​ 73,593 ​ ​ - Total deferred income tax expense (benefit) ​ ​ (14,501) ​ ​ ​ (59,092) ​ ​ 72,220 ​ ​ 1,373 Total ​ $ (12,038) ​ ​ $ (56,374) ​ $ 72,220 ​ $ 1,373 ​ Income tax expense (benefit) differed from amounts that would result from applying the U.S. statutory income tax rate of 21% to income before income taxes as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ Four Months Ended December 31, 2020 ​ ​ Eight Months Ended August 31, 2020 ​ Year Ended December 31, 2019 ​ Year Ended December 31, 2018 Federal and state tax expense (benefit) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. statutory income tax expense (benefit) ​ $ 5,676 ​ ​ $ (844,471) ​ $ (35,479) ​ $ 72,211 State income taxes, net of federal benefit ​ ​ 724 ​ ​ ​ (148,305) ​ ​ (8,288) ​ ​ 14,324 Executive compensation ​ ​ (765) ​ ​ ​ 2,182 ​ ​ - ​ ​ - Reorganization costs ​ ​ - ​ ​ ​ 10,584 ​ ​ - ​ ​ - IRC Section 382 and other restructuring adjustments ​ ​ 549,323 ​ ​ ​ 5,433 ​ ​ - ​ ​ - State net operating loss adjustments due to subsidiary restructuring ​ ​ 25,864 ​ ​ ​ - ​ ​ - ​ ​ - Market-based equity awards ​ ​ 415 ​ ​ ​ 441 ​ ​ 910 ​ ​ 2,215 Other ​ ​ (1,105) ​ ​ ​ (4,040) ​ ​ 1,812 ​ ​ 397 Valuation allowance ​ ​ (580,132) ​ ​ ​ 977,148 ​ ​ 39,672 ​ ​ (87,774) Total federal and state tax expense (benefit) ​ ​ - ​ ​ ​ (1,028) ​ ​ (1,373) ​ ​ 1,373 Foreign tax expense (benefit) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign tax expense ​ ​ 2,463 ​ ​ ​ 3,746 ​ ​ (147) ​ ​ - ASC 740-30-25-19 outside basis difference recognition ​ ​ (14,501) ​ ​ ​ (59,092) ​ ​ 73,740 ​ ​ - Total foreign tax expense (benefit) ​ ​ (12,038) ​ ​ ​ (55,346) ​ ​ 73,593 ​ ​ - Total ​ $ (12,038) ​ ​ $ (56,374) ​ $ 72,220 ​ $ 1,373 ​ The principal components of the Company’s deferred income tax assets and liabilities at December 31, 2020 and 2019 were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ ​ December 31, ​ ​ December 31, ​ 2020 ​ 2019 Deferred income tax assets ​ ​ ​ ​ ​ ​ ​ Net operating loss carryforward ​ $ 248,835 ​ ​ $ 944,709 Derivative instruments ​ ​ 14,119 ​ ​ ​ 2,451 Asset retirement obligations ​ ​ 23,390 ​ ​ ​ 32,152 Restricted stock compensation ​ ​ 123 ​ ​ ​ 2,033 EOR credit carryforwards ​ ​ 7,946 ​ ​ ​ 7,946 Lease obligations ​ ​ 9,409 ​ ​ ​ 14,463 Oil and gas properties ​ ​ 291,698 ​ ​ ​ - Other ​ ​ 5,011 ​ ​ ​ 12,847 Total deferred income tax assets ​ ​ 600,531 ​ ​ ​ 1,016,601 Less valuation allowance ​ ​ (585,296) ​ ​ ​ (188,281) Net deferred income tax assets ​ ​ 15,235 ​ ​ ​ 828,320 Deferred income tax liabilities ​ ​ ​ ​ ​ ​ ​ Oil and gas properties ​ ​ - ​ ​ ​ 805,989 Trust distributions ​ ​ 6,061 ​ ​ ​ 10,517 Lease assets ​ ​ 9,174 ​ ​ ​ 10,993 Discount on convertible senior notes ​ ​ - ​ ​ ​ 674 Foreign outside basis difference ​ ​ - ​ ​ ​ 73,740 Total deferred income tax liabilities ​ ​ 15,235 ​ ​ ​ 901,913 Total net deferred income tax liabilities ​ $ - ​ ​ $ 73,593 ​ Internal Revenue Code (“IRC”) Section 382 addresses company ownership changes and specifically limits the utilization of certain deductions and other tax attributes on an annual basis following an ownership change. As a result of the chapter 11 reorganization and related transactions, the Successor experienced an ownership change within the meaning of IRC Section 382 on the Emergence Date. This ownership change subjected certain of the Company’s tax attributes to an IRC Section 382 limitation. This limitation has not resulted in a current tax liability for the Successor Period, or any intervening period since the Emergence Date. The ownership changes and resulting annual limitation will result in the expiration of net operating loss carryforwards (“NOLs”) or other tax attributes otherwise available, with a corresponding decrease in the Company’s valuation allowance. As of December 31, 2020, the Company had federal NOL carryforwards of $3.1 billion, which are subject to IRC Section 382 limitations due to the Company incurring a Section 382 ownership event at the time of emergence from the Chapter 11 Cases. The Company currently estimates that approximately $2.3 billion of these federal NOLs will expire before they are able to be used. The determination of the state NOL carryforwards is dependent upon apportionment percentages and state laws that can change from year to year and that can thereby impact the amount of such carryforwards. If unutilized, the majority of the federal and state NOLs will expire between 2022 and 2037. Any federal NOLs generated in 2018 or subsequent do not expire. EOR credits are a credit against federal income taxes for certain costs related to extracting high-cost oil, utilizing certain prescribed enhanced tertiary recovery methods. As of December 31, 2020, the Company had recognized aggregate EOR credits of $8 million. As a result of a IRC Section 382 limitation in July 2016, the Company recorded a full valuation allowance on these credits. In assessing the realizability of deferred tax assets (“DTAs”), management considers whether it is more likely than not that some portion, or all, of the Company’s DTAs will not be realized. In making such determination, the Company considers all available positive and negative evidence, including future reversals of temporary differences, tax-planning strategies and projected future taxable income and results of operations. If the Company concludes that it is more likely than not that some portion, or all, of its DTAs will not be realized, the tax asset is reduced by a valuation allowance. At December 31, 2020, the Company had a valuation allowance totaling $585 million. During the fourth quarter of 2019, the Company determined it no longer had the ability to indefinitely prevent the reversal of the outside basis difference related to Whiting Canadian Holding Company ULC, Whiting’s wholly owned subsidiary, which at that time owned a portion of Whiting’s U.S. assets obtained through the acquisition of Kodiak Oil and Gas Corporation during 2014. Accordingly, the Company revised its assessment related to noncurrent Canadian deferred taxes pursuant to ASC 740-30-25-17 and recognized a $74 million deferred tax liability as well as the same amount of deferred income tax expense as of and for the year ended December 31, 2019 (Predecessor) associated with the outside basis difference related to Whiting Canadian Holding Company ULC. During the third quarter of 2020, the Company partially executed a legal entity restructuring plan to reduce administrative expenses and burden with a simplified corporate structure. The final steps of the legal entity restructuring were completed during the fourth quarter of 2020, ultimately resulting with Whiting Oil & Gas, under its parent Whiting Petroleum Corporation, holding all of the Company’s oil and gas operations. As a result of impacts from fresh start accounting, the Company reduced its deferred tax liability for its outside basis difference related to Whiting Canadian Holding Company ULC and recorded a tax benefit of $55 million during the Current Predecessor YTD Period. As a result of the restructuring, the Company reduced its deferred tax liability and recorded a tax benefit of $12 million during the Successor Period. The Company paid Canadian cash taxes of $6 million during the fourth quarter of 2020. As of December 31, 2020 and 2019, the Company did not have any uncertain tax positions. For the periods presented, the Company did not recognize any interest or penalties with respect to unrecognized tax benefits, nor did the Company have any such interest or penalties previously accrued. The Company files income tax returns in the U.S. federal jurisdiction and in various states, each with varying statutes of limitations. The 2017 through 2020 tax years generally remain subject to examination by federal and state tax authorities. Additionally, the Company has Canadian income tax filings which remain subject to examination by the related tax authorities for the 2016 through 2020 tax years.

EARNINGS PER SHARE

EARNINGS PER SHARE	12 Months Ended
	Dec. 31, 2020
EARNINGS PER SHARE [Abstract]
EARNINGS PER SHARE	15. EARNINGS PER SHARE The reconciliations between basic and diluted earnings (loss) per share are as follows (in thousands, except per share data): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ Four Months Ended December 31, 2020 ​ ​ Eight Months Ended August 31, 2020 ​ Year Ended December 31, 2019 ​ Year Ended December 31, 2018 Basic earnings (loss) per share ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income (loss) ​ $ 39,073 ​ ​ $ (3,965,461) ​ $ (241,166) ​ $ 342,494 Weighted average shares outstanding ​ ​ 38,080 ​ ​ ​ 91,423 ​ ​ 91,285 ​ ​ 90,953 Earnings (loss) per common share, basic ​ $ 1.03 ​ ​ $ (43.37) ​ $ (2.64) ​ $ 3.77 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Diluted earnings (loss) per share ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income (loss) ​ $ 39,073 ​ ​ $ (3,965,461) ​ $ (241,166) ​ $ 342,494 Weighted average shares outstanding, basic ​ ​ 38,080 ​ ​ ​ 91,423 ​ ​ 91,285 ​ ​ 90,953 Service-based awards, market-based awards and stock options ​ ​ 39 ​ ​ ​ - ​ ​ - ​ ​ 916 Weighted average shares outstanding ​ ​ 38,119 ​ ​ ​ 91,423 ​ ​ 91,285 ​ ​ 91,869 Earnings (loss) per common share, diluted ​ $ 1.03 ​ ​ $ (43.37) ​ $ (2.64) ​ $ 3.73 ​ Successor During the Successor Period, the diluted earnings per share calculation excludes the effect of 4,837,387 common shares for Series A Warrants and 2,418,840 common shares for Series B Warrants that were out-of-the-money as of December 31, 2020, as well as 189,900 shares of market-based awards that did not meet the market-based vesting criteria as of December 31, 2020. Further, the calculation excludes the effect of 3,021,304 contingently issuable shares related to the settlement of general unsecured claims associated with the Chapter 11 Cases as all necessary conditions had not been met to be considered dilutive shares as of December 31, 2020. However, subsequent to December 31, 2020 we issued 948,897 of such contingently issuable shares. Refer to the “Subsequent Event” footnote for more information on this share issuance. The basic weighted average shares outstanding calculation for the Successor Period includes 48,897 of these shares as all necessary conditions to be included in the calculation per FASB ASC Topic 260 – Earnings per Share Predecessor For the eight months ended August 31, 2020, the Company had a net loss and therefore the diluted earnings per share calculation excludes the antidilutive effect of 314,896 shares of service-based awards. In addition, the diluted earnings per share calculation for the eight months ended August 31, 2020 excludes the effect of 29,465 common shares for stock options that were out of the money as of August 31, 2020. For the year ended December 31, 2019 the Company had a net loss and therefore the diluted earnings per share calculation for that period excludes the anti-dilutive effect of 344,671 shares of service-based awards and 3,511 shares of market-based awards. In addition, the diluted earnings per share calculation for the year ended December 31, 2019 excludes the effect of 45,588 common shares for stock options that were out of the money as of December 31, 2019. For the year ended December 31, 2018, the diluted earnings per share calculation excludes the effect of 100,708 common shares for stock options that were out of the money as of December 31, 2018. Refer to the “Stock-Based Compensation” footnote for further information on the Company’s service-based awards, market-based awards and stock options. The Company had the option to settle conversions of the Convertible Senior Notes with cash, shares of common stock or any combination thereof. As the conversion value of the Convertible Senior Notes did not exceed the principal amount of the notes for any time during the conversion period ending April 1, 2020, there was no impact to diluted earnings per share or the related disclosures for the periods presented.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2020
COMMITMENTS AND CONTINGENCIES [Abstract]
COMMITMENTS AND CONTINGENCIES	The table below shows the Company’s minimum future payments due by period under unconditional purchase obligations as of December 31, 2020 (in thousands): ​ ​ ​ ​ ​ ​ Pipeline ​ ​ Transportation Year ending December 31, ​ Agreements 2021 ​ $ 2,189 2022 ​ ​ 2,189 2023 ​ ​ 2,189 2024 ​ ​ 547 Total payments ​ $ 7,114 ​ Pipeline Transportation Agreements — The remaining contract contains a commitment to transport a minimum volume of crude oil or else pay for any deficiencies at a price stipulated in the contract. Although minimum annual quantities are specified in the agreement, the actual oil volumes transported and their corresponding unit prices are variable over the term of the contract. As a result, the future minimum payments for each of the five succeeding fiscal years are not fixed and determinable and are not therefore included in the table above. As of December 31, 2020, the Company estimated the minimum future commitments under this transportation agreement to approximate $5 million through 2022. During the Successor Period, Current Predecessor YTD Period and years ended December 31, 2019 and 2018, the cost of transportation of crude oil, natural gas and NGLs under these contracts amounted to $1 million, $1 million, $2 million and $2 million, respectively. Delivery Commitments Chapter 11 Cases — However, it is reasonably possible that as a result of the legal proceedings associated with bankruptcy claims administration process or the matters detailed below, the Bankruptcy Court may rule, or it may be determined, that (i) the applicable contracts cannot be rejected or allow the claim amounts as administrative claims, or (ii) a claim is not a general unsecured claim. Any of these outcomes could require the Company to make cash payments to settle those claims instead of or in addition to issuing shares of the Successor’s common stock, and such cash payments would result in losses in future periods. Arguello Inc. and Freeport-McMoRan Oil & Gas LLC . WOG had interests in federal oil and gas leases in the Point Arguello Unit located offshore in California. While those interests have expired, pursuant to certain related agreements (the “Point Arguello Agreements”), WOG may be subject to abandonment and decommissioning obligations. WOG and Whiting Petroleum Corporation Arguello Inc. and Freeport-McMoRan Oil & Gas LLC, individually and in its capacity as the designated Point Arguello Unit operator (collectively, the “FMOG Entities”) filed with the Bankruptcy Court an application for allowance of certain administrative claims arguing the FMOG Entities are entitled to recover Whiting’s proportionate share of decommissioning obligations owed to the U.S. government through subrogation to the U.S. government’s economic rights. The FMOG Entities’ application alleges administrative claims of approximately $25 million for estimated decommissioning costs owed to the U.S. government, at least $60 million of estimated decommissioning costs owed to the FMOG Entities and other insignificant amounts. On September 14, 2020, the FMOG Entities also filed with the Bankruptcy Court proofs of claim for rejection damages to serve as an alternative course of action in the event that a court should determine that the FMOG Entities do not hold any applicable administrative claims. The U.S. government may also be able to bring claims against WOG directly for decommissioning costs. The Bankruptcy Court has not issued a ruling on the damages for rejection of the Point Arguello Agreements or the FMOG Entities’ application for administrative claims. Although WOG intends to vigorously defend this legal proceeding, if the FMOG Entities were to prevail on certain of their respective claims on the merits or the U.S. government were to bring claims against WOG, Whiting could be liable for administrative claims that must be paid in cash pursuant to the Plan. Litigation — The Company was involved in litigation related to a payment arrangement with a third party. In June 2020, the Company and the third party reached a settlement agreement resulting in the Company paying the third party a settlement amount of $14 million. The Company recognized $11 million in accrued liabilities and other in the consolidated balance sheets as of December 31, 2019 and general and administrative expenses in the consolidated statements of operations for the year ended December 31, 2019 as it was determined that a loss as a result of this litigation was probable. The Company recorded $3 million of additional litigation settlement expense in general and administrative expenses in the consolidated statements of operations for the Current Predecessor YTD Period upon settling this litigation. Upon settlement, the Company agreed to indemnify a party involved in the litigation for any further claims resulting from these matters up to $25 million. This indemnity will terminate on the later of: (i) June 1, 2021 or (ii) the date on which the statute of limitations for the relevant claims expires. The Company does not expect to pay additional amounts to this party as a result of this indemnity, and thus has not recorded any liability related to the indemnity as of December 31, 2020.

CAPITALIZED EXPLORATORY WELL CO

CAPITALIZED EXPLORATORY WELL COSTS	12 Months Ended
	Dec. 31, 2020
CAPITALIZED EXPLORATORY WELL COSTS [Abstract]
CAPITALIZED EXPLORATORY WELL COSTS	17. CAPITALIZED EXPLORATORY WELL COSTS Exploratory well costs that are incurred and expensed in the same annual period have not been included in the table below. The net changes in capitalized exploratory well costs were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ ​ Four Months Ended December 31, 2020 ​ ​ Eight Months Ended August 31, 2020 ​ Year Ended December 31, 2019 ​ Year Ended December 31, 2018 Beginning balance ​ $ - ​ ​ $ - ​ $ - ​ $ 13,894 Additions to capitalized exploratory well costs pending the determination of proved reserves ​ ​ - ​ ​ ​ - ​ ​ - ​ ​ 10,831 Reclassifications to wells, facilities and equipment based on the determination of proved reserves ​ ​ - ​ ​ ​ - ​ ​ - ​ ​ (24,725) Ending balance ​ $ - ​ ​ $ - ​ $ - ​ $ - ​ At December 31, 2020, the Company had no costs capitalized for exploratory wells in progress for a period of greater than one year after the completion of drilling.

COMPANY RESTRUCTURINGS

COMPANY RESTRUCTURINGS	12 Months Ended
	Dec. 31, 2020
COMPANY RESTRUCTURINGS [Abstract]
COMPANY RESTRUCTURINGS	18. COMPANY RESTRUCTURINGS During September 2020 and August 2019, the Company executed workforce reductions as part of an organizational redesign and cost reduction strategy to better align its business with the current operating environment and drive long-term value. For each of these workforce reductions, the Company incurred one-time net charges related to these restructurings of $8 million in net restructuring costs associated with one-time employee termination benefits. These charges were recorded to general and administrative expenses during the relevant periods in the consolidated statements of operations.

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	12 Months Ended
	Dec. 31, 2020
SUBSEQUENT EVENTS [Abstract]
SUBSEQUENT EVENTS	19. SUBSEQUENT EVENT Prior to the Chapter 11 Cases, WOG was party to various executory contracts with BNN Western, LLC, subsequently renamed Tallgrass Water Western, LLC (“Tallgrass”), including a Produced Water Gathering and Disposal Agreement (the “PWA”). In January 2021, WOG and Tallgrass entered into a settlement agreement to resolve all of the related claims before the Bankruptcy Court relating to such executory contracts, terminated the PWA and entered into a new Water Transport, Gathering and Disposal Agreement. In accordance with the settlement agreement, Whiting made a $2 million cash payment and issued 948,897 shares of New Common Stock pursuant to the confirmed Plan to a Tallgrass entity in February 2021.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2020
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]
Voluntary Reorganization under Chapter 11 of the Bankruptcy Code	Voluntary Reorganization under Chapter 11 of the Bankruptcy Code Upon emergence, the Company adopted fresh start accounting in accordance with FASB ASC Topic 852 – Reorganizations During the Current Predecessor YTD Period, the Company applied ASC 852 in preparing the consolidated financial statements, which requires distinguishing transactions associated with the reorganization separate from activities related to the ongoing operations of the business. Accordingly, pre-petition liabilities that could have been impacted by the chapter 11 proceedings were classified as liabilities subject to compromise. Additionally, certain expenses, realized gains and losses and provisions for losses that were realized or incurred during the Chapter 11 Cases, including adjustments to the carrying value of certain assets and indebtedness were recorded as reorganization items, net in the consolidated statements of operations for the relevant Predecessor periods.
Ability to Continue as a Going Concern	Ability to Continue as a Going Concern
Basis of Presentation of Consolidated Financial Statements	Basis of Presentation of Consolidated Financial Statements
Reclassifications	Reclassifications
Use of Estimates	Use of Estimates —
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted Cash — The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheets and statements of cash flows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ ​ December 31, ​ ​ December 31, ​ ​ 2020 ​ ​ 2019 Cash and cash equivalents ​ $ 25,607 ​ ​ $ 8,652 Restricted cash ​ ​ 2,760 ​ ​ ​ - Total cash, cash equivalents and restricted cash ​ $ 28,367 ​ ​ $ 8,652 ​ Restricted cash as of December 31, 2020 shown in the table above consists of funds remaining in a professional fee escrow account that were reserved to pay certain professional fees upon emergence from the Chapter 11 Cases (the “Professional Fee Escrow Account”).
Accounts Receivable Trade	Accounts Receivable Trade The Company routinely evaluates expected credit losses for all material trade and other receivables to determine if an allowance for credit losses is warranted. Expected credit losses are estimated based on (i) historic loss experience for pools of receivable balances with similar characteristics, (ii) the length of time balances have been outstanding and (iii) the economic status of each counterparty. These loss estimates are then adjusted for current and expected future economic conditions, which may include an assessment of the probability of non-payment, financial distress or expected future commodity prices and the impact that any current or future conditions could have on a counterparty’s credit quality and liquidity. As of December 31, 2020 (Successor), the Company had an immaterial allowance for credit losses due to the application of fresh start accounting. As of December 31, 2019 (Predecessor), the Company had an allowance for credit losses of $9 million.
Inventories	Inventories —
Oil and Gas Properties	Oil and Gas Properties Proved. The Company assesses its proved oil and gas properties for impairment whenever events or circumstances indicate that the carrying value of the assets may not be recoverable. Such events include, but are not limited to, declines in commodity prices, increases in operating costs, unfavorable reserve revisions, poor well performance, changes in development plans and potential property divestitures. The impairment test compares undiscounted future net cash flows to the assets’ net book value. These undiscounted cash flows are driven by significant assumptions, including the Company’s expected future development activity, reserve estimates, forecasted pricing, future operating costs, capital expenditures and severance taxes. If the net capitalized costs exceed undiscounted future net cash flows, then the cost of the property is written down to fair value utilizing a discounted future net cash flow analysis. Impairment expense for proved properties totaled $4 billion for the Current Predecessor YTD Period, which is reported in exploration and impairment expense in the consolidated statements of operations. Net carrying values of retired, sold or abandoned properties that constitute less than a complete unit of depreciable property are charged or credited, net of proceeds, to accumulated depreciation, depletion and amortization unless doing so significantly affects the unit-of-production amortization rate, in which case a gain or loss is recognized in income. Gains or losses from the disposal of complete units of depreciable property are recognized to earnings. Unproved. Exploratory. Costs of drilling exploratory wells are initially capitalized, pending determination of whether the well has found proved reserves. If an exploratory well has not found proved reserves, the costs of drilling the well and other associated costs are charged to expense. Costs incurred for exploratory wells that find reserves, which cannot yet be classified as proved, continue to be capitalized if (i) the well has found a sufficient quantity of reserves to justify completion as a producing well and (ii) the Company is making sufficient progress assessing the reserves and the economic and operating viability of the project. If either condition is not met, or if the Company obtains information that raises substantial doubt about the economic or operational viability of the project, the exploratory well costs, net of any salvage value, are expensed.
Other Property and Equipment	Other Property and Equipment — buildings and leasehold improvements equipment
Debt Issuance Costs	Debt Issuance Costs
Debt Discount and Premiums	Debt Discounts and Premiums
Derivative Instruments	Derivative Instruments Derivatives and Hedging Cash flows from derivatives used to manage commodity price risk are classified in operating activities along with the cash flows of the underlying hedged transactions. The Company does not enter into derivative instruments for speculative or trading purposes. Refer to the “Derivative Financial Instruments” footnote for further information.
Asset Retirement Obligations and Environmental Costs	Asset Retirement Obligations and Environmental Costs Asset Retirement and Environmental Obligations Liabilities for environmental costs are recorded on an undiscounted basis when it is probable that obligations have been incurred and the amounts can be reasonably estimated. These liabilities are not reduced by possible recoveries from third parties.
Deferred Gain On Sale	Deferred Gain on Sale
Revenue Recognition	Revenue Recognition Revenue from Contracts with Customers one Taxes collected and remitted to governmental agencies on behalf of customers are not included in revenues or costs and expenses.
General and Administrative Expenses	General and Administrative Expenses
Stock-based Compensation Expense	Stock-based Compensation Expense
401 (k) Plan	401(k) Plan
Acquisition Cost	Acquisition Costs —
Maintenance and Repairs	Maintenance and Repairs
Income Taxes	Income Taxes
Earnings Per Share	Earnings Per Share
Industry Segment and Geographic Information	Industry Segment and Geographic Information
Concentration of Credit Risk	Concentration of Credit Risk ​ ​ ​ ​ ​ Year Ended December 31, 2020 Shell Trading (US) Company ​ 14 % Tesoro Crude Oil Co ​ 13 % ​ ​ ​ ​ ​ Year Ended December 31, 2019 Tesoro Crude Oil Co ​ 14 % Philips 66 Company ​ 12 % ​ ​ ​ ​ ​ Year Ended December 31, 2018 United Energy Trading, LLC ​ 17 % Tesoro Crude Oil Co ​ 14 % Philips 66 Company ​ 11 % ​ Commodity derivative contracts held by the Company are with six counterparties, all of which are participants in Whiting’s credit facility and all of which have investment-grade ratings from Moody’s and Standard & Poor’s. As of December 31, 2020, outstanding derivative contracts with Wells Fargo Bank, N.A., Bank of Oklahoma, JP Morgan Chase Bank, N.A. and Citibank, N.A. represented 31%, 23%, 19%, and 18% respectively, of total volumes hedged.

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2020
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]
Reconciliation Of cash, cash equivalents and restricted cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheets and statements of cash flows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ ​ December 31, ​ ​ December 31, ​ ​ 2020 ​ ​ 2019 Cash and cash equivalents ​ $ 25,607 ​ ​ $ 8,652 Restricted cash ​ ​ 2,760 ​ ​ ​ - Total cash, cash equivalents and restricted cash ​ $ 28,367 ​ ​ $ 8,652
Percentages of total oil and gas sales to significant purchasers	​ ​ ​ ​ ​ Year Ended December 31, 2020 Shell Trading (US) Company ​ 14 % Tesoro Crude Oil Co ​ 13 % ​ ​ ​ ​ ​ Year Ended December 31, 2019 Tesoro Crude Oil Co ​ 14 % Philips 66 Company ​ 12 % ​ ​ ​ ​ ​ Year Ended December 31, 2018 United Energy Trading, LLC ​ 17 % Tesoro Crude Oil Co ​ 14 % Philips 66 Company ​ 11 %

FRESH START ACCOUNTING (Tables)

FRESH START ACCOUNTING (Tables)	12 Months Ended
	Dec. 31, 2020
FRESH START ACCOUNTING [Abstract]
Schedule of the reconciliation of the enterprise value to the implied value of the successor company's common stock	The following table reconciles the Company’s enterprise value to the implied value of the Successor’s common stock as of September 1, 2020 (in thousands): ​ ​ ​ ​ Enterprise value ​ $ 1,591,887 Plus: Cash and cash equivalents ​ ​ 22,657 Less: Fair value of debt ​ ​ (425,328) Implied value of Successor common stock ​ $ 1,189,216
Schedule of the reconciliation of the enterprise value to the reorganization value	The following table reconciles the Company’s enterprise value to its reorganization value as of September 1, 2020 (in thousands): ​ ​ ​ ​ Enterprise value ​ $ 1,591,887 Plus: ​ ​ ​ Cash and cash equivalents ​ ​ 22,657 Accounts payable trade ​ ​ 56,432 Revenues and royalties payable ​ ​ 145,506 Other current liabilities ​ ​ 143,790 Asset retirement obligations ​ ​ 121,343 Operating lease obligations ​ ​ 17,839 Deferred income taxes ​ ​ 14,501 Other long-term liabilities ​ ​ 28,773 Reorganization value ​ $ 2,142,728
Schedule of reorganization balance sheet and fresh-start accounting adjustments	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of September 1, 2020 ​ ​ ​ ​ Reorganization ​ ​ Fresh Start ​ ​ ​ ​ ​ Predecessor ​ Adjustments ​ ​ Adjustments ​ ​ Successor ASSETS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Current assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash and cash equivalents ​ $ 547,354 ​ $ (524,697) (a) ​ $ - ​ ​ $ 22,657 Restricted cash ​ ​ 28,955 ​ ​ (2,205) (b) ​ ​ - ​ ​ ​ 26,750 Accounts receivable trade, net ​ ​ 136,881 ​ ​ - ​ ​ ​ 81 (o) ​ ​ 136,962 Prepaid expenses and other ​ ​ 18,722 ​ ​ 231 (c) ​ ​ 2,260 (p) ​ ​ 21,213 Total current assets ​ ​ 731,912 ​ ​ (526,671) ​ ​ ​ 2,341 ​ ​ ​ 207,582 Property and equipment: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Oil and gas properties, successful efforts method ​ ​ 4,885,013 ​ ​ - ​ ​ ​ (3,058,899) (q) ​ ​ 1,826,114 Other property and equipment ​ ​ 159,866 ​ ​ (909) (d) ​ ​ (87,642) (o)(r) ​ ​ 71,315 Total property and equipment ​ ​ 5,044,879 ​ ​ (909) ​ ​ ​ (3,146,541) ​ ​ ​ 1,897,429 Less accumulated depreciation, depletion and amortization ​ ​ (2,085,266) ​ ​ - ​ ​ ​ 2,085,266 (o)(q)(r) ​ ​ - Total property and equipment, net ​ ​ 2,959,613 ​ ​ (909) ​ ​ ​ (1,061,275) ​ ​ ​ 1,897,429 Debt issuance costs ​ ​ 1,834 ​ ​ 10,950 (e) ​ ​ - ​ ​ ​ 12,784 Other long-term assets ​ ​ 37,010 ​ ​ (8,760) (d) ​ ​ (3,317) (o)(s) ​ ​ 24,933 TOTAL ASSETS ​ $ 3,730,369 ​ $ (525,390) ​ ​ $ (1,062,251) ​ ​ $ 2,142,728 LIABILITIES AND EQUITY (DEFICIT) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Current liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Current portion of long-term debt ​ $ 912,259 ​ $ (912,259) (f) ​ $ - ​ ​ $ - Accounts payable trade ​ ​ 47,168 ​ ​ 9,264 (g)(h) ​ ​ - ​ ​ ​ 56,432 Revenues and royalties payable ​ ​ 145,506 ​ ​ - ​ ​ ​ - ​ ​ ​ 145,506 Accrued capital expenditures ​ ​ 14,037 ​ ​ 1,305 (g) ​ ​ - ​ ​ ​ 15,342 Accrued liabilities and other ​ ​ 46,327 ​ ​ 21,942 (g)(i) ​ ​ (6,529) (o)(t) ​ ​ 61,740 Accrued lease operating expenses ​ ​ 25,344 ​ ​ 1,394 (g) ​ ​ - ​ ​ ​ 26,738 Accrued interest ​ ​ 3,459 ​ ​ (3,332) (g)(j) ​ ​ (127) (o) ​ ​ - Taxes payable ​ ​ 13,972 ​ ​ - ​ ​ ​ - ​ ​ ​ 13,972 Derivative liabilities ​ ​ 25,998 ​ ​ - ​ ​ ​ - ​ ​ ​ 25,998 Total current liabilities ​ ​ 1,234,070 ​ ​ (881,686) ​ ​ ​ (6,656) ​ ​ ​ 345,728 Long-term debt ​ ​ - ​ ​ 425,328 (k) ​ ​ - ​ ​ ​ 425,328 Asset retirement obligations ​ ​ 150,925 ​ ​ - ​ ​ ​ (29,582) (u) ​ ​ 121,343 Operating lease obligations ​ ​ - ​ ​ 17,652 (d)(g) ​ ​ 187 (o) ​ ​ 17,839 Deferred income taxes ​ ​ 69,847 ​ ​ - ​ ​ ​ (55,346) (v) ​ ​ 14,501 Other long-term liabilities ​ ​ 18,160 ​ ​ 11,071 (g) ​ ​ (458) (o)(t) ​ ​ 28,773 Total liabilities not subject to compromise ​ ​ 1,473,002 ​ ​ (427,635) ​ ​ ​ (91,855) ​ ​ ​ 953,512 Liabilities subject to compromise ​ ​ 2,526,925 ​ ​ (2,526,925) (g) ​ ​ - ​ ​ ​ - Total liabilities ​ ​ 3,999,927 ​ ​ (2,954,560) ​ ​ ​ (91,855) ​ ​ ​ 953,512 Commitments and contingencies ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity (deficit): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Predecessor common stock ​ ​ 92 ​ ​ (92) (l) ​ ​ - ​ ​ ​ - Successor common stock ​ ​ - ​ ​ 38 (m) ​ ​ - ​ ​ ​ 38 Predecessor additional paid-in capital ​ ​ 6,410,410 ​ ​ (6,410,410) (l) ​ ​ - ​ ​ ​ - Successor additional paid-in capital ​ ​ - ​ ​ 1,189,178 (m) ​ ​ - ​ ​ ​ 1,189,178 Accumulated earnings (deficit) ​ ​ (6,680,060) ​ ​ 7,650,456 (n) ​ ​ (970,396) (w) ​ ​ - Total equity (deficit) ​ ​ (269,558) ​ ​ 2,429,170 ​ ​ ​ (970,396) ​ ​ ​ 1,189,216 TOTAL LIABILITIES AND EQUITY (DEFICIT) ​ $ 3,730,369 ​ $ (525,390) ​ ​ $ (1,062,251) ​ ​ $ 2,142,728
Schedule of sources and uses of cash on the effective date	​ ​ ​ ​ ​ Sources: ​ ​ ​ Release of restricted cash upon bankruptcy emergence ​ $ 28,205 Borrowings under the Exit Credit Agreement ​ ​ 425,328 Total sources of cash ​ ​ 453,533 Uses: ​ ​ ​ Payment of outstanding borrowings under the Predecessor Credit Agreement ​ ​ (912,259) Payment of accrued interest on the Predecessor Credit Agreement ​ ​ (3,437) Payment of debt issuance costs related to Exit Credit Agreement ​ ​ (10,950) Funding of the Professional Fee Escrow Account ​ ​ (26,000) Payment of professional fees upon emergence ​ ​ (14,470) Payment of contract cure amounts ​ ​ (11,114) Total uses of cash ​ ​ (978,230) ​ ​ ​ ​ Net uses of cash ​ $ (524,697)
Schedule of reclassification of cash balances to and from restricted cash	​ ​ ​ ​ ​ Funding of the Professional Fee Escrow Account ​ $ 26,000 Release of restricted cash upon bankruptcy emergence (1) ​ ​ (28,205) Net reclassifications from restricted cash ​ $ (2,205) (1) Includes $23 million of funds related to derivative termination settlements that were directed by the counterparty to be held in a segregated account until the Company emerged from bankruptcy, as well as $5 million of amounts set aside as adequate assurance for utility providers that were restricted until emergence. (c) Reflects the payment of professional fee retainers upon emergence. (d) The Company amended a corporate office lease agreement and terminated the lease of certain floors within that agreement, which amendment was effective upon emergence from the Chapter 11 Cases. As a result of the lease modification and terminations, the Company reduced the associated right-of-use assets and operating lease obligations by $10 million and $15 million, respectively, resulting in a $5 million gain on settlement of liabilities subject to compromise, which was recorded to reorganization items, net in the consolidated statements of operations. The corporate office lease was classified as an operating lease and the modification did not result in a change to the lease’s classification. Additionally, $18 million of long-term operating lease obligations in liabilities subject to compromise were reinstated to be satisfied in the ordinary course of business. (e) Represents $11 million of financing costs related to the Exit Credit Agreement which were capitalized as debt issuance costs and will be amortized to interest expense through the maturity date of April 1, 2024. (f) Reflects the payment in full of the borrowings outstanding under the Predecessor Credit Agreement on the Emergence Date.
Schedule of disposition of liabilities subject to compromise	​ ​ ​ ​ Liabilities subject to compromise pre-emergence ​ $ 2,526,925 Amounts reinstated on the Emergence Date: ​ ​ ​ Accounts payable trade ​ ​ (10,866) Accrued capital expenditures ​ ​ (1,305) Accrued lease operating expenses ​ ​ (1,394) Accrued liabilities and other ​ ​ (13,961) Accrued interest ​ ​ (105) Operating lease obligations ​ ​ (17,652) Other long-term liabilities ​ ​ (11,071) Total liabilities reinstated ​ ​ (56,354) Less: Amounts settled per the Plan ​ ​ ​ Issuance of common stock to general unsecured claim holders ​ ​ (1,125,062) Payment of contract cure amounts ​ ​ (10,836) Operating lease modification and terminations ​ ​ (9,669) Issuance of Successor common stock to holders of unvested cash-settled equity awards (1) ​ ​ (64) Total amounts settled ​ ​ (1,145,631) Gain on settlement of liabilities subject to compromise ​ $ 1,324,940 (1) Holders of unvested cash-settled restricted stock awards were included as existing equity interests in the Plan and thus received Successor common stock on a pro rata basis based on the amount of unvested awards held. This amount represents the gain on the liability related to those awards, which was included in liabilities subject to compromise prior to emergence. (h) Reflects the reinstatement of $11 million of accounts payable included in liabilities subject to compromise to be satisfied in the ordinary course of business, partially offset by $2 million of professional fees paid on the Emergence Date. (i) Represents the accrual of success fees payable upon emergence as well as certain other expenses, the payment of certain professional fees that were accrued for prior to emergence and the reinstatement of certain accrued liabilities included in liabilities subject to compromise to be satisfied in the ordinary course of business, as detailed in the following table (in thousands):
Schedule of accrued liabilities and other	​ ​ ​ ​ ​ Reinstatement of accrued expenses from liabilities subject to compromise ​ $ 13,961 Recognition of success fee payable upon emergence ​ ​ 11,500 Other expenses accrued at emergence ​ ​ 3,315 Payment of certain professional fees accrued prior to emergence ​ ​ (6,834) Net impact to accrued liabilities and other ​ $ 21,942
Schedule of equity issued to each class of claims	​ ​ ​ ​ ​ Issuance of common stock to general unsecured claim holders ​ $ 1,125,062 Issuance of common stock to Predecessor common stockholders and holders of unvested cash-settled equity awards ​ ​ 34,794 Issuance of warrants to Predecessor common stockholders and holders of unvested cash-settled equity awards ​ ​ 29,360 Fair value of Successor equity ​ $ 1,189,216
Schedule of impact on accumulated earnings (deficit)	​ ​ ​ ​ ​ Gain on settlement of liabilities subject to compromise ​ $ 1,324,940 Cancellation of Predecessor equity (1) ​ ​ 6,414,541 Fair value of equity issued to Predecessor common stockholders and holders of unvested cash-settled equity awards ​ ​ (34,794) Fair value of warrants issued to Predecessor common stockholders and holders of unvested cash-settled equity awards ​ ​ (29,360) Success fees incurred upon emergence ​ ​ (17,303) Acceleration of unvested stock-based compensation awards ​ ​ (4,161) Other expenses incurred upon emergence ​ ​ (3,407) Net impact on accumulated earnings (deficit) ​ $ 7,650,456 (1) This value is reflective of Predecessor common stock, Predecessor additional paid in capital and the recognition of $4 million in compensation expense related to the unrecognized portion of share-based compensation.
Schedule of fair value adjustment to the Company's leases	​ ​ ​ ​ ​ ​ Lease Asset/Liability ​ Balance Sheet Classification ​ Fair Value Adjustment Accounts receivable, net ​ Accounts receivable, net ​ $ 81 Operating lease assets, net ​ Other long-term assets ​ ​ (1,480) Finance lease assets ​ Other property and equipment ​ ​ (10,765) Accumulated depreciation - finance leases ​ Less accumulated depreciation, depletion and amortization ​ ​ 15,099 Accrued interest - finance leases ​ Accrued interest ​ ​ 127 Short-term finance lease obligation ​ Accrued liabilities and other ​ ​ (576) Short-term operating lease obligation ​ Accrued liabilities and other ​ ​ 319 Long-term finance lease obligation ​ Other long-term liabilities ​ ​ (1,174) Long-term operating lease obligation ​ Operating lease obligations ​ ​ (187) ​ ​ ​ ​ $ 1,444 (p) Reflects the adjustment to fair value of the Company's oil in tank inventory based on market prices as of the Emergence Date. (q) Reflects the adjustments to fair value of the Company's oil and natural gas properties and undeveloped properties, as well as the elimination of accumulated depletion, depreciation and amortization.
Schedule of components of reorganization items	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ ​ Four Months Ended December 31, 2020 ​ ​ Eight Months Ended August 31, 2020 Legal and professional advisory fees ​ $ - ​ ​ $ 57,170 Net gain on liabilities subject to compromise ​ ​ - ​ ​ ​ (1,324,940) Fresh start adjustments, net ​ ​ - ​ ​ ​ 1,025,742 Write-off of unamortized debt issuance costs and premium (1) ​ ​ - ​ ​ ​ 15,145 Other items, net ​ ​ - ​ ​ ​ 9,464 Total reorganization items, net ​ $ - ​ ​ $ (217,419) ​ (1) As a result of the Chapter 11 Cases and the adoption of ASC 852, the Company wrote off all unamortized premium and issuance cost balances related to its senior notes on the Petition Date .

OIL AND GAS PROPERTIES (Tables)

OIL AND GAS PROPERTIES (Tables)	12 Months Ended
	Dec. 31, 2020
OIL AND GAS PROPERTIES [Abstract]
Net capitalized costs related to the Company's oil and gas producing activities	Net capitalized costs related to the Company’s oil and gas producing activities at December 31, 2020 and 2019 are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ ​ December 31, ​ ​ December 31, ​ 2020 ​ ​ 2019 Proved oil and gas properties ​ $ 1,701,163 ​ ​ $ 12,549,395 Unproved leasehold costs ​ ​ 105,073 ​ ​ ​ 103,278 Wells and facilities in progress ​ ​ 6,365 ​ ​ ​ 159,334 Total oil and gas properties, successful efforts method ​ ​ 1,812,601 ​ ​ ​ 12,812,007 Accumulated depletion ​ ​ (71,064) ​ ​ ​ (5,656,929) Oil and gas properties, net ​ $ 1,741,537 ​ ​ $ 7,155,078

ACQUISITIONS AND DIVESTITURES (

ACQUISITIONS AND DIVESTITURES (Tables)	12 Months Ended
	Dec. 31, 2020
ACQUISITIONS AND DIVESTITURES [Abstract]
Schedule of purchase price allocation	​ ​ ​ ​ ​ Cash consideration ​ $ 122,861 ​ ​ ​ ​ Fair value of assets acquired: ​ ​ ​ Accounts receivable trade, net ​ $ 30 Prepaid expenses and other ​ ​ 43 Oil and gas properties, successful efforts method: ​ ​ ​ Proved oil and gas properties ​ ​ 106,860 Unproved oil and gas properties ​ ​ 21,769 Total fair value of assets acquired ​ ​ 128,702 ​ ​ ​ ​ Fair value of liabilities assumed: ​ ​ ​ Revenue and royalties payable ​ ​ 3,309 Asset retirement obligations ​ ​ 2,532 Total fair value of liabilities assumed ​ ​ 5,841 ​ ​ ​ ​ Total fair value of assets and liabilities acquired ​ $ 122,861

LEASES (Tables)

LEASES (Tables)	12 Months Ended
	Dec. 31, 2020
LEASES [Abstract]
Summary of lease balance sheet information	Supplemental balance sheet information for the Company’s leases as of December 31, 2020 and December 31, 2019 consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor Leases ​ Balance Sheet Classification ​ December 31, 2020 ​ ​ December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating leases ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating lease ROU assets ​ Other long-term assets ​ $ 21,962 ​ ​ $ 31,882 Accumulated depreciation ​ Other long-term assets ​ ​ (1,096) ​ ​ ​ (4,895) Operating lease ROU assets, net ​ ​ ​ $ 20,866 ​ ​ $ 26,987 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Short-term operating lease obligations ​ Accrued liabilities and other ​ $ 4,031 ​ ​ $ 7,346 Long-term operating lease obligations ​ Operating lease obligations ​ ​ 17,415 ​ ​ ​ 31,722 Total operating lease obligations ​ ​ ​ $ 21,446 ​ ​ $ 39,068 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Finance leases ​ ​ ​ ​ ​ ​ ​ ​ ​ Finance lease ROU assets ​ Other property and equipment ​ $ 19,706 ​ ​ $ 33,312 Accumulated depreciation ​ Accumulated depreciation, depletion and amortization ​ ​ (1,797) ​ ​ ​ (14,180) Finance lease ROU assets, net ​ ​ ​ $ 17,909 ​ ​ $ 19,132 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Short-term finance lease obligations ​ Accrued liabilities and other ​ $ 4,830 ​ ​ $ 4,974 Long-term finance lease obligations ​ Other long-term liabilities ​ ​ 13,138 ​ ​ ​ 16,638 Total finance lease obligations ​ ​ ​ $ 17,968 ​ ​ $ 21,612 The Company’s leases have remaining terms between less than one year to 10 years. Most of the Company’s leases do not state or imply a discount rate. Accordingly, the Company uses its incremental borrowing rate based on information available at lease commencement to determine the present value of the lease payments. Information regarding the Company’s lease terms and discount rates as of December 31, 2020 and December 31, 2019 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor Predecessor ​ ​ ​ ​ December 31, 2020 ​ ​ December 31, 2019 Weighted average remaining lease term ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating leases ​ ​ ​ ​ 7 years ​ ​ ​ 8 years Finance leases ​ ​ ​ ​ 4 years ​ ​ ​ 5 years ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average discount rate ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating leases ​ ​ ​ ​ 4.4% ​ ​ ​ 4.6% Finance leases ​ ​ ​ ​ 4.2% ​ ​ ​ 8.6%
Summary of lease cost	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor Predecessor ​ ​ Four Months Ended ​ ​ Eight Months Ended ​ Year Ended ​ ​ December 31, 2020 ​ ​ August 31, 2020 ​ December 31, 2019 Operating lease cost ​ $ 1,462 ​ ​ $ 4,691 ​ $ 11,512 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Finance lease cost: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortization of ROU assets ​ $ 1,842 ​ ​ $ 3,347 ​ $ 5,661 Interest on lease liabilities ​ ​ 260 ​ ​ ​ 1,131 ​ ​ 1,996 Total finance lease cost ​ $ 2,102 ​ ​ $ 4,478 ​ $ 7,657 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Short-term lease payments ​ $ 26,430 ​ ​ $ 164,815 ​ $ 676,850 Variable lease payments ​ $ 99 ​ ​ $ 23,307 ​ $ 31,812
Summary of lease cash flow information	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor Predecessor ​ ​ Four Months Ended ​ ​ Eight Months Ended ​ Year Ended ​ ​ December 31, 2020 ​ ​ August 31, 2020 ​ December 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating cash flows from operating leases ​ $ 2,174 ​ ​ $ 5,813 ​ $ 11,978 Operating cash flows from finance leases ​ $ 197 ​ ​ $ 1,156 ​ $ 2,006 Financing cash flows from finance leases ​ $ 1,773 ​ ​ $ 3,198 ​ $ 5,140 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ROU assets obtained in exchange for new operating lease obligations ​ $ 6,368 ​ ​ $ 3,252 ​ $ 18,658 ROU assets obtained in exchange for new finance lease obligations ​ $ - ​ ​ $ 170 ​ $ 4,158
Summary of operating lease obligations	The Company’s lease obligations as of December 31, 2020 will mature as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ Year ending December 31, ​ Operating Leases ​ Finance Leases 2021 ​ $ 4,500 ​ $ 5,489 2022 ​ ​ 3,572 ​ ​ 4,693 2023 ​ ​ 3,255 ​ ​ 3,833 2024 ​ ​ 2,898 ​ ​ 3,214 2025 ​ ​ 1,903 ​ ​ 2,385 Remaining ​ ​ 9,349 ​ ​ — Total lease payments ​ ​ 25,477 ​ ​ 19,614 Less imputed interest ​ ​ (4,031) ​ ​ (1,646) Total discounted lease payments ​ $ 21,446 ​ $ 17,968
Summary of finance lease obligations	​ ​ ​ ​ ​ ​ ​ ​ Year ending December 31, ​ Operating Leases ​ Finance Leases 2021 ​ $ 4,500 ​ $ 5,489 2022 ​ ​ 3,572 ​ ​ 4,693 2023 ​ ​ 3,255 ​ ​ 3,833 2024 ​ ​ 2,898 ​ ​ 3,214 2025 ​ ​ 1,903 ​ ​ 2,385 Remaining ​ ​ 9,349 ​ ​ — Total lease payments ​ ​ 25,477 ​ ​ 19,614 Less imputed interest ​ ​ (4,031) ​ ​ (1,646) Total discounted lease payments ​ $ 21,446 ​ $ 17,968

LONG-TERM DEBT (Tables)

LONG-TERM DEBT (Tables)	12 Months Ended
	Dec. 31, 2020
LONG-TERM DEBT [Abstract]
Schedule of long-term debt	Long-term debt consisted of the following at December 31, 2020 and 2019 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ ​ December 31, ​ ​ December 31, ​ 2020 ​ ​ 2019 Exit Credit Agreement ​ $ 360,000 ​ ​ $ - Predecessor Credit Agreement ​ ​ - ​ ​ ​ 375,000 1.25% Convertible Senior Notes due 2020 ​ ​ - ​ ​ ​ 262,075 5.75% Senior Notes due 2021 ​ ​ - ​ ​ ​ 773,609 6.25% Senior Notes due 2023 ​ ​ - ​ ​ ​ 408,296 6.625% Senior Notes due 2026 ​ ​ - ​ ​ ​ 1,000,000 Total principal ​ ​ 360,000 ​ ​ ​ 2,818,980 Unamortized debt discounts and premiums ​ ​ - ​ ​ ​ (2,575) Unamortized debt issuance costs on notes ​ ​ - ​ ​ ​ (16,520) Total long-term debt ​ $ 360,000 ​ ​ $ 2,799,885
Schedule of convertible senior notes	The Convertible Senior Notes consisted of the following at December 31, 2019 (in thousands): ​ ​ ​ ​ Liability component ​ ​ ​ Principal ​ $ 262,075 Less: unamortized note discount ​ ​ (2,829) Less: unamortized debt issuance costs ​ ​ (220) Net carrying value ​ $ 259,026 Equity component (1) ​ $ 128,452 (1) Recorded in additional paid-in capital, net of $5 million of issuance costs and $50 million of deferred taxes as of December 31, 2019.

ASSET RETIREMENT OBLIGATIONS (T

ASSET RETIREMENT OBLIGATIONS (Tables)	12 Months Ended
	Dec. 31, 2020
ASSET RETIREMENT OBLIGATIONS [Abstract]
Schedule of reconciliation of the Company's asset retirement obligations	​ ​ ​ ​ Asset retirement obligation at January 1, 2019 (Predecessor) ​ $ 135,834 Additional liability incurred ​ ​ 2,097 Revisions to estimated cash flows ​ ​ (10,945) Accretion expense ​ ​ 11,602 Obligations on sold properties ​ ​ (2,078) Liabilities settled ​ ​ (1,617) Asset retirement obligation at December 31, 2019 (Predecessor) ​ ​ 134,893 Additional liability incurred ​ ​ 76 Revisions to estimated cash flows ​ ​ 56,702 Accretion expense ​ ​ 8,199 Obligations on sold properties ​ ​ (693) Liabilities settled (1) ​ ​ (42,854) Asset retirement obligation at August 31, 2020 (Predecessor) ​ ​ 156,323 ​ ​ ​ ​ Fresh start adjustment (2) ​ ​ (29,582) ​ ​ ​ ​ ​ ​ ​ ​ Asset retirement obligation at September 1, 2020 (Successor) ​ ​ 126,741 Additional liability incurred ​ ​ 20 Revisions to estimated cash flows ​ ​ (30,623) Accretion expense ​ ​ 3,801 Liabilities settled ​ ​ (1,809) Asset retirement obligation at December 31, 2020 (Successor) ​ $ 98,130 (1) A portion of the Predecessor’s asset retirement obligations related to a contractual obligation to remove certain offshore facilities in California. The Company included the related contract in its schedule of rejected contracts as part of the Plan, and the related amounts of the obligations were included in liabilities subject to compromise on the consolidated balance sheets of the Predecessor as of August 31, 2020. A final ruling from the Bankruptcy Court on the rejection of this contract has not yet been issued. Refer to the “Fresh Start Accounting” and “Commitments and Contingencies” footnotes for additional information. (2) Refer to the “Fresh Start Accounting” footnote for more information on fresh start adjustments .

DERIVATIVE FINANCIAL INSTRUME_2

DERIVATIVE FINANCIAL INSTRUMENTS (Tables)	12 Months Ended
	Dec. 31, 2020
DERIVATIVE FINANCIAL INSTRUMENTS [Abstract]
Derivative instruments	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Average Settlement Period ​ Index ​ Derivative Instrument ​ Total Volumes (1) ​ Units ​ Swap Price ​ Floor ​ Ceiling Crude Oil ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ NYMEX WTI ​ Fixed Price Swaps ​ 4,386,000 ​ Bbl ​ $41.85 ​ - ​ - 2021 ​ NYMEX WTI ​ Two-way Collars ​ 6,956,000 ​ Bbl ​ - ​ $38.82 ​ $47.11 2022 ​ NYMEX WTI ​ Two-way Collars ​ 4,530,000 ​ Bbl ​ - ​ $38.41 ​ $48.75 ​ ​ ​ ​ Total ​ 15,872,000 ​ ​ ​ ​ ​ ​ ​ ​ Natural Gas ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ NYMEX Henry Hub ​ Fixed Price Swaps ​ 12,530,000 ​ MMBtu ​ $2.69 ​ - ​ - 2021 ​ NYMEX Henry Hub ​ Two-way Collars ​ 10,950,000 ​ MMBtu ​ - ​ $2.60 ​ $2.79 2022 ​ NYMEX Henry Hub ​ Fixed Price Swaps ​ 1,365,000 ​ MMBtu ​ $2.60 ​ - ​ - 2022 ​ NYMEX Henry Hub ​ Two-way Collars ​ 10,720,000 ​ MMBtu ​ - ​ $2.35 ​ $2.85 ​ ​ ​ ​ Total ​ 35,565,000 ​ ​ ​ ​ ​ ​ ​ ​ (1) Subsequent to December 31, 2020, the Successor entered into additional swaps for 1,447,000 Bbl of crude oil volumes and 6,120,000 MMBtu of natural gas volumes for the remainder of 2021 and 630,000 Bbl of crude oil volumes and 2,025,000 MMBtu of natural gas volumes for 2022. The Company also entered into additional two-way collars for 3,930,000 Bbl of crude oil volumes for 2022 and 1,980,000 Bbl of crude oil volumes and 1,800,000 MMBtu of natural gas volumes for the first three months of 2023. Finally, the Company entered into basis swaps for 6,120,000 MMBtu of natural gas volumes for the remainder of 2021 which are settled based on the difference between the Northern Natural Gas Ventura index price and NYMEX Henry Hub.
Schedule of effects of commodity derivative instruments	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (Gain) Loss Recognized in Income ​ ​ ​ ​ Successor ​ ​ Predecessor Not Designated as ASC 815 Hedges Statements of Operations Classification Four Months Ended December 31, 2020 Eight Months Ended August 31, 2020 Year Ended December 31, 2019 Year Ended December 31, 2018 Commodity contracts ​ Derivative (gain) loss, net ​ $ 24,714 ​ ​ $ (181,614) ​ $ 53,769 ​ $ 17,170
Location and fair value of derivative instruments	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ ​ ​ December 31, 2020 (1) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net ​ ​ ​ ​ Gross ​ ​ ​ ​ Recognized ​ ​ ​ ​ Recognized ​ Gross ​ Fair Value Not Designated as ​ ​ ​ Assets/ ​ Amounts ​ Assets/ ASC 815 Hedges Balance Sheet Classification Liabilities Offset Liabilities Derivative assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commodity contracts - current ​ Prepaid expenses and other ​ $ 14,287 ​ $ (14,287) ​ $ - Commodity contracts - non-current ​ Other long-term assets ​ ​ 19,991 ​ ​ (19,991) ​ ​ - Total derivative assets ​ ​ ​ $ 34,278 ​ $ (34,278) ​ $ - Derivative liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commodity contracts - current ​ Derivative liabilities ​ $ 63,772 ​ $ (14,287) ​ $ 49,485 Commodity contracts - non-current ​ Other long-term liabilities ​ ​ 29,741 ​ ​ (19,991) ​ ​ 9,750 Total derivative liabilities ​ ​ ​ $ 93,513 ​ $ (34,278) ​ $ 59,235 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Predecessor ​ ​ ​ ​ December 31, 2019 (1) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net ​ ​ ​ ​ Gross ​ ​ ​ ​ Recognized ​ ​ ​ ​ Recognized ​ Gross ​ Fair Value Not Designated as ​ ​ ​ Assets/ ​ Amounts ​ Assets/ ASC 815 Hedges Balance Sheet Classification Liabilities Offset Liabilities Derivative assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commodity contracts - current ​ Prepaid expenses and other ​ $ 75,654 ​ $ (74,768) ​ $ 886 Commodity contracts - non-current ​ Other long-term assets ​ ​ 5,648 ​ ​ (5,648) ​ ​ - Total derivative assets ​ ​ ​ $ 81,302 ​ $ (80,416) ​ $ 886 Derivative liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commodity contracts - current ​ Derivative liabilities ​ $ 85,053 ​ $ (74,768) ​ $ 10,285 Commodity contracts - non-current ​ Other long-term liabilities ​ ​ 6,534 ​ ​ (5,648) ​ ​ 886 Total derivative liabilities ​ ​ ​ $ 91,587 ​ $ (80,416) ​ $ 11,171 (1) All of the counterparties to the Company’s financial derivative contracts subject to master netting arrangements are lenders under both the Exit Credit Agreement and the Predecessor Credit Agreement, which eliminates the need to post or receive collateral associated with its derivative positions. Therefore, columns for cash collateral pledged or received have not been presented in these tables.

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
	Dec. 31, 2020
FAIR VALUE MEASUREMENTS [Abstract]
Summary of the fair values and carrying value of debt instruments	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Predecessor ​ ​ December 31, 2019 ​ ​ Fair ​ Carrying ​ Value (1) Value (2) 1.25% Convertible Senior Notes due 2020 ​ $ 260,214 ​ $ 259,026 5.75% Senior Notes due 2021 ​ ​ 732,995 ​ ​ 772,080 6.25% Senior Notes due 2023 ​ ​ 343,989 ​ ​ 405,392 6.625% Senior Notes due 2026 ​ ​ 681,250 ​ ​ 988,387 Total ​ $ 2,018,448 ​ $ 2,424,885 (1) Fair values are based on quoted market prices for these debt securities, and such fair values are therefore designated as Level 1 within the valuation hierarchy. (2) Carrying values are presented net of unamortized debt issuance costs and debt discounts or premiums.
Fair value assets and liabilities measured on a recurring basis	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Fair Value ​ Level 1 Level 2 Level 3 December 31, 2020 Financial liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commodity derivatives – current ​ $ - ​ $ 49,485 ​ $ - ​ $ 49,485 Commodity derivatives – non-current ​ ​ - ​ ​ 9,750 ​ ​ - ​ ​ 9,750 Total financial liabilities ​ $ - ​ $ 59,235 ​ $ - ​ $ 59,235 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Predecessor ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Fair Value ​ Level 1 Level 2 Level 3 December 31, 2019 Financial assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commodity derivatives – current ​ $ - ​ $ 886 ​ $ - ​ $ 886 Total financial assets ​ $ - ​ $ 886 ​ $ - ​ $ 886 Financial liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commodity derivatives – current ​ $ - ​ $ 10,285 ​ $ - ​ $ 10,285 Commodity derivatives – non-current ​ ​ - ​ ​ 886 ​ ​ - ​ ​ 886 Total financial liabilities ​ $ - ​ $ 11,171 ​ $ - ​ $ 11,171
Non-financial assets and liabilities measured at fair value on a nonrecurring basis	The following tables presents information about the Company’s non-financial assets measured at fair value on a non-recurring basis for the Current Predecessor YTD Period, and indicates the fair value hierarchy of the valuation techniques utilized by the Company to determine such fair value (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Predecessor ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loss (Before ​ ​ Net Carrying ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tax) During the ​ ​ Value as of ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Current ​ ​ March 31, ​ Fair Value Measurements Using ​ Predecessor ​ 2020 Level 1 Level 2 Level 3 Period Proved property (1) ​ $ 816,234 ​ $ - ​ $ - ​ $ 816,234 ​ $ 3,732,096 (1) During the first quarter of 2020, certain proved oil and gas properties across the Company’s Williston Basin resource play with a previous carrying amount of $4.5 billion were written down to their fair value as of March 31, 2020 of $816 million, resulting in a non-cash impairment charge of $3.7 billion, which was recorded within exploration and impairment expense. These impaired properties were written down due to a reduction in anticipated future cash flows primarily driven by an expectation of sustained depressed oil prices and a resultant decline in future development plans for the properties. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Predecessor ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loss (Before ​ ​ Net Carrying ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tax) During the ​ ​ Value as of ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Current ​ ​ June 30, ​ Fair Value Measurements Using ​ Predecessor YTD ​ 2020 Level 1 Level 2 Level 3 Period Proved property (2) ​ $ 85,418 ​ $ - ​ $ - ​ $ 85,418 ​ $ 409,079 (2) During the second quarter of 2020, other proved oil and gas properties in the Company’s Williston Basin resource play with a previous carrying amount of $494 million were written down to their fair value as of June 30, 2020 of $85 million, resulting in a non-cash impairment charge of $409 million, which was recorded within exploration and impairment expense. These impaired properties were written down due to a reduction in anticipated future cash flows primarily driven by an expectation of sustained depressed oil prices and a resultant decline in future development plans for the properties assessed during the second quarter of 2020.

REVENUE RECOGNITION (Tables)

REVENUE RECOGNITION (Tables)	12 Months Ended
	Dec. 31, 2020
REVENUE RECOGNITION [Abstract]
Summary of revenue disaggregation	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor OPERATING REVENUES ​ Four Months Ended December 31, 2020 ​ ​ Eight Months Ended August 31, 2020 ​ Year Ended December 31, 2019 ​ Year Ended December 31, 2018 Oil sales ​ $ 254,024 ​ ​ $ 440,820 ​ $ 1,492,218 ​ $ 1,850,052 NGL and natural gas sales ​ ​ 19,334 ​ ​ ​ 18,184 ​ ​ 80,027 ​ ​ 231,362 Oil, NGL and natural gas sales ​ $ 273,358 ​ ​ $ 459,004 ​ $ 1,572,245 ​ $ 2,081,414

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	12 Months Ended
	Dec. 31, 2020
Successor Awards [Member]
Share-based compensation disclosures
Assumption for valuing market based restricted shares	​ ​ ​ Number of simulations 100,000 Expected volatility 40% Risk-free interest rate 0.66% Dividend yield —
Predecessor Awards [Member]
Share-based compensation disclosures
Assumption for valuing market based restricted shares	​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 ​ 2018 Number of simulations 2,500,000 2,500,000 2,500,000 Expected volatility 76.52% ​ 72.95% ​ 72.80% Risk-free interest rate 1.51% ​ 2.60% ​ 2.12% Dividend yield — — —

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2020
INCOME TAXES [Abstract]
Schedule of income tax expense	Income tax expense (benefit) consists of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ Four Months Ended December 31, 2020 ​ ​ Eight Months Ended August 31, 2020 ​ Year Ended December 31, 2019 ​ Year Ended December 31, 2018 Current income tax expense (benefit) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Federal ​ $ - ​ ​ $ (1,028) ​ $ - ​ $ - Foreign ​ ​ 2,463 ​ ​ ​ 3,746 ​ ​ - ​ ​ - Total current income tax benefit ​ ​ 2,463 ​ ​ ​ 2,718 ​ ​ - ​ ​ - Deferred income tax expense (benefit) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Federal ​ ​ - ​ ​ ​ - ​ ​ 2,140 ​ ​ (10,960) State ​ ​ - ​ ​ ​ - ​ ​ (3,513) ​ ​ 12,333 Foreign ​ ​ (14,501) ​ ​ ​ (59,092) ​ ​ 73,593 ​ ​ - Total deferred income tax expense (benefit) ​ ​ (14,501) ​ ​ ​ (59,092) ​ ​ 72,220 ​ ​ 1,373 Total ​ $ (12,038) ​ ​ $ (56,374) ​ $ 72,220 ​ $ 1,373
Reconciliation of statutory income tax expense to income tax expense	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ Four Months Ended December 31, 2020 ​ ​ Eight Months Ended August 31, 2020 ​ Year Ended December 31, 2019 ​ Year Ended December 31, 2018 Federal and state tax expense (benefit) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. statutory income tax expense (benefit) ​ $ 5,676 ​ ​ $ (844,471) ​ $ (35,479) ​ $ 72,211 State income taxes, net of federal benefit ​ ​ 724 ​ ​ ​ (148,305) ​ ​ (8,288) ​ ​ 14,324 Executive compensation ​ ​ (765) ​ ​ ​ 2,182 ​ ​ - ​ ​ - Reorganization costs ​ ​ - ​ ​ ​ 10,584 ​ ​ - ​ ​ - IRC Section 382 and other restructuring adjustments ​ ​ 549,323 ​ ​ ​ 5,433 ​ ​ - ​ ​ - State net operating loss adjustments due to subsidiary restructuring ​ ​ 25,864 ​ ​ ​ - ​ ​ - ​ ​ - Market-based equity awards ​ ​ 415 ​ ​ ​ 441 ​ ​ 910 ​ ​ 2,215 Other ​ ​ (1,105) ​ ​ ​ (4,040) ​ ​ 1,812 ​ ​ 397 Valuation allowance ​ ​ (580,132) ​ ​ ​ 977,148 ​ ​ 39,672 ​ ​ (87,774) Total federal and state tax expense (benefit) ​ ​ - ​ ​ ​ (1,028) ​ ​ (1,373) ​ ​ 1,373 Foreign tax expense (benefit) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign tax expense ​ ​ 2,463 ​ ​ ​ 3,746 ​ ​ (147) ​ ​ - ASC 740-30-25-19 outside basis difference recognition ​ ​ (14,501) ​ ​ ​ (59,092) ​ ​ 73,740 ​ ​ - Total foreign tax expense (benefit) ​ ​ (12,038) ​ ​ ​ (55,346) ​ ​ 73,593 ​ ​ - Total ​ $ (12,038) ​ ​ $ (56,374) ​ $ 72,220 ​ $ 1,373
Components of deferred income tax assets and liabilities	The principal components of the Company’s deferred income tax assets and liabilities at December 31, 2020 and 2019 were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ ​ December 31, ​ ​ December 31, ​ 2020 ​ 2019 Deferred income tax assets ​ ​ ​ ​ ​ ​ ​ Net operating loss carryforward ​ $ 248,835 ​ ​ $ 944,709 Derivative instruments ​ ​ 14,119 ​ ​ ​ 2,451 Asset retirement obligations ​ ​ 23,390 ​ ​ ​ 32,152 Restricted stock compensation ​ ​ 123 ​ ​ ​ 2,033 EOR credit carryforwards ​ ​ 7,946 ​ ​ ​ 7,946 Lease obligations ​ ​ 9,409 ​ ​ ​ 14,463 Oil and gas properties ​ ​ 291,698 ​ ​ ​ - Other ​ ​ 5,011 ​ ​ ​ 12,847 Total deferred income tax assets ​ ​ 600,531 ​ ​ ​ 1,016,601 Less valuation allowance ​ ​ (585,296) ​ ​ ​ (188,281) Net deferred income tax assets ​ ​ 15,235 ​ ​ ​ 828,320 Deferred income tax liabilities ​ ​ ​ ​ ​ ​ ​ Oil and gas properties ​ ​ - ​ ​ ​ 805,989 Trust distributions ​ ​ 6,061 ​ ​ ​ 10,517 Lease assets ​ ​ 9,174 ​ ​ ​ 10,993 Discount on convertible senior notes ​ ​ - ​ ​ ​ 674 Foreign outside basis difference ​ ​ - ​ ​ ​ 73,740 Total deferred income tax liabilities ​ ​ 15,235 ​ ​ ​ 901,913 Total net deferred income tax liabilities ​ $ - ​ ​ $ 73,593 ​

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	12 Months Ended
	Dec. 31, 2020
EARNINGS PER SHARE [Abstract]
Reconciliations between basic and diluted earnings per share	The reconciliations between basic and diluted earnings (loss) per share are as follows (in thousands, except per share data): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ Four Months Ended December 31, 2020 ​ ​ Eight Months Ended August 31, 2020 ​ Year Ended December 31, 2019 ​ Year Ended December 31, 2018 Basic earnings (loss) per share ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income (loss) ​ $ 39,073 ​ ​ $ (3,965,461) ​ $ (241,166) ​ $ 342,494 Weighted average shares outstanding ​ ​ 38,080 ​ ​ ​ 91,423 ​ ​ 91,285 ​ ​ 90,953 Earnings (loss) per common share, basic ​ $ 1.03 ​ ​ $ (43.37) ​ $ (2.64) ​ $ 3.77 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Diluted earnings (loss) per share ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income (loss) ​ $ 39,073 ​ ​ $ (3,965,461) ​ $ (241,166) ​ $ 342,494 Weighted average shares outstanding, basic ​ ​ 38,080 ​ ​ ​ 91,423 ​ ​ 91,285 ​ ​ 90,953 Service-based awards, market-based awards and stock options ​ ​ 39 ​ ​ ​ - ​ ​ - ​ ​ 916 Weighted average shares outstanding ​ ​ 38,119 ​ ​ ​ 91,423 ​ ​ 91,285 ​ ​ 91,869 Earnings (loss) per common share, diluted ​ $ 1.03 ​ ​ $ (43.37) ​ $ (2.64) ​ $ 3.73

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2020
COMMITMENTS AND CONTINGENCIES [Abstract]
Minimum future payments under non-cancelable unconditional purchase obligations	The table below shows the Company’s minimum future payments due by period under unconditional purchase obligations as of December 31, 2020 (in thousands): ​ ​ ​ ​ ​ ​ Pipeline ​ ​ Transportation Year ending December 31, ​ Agreements 2021 ​ $ 2,189 2022 ​ ​ 2,189 2023 ​ ​ 2,189 2024 ​ ​ 547 Total payments ​ $ 7,114

CAPITALIZED EXPLORATORY WELL _2

CAPITALIZED EXPLORATORY WELL COSTS (Tables)	12 Months Ended
	Dec. 31, 2020
CAPITALIZED EXPLORATORY WELL COSTS [Abstract]
Net changes in capitalized exploratory well costs	Exploratory well costs that are incurred and expensed in the same annual period have not been included in the table below. The net changes in capitalized exploratory well costs were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ ​ Four Months Ended December 31, 2020 ​ ​ Eight Months Ended August 31, 2020 ​ Year Ended December 31, 2019 ​ Year Ended December 31, 2018 Beginning balance ​ $ - ​ ​ $ - ​ $ - ​ $ 13,894 Additions to capitalized exploratory well costs pending the determination of proved reserves ​ ​ - ​ ​ ​ - ​ ​ - ​ ​ 10,831 Reclassifications to wells, facilities and equipment based on the determination of proved reserves ​ ​ - ​ ​ ​ - ​ ​ - ​ ​ (24,725) Ending balance ​ $ - ​ ​ $ - ​ $ - ​ $ -

SUMMARY OF SIGNIFICANT ACCOUN_4

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Cash, Cash Equivalents And Restricted Cash) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Sep. 01, 2020	Aug. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]
Cash and cash equivalents	$ 25,607	$ 22,657	$ 547,354	$ 8,652
Restricted cash	2,760	$ 26,750	28,955
Total cash, cash equivalents and restricted cash	$ 28,367		$ 49,407	$ 8,652	$ 13,607	$ 879,379

SUMMARY OF SIGNIFICANT ACCOUN_5

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Narrative I) (Details) - USD ($) $ in Millions	3 Months Ended		4 Months Ended	8 Months Ended	12 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2020	Aug. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Summary Of Significant Accounting Policies [Line Items]
Allowance for doubtful account						$ 9
Materials and supplies inventories			$ 29		$ 29	39
Oil in tanks			6		$ 6	6
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life					30 years
Furniture and Fixtures [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life					4 years
Buildings [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life					4 years
Buildings [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life					30 years
Leasehold Improvements [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life					4 years
Leasehold Improvements [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life					30 years
Office Equipment [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life					30 years
Automobiles [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life					5 years
Automobiles [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life					30 years
Proved Properties [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairment of properties	$ 409	$ 3,700		$ 4,000
Unproved Properties [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairment of properties			$ 1	$ 13		$ 9	$ 37

SUMMARY OF SIGNIFICANT ACCOUN_6

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Narrative II) (Details) $ in Millions	4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2020USD ($)	Aug. 31, 2020USD ($)	Dec. 31, 2020segmentshares	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Summary Of Significant Accounting Policies [Line Items]
Employer's contribution in employees retirement plan | $	$ 1	$ 4		$ 7	$ 7
Employees vest in employer contribution Percentage, per year of completed service			20.00%
Service period			5 years
Number of operating segments | segment			1
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Payment received for product sales, period			1 month
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Payment received for product sales, period			3 months
Whiting USA Trust II Units [Member]
Summary Of Significant Accounting Policies [Line Items]
Trust units sold to the public (in shares) | shares			18,400,000

SUMMARY OF SIGNIFICANT ACCOUN_7

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Credit risk) (Details) - item	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Customer Concentration Risk [Member] | Oil And Gas Sales [Member] | Shell Trading (US) Company
Concentration Risk [Line Items]
Concentration risk (as a percent)	14.00%
Customer Concentration Risk [Member] | Oil And Gas Sales [Member] | United Energy Trading, LLC [Member]
Concentration Risk [Line Items]
Concentration risk (as a percent)			17.00%
Customer Concentration Risk [Member] | Oil And Gas Sales [Member] | Tesoro Crude Oil Co [Member]
Concentration Risk [Line Items]
Concentration risk (as a percent)	13.00%	14.00%	14.00%
Customer Concentration Risk [Member] | Oil And Gas Sales [Member] | Philips 66 Company [Member]
Concentration Risk [Line Items]
Concentration risk (as a percent)		12.00%	11.00%
Commodity Price Risk [Member] | Derivative Contracts [Member]
Concentration Risk [Line Items]
Number of counterparties	6
Commodity Price Risk [Member] | Derivative Contracts [Member] | Wells Fargo Bank [Member]
Concentration Risk [Line Items]
Concentration risk (as a percent)	31.00%
Commodity Price Risk [Member] | Derivative Contracts [Member] | Bank of Oklahoma [Member]
Concentration Risk [Line Items]
Concentration risk (as a percent)	23.00%
Commodity Price Risk [Member] | Derivative Contracts [Member] | JP Morgan Chase [Member]
Concentration Risk [Line Items]
Concentration risk (as a percent)	19.00%
Commodity Price Risk [Member] | Derivative Contracts [Member] | Citibank, N.A. [Member]
Concentration Risk [Line Items]
Concentration risk (as a percent)	18.00%

CHAPTER 11 EMERGENCE (Details)

CHAPTER 11 EMERGENCE (Details) - USD ($) $ in Millions	Sep. 01, 2020	Feb. 28, 2021	Dec. 31, 2020	Aug. 31, 2020	Aug. 31, 2020
Chapter 11 Cases
Financial Designation, Predecessor and Successor [Fixed List]			Successor		Predecessor
Issuance of Successor stock (in shares)	38,051,125
Number of shares authorized upon shareholder's approval	4,035,885
Interest expense not recognized				$ 57
Exit Credit Agreement [Member]
Chapter 11 Cases
Maximum borrowing capacity of credit facility	$ 750		$ 750
Additional contingent borrowings	$ 750
Series A [Member]
Chapter 11 Cases
Warrants outstanding (in shares)	4,837,387
Series B [Member]
Chapter 11 Cases
Warrants outstanding (in shares)	2,418,840
Senior Notes Holders [Member]
Chapter 11 Cases
Issuance of Successor stock (in shares)	36,817,630
Existing Stockholders [Member]
Chapter 11 Cases
Issuance of Successor stock (in shares)	1,233,495
General Unsecured Claimants [Member]
Chapter 11 Cases
Reserved for future issuance (in shares)	3,070,201
General Unsecured Claimants [Member] | Subsequent Event [Member]
Chapter 11 Cases
Issuance of Successor stock (in shares)		948,897

FRESH START ACCOUNTING - Fresh

FRESH START ACCOUNTING - Fresh start (Details) $ in Thousands	Sep. 01, 2020USD ($)
Fresh-Start Adjustment [Line Items]
Enterprise value	$ 1,591,887
Weighted average cost of capital rate	14.00%
Minimum [Member]
Fresh-Start Adjustment [Line Items]
Enterprise value	$ 1,350,000
Maximum [Member]
Fresh-Start Adjustment [Line Items]
Enterprise value	$ 1,750,000

FRESH START ACCOUNTING - Enterp

FRESH START ACCOUNTING - Enterprise value (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Sep. 01, 2020	Aug. 31, 2020	Dec. 31, 2019
FRESH START ACCOUNTING [Abstract]
Enterprise value		$ 1,591,887
Plus: Cash and cash equivalents	$ 25,607	22,657	$ 547,354	$ 8,652
Less: Fair value of debt	$ (360,000)	(425,328)		$ (2,799,885)
Implied value of Successor common stock		$ 1,189,216

FRESH START ACCOUNTING - Reorga

FRESH START ACCOUNTING - Reorganization value (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Sep. 01, 2020	Aug. 31, 2020	Dec. 31, 2019
FRESH START ACCOUNTING [Abstract]
Enterprise value		$ 1,591,887
Cash and cash equivalents	$ 25,607	22,657	$ 547,354	$ 8,652
Accounts payable trade	23,697	56,432	47,168	80,100
Revenues and royalties payable	151,196	145,506	145,506	202,010
Other current liabilities		143,790
Asset retirement obligations	91,864	121,343	150,925	131,208
Operating lease obligations	17,415	17,839		31,722
Deferred income taxes		14,501	69,847	73,593
Other long-term liabilities	$ 23,863	28,773	$ 18,160	$ 24,928
Reorganization value		$ 2,142,728

FRESH START ACCOUNTING - Balanc

FRESH START ACCOUNTING - Balance sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Sep. 01, 2020	Aug. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 25,607	$ 22,657	$ 547,354	$ 8,652
Restricted cash	2,760	26,750	28,955
Accounts receivable trade, net	142,830	136,962	136,881	308,249
Prepaid expenses and other	19,224	21,213	18,722	14,082
Total current assets	190,421	207,582	731,912	330,983
Property and equipment:
Oil and gas properties, successful efforts method	1,812,601	1,826,114	4,885,013	12,812,007
Other property and equipment	74,064	71,315	159,866	178,689
Total property and equipment	1,886,665	1,897,429	5,044,879	12,990,696
Less accumulated depreciation, depletion and amortization			(2,085,266)
Total property and equipment, net	1,812,796	1,897,429	2,959,613	7,255,457
Debt issuance costs		12,784	1,834
Other long-term assets	40,723	24,933	37,010	50,281
TOTAL ASSETS	2,043,940	2,142,728	3,730,369	7,636,721
Current liabilities:
Current portion of long-term debt			912,259
Accounts payable trade	23,697	56,432	47,168	80,100
Revenues and royalties payable	151,196	145,506	145,506	202,010
Accrued capital expenditures	20,155	15,342	14,037	64,263
Accrued liabilities and other	476	61,740	46,327	53,928
Accrued lease operating expenses	23,457	26,738	25,344	38,262
Accrued interest	36,170		3,459	53,597
Taxes payable	11,997	13,972	13,972	26,844
Derivative liabilities	49,485	25,998	25,998	10,285
Total current liabilities	321,994	345,728	1,234,070	550,414
Long-term debt	360,000	425,328		2,799,885
Asset retirement obligations	91,864	121,343	150,925	131,208
Operating lease obligations	17,415	17,839		31,722
Deferred income taxes		14,501	69,847	73,593
Other long-term liabilities	23,863	28,773	18,160	24,928
Total liabilities not subject to compromise		953,512	1,473,002
Liabilities subject to compromise			2,526,925
Total liabilities	815,136	953,512	3,999,927	3,611,750
Commitments and contingencies
Equity (Deficit):
Common stock	38	38	92	92
Additional paid-in capital	1,189,693	1,189,178	6,410,410	6,409,991
Accumulated earnings (deficit)	39,073		(6,680,060)	(2,385,112)
Total equity	1,228,804	1,189,216	(269,558)	4,024,971
TOTAL LIABILITIES AND EQUITY	$ 2,043,940	2,142,728	3,730,369	$ 7,636,721
Reorganization Adjustments [Member]
Current assets:
Cash and cash equivalents		(524,697)
Restricted cash		(2,205)
Prepaid expenses and other		231
Total current assets		(526,671)
Property and equipment:
Other property and equipment		(909)
Total property and equipment		(909)
Total property and equipment, net		(909)
Debt issuance costs		10,950
Other long-term assets		(8,760)
TOTAL ASSETS		(525,390)
Current liabilities:
Current portion of long-term debt		(912,259)
Accounts payable trade		9,264
Accrued capital expenditures		1,305
Accrued liabilities and other		21,942
Accrued lease operating expenses		1,394
Accrued interest		(3,332)
Total current liabilities		(881,686)
Long-term debt		425,328
Operating lease obligations		17,652
Other long-term liabilities		11,071
Total liabilities not subject to compromise		(427,635)
Liabilities subject to compromise		(2,526,925)	$ 2,526,925
Total liabilities		(2,954,560)
Equity (Deficit):
Accumulated earnings (deficit)		7,650,456
Total equity		2,429,170
TOTAL LIABILITIES AND EQUITY		(525,390)
Reorganization Adjustments [Member] | Predecessor adjustment
Equity (Deficit):
Common stock		(92)
Additional paid-in capital		(6,410,410)
Reorganization Adjustments [Member] | Successor adjustment
Equity (Deficit):
Common stock		38
Additional paid-in capital		1,189,178
Fresh Start Accounting Adjustments [Member]
Current assets:
Accounts receivable trade, net		81
Prepaid expenses and other		2,260
Total current assets		2,341
Property and equipment:
Oil and gas properties, successful efforts method		(3,058,899)
Other property and equipment		(87,642)
Total property and equipment		(3,146,541)
Less accumulated depreciation, depletion and amortization		2,085,266
Total property and equipment, net		(1,061,275)
Other long-term assets		(3,317)
TOTAL ASSETS		(1,062,251)
Current liabilities:
Accrued liabilities and other		(6,529)
Accrued interest		(127)
Total current liabilities		(6,656)
Asset retirement obligations		(29,582)
Operating lease obligations		187
Deferred income taxes		(55,346)
Other long-term liabilities		(458)
Total liabilities not subject to compromise		(91,855)
Total liabilities		(91,855)
Equity (Deficit):
Accumulated earnings (deficit)		(970,396)
Total equity		(970,396)
TOTAL LIABILITIES AND EQUITY		$ (1,062,251)

FRESH START ACCOUNTING - Source

FRESH START ACCOUNTING - Sources and uses of cash (Details) - Reorganization Adjustments [Member] $ in Thousands	Sep. 01, 2020USD ($)
Fresh-Start Adjustment [Line Items]
Net uses of cash	$ (524,697)
Source of Cash [Member]
Fresh-Start Adjustment [Line Items]
Net uses of cash	453,533
Release of restricted cash upon bankruptcy emergence [Member]
Fresh-Start Adjustment [Line Items]
Net uses of cash	28,205
Borrowings Under the Exit Credit Agreement [Member]
Fresh-Start Adjustment [Line Items]
Net uses of cash	425,328
Use of Cash [Member]
Fresh-Start Adjustment [Line Items]
Net uses of cash	(978,230)
Payment of outstanding borrowings under the Predecessor Credit Agreement [Member]
Fresh-Start Adjustment [Line Items]
Net uses of cash	(912,259)
Payment of accrued interest on the Predecessor Credit Agreement [Member]
Fresh-Start Adjustment [Line Items]
Net uses of cash	(3,437)
Payment of debt issuance costs related to Exit Credit Agreement [Member]
Fresh-Start Adjustment [Line Items]
Net uses of cash	(10,950)
Funding of the Professional Fee Escrow Account [Member]
Fresh-Start Adjustment [Line Items]
Net uses of cash	(26,000)
Payment of professional fees [Member]
Fresh-Start Adjustment [Line Items]
Net uses of cash	(14,470)
Payment of contract cure amounts [Member]
Fresh-Start Adjustment [Line Items]
Net uses of cash	$ (11,114)

FRESH START ACCOUNTING - Reclas

FRESH START ACCOUNTING - Reclassification of cash balance (Details) - Reorganization Adjustments [Member] $ in Thousands	Sep. 01, 2020USD ($)
Fresh-Start Adjustment [Line Items]
Net reclassifications from restricted cash	$ (2,205)
Funding of the Professional Fee Escrow Account [Member]
Fresh-Start Adjustment [Line Items]
Net reclassifications from restricted cash	26,000
Release of restricted cash upon bankruptcy emergence [Member]
Fresh-Start Adjustment [Line Items]
Net reclassifications from restricted cash	(28,205)
Derivative Settlement Amount [Member]
Fresh-Start Adjustment [Line Items]
Net reclassifications from restricted cash	23,000
Assurance For Utility Providers [Member]
Fresh-Start Adjustment [Line Items]
Net reclassifications from restricted cash	$ 5,000

FRESH START ACCOUNTING - Effect

FRESH START ACCOUNTING - Effect on leases and other liabilities (Details) - USD ($) $ in Thousands	Sep. 01, 2020	Aug. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Fresh-Start Adjustment [Line Items]
Operating lease ROU assets, net			$ 20,866	$ 26,987
Operating Lease, Liability			21,446	39,068
Long-term operating lease obligations	$ 17,839		$ 17,415	$ 31,722
Gain on settlement of liabilities		$ 1,324,940
Debt issuance costs	12,784	$ 1,834
Reorganization Adjustments [Member]
Fresh-Start Adjustment [Line Items]
Long-term operating lease obligations	17,652
Gain on settlement of liabilities	1,324,940
Debt issuance costs	10,950
Reorganization Adjustments [Member] | Corporate office lease agreement modification [Member]
Fresh-Start Adjustment [Line Items]
Operating lease ROU assets, net	10,000
Operating Lease, Liability	15,000
Gain on settlement of liabilities	5,000
Reorganization Adjustments [Member] | Operating lease obligations reinstated [Member]
Fresh-Start Adjustment [Line Items]
Operating Lease, Liability	18,000
Reorganization Adjustments [Member] | Financing Cost Credit Agreement [Member]
Fresh-Start Adjustment [Line Items]
Debt issuance costs	$ (11,000)

FRESH START ACCOUNTING - Dispos

FRESH START ACCOUNTING - Disposition of liabilities (Details) - USD ($) $ in Thousands	Sep. 01, 2020	Aug. 31, 2020
Liabilities subject to compromise pre-emergence
Liabilities subject to compromise		$ 2,526,925
Less: Amounts settled per the Plan
Gain on settlement of liabilities subject to compromise		1,324,940
Reorganization Adjustments [Member]
Liabilities subject to compromise pre-emergence
Liabilities subject to compromise	$ (2,526,925)	$ 2,526,925
Accounts payable trade	(10,866)
Accrued capital expenditures	(1,305)
Accrued lease operating expenses	(1,394)
Accrued liabilities and other	(13,961)
Accrued interest	(105)
Operating lease obligations	(17,652)
Other long-term liabilities	(11,071)
Total liabilities reinstated	(56,354)
Less: Amounts settled per the Plan
Total amounts settled	(1,145,631)
Gain on settlement of liabilities subject to compromise	1,324,940
Reorganization Adjustments [Member] | Issuance of common stock to general unsecured claim holders [Member]
Less: Amounts settled per the Plan
Total amounts settled	(1,125,062)
Reorganization Adjustments [Member] | Payment of contract cure amounts [Member]
Less: Amounts settled per the Plan
Total amounts settled	(10,836)
Reorganization Adjustments [Member] | Operating lease modification and terminations [Member]
Less: Amounts settled per the Plan
Total amounts settled	(9,669)
Reorganization Adjustments [Member] | Issuance of Successor common stock to holders of unvested cash-settled equity awards [Member]
Less: Amounts settled per the Plan
Total amounts settled	(64)
Reorganization Adjustments [Member] | Payment of professional fees [Member]
Less: Amounts settled per the Plan
Accounts payable	2,000
Reorganization Adjustments [Member] | Reinstatement of accounts payable subject to compromise [Member]
Less: Amounts settled per the Plan
Accounts payable	$ 11,000

FRESH START ACCOUNTING - Accrue

FRESH START ACCOUNTING - Accrued Liabilities and Other (Details) - USD ($) $ in Thousands	Sep. 01, 2020	Aug. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Fresh-Start Adjustment [Line Items]
Accrued liabilities and other	$ 61,740	$ 46,327	$ 476	$ 53,928
Accelerated expense	4,000	$ 4,000
Reorganization Adjustments [Member]
Fresh-Start Adjustment [Line Items]
Accrued liabilities and other	21,942
Net uses of cash	(524,697)
Accelerated expense	4,161
Reorganization Adjustments [Member] | Reinstatement of accrued expenses from liabilities subject to compromise [Member]
Fresh-Start Adjustment [Line Items]
Accrued liabilities and other	13,961
Reorganization Adjustments [Member] | Recognition of success fee payable upon emergence [Member]
Fresh-Start Adjustment [Line Items]
Accrued liabilities and other	11,500
Reorganization Adjustments [Member] | Other expenses accrued at emergence [Member]
Fresh-Start Adjustment [Line Items]
Accrued liabilities and other	3,315
Reorganization Adjustments [Member] | Payment of professional fees [Member]
Fresh-Start Adjustment [Line Items]
Accrued liabilities and other	(6,834)
Net uses of cash	(14,470)
Reorganization Adjustments [Member] | Accrued Interest Predecessor Credit Agreement [Member]
Fresh-Start Adjustment [Line Items]
Net uses of cash	$ 3,000

FRESH START ACCOUNTING - Equity

FRESH START ACCOUNTING - Equity Issued (Details) - USD ($) $ / shares in Units, $ in Thousands	Sep. 01, 2020	Dec. 31, 2020	Dec. 31, 2019
Fresh-Start Adjustment [Line Items]
Common stock issued	38,051,125
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001	$ 0.001
Issuance of Successor stock	$ 1,159,856
Issuance of Successor warrants	$ 29,360
Reorganization Adjustments [Member]
Fresh-Start Adjustment [Line Items]
Common stock issued	38,051,125
Warrants to purchase shares	7,256,227
Common stock, par value (in dollars per share)	$ 0.001
Fair value of Successor equity	$ 1,189,216
Reorganization Adjustments [Member] | Issuance of common stock to general unsecured claim holders [Member]
Fresh-Start Adjustment [Line Items]
Fair value of Successor equity	1,125,062
Reorganization Adjustments [Member] | Issuance of common stock to Predecessor common stockholders and holders of unvested cash-settled equity awards
Fresh-Start Adjustment [Line Items]
Fair value of Successor equity	34,794
Reorganization Adjustments [Member] | Issuance of warrants to Predecessor common stockholders and holders of unvested cash-settled equity awards
Fresh-Start Adjustment [Line Items]
Fair value of Successor equity	$ 29,360

FRESH START ACCOUNTING - Cumula

FRESH START ACCOUNTING - Cumulative impact (Details) - USD ($) $ in Thousands	Sep. 01, 2020	Aug. 31, 2020
Fresh-Start Adjustment [Line Items]
Gain on settlement of liabilities		$ 1,324,940
Acceleration of unvested stock-based compensation awards	$ (4,000)	(4,000)
Other expenses incurred upon emergence		$ (9,464)
Cancellation of Predecessor Equity [Member]
Fresh-Start Adjustment [Line Items]
Acceleration of unvested stock-based compensation awards	(4,000)
Reorganization Adjustments [Member]
Fresh-Start Adjustment [Line Items]
Gain on settlement of liabilities	1,324,940
Cancellation of Predecessor equity	6,414,541
Fair value of equity issued to Predecessor common stockholders and holders of unvested cash-settled equity awards	(34,794)
Fair value of warrants issued to Predecessor common stockholders and holders of unvested cash-settled equity awards	(29,360)
Success fees incurred upon emergence	(17,303)
Acceleration of unvested stock-based compensation awards	(4,161)
Other expenses incurred upon emergence	(3,407)
Net impact on accumulated earnings (deficit)	$ 7,650,456

FRESH START ACCOUNTING - Fres_2

FRESH START ACCOUNTING - Fresh Start Adjustments (Details) $ in Thousands	Sep. 01, 2020USD ($)
Fresh-Start Adjustment [Line Items]
Weighted average cost of capital rate	14.00%
Fresh Start Accounting Adjustments [Member]
Fresh-Start Adjustment [Line Items]
Accounts receivable, net	$ 81
Operating lease assets, net	(1,480)
Finance lease assets	(10,765)
Accumulated depreciation - finance leases	15,099
Accrued interest - finance leases	127
Short-term finance lease obligation	(576)
Short-term operating lease obligation	319
Long-term finance lease obligation	(1,174)
Long-term operating lease obligation	(187)
Fresh start adjustments to lease assets and liabilities	1,444
Decrease in land and building	(16,000)
Decrease in other property and equipment	(61,000)
Decrease in accumulated depletion, depreciation and amortization.	(66,000)
Fresh start adjustments to other long-term assets	2,000
Fresh Start Accounting Adjustments [Member] | Revaluation of Liabilities [Member]
Fresh-Start Adjustment [Line Items]
Write-off of deferred gain	9,000
Write-off of deferred gain, short term	7,000
Write-off of deferred gain, long term	$ 2,000

FRESH START ACCOUNTING - Reor_2

FRESH START ACCOUNTING - Reorganization Items, Net (Details) $ in Thousands	8 Months Ended
	Aug. 31, 2020USD ($)
FRESH START ACCOUNTING [Abstract]
Legal and professional advisory fees	$ 57,170
Net gain on Liabilities subject to compromise	(1,324,940)
Fresh start adjustments, net	1,025,742
Write-off of unamortized debt issuance costs and premium	15,145
Other items, net	9,464
Total reorganization items, net	$ (217,419)

OIL AND GAS PROPERTIES (Details

OIL AND GAS PROPERTIES (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Sep. 01, 2020	Aug. 31, 2020	Dec. 31, 2019
OIL AND GAS PROPERTIES [Abstract]
Proved oil and gas properties	$ 1,701,163			$ 12,549,395
Unproved leasehold costs	105,073			103,278
Wells and facilities in progress	6,365			159,334
Total oil and gas properties, successful efforts method	1,812,601	$ 1,826,114	$ 4,885,013	12,812,007
Accumulated depletion	(71,064)			(5,656,929)
Oil and gas properties, net	$ 1,741,537			$ 7,155,078

ACQUISITIONS AND DIVESTITURES_2

ACQUISITIONS AND DIVESTITURES (Acquisition) (Details) $ in Thousands	Jul. 31, 2018USD ($)aitem	Dec. 31, 2020USD ($)	Aug. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Business Acquisition [Line Items]
Cash consideration		$ 166	$ 493	$ 6,031	$ 142,723
Richland and McKenzie Counties [Member]
Business Acquisition [Line Items]
Aggregate purchase price	$ 130,000
Net acquisition area (in acres) | a	54,800
Number of wells acquired | item	117
Cash consideration	$ 122,861
Fair value of assets acquired:
Accounts receivable trade, net	30
Prepaid expenses and other	43
Oil and gas properties, successful efforts method:
Proved oil and gas properties	106,860
Unproved oil and gas properties	21,769
Total fair value of assets acquired	128,702
Fair value of liabilities assumed:
Revenue and royalties payable	3,309
Asset retirement obligations	2,532
Total fair value of liabilities assumed	5,841
Total fair value of assets and liabilities acquired	$ 122,861

ACQUISITIONS AND DIVESTITURES_3

ACQUISITIONS AND DIVESTITURES (Divestitures) (Details) $ in Thousands	Jan. 09, 2020USD ($)item	Aug. 15, 2019USD ($)item	Jul. 29, 2019USD ($)item	Dec. 31, 2020USD ($)	Aug. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Dispositions
Proceeds from sale of properties				$ 532	$ 29,273	$ 72,000	$ 4,746
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Dispositions
Number of well sold | item	30		137
Proceeds from sale of properties	$ 25,000		$ 27,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Richland County, Montana And Mountrail and Williams Counties [Member]
Dispositions
Number of well sold | item		58
Proceeds from sale of properties		$ 26,000

LEASES (Details)

LEASES (Details)	12 Months Ended
	Dec. 31, 2020
LEASES [Abstract]
Lease, Practical Expedients, Package [true false]	true

LEASES (Balance Sheet and Terms

LEASES (Balance Sheet and Terms) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Sep. 01, 2020	Dec. 31, 2019
Operating Leases
Operating lease ROU assets	$ 21,962		$ 31,882
Operating lease, Accumulated depreciation	(1,096)		(4,895)
Operating lease ROU assets, net	$ 20,866		$ 26,987
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Other Assets, Noncurrent		Other Assets, Noncurrent
Short-term operating lease obligations	$ 4,031		$ 7,346
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Other Liabilities, Current		Other Liabilities, Current
Long-term operating lease obligations	$ 17,415	$ 17,839	$ 31,722
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Long-term operating lease obligations		Long-term operating lease obligations
Total operating lease obligations	$ 21,446		$ 39,068
Finance Leases
Finance lease ROU assets	19,706		33,312
Finance lease, Accumulated depreciation	(1,797)		(14,180)
Finance lease ROU assets, net	$ 17,909		$ 19,132
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Property, Plant and Equipment, Net		Property, Plant and Equipment, Net
Short-term finance lease obligations	$ 4,830		$ 4,974
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Other Liabilities, Current		Other Liabilities, Current
Long-term finance lease obligations	$ 13,138		$ 16,638
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other Liabilities, Noncurrent		Other Liabilities, Noncurrent
Total finance lease obligations	$ 17,968		$ 21,612
Weighted average remaining lease term, Operating lease	7 years		8 years
Weighted average remaining lease term, Finance lease	4 years		5 years
Weighted average discount rate, Operating lease (as a percent)	4.40%		4.60%
Weighted average discount rate, Finance lease (as a percent)	4.20%		8.60%
Minimum [Member]
Finance Leases
Lease remaining term	1 year
Maximum [Member]
Finance Leases
Lease remaining term	10 years

LEASES (Lease cost) (Details)

LEASES (Lease cost) (Details) - USD ($) $ in Thousands	4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2020	Aug. 31, 2020	Dec. 31, 2019
LEASES [Abstract]
Operating lease cost	$ 1,462	$ 4,691	$ 11,512
Amortization of ROU assets	1,842	3,347	5,661
Interest on lease liabilities	260	1,131	1,996
Total finance lease cost	2,102	4,478	7,657
Short-term lease payments	26,430	164,815	676,850
Variable lease payments	$ 99	$ 23,307	$ 31,812

LEASES (Cash flow) (Details)

LEASES (Cash flow) (Details) - USD ($) $ in Thousands	4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2020	Aug. 31, 2020	Dec. 31, 2019
LEASES [Abstract]
Operating cash flows from operating leases	$ 2,174	$ 5,813	$ 11,978
Operating cash flows from finance leases	197	1,156	2,006
Financing cash flows from finance leases	1,773	3,198	5,140
ROU assets obtained in exchange for new operating lease obligations	$ 6,368	3,252	18,658
ROU assets obtained in exchange for new financing lease obligations		$ 170	$ 4,158

LEASES (Obligations) (Details)

LEASES (Obligations) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Operating Leases
2021	$ 4,500
2022	3,572
2023	3,255
2024	2,898
2025	1,903
Remaining	9,349
Total lease payments	25,477
Less imputed interest	(4,031)
Total operating lease obligations	21,446	$ 39,068
Finance Leases
2021	5,489
2022	4,693
2023	3,833
2024	3,214
2025	2,385
Total lease payments	19,614
Less imputed interest	(1,646)
Total finance lease obligations	$ 17,968	$ 21,612

LONG-TERM DEBT (Schedule of lon

LONG-TERM DEBT (Schedule of long-term debt) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Sep. 01, 2020	Aug. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Total principal	$ 360,000			$ 2,818,980
Unamortized debt discounts and premiums				(2,575)
Unamortized debt issuance costs on notes				(16,520)
Less current portion of long-term debt			$ (912,259)
Total long-term debt	360,000	$ 425,328		2,799,885
Exit Credit Agreement [Member]
Debt Instrument [Line Items]
Total principal	$ 360,000
Predecessor Credit Agreement [Member]
Debt Instrument [Line Items]
Total principal				375,000
1.25% Convertible Senior Notes due 2020 [Member]
Debt Instrument [Line Items]
Total principal				262,075
Unamortized debt issuance costs on notes				$ (220)
Interest rate on debt instrument (as a percent)	1.25%		1.25%	1.25%
5.75% Senior Notes due 2021 [Member]
Debt Instrument [Line Items]
Total principal				$ 773,609
Interest rate on debt instrument (as a percent)	5.75%		5.75%	5.75%
6.25% Senior Notes due 2023 [Member]
Debt Instrument [Line Items]
Total principal				$ 408,296
Interest rate on debt instrument (as a percent)	6.25%		6.25%	6.25%
6.625% Senior Notes due 2026 [Member]
Debt Instrument [Line Items]
Total principal				$ 1,000,000
Interest rate on debt instrument (as a percent)	6.625%		6.625%	6.625%

LONG-TERM DEBT (Credit agreemen

LONG-TERM DEBT (Credit agreement) (Details) - USD ($) $ in Thousands	Sep. 01, 2020	Dec. 31, 2020	Aug. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Exit Credit Agreement [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity of credit facility	$ 750,000	$ 750,000
Borrowing capacity of credit facility, net of letter of credit		388,000
Outstanding borrowings under credit facility		360,000
Letters of credit borrowings outstanding		$ 2,000
Additional contingent borrowings	750,000
Maximum cash balance prior to mandatory repayment	$ 75,000
Commitment fees (as a percent)	0.50%
Weighted average interest rate		4.10%
Debt threshold, dividend payments and distributions (as a percent)	20.00%
Leverage ratio	2
Current year production covered by hedges (as a percent)	65.00%
Maximum percentage of production from proved reserves (as a percent)	85.00%
Subsequent year production covered by hedges (as a percent)	35.00%
Minimum consolidated current assets to consolidated current liabilities ratio	1
Total debt to EBITDAX ratio	3.5
Repayments of borrowings under credit agreement		$ 337,828
Exit Credit Agreement [Member] | Minimum [Member]
Debt Instrument [Line Items]
Basis points added to reference rate (as a percent)	2.75%
Exit Credit Agreement [Member] | Maximum [Member]
Debt Instrument [Line Items]
Basis points added to reference rate (as a percent)	3.75%
Exit Credit Agreement [Member] | Base Rate [Member] | Minimum [Member]
Debt Instrument [Line Items]
Basis points added to reference rate (as a percent)	1.75%
Exit Credit Agreement [Member] | Base Rate [Member] | Maximum [Member]
Debt Instrument [Line Items]
Basis points added to reference rate (as a percent)	2.75%
Exit Credit Agreement [Member] | Fed Funds Rate [Member]
Debt Instrument [Line Items]
Basis points added to reference rate (as a percent)	0.50%
Exit Credit Agreement [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Basis points added to reference rate (as a percent)	1.00%
Letter of Credit [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity of credit facility	$ 50,000
Borrowing capacity of credit facility, net of letter of credit		$ 48,000
Predecessor Credit Agreement [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity of credit facility			$ 2,050,000
Maximum aggregate commitments			1,750,000
Repayments of borrowings under credit agreement	912,000		$ 1,402,259	$ 2,275,000	$ 2,214,265
Interest paid	$ 3,000

LONG-TERM DEBT (Schedule of con

LONG-TERM DEBT (Schedule of convertible senior notes) (Details) - USD ($) $ in Thousands	Sep. 01, 2020	Sep. 30, 2019	Dec. 31, 2020	Aug. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Less: unamortized debt issuance costs					$ (16,520)
Interest expense			$ 8,080	$ 73,054	191,047	$ 197,474
Issuance of Successor stock (in shares)	38,051,125
Senior Notes Holders [Member]
Debt Instrument [Line Items]
Issuance of Successor stock (in shares)	36,817,630
Existing Stockholders [Member]
Debt Instrument [Line Items]
Issuance of Successor stock (in shares)	1,233,495
1.25% Convertible Senior Notes due 2020 [Member]
Debt Instrument [Line Items]
Principal				187,000	262,075
Less: unamortized note discount			$ (238,000)		(2,829)
Less: unamortized debt issuance costs					(220)
Net carrying value					259,026
Equity component of convertible debt, deferred taxes		$ 0
Interest expense				$ 1,000	26,000	$ 29,000
Equity Component Of Convertible Senior Note [Member]
Debt Instrument [Line Items]
Less: unamortized debt issuance costs					(5,000)
Equity component					128,452
Equity component of convertible debt, deferred taxes					$ 50,000

LONG-TERM DEBT (Senior notes) (

LONG-TERM DEBT (Senior notes) (Details) - USD ($) $ in Thousands	Sep. 01, 2020	Mar. 31, 2020	Sep. 30, 2019	Jan. 31, 2018	Oct. 31, 2019	Aug. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020
Debt Instrument [Line Items]
Issuance of Successor stock (in shares)	38,051,125
Gain (loss) on extinguishment of debt						$ 25,883	$ 7,830	$ (31,968)
Repurchase of notes							95,279
Total principal							2,818,980		$ 360,000
Adjustment to equity component of 2020 Convertible Senior Notes						3,461	$ 8,070
Senior Notes [Member]
Debt Instrument [Line Items]
Issuance of Successor stock (in shares)	36,817,630
5.0% Senior Notes due 2019 [Member]
Debt Instrument [Line Items]
Interest rate on debt instrument (as a percent)				5.00%			5.00%
Notes repurchased, principal amount				$ 961,000
Percentage of redemption price				102.976%
Gain (loss) on extinguishment of debt								$ (31,000)
Repurchase of notes				$ 1,000,000
5.75% Senior Notes due 2021 [Member]
Debt Instrument [Line Items]
Notes Issued						$ 774,000
Interest rate on debt instrument (as a percent)						5.75%	5.75%		5.75%
Notes repurchased, principal amount					$ 100,000
Percentage of redemption price					95.279%
Gain (loss) on extinguishment of debt							$ 1,000
Repurchase of notes					$ 96,000
Total principal							$ 773,609
6.25% Senior Notes due 2023 [Member]
Debt Instrument [Line Items]
Notes Issued						$ 408,000
Interest rate on debt instrument (as a percent)						6.25%	6.25%		6.25%
Total principal							$ 408,296
6.625% Senior Notes due 2026 [Member]
Debt Instrument [Line Items]
Notes Issued						$ 1,000,000
Interest rate on debt instrument (as a percent)						6.625%	6.625%		6.625%
Total principal							$ 1,000,000
1.25% Convertible Senior Notes due 2020 [Member]
Debt Instrument [Line Items]
Notes Issued						$ 187,000	$ 262,075
Interest rate on debt instrument (as a percent)						1.25%	1.25%		1.25%
Debt, effective interest rate									5.60%
Notes repurchased, principal amount		$ 73,000	$ 300,000
Principal amount of debt redeemed (as a percent)		72.50%
Percentage of redemption price			99.00%
Gain (loss) on extinguishment of debt		$ 23,000	$ 4,000
Unamortized debt discount							$ 2,829		$ 238,000
Repurchase of notes		53,000	299,000
Total principal							$ 262,075
Adjustment to equity component of 2020 Convertible Senior Notes		3,000	8,000
Non cash charges		$ 200	$ 7,000

LONG-TERM DEBT (2020 Convertibl

LONG-TERM DEBT (2020 Convertible senior notes) (Details) - USD ($) $ in Thousands	1 Months Ended			2 Months Ended	4 Months Ended	8 Months Ended	12 Months Ended
	Mar. 31, 2020	Sep. 30, 2019	Jan. 31, 2018	Oct. 31, 2019	Dec. 31, 2020	Aug. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Debt finance cost							$ 16,520
Repurchase of notes							95,279
Gain (loss) on extinguishment of debt						$ 25,883	7,830	$ (31,968)
Amortization of debt issuance costs, debt discount and debt premium					$ 1,258	13,535	28,340	30,700
Adjustment to equity component of 2020 Convertible Senior Notes						3,461	8,070
Carrying value of debt instrument					$ 360,000		2,818,980
1.25% Convertible Senior Notes due 2020 [Member]
Debt Instrument [Line Items]
Principal						$ 187,000	$ 262,075
Interest rate on debt instrument (as a percent)					1.25%	1.25%	1.25%
Debt finance cost							$ 220
Repurchase of notes	$ 53,000	$ 299,000
Notes repurchased, principal amount	$ 73,000	$ 300,000
Principal amount of debt redeemed (as a percent)	72.50%
Percentage of redemption price		99.00%
Gain (loss) on extinguishment of debt	$ 23,000	$ 4,000
Non cash charges	200	7,000
Transaction costs		1,000
Adjustment to equity component of 2020 Convertible Senior Notes	$ 3,000	8,000
Equity component of convertible debt, deferred taxes		$ 0
Carrying value of debt instrument							262,075
Debt, effective interest rate					5.60%
Estimated fair value of Notes					$ 1,000,000
Debt discount					$ 238,000		$ 2,829
5.0% Senior Notes due 2019 [Member]
Debt Instrument [Line Items]
Interest rate on debt instrument (as a percent)			5.00%				5.00%
Repurchase of notes			$ 1,000,000
Notes repurchased, principal amount			$ 961,000
Percentage of redemption price			102.976%
Gain (loss) on extinguishment of debt								$ (31,000)
5.75% Senior Notes due 2021 [Member]
Debt Instrument [Line Items]
Principal						$ 774,000
Interest rate on debt instrument (as a percent)					5.75%	5.75%	5.75%
Repurchase of notes				$ 96,000
Notes repurchased, principal amount				$ 100,000
Percentage of redemption price				95.279%
Gain (loss) on extinguishment of debt							$ 1,000
Carrying value of debt instrument							$ 773,609

ASSET RETIREMENT OBLIGATIONS (D

ASSET RETIREMENT OBLIGATIONS (Details) - USD ($) $ in Thousands	4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2020	Aug. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Sep. 01, 2020	Dec. 31, 2019
Asset Retirement Obligations
Asset retirement obligations, current portion				$ 6,000	$ 5,000	$ 4,000
Asset retirement obligation	$ 98,130	$ 156,323	$ 134,893	$ 98,130	126,741	$ 134,893
Reconciliation of the Company's asset retirement obligations
Balance at the beginning of the period	156,323	134,893	135,834
Additional liability incurred	20	76	2,097
Revisions to estimated cash flows	(30,623)	56,702	(10,945)
Accretion expense	3,801	8,199	11,602
Obligations on sold properties		(693)	(2,078)
Liabilities settled	(1,809)	(42,854)	(1,617)
Balance at the end of the period	$ 98,130	$ 156,323	$ 134,893
Fresh Start Accounting Adjustments [Member]
Asset Retirement Obligations
Asset retirement obligation					$ (29,582)

DERIVATIVE FINANCIAL INSTRUME_3

DERIVATIVE FINANCIAL INSTRUMENTS (Instruments) (Details) $ in Thousands	Feb. 01, 2018USD ($)	Apr. 30, 2020USD ($)	Dec. 31, 2020USD ($)item$ / item	Aug. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Jan. 01, 2021item
Derivative Financial Instruments [Line Items]
Derivative settlement | $		$ 145,000
Derivative gain (loss), net | $		$ 13,000	$ (24,714)	$ 181,614	$ (53,769)	$ (17,170)
Derivative instrument proceeds held in escrow | $				$ 23,000
Payment to settle future minimum volume commitments | $						$ 61,036
Crude Oil [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives			15,872,000
Crude Oil [Member] | 2021 [Member] | Fixed Price Swaps [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives			4,386,000				1,447,000
Swap Price | $ / item			41.85
Crude Oil [Member] | 2021 [Member] | Two-way Collars [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives			6,956,000
Derivative, Floor Price (in dollars per unit) | $ / item			38.82
Derivative, Ceiling Price (in dollars per unit) | $ / item			47.11
Crude Oil [Member] | 2022 [Member] | Fixed Price Swaps [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives							630,000
Crude Oil [Member] | 2022 [Member] | Two-way Collars [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives			4,530,000				3,930,000
Derivative, Floor Price (in dollars per unit) | $ / item			38.41
Derivative, Ceiling Price (in dollars per unit) | $ / item			48.75
Crude Oil [Member] | March 2023 [Member] | Two-way Collars [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives							1,980,000
Natural Gas [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives			35,565,000
Natural Gas [Member] | 2021 [Member] | Fixed Price Swaps [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives			12,530,000				6,120,000
Swap Price | $ / item			2.69
Natural Gas [Member] | 2021 [Member] | Two-way Collars [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives			10,950,000
Derivative, Floor Price (in dollars per unit) | $ / item			2.60
Derivative, Ceiling Price (in dollars per unit) | $ / item			2.79
Natural Gas [Member] | 2021 [Member] | Basis Swap [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives							6,120,000
Natural Gas [Member] | 2022 [Member] | Fixed Price Swaps [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives			1,365,000				2,025,000
Swap Price | $ / item			2.60
Natural Gas [Member] | 2022 [Member] | Two-way Collars [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives			10,720,000
Derivative, Floor Price (in dollars per unit) | $ / item			2.35
Derivative, Ceiling Price (in dollars per unit) | $ / item			2.85
Natural Gas [Member] | March 2023 [Member] | Two-way Collars [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives							1,800,000
Crude Oil Sales And Delivery Contract [Member]
Derivative Financial Instruments [Line Items]
Derivative liability | $	$ 0
Payment to settle future minimum volume commitments | $	$ 61,000

DERIVATIVE FINANCIAL INSTRUME_4

DERIVATIVE FINANCIAL INSTRUMENTS (Effects of derivatives) (Details) - USD ($) $ in Thousands	1 Months Ended	4 Months Ended	8 Months Ended	12 Months Ended
	Apr. 30, 2020	Dec. 31, 2020	Aug. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative Financial Instruments [Line Items]
Derivative (gain) loss, net	$ (13,000)	$ 24,714	$ (181,614)	$ 53,769	$ 17,170
Commodity contracts [Member] | Not Designated as ASC 815 Hedges [Member]
Derivative Financial Instruments [Line Items]
Derivative (gain) loss, net		$ 24,714	$ (181,614)	$ 53,769	$ 17,170

DERIVATIVE FINANCIAL INSTRUME_5

DERIVATIVE FINANCIAL INSTRUMENTS (Asset location) (Details) - Not Designated as ASC 815 Hedges [Member] - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Gross amounts of derivative assets and gross amounts offset [Line Items]
Gross Amounts of Recognized Assets	$ 34,278	$ 81,302
Gross Amounts Offset	(34,278)	(80,416)
Total financial assets		886
Commodity contracts [Member] | Prepaid Expenses and Other [Member]
Gross amounts of derivative assets and gross amounts offset [Line Items]
Gross Amounts of Recognized Assets	14,287	75,654
Gross Amounts Offset	(14,287)	(74,768)
Total financial assets		886
Commodity contracts [Member] | Other long-term assets [Member]
Gross amounts of derivative assets and gross amounts offset [Line Items]
Gross Amounts of Recognized Assets	19,991	5,648
Gross Amounts Offset	$ (19,991)	$ (5,648)

DERIVATIVE FINANCIAL INSTRUME_6

DERIVATIVE FINANCIAL INSTRUMENTS (Liability location) (Details) - Not Designated as ASC 815 Hedges [Member] - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Gross amounts of derivative liabilities and gross amounts offset [Line Items]
Gross Amounts of Recognized Liabilities	$ 93,513	$ 91,587
Gross Amounts Offset	(34,278)	(80,416)
Total financial liabilities	59,235	11,171
Commodity contracts [Member] | Derivative Liabilities [Member]
Gross amounts of derivative liabilities and gross amounts offset [Line Items]
Gross Amounts of Recognized Liabilities	63,772	85,053
Gross Amounts Offset	(14,287)	(74,768)
Total financial liabilities	49,485	10,285
Commodity contracts [Member] | Other long-term liabilities [Member]
Gross amounts of derivative liabilities and gross amounts offset [Line Items]
Gross Amounts of Recognized Liabilities	29,741	6,534
Gross Amounts Offset	(19,991)	(5,648)
Total financial liabilities	$ 9,750	$ 886

FAIR VALUE MEASUREMENTS (Debt i

FAIR VALUE MEASUREMENTS (Debt instruments) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Aug. 31, 2020	Dec. 31, 2019
Fair Value [Member]
Debt Instrument [Line Items]
Debt Instrument, Fair Value Disclosure			$ 2,018,448
Carrying Value [Member]
Debt Instrument [Line Items]
Debt Instrument, Fair Value Disclosure			$ 2,424,885
1.25% Convertible Senior Notes due 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Fair Value Disclosure	$ 1,000,000
Interest Rate (as a percent)	1.25%	1.25%	1.25%
1.25% Convertible Senior Notes due 2020 [Member] | Fair Value [Member]
Debt Instrument [Line Items]
Debt Instrument, Fair Value Disclosure			$ 260,214
1.25% Convertible Senior Notes due 2020 [Member] | Carrying Value [Member]
Debt Instrument [Line Items]
Debt Instrument, Fair Value Disclosure			$ 259,026
5.75% Senior Notes due 2021 [Member]
Debt Instrument [Line Items]
Interest Rate (as a percent)	5.75%	5.75%	5.75%
5.75% Senior Notes due 2021 [Member] | Fair Value [Member]
Debt Instrument [Line Items]
Debt Instrument, Fair Value Disclosure			$ 732,995
5.75% Senior Notes due 2021 [Member] | Carrying Value [Member]
Debt Instrument [Line Items]
Debt Instrument, Fair Value Disclosure			$ 772,080
6.25% Senior Notes due 2023 [Member]
Debt Instrument [Line Items]
Interest Rate (as a percent)	6.25%	6.25%	6.25%
6.25% Senior Notes due 2023 [Member] | Fair Value [Member]
Debt Instrument [Line Items]
Debt Instrument, Fair Value Disclosure			$ 343,989
6.25% Senior Notes due 2023 [Member] | Carrying Value [Member]
Debt Instrument [Line Items]
Debt Instrument, Fair Value Disclosure			$ 405,392
6.625% Senior Notes due 2026 [Member]
Debt Instrument [Line Items]
Interest Rate (as a percent)	6.625%	6.625%	6.625%
6.625% Senior Notes due 2026 [Member] | Fair Value [Member]
Debt Instrument [Line Items]
Debt Instrument, Fair Value Disclosure			$ 681,250
6.625% Senior Notes due 2026 [Member] | Carrying Value [Member]
Debt Instrument [Line Items]
Debt Instrument, Fair Value Disclosure			$ 988,387

FAIR VALUE MEASUREMENTS (Recurr

FAIR VALUE MEASUREMENTS (Recurring basis) (Details) - Recurring Basis [Member] - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Financial Assets
Total financial assets		$ 886
Financial Liabilities
Total financial liabilities	$ 59,235	11,171
Commodity contracts [Member]
Financial Assets
Financial assets - current		886
Financial Liabilities
Financial liabilities - current	49,485	10,285
Financial liabilities - non-current	9,750	886
Level 2 [Member]
Financial Assets
Total financial assets		886
Financial Liabilities
Total financial liabilities	59,235	11,171
Level 2 [Member] | Commodity contracts [Member]
Financial Assets
Financial assets - current		886
Financial Liabilities
Financial liabilities - current	49,485	10,285
Financial liabilities - non-current	$ 9,750	$ 886

FAIR VALUE MEASUREMENTS (Non-re

FAIR VALUE MEASUREMENTS (Non-recurring) (Details) - Proved Properties [Member] - USD ($) $ in Thousands	Sep. 01, 2020	Jun. 30, 2020	Mar. 31, 2020	Aug. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Proved property		$ 85,000	$ 494,000
Non-recurring assets at fair value, impairment loss (before tax)		$ 409,000	$ 3,700,000	$ 4,000,000
Measurement Input, Discount Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Value of measurement input	14.00%	17.00%	16.00%
Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Proved property		$ 85,418	$ 816,000		$ 4,500,000
Non-recurring assets at fair value, impairment loss (before tax)		409,079
Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Proved property		$ 85,418

REVENUE RECOGNITION (Revenue Re

REVENUE RECOGNITION (Revenue Reclassification) (Details) - USD ($) $ in Thousands	4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2020	Aug. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue
Sales	$ 273,358	$ 459,004	$ 1,572,245	$ 2,081,414
Oil sales [Member]
Revenue
Sales	254,024	440,820	1,492,218	1,850,052
NGL and natural gas sales [Member]
Revenue
Sales	$ 19,334	$ 18,184	$ 80,027	$ 231,362

REVENUE RECOGNITION (Narrative)

REVENUE RECOGNITION (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenue
Receivable balance	$ 88	$ 161
Revenue, Practical Expedient, Initial Application and Transition, Nondisclosure of Transaction Price Allocation to Remaining Performance Obligation [true false]	true
Minimum [Member]
Revenue
Payment received for product sales, period	1 month
Maximum [Member]
Revenue
Payment received for product sales, period	3 months

SHAREHOLDERS' EQUITY (Details)

SHAREHOLDERS' EQUITY (Details) - $ / shares	Sep. 01, 2020	Dec. 31, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Capital stock, shares authorized	550,000,000
Common stock, shares authorized	500,000,000	500,000,000	225,000,000
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001	$ 0.001
Preferred stock, shares authorized	50,000,000
Preferred Stock, par value (in dollars per share)	$ 0.001
Issuance of Successor stock (in shares)	38,051,125
Series A [Member]
Class of Stock [Line Items]
Warrants outstanding (in shares)	4,837,387
Warrant exercise price (in dollars per share)	$ 73.44
Series A [Member] | Maximum [Member]
Class of Stock [Line Items]
Warrants outstanding (in shares)	4,837,821
Series B [Member]
Class of Stock [Line Items]
Warrants outstanding (in shares)	2,418,840
Warrant exercise price (in dollars per share)	$ 83.45
Series B [Member] | Maximum [Member]
Class of Stock [Line Items]
Warrants outstanding (in shares)	2,418,910

STOCK-BASED COMPENSATION (Narra

STOCK-BASED COMPENSATION (Narrative) (Details)	Sep. 29, 2020D$ / sharesshares	Sep. 01, 2020USD ($)shares	Mar. 31, 2020USD ($)	Dec. 31, 2020USD ($)$ / sharesshares	Aug. 31, 2020USD ($)$ / sharesshares	Dec. 31, 2020USD ($)itemshares	Dec. 31, 2019USD ($)$ / sharesshares	Dec. 31, 2018USD ($)$ / sharesshares
Share-based compensation disclosures
Issuance of Successor stock (in shares)		38,051,125
Number of shares authorized upon shareholder's approval		4,035,885
Maximum fair value non-employee director grant | $		$ 500,000
Number of shares available for grant				3,756,964		3,756,964
Unrecognized compensation cost, restricted stock | $				$ 2,000,000		$ 2,000,000
Weighted average period over which cost will be recognized						2 years 8 months 12 days
Total fair value | $					$ 1,000,000		$ 12,000,000	$ 16,000,000
Stock compensation expense | $				$ 1,000,000	3,000,000		$ 8,000,000	$ 18,000,000
Accelerated expense | $		$ 4,000,000			$ 4,000,000
Stock Option [Member]
Share-based compensation disclosures
Stock options granted					0		0	0
Vesting (service) period					3 years
Aggregate Intrinsic Value, options Exercised | $								$ 100,000
Exercised (in shares)					0		0
Service Based Restricted Stock [Member]
Share-based compensation disclosures
Granted (in shares)				89,021
Granted (in dollars per share) | $ / shares				$ 17.47
Market Based Restricted Stock [Member]
Share-based compensation disclosures
Granted (in shares)	189,900
Granted (in dollars per share) | $ / shares	$ 6.54
Threshold consecutive trading day | D	20
Market Based Restricted Stock [Member] | Minimum [Member]
Share-based compensation disclosures
Weighted average period over which cost will be recognized	1 year 9 months 18 days
Market Based Restricted Stock [Member] | Maximum [Member]
Share-based compensation disclosures
Weighted average period over which cost will be recognized	3 years 9 months 18 days
Market Based Restricted Stock [Member] | Share-based Payment Arrangement, Tranche One [Member]
Share-based compensation disclosures
Vesting (as a percent)	50.00%
Share price (in dollars per share) | $ / shares	$ 32.57
Market Based Restricted Stock [Member] | Share-based Payment Arrangement, Tranche Two [Member]
Share-based compensation disclosures
Vesting (as a percent)	25.00%
Share price (in dollars per share) | $ / shares	$ 48.86
Market Based Restricted Stock [Member] | Share-based Payment Arrangement, Tranche Three [Member]
Share-based compensation disclosures
Vesting (as a percent)	25.00%
Share price (in dollars per share) | $ / shares	$ 65.14
Service-based [Member]
Share-based compensation disclosures
Granted (in shares)					53,198		467,055	249,983
Granted (in dollars per share) | $ / shares					$ 4.94		$ 24.65	$ 32.34
Service-based [Member] | Share-based Payment Arrangement, Employee [Member]
Share-based compensation disclosures
Vesting (service) period						3 years
Service-based [Member] | Share-based Payment Arrangement, Nonemployee [Member]
Share-based compensation disclosures
Vesting (service) period						1 year
RSU [Member]
Share-based compensation disclosures
Granted (in shares)					1,616,504		774,665	308,432
Market-based [Member]
Share-based compensation disclosures
Vesting (service) period					3 years	3 years
Granted (in shares)					1,665,153		347,493	230,932
Granted (in dollars per share) | $ / shares					$ 4.31		$ 25.97	$ 27.28
Target share granted percent, will be share-settled						100.00%
Market-based [Member] | Minimum [Member]
Share-based compensation disclosures
Possible multiplier of shares earned | item						0
Market-based [Member] | Maximum [Member]
Share-based compensation disclosures
Possible multiplier of shares earned | item						2
Cash Retention Incentives [Member]
Share-based compensation disclosures
Replacement award fair value | $			$ 12,000,000
Cash bonus paid taxes | $			$ 9,000,000
Existing Stockholders [Member]
Share-based compensation disclosures
Issuance of Successor stock (in shares)		1,233,495

STOCK-BASED COMPENSATION (Assum

STOCK-BASED COMPENSATION (Assumptions) (Details) - item	4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2020	Aug. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Market Based Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of simulations	100,000
Expected volatility (as a percent)	40.00%
Risk-free interest rate (as a percent)	0.66%
Dividend yield (as a percent)	0.00%
Market-based [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of simulations		2,500,000	2,500,000	2,500,000
Expected volatility (as a percent)		76.52%	72.95%	72.80%
Risk-free interest rate (as a percent)		1.51%	2.60%	2.12%
Dividend yield (as a percent)		0.00%	0.00%	0.00%

INCOME TAXES (Schedule of incom

INCOME TAXES (Schedule of income expense) (Details) - USD ($) $ in Thousands	4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2020	Aug. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
INCOME TAXES [Abstract]
Federal		$ (1,028)
Foreign	$ 2,463	3,746
Total current income tax benefit	2,463	2,718
Federal			$ 2,140	$ (10,960)
State			(3,513)	12,333
Foreign	(14,501)	(59,092)	73,593
Total deferred income tax expense (benefit)	(14,501)	(59,092)	72,220	1,373
Total income tax benefit	$ (12,038)	$ (56,374)	$ 72,220	$ 1,373

INCOME TAXES (Reconciliation of

INCOME TAXES (Reconciliation of statutory income tax expense to income expense) (Details) - USD ($) $ in Thousands	4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2020	Aug. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
INCOME TAXES [Abstract]
U.S. statutory income tax rate (as a percent)			21.00%	21.00%	21.00%
U.S. statutory income tax expense (benefit)	$ 5,676	$ (844,471)		$ (35,479)	$ 72,211
State income taxes, net of federal benefit	724	(148,305)		(8,288)	14,324
Executive compensation	(765)	2,182
Reorganization costs		10,584
IRC Section 382 and other restructuring adjustments	549,323	5,433
State net operating loss adjustments due to subsidiary restructuring	25,864
Market-based equity awards	415	441		910	2,215
Other	(1,105)	(4,040)		1,812	397
Valuation allowance	(580,132)	977,148		39,672	(87,774)
Total federal and state tax expense (benefit)		(1,028)		(1,373)	1,373
Foreign tax expense	2,463	3,746		(147)
ASC 740-30-25-19 outside basis difference recognition	(14,501)	(59,092)		73,740
Total foreign tax expense (benefit)	(12,038)	(55,346)		73,593
Total income tax benefit	$ (12,038)	$ (56,374)		$ 72,220	$ 1,373

INCOME TAXES (Components of def

INCOME TAXES (Components of deferred income tax assets and liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
INCOME TAXES [Abstract]
Net operating loss carryforward	$ 248,835	$ 944,709
Derivative instruments	14,119	2,451
Asset retirement obligations	23,390	32,152
Restricted stock compensation	123	2,033
EOR credit carryforwards	7,946	7,946
Lease obligations	9,409	14,463
Oil and gas properties	291,698
Other	5,011	12,847
Total deferred income tax assets	600,531	1,016,601
Less valuation allowances	(585,296)	(188,281)
Net deferred income tax assets	15,235	828,320
Oil and gas properties		805,989
Trust distributions	6,061	10,517
Lease assets	9,174	10,993
Discount on convertible senior notes		674
Foreign outside basis difference		73,740
Total deferred income tax liabilities	$ 15,235	901,913
Total net deferred income tax liabilities		$ 73,593

INCOME TAXES (Narrative) (Detai

INCOME TAXES (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020	Aug. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Federal operating loss carryforwards	$ 3,100,000	$ 3,100,000		$ 3,100,000
Operating loss carryforwards expiration amount	2,300,000	2,300,000		2,300,000
EOR credit carryforwards	7,946	7,946		7,946	$ 7,946
Valuation allowance	585,296	585,296		585,296	188,281
Foreign outside basis difference					73,740
Deferred tax liability recognized					73,740
Income tax benefit (expense)		(12,038)	$ (56,374)		72,220	$ 1,373
Income taxes paid (refunded), net		6,209	(1,028)		(7,508)	$ (32)
Uncertain tax positions	0	0		0	0
Unrecognized tax benefits, penalties and interest expense				$ 0	$ 0
CANADA
Operating Loss Carryforwards [Line Items]
Income tax benefit (expense)		$ (12,000)	$ (55,000)
Income taxes paid (refunded), net	$ 6,000

EARNINGS PER SHARE (Reconciliat

EARNINGS PER SHARE (Reconciliation) (Details) - USD ($) $ / shares in Units, $ in Thousands	4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2020	Aug. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Basic Earnings (Loss) Per Share
Net income (loss)	$ 39,073	$ (3,965,461)	$ (241,166)	$ 342,494
Weighted average shares outstanding	38,080	91,423	91,285	90,953
Earnings (loss) per common share, basic	$ 1.03	$ (43.37)	$ (2.64)	$ 3.77
Diluted Earnings (Loss) Per Share
Net income (loss)	$ 39,073	$ (3,965,461)	$ (241,166)	$ 342,494
Service-based awards, market-based awards and stock options	39			916
Weighted average shares outstanding	38,119	91,423	91,285	91,869
Earnings (loss) per common share, diluted	$ 1.03	$ (43.37)	$ (2.64)	$ 3.73

EARNINGS PER SHARE (Narrative)

EARNINGS PER SHARE (Narrative) (Details) - shares	Sep. 01, 2020	Feb. 28, 2021	Dec. 31, 2020	Aug. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Shares excluded from Earnings Per Share calculation [Line Items]
Common stock issued	38,051,125
Basic weighted average shares outstanding			48,897
General Unsecured Claimants [Member] | Subsequent Event [Member]
Shares excluded from Earnings Per Share calculation [Line Items]
Common stock issued		948,897
Service Based Restricted Stock [Member]
Shares excluded from Earnings Per Share calculation [Line Items]
Antidilutive securities excluded from computation of earnings per share					344,671
Market Based Restricted Stock [Member]
Shares excluded from Earnings Per Share calculation [Line Items]
Antidilutive securities excluded from computation of earnings per share					3,511
Series A [Member]
Shares excluded from Earnings Per Share calculation [Line Items]
Antidilutive securities excluded from computation of earnings per share			4,837,387
Series B [Member]
Shares excluded from Earnings Per Share calculation [Line Items]
Antidilutive securities excluded from computation of earnings per share			2,418,840
Contingently Issuable Shares [Member]
Shares excluded from Earnings Per Share calculation [Line Items]
Antidilutive securities excluded from computation of earnings per share			3,021,304
Market-based [Member]
Shares excluded from Earnings Per Share calculation [Line Items]
Antidilutive securities excluded from computation of earnings per share			189,900
Service-based [Member]
Shares excluded from Earnings Per Share calculation [Line Items]
Antidilutive securities excluded from computation of earnings per share				314,896
Stock Option [Member]
Shares excluded from Earnings Per Share calculation [Line Items]
Stock options excluded from earnings per share calculation (in shares)				29,465	45,588	100,708

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES (Minimum future payments) (Details) $ in Thousands	Dec. 31, 2020USD ($)
COMMITMENTS AND CONTINGENCIES [Abstract]
2021	$ 2,189
2022	2,189
2023	2,189
2024	547
Total	$ 7,114

COMMITMENTS AND CONTINGENCIES_3

COMMITMENTS AND CONTINGENCIES (Narrative) (Details) MBbls in Thousands, $ in Thousands	Oct. 01, 2020USD ($)	Jun. 30, 2020USD ($)	Dec. 31, 2020USD ($)	Aug. 31, 2020USD ($)	Dec. 31, 2020USD ($)MBblscontract	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Commitments
Contractual Obligation			$ 7,114		$ 7,114
Payment made		$ 14,000
Contingency accrual						$ 11,000
Additional litigation settlement expense				$ 3,000
Indemnity amount		$ 25,000
US Government [Member]
Commitments
Bankruptcy Claims, Amount of Claims Filed	$ 25,000
FMOG Entities [Member]
Commitments
Bankruptcy Claims, Amount of Claims Filed	$ 60,000
Crude Oil Sales And Delivery Contract [Member]
Commitments
Number of contracts | contract					1
Delivery commitments, volume per day | MBbls					15
Agreement term					4 years 1 month 6 days
Pipeline Transportation Agreements [Member]
Commitments
Number of contracts | contract					2
Contractual Obligation			7,000		$ 7,000
Future estimated commitments			5,000		$ 5,000
Payments under purchase contracts			$ 1,000	$ 1,000		$ 2,000	$ 2,000

CAPITALIZED EXPLORATORY WELL _3

CAPITALIZED EXPLORATORY WELL COSTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2020
CAPITALIZED EXPLORATORY WELL COSTS [Abstract]
Balance at the beginning of the period	$ 13,894
Additions to capitalized exploratory well costs pending the determination of proved reserves	10,831
Reclassifications to wells, facilities and equipment based on the determination of proved reserves	$ (24,725)
Capitalized exploratory cost for exploratory wells in progress		$ 0

COMPANY RESTRUCTURINGS (Details

COMPANY RESTRUCTURINGS (Details) - USD ($) $ in Millions	1 Months Ended
	Sep. 30, 2020	Aug. 31, 2019
One-time employee termination benefits [Member]
Restructuring
Restructuring costs incurred	$ 8	$ 8

SUBSEQUENT EVENTS (Details)

SUBSEQUENT EVENTS (Details) - USD ($) $ in Millions	Sep. 01, 2020	Feb. 28, 2021
Subsequent Event [Line Items]
Common stock issued	38,051,125
Subsequent Event [Member] | General Unsecured Claimants [Member]
Subsequent Event [Line Items]
Bankruptcy claims, amount paid		$ 2
Common stock issued		948,897