Chord Energy (WLLBW) 10-Q 3 Nov 21 2021 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Nov. 01, 2021
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
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 Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Bankruptcy Proceedings, Reporting Current	true
Entity Common Stock, Shares Outstanding		39,133,637
Entity Central Index Key	0001255474
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Amendment Flag	false

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash, cash equivalents and restricted cash	$ 12,909	$ 28,367
Accounts receivable trade, net	217,698	142,830
Prepaid expenses and other	14,325	19,224
Total current assets	244,932	190,421
Property and equipment:
Oil and gas properties, successful efforts method	2,166,379	1,812,601
Other property and equipment	45,671	74,064
Total property and equipment	2,212,050	1,886,665
Less accumulated depreciation, depletion and amortization	(203,628)	(73,869)
Total property and equipment, net	2,008,422	1,812,796
Other long-term assets	37,883	40,723
TOTAL ASSETS	2,291,237	2,043,940
Current liabilities:
Accounts payable trade	57,518	23,697
Revenues and royalties payable	193,474	151,196
Accrued capital expenditures	38,255	20,155
Accrued liabilities and other	35,572	42,007
Accrued lease operating expenses	22,730	23,457
Taxes payable	16,744	11,997
Derivative liabilities	299,602	49,485
Total current liabilities	663,895	321,994
Long-term debt	72,000	360,000
Asset retirement obligations	85,120	91,864
Operating lease obligations	15,550	17,415
Long-term derivative liabilities	83,355	9,750
Other long-term liabilities	2,159	14,113
Total liabilities	922,079	815,136
Commitments and contingencies
Equity:
Successor common stock, $0.001 par value, 500,000,000 shares authorized; 39,127,389 issued and outstanding as of September 30, 2021 and 38,051,125 issued and outstanding as of December 31, 2020	39	38
Additional paid-in capital	1,194,319	1,189,693
Accumulated earnings	174,800	39,073
Total equity	1,369,158	1,228,804
TOTAL LIABILITIES AND EQUITY	$ 2,291,237	$ 2,043,940

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2021	Dec. 31, 2020
CONSOLIDATED BALANCE SHEETS [Abstract]
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	39,127,389	38,051,125
Common stock, shares outstanding	39,127,389	38,051,125

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	1 Months Ended	2 Months Ended	3 Months Ended	8 Months Ended	9 Months Ended
	Sep. 30, 2020	Aug. 31, 2020	Sep. 30, 2021	Aug. 31, 2020	Sep. 30, 2021
OPERATING REVENUES
Operating revenues	$ 61,084	$ 122,558	$ 401,037	$ 459,004	$ 1,060,074
OPERATING EXPENSES
Lease operating expenses	18,526	32,646	56,562	158,228	180,083
Transportation, gathering, compression and other	1,980	4,259	8,835	22,266	23,306
Purchased gas expense			5,496		8,576
Production and ad valorem taxes	5,908	10,362	28,712	41,204	78,531
Depreciation, depletion and amortization	20,110	71,240	51,927	338,757	157,274
Exploration and impairment	4,207	10,217	3,446	4,184,830	8,115
General and administrative	10,345	16,513	11,961	91,816	34,247
Derivative (gain) loss, net	(30,594)	43,125	122,559	(181,614)	524,661
(Gain) loss on sale of properties	395	1,280	(90,194)	927	(100,304)
Amortization of deferred gain on sale		(1,171)		(5,116)
Total operating expenses	30,877	188,471	199,304	4,651,298	914,489
INCOME (LOSS) FROM OPERATIONS	30,207	(65,913)	201,733	(4,192,294)	145,585
OTHER INCOME (EXPENSE)
Interest expense	(2,128)	(11,379)	(3,871)	(73,054)	(12,955)
Gain on extinguishment of debt				25,883
Interest income and other	6	139	300	211	3,097
Reorganization items, net		259,232		217,419
Total other income (expense)	(2,122)	247,992	(3,571)	170,459	(9,858)
INCOME (LOSS) BEFORE INCOME TAXES	28,085	182,079	198,162	(4,021,835)	135,727
INCOME TAX EXPENSE (BENEFIT)
Current	2,316			2,718
Deferred	(14,501)	(55,346)		(59,092)
Total income tax benefit	(12,185)	(55,346)	0	(56,374)	0
NET INCOME (LOSS)	$ 40,270	$ 237,425	$ 198,162	$ (3,965,461)	$ 135,727
INCOME (LOSS) PER COMMON SHARE
Basic (in dollars per share)	$ 1.06	$ 2.60	$ 5.07	$ (43.37)	$ 3.48
Diluted (in dollars per share)	$ 1.06	$ 2.60	$ 5	$ (43.37)	$ 3.44
WEIGHTED AVERAGE SHARES OUTSTANDING
Basic (in shares)	38,051	91,464	39,121	91,423	38,963
Diluted (in shares)	38,051	91,464	39,622	91,423	39,479
Oil, NGL and natural gas sales [Member]
OPERATING REVENUES
Operating revenues	$ 61,084	$ 122,558	$ 394,333	$ 459,004	$ 1,048,995
Purchased gas sales [Member]
OPERATING REVENUES
Operating revenues			$ 6,704		$ 11,079

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	1 Months Ended	8 Months Ended	9 Months Ended
	Sep. 30, 2020	Aug. 31, 2020	Sep. 30, 2021
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 40,270	$ (3,965,461)	$ 135,727
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, depletion and amortization	20,110	338,757	157,274
Deferred income tax benefit	(14,501)	(59,092)
Amortization of debt issuance costs, debt discount and debt premium	371	13,535	2,660
Stock-based compensation		4,188	7,508
Amortization of deferred gain on sale		(5,116)
(Gain) loss on sale of properties	395	927	(100,304)
Oil and gas property impairments		4,161,885	5,130
Gain on extinguishment of debt		(25,883)
Non-cash derivative (gain) loss	(29,563)	(136,131)	326,395
Non-cash reorganization items, net		(274,588)
Other, net	(438)	(223)	(6,103)
Changes in current assets and liabilities:
Accounts receivable trade, net	7,752	181,416	(73,198)
Prepaid expenses and other	1,133	(5,491)	4,351
Accounts payable trade and accrued liabilities	(18,163)	(46,734)	26,455
Revenues and royalties payable	1,261	(56,504)	35,452
Taxes payable	3,013	(12,872)	4,982
Net cash provided by operating activities	11,640	112,613	526,329
CASH FLOWS FROM INVESTING ACTIVITIES
Drilling and development capital expenditures	(9,040)	(238,456)	(151,394)
Acquisition of oil and gas properties	(162)	(493)	(272,043)
Other property and equipment, proceeds	56
Other property and equipment, payments		(1,072)	(3,539)
Proceeds from sale of properties	532	29,273	179,680
Net cash used in investing activities	(8,614)	(210,748)	(247,296)
CASH FLOWS FROM FINANCING ACTIVITIES
Repurchase of 1.25% Convertible Senior Notes due 2020		(52,890)
Debt issuance costs		(12,784)
Principal payments on finance lease obligations	(498)	(3,198)	(3,610)
Restricted stock used for tax withholdings		(307)	(2,881)
Net cash provided by (used in) financing activities	(25,498)	138,890	(294,491)
NET CHANGE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(22,472)	40,755	(15,458)
CASH, CASH EQUIVALENTS AND RESTRICTED CASH
Beginning of period	49,407	8,652	28,367
End of period	26,935	49,407	12,909
SUPPLEMENTAL CASH FLOW DISCLOSURES
Interest paid, net of amounts capitalized	301	80,220	8,739
Cash paid for reorganization items	14,353	33,238	396
NONCASH INVESTING ACTIVITIES
Accrued capital expenditures and accounts payable related to property additions	23,245	26,796	42,606
Predecessor Credit Agreement
CASH FLOWS FROM FINANCING ACTIVITIES
Borrowings under Credit Agreement		1,185,000
Repayments of borrowings under Credit Agreement		(1,402,259)
NONCASH INVESTING ACTIVITIES
Derivative termination settlement payments used to repay borrowings under Predecessor Credit Agreement		157,741
Credit Agreement [Member]
CASH FLOWS FROM FINANCING ACTIVITIES
Borrowings under Credit Agreement	75,000	$ 425,328	1,262,000
Repayments of borrowings under Credit Agreement	$ (100,000)		$ (1,550,000)

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical)	Sep. 30, 2020	Aug. 31, 2020
1.25% Convertible Senior Notes due 2020 [Member]
Interest Rate (as a percent)	1.25%	1.25%

CONSOLIDATED STATEMENTS OF EQUI

CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Total
BALANCES at Dec. 31, 2019	$ 92	$ 6,409,991	$ (2,385,112)	$ 4,024,971
BALANCES (in shares) at Dec. 31, 2019	91,744,000
Increase (Decrease) in Shareholders' Equity
Net income			(3,628,571)	(3,628,571)
Adjustment to equity component of Convertible Senior Notes upon extinguishment		(3,461)		(3,461)
Restricted stock issued (in shares)	185,000
Restricted stock forfeited (in shares)	(238,000)
Restricted stock used for tax withholdings		(304)		(304)
Restricted stock used for tax withholdings (in shares)	(54,000)
Stock-based compensation		2,068		2,068
BALANCES at Mar. 31, 2020	$ 92	6,408,294	(6,013,683)	394,703
BALANCES (in shares) at Mar. 31, 2020	91,637,000
BALANCES at Dec. 31, 2019	$ 92	6,409,991	(2,385,112)	4,024,971
BALANCES (in shares) at Dec. 31, 2019	91,744,000
Increase (Decrease) in Shareholders' Equity
Net income				(3,965,461)
BALANCES at Aug. 31, 2020
BALANCES (in shares) at Aug. 31, 2020
BALANCES at Mar. 31, 2020	$ 92	6,408,294	(6,013,683)	394,703
BALANCES (in shares) at Mar. 31, 2020	91,637,000
Increase (Decrease) in Shareholders' Equity
Net income			(574,315)	(574,315)
Stock-based compensation		1,333		1,333
BALANCES at Jun. 30, 2020	$ 92	6,409,627	(6,587,998)	(178,279)
BALANCES (in shares) at Jun. 30, 2020	91,637,000
Increase (Decrease) in Shareholders' Equity
Net income			237,425	237,425
Restricted stock issued (in shares)	9,000
Restricted stock used for tax withholdings		(4)		(4)
Restricted stock used for tax withholdings (in shares)	(4,000)
Stock-based compensation		787		787
Cancellation of Predecessor stock	$ (92)	(6,410,410)	6,350,573	(59,929)
Cancellation of Predecessor stock (in shares)	(91,642,000)
BALANCES at Aug. 31, 2020
BALANCES (in shares) at Aug. 31, 2020
Increase (Decrease) in Shareholders' Equity
Common stock issued	$ 38	1,159,818		$ 1,159,856
Common stock issued (in shares)	38,051,000			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			40,270	40,270
BALANCES at Sep. 30, 2020	$ 38	1,189,178	40,270	1,229,486
BALANCES (in shares) at Sep. 30, 2020	38,051,000
Increase (Decrease) in Shareholders' Equity
Balance Successor	$ 38	1,189,178		1,189,216
Balance Successor, Shares	38,051,000
BALANCES at Dec. 31, 2020	$ 38	1,189,693	39,073	1,228,804
BALANCES (in shares) at Dec. 31, 2020	38,051,000
Increase (Decrease) in Shareholders' Equity
Net income			(946)	(946)
Common stock issued	$ 1	(1)
Common stock issued (in shares)	949,000
Restricted stock issued (in shares)	95,000
Restricted stock used for tax withholdings		(1,357)		(1,357)
Restricted stock used for tax withholdings (in shares)	(41,000)
Stock-based compensation		2,309		2,309
BALANCES at Mar. 31, 2021	$ 39	1,190,644	38,127	1,228,810
BALANCES (in shares) at Mar. 31, 2021	39,054,000
BALANCES at Dec. 31, 2020	$ 38	1,189,693	39,073	1,228,804
BALANCES (in shares) at Dec. 31, 2020	38,051,000
Increase (Decrease) in Shareholders' Equity
Net income				135,727
BALANCES at Sep. 30, 2021	$ 39	1,194,319	174,800	1,369,158
BALANCES (in shares) at Sep. 30, 2021	39,127,000
BALANCES at Mar. 31, 2021	$ 39	1,190,644	38,127	1,228,810
BALANCES (in shares) at Mar. 31, 2021	39,054,000
Increase (Decrease) in Shareholders' Equity
Net income			(61,489)	(61,489)
Restricted stock issued (in shares)	37,000
Restricted stock used for tax withholdings		(4)		(4)
Stock-based compensation		2,455		2,455
BALANCES at Jun. 30, 2021	$ 39	1,193,095	(23,362)	1,169,772
BALANCES (in shares) at Jun. 30, 2021	39,091,000
Increase (Decrease) in Shareholders' Equity
Net income			198,162	198,162
Restricted stock issued (in shares)	64,000
Restricted stock used for tax withholdings		(1,520)		(1,520)
Restricted stock used for tax withholdings (in shares)	(28,000)
Stock-based compensation		2,744		2,744
BALANCES at Sep. 30, 2021	$ 39	$ 1,194,319	$ 174,800	$ 1,369,158
BALANCES (in shares) at Sep. 30, 2021	39,127,000

BASIS OF PRESENTATION

BASIS OF PRESENTATION	9 Months Ended
	Sep. 30, 2021
BASIS OF PRESENTATION [Abstract]
BASIS OF PRESENTATION	1. BASIS OF PRESENTATION 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 Predecessor YTD Period, the Company applied ASC 852 in preparing the condensed consolidated financial statements, which requires distinguishing transactions associated with the reorganization separate from activities related to the ongoing operations of the business. Accordingly, 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 indebtedness, were recorded as reorganization items, net in the condensed consolidated statements of operations for the Predecessor periods. Condensed Consolidated Financial Statements operating results for the periods presented are not necessarily indicative of the results that may be expected for the full year. The condensed consolidated financial statements and related notes included in this Quarterly Report on Form 10-Q should be read in conjunction with Whiting’s consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the period ended December 31, 2020. Except as disclosed herein, there have been no material changes to the information disclosed in the notes to consolidated financial statements included in the Company’s Annual Report on Form 10-K for the period ending December 31, 2020. Reclassifications — Cash, Cash Equivalents and Restricted Cash — ​ Restricted cash as of December 31, 2020 consisted 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 following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the condensed consolidated balance sheets and statements of cash flows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ September 30, ​ December 31, ​ ​ 2021 ​ 2020 Cash and cash equivalents ​ $ 12,909 ​ $ 25,607 Restricted cash ​ ​ - ​ ​ 2,760 Total cash, cash equivalents and restricted cash ​ $ 12,909 ​ $ 28,367 ​ 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 September 30, 2021 and December 31, 2020 (Successor), the Company had immaterial allowances for credit losses. ​

CHAPTER 11 EMERGENCE

CHAPTER 11 EMERGENCE	9 Months Ended
	Sep. 30, 2021
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 “Basis of Presentation” footnote above. On April 23, 2020, the Debtors entered into a restructuring support agreement 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. 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 “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 Credit Agreement. The Company utilized borrowings from the 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, and the Predecessor Credit Agreement 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 has been issued by the Bankruptcy Court. Further, nothing herein is or shall be deemed an admission with respect to any claim amounts or calculations arising from the rejection of any executory contract or unexpired lease and the Debtors expressly reserve all of their rights in that regard. Refer to the “Commitments and Contingencies” footnote for more information on potential future rejection damages related to general unsecured claims. Interest Expense Claims Resolution Process

FRESH START ACCOUNTING

FRESH START ACCOUNTING	9 Months Ended
	Sep. 30, 2021
FRESH START ACCOUNTING [Abstract]
FRESH START ACCOUNTING	3. FRESH START ACCOUNTING Fresh Start Fair Value Measurement Business Combinations For further information on the Company’s reorganization value and the resulting fresh start adjustments made on the Emergence Date, refer to the “Fresh Start Accounting” footnote in the notes to the consolidated financial statements in Item 8 of the Company’s Annual Report on Form 10-K for the period ending December 31, 2020. Reorganization Items, Net ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ ​ One Month Ended September 30, 2020 ​ ​ Two Months Ended August 31, 2020 ​ Eight Months Ended August 31, 2020 Legal and professional advisory fees ​ $ - ​ ​ $ 30,502 ​ $ 57,170 Net gain on liabilities subject to compromise ​ ​ - ​ ​ ​ (1,324,940) ​ ​ (1,324,940) Fresh start adjustments, net ​ ​ - ​ ​ ​ 1,025,742 ​ ​ 1,025,742 Write-off of unamortized debt issuance costs and premium (1) ​ ​ - ​ ​ ​ - ​ ​ 15,145 Other items, net ​ ​ - ​ ​ ​ 9,464 ​ ​ 9,464 Total reorganization items, net ​ $ - ​ ​ $ (259,232) ​ $ (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	9 Months Ended
	Sep. 30, 2021
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 September 30, 2021 and December 31, 2020 are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ September 30, ​ December 31, ​ 2021 ​ 2020 Proved oil and gas properties ​ $ 1,905,535 ​ $ 1,701,163 Unproved leasehold costs ​ ​ 197,525 ​ ​ 105,073 Wells and facilities in progress ​ ​ 63,319 ​ ​ 6,365 Total oil and gas properties, successful efforts method ​ ​ 2,166,379 ​ ​ 1,812,601 Accumulated depletion ​ ​ (198,604) ​ ​ (71,064) Oil and gas properties, net ​ $ 1,967,775 ​ $ 1,741,537 ​ The following tables present impairment expense for unproved properties for the periods presented, which is reported in exploration and impairment expense in the condensed consolidated statements of operations (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ ​ Three Months Ended September 30, 2021 ​ One Month Ended September 30, 2020 ​ ​ Two Months Ended August 31, 2020 Impairment expense for unproved properties ​ $ 836 ​ $ - ​ ​ $ 83 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ ​ Nine Months Ended September 30, 2021 ​ One Month Ended September 30, 2020 ​ ​ Eight Months Ended August 31, 2020 Impairment expense for unproved properties ​ $ 2,487 ​ $ - ​ ​ $ 12,566 ​ Refer to the “Fair Value Measurements” footnote for more information on proved property impairments recorded during the Predecessor YTD Period.

ACQUISITIONS AND DIVESTITURES

ACQUISITIONS AND DIVESTITURES	9 Months Ended
	Sep. 30, 2021
ACQUISITIONS AND DIVESTITURES [Abstract]
ACQUISITIONS AND DIVESTITURES	5. ACQUISITIONS AND DIVESTITURES 2021 Acquisitions and Divestitures On September 14, 2021, the Company completed the acquisition of interests in approximately 8,750 net acres in the Williston Basin, including interests in 76 gross (50.2 net) producing wells, 5 gross (2.4 net) drilled and uncompleted oil and gas wells and undeveloped acreage located in Mountrail County, North Dakota for an aggregate purchase price of $271 million (before post-closing adjustments). The transaction was funded primarily with borrowings under the Credit Agreement. The revenue and earnings from these properties since the acquisition date are included in our condensed consolidated financial statements for the three and nine months ended September 30, 2021 and are not material. Pro forma revenue and earnings for the acquired properties are not material to our condensed consolidated financial statements and have therefore not been presented. The acquisition was accounted for as a business combination and was recorded using the acquisition method of accounting. The following table summarizes the preliminary allocation of the $271 million adjusted purchase price (which is still subject to post-closing adjustments) to the assets acquired and liabilities assumed in this acquisition based on their respective fair values at the acquisition date, which did not result in the recognition of goodwill or a bargain purchase gain. Refer to the “Fair Value Measurements” footnote for a detailed discussion of the fair value inputs used by the Company in determining the valuation of the significant assets acquired and liabilities assumed. As the purchase price is further adjusted for post-close adjustments and as the oil and gas property valuation is completed, the final purchase price allocation may result in a different allocation than what is presented in the table below (in thousands): ​ ​ ​ ​ ​ Cash consideration ​ $ 270,800 ​ ​ ​ ​ Fair value of assets acquired: ​ ​ ​ Prepaid expenses and other ​ $ 730 Oil and gas properties, successful efforts method: ​ ​ ​ Proved oil and gas properties ​ ​ 167,435 Unproved leasehold costs ​ ​ 105,950 Total fair value of assets acquired ​ ​ 274,115 ​ ​ ​ ​ Fair value of liabilities assumed: ​ ​ ​ Asset retirement obligations ​ ​ 2,242 Revenue and royalties payable ​ ​ 1,073 Total fair value of liabilities assumed ​ ​ 3,315 ​ ​ ​ ​ Total fair value of assets acquired and liabilities assumed ​ $ 270,800 ​ On September 23, 2021, the Company completed the sale of all of its interests in producing assets and undeveloped acreage, including the associated midstream assets, of its Redtail field located in the Denver-Julesburg Basin of Weld County, Colorado for aggregate net sales proceeds of $171 million (before post-closing adjustments). The sale was effective June 1, 2021 and resulted in a pre-tax gain on sale of $90 million. The Company used the net proceeds from the sale to repay a portion of the borrowings outstanding under the Credit Agreement. This transaction included the removal of approximately $20 million in asset retirement obligations as well as certain finance leases for a pipeline and vehicles, which resulted in the termination of approximately $16 million of finance lease right-of-use assets, $3 million of accumulated depreciation and $12 million of long-term finance lease obligations. 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 nine months ended September 30, 2020.

LONG-TERM DEBT

LONG-TERM DEBT	9 Months Ended
	Sep. 30, 2021
LONG-TERM DEBT [Abstract]
LONG-TERM DEBT	6. LONG-TERM DEBT Long-term debt, consisting entirely of borrowings outstanding under the Credit Agreement, totaled $72 million and $360 million at September 30, 2021 and December 31, 2020, respectively. Credit Agreement (Successor) On the Emergence Date, Whiting Petroleum Corporation, as parent guarantor, and Whiting Oil and Gas, as borrower, entered into the Credit Agreement, a reserves-based credit facility, with a syndicate of banks . As of September 30, 2021, the Credit Agreement had a borrowing base and aggregate commitments of $750 million. As of September 30, 2021, the Company had $676 million of available borrowing capacity under the Credit Agreement, which was net of $72 million of borrowings outstanding and $2 The borrowing base under the 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 regular redeterminations on April 1 and October 1 of each year, as well as special redeterminations described in the 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. Up to $50 million of the borrowing base 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 September 30, 2021, $48 million was available for additional letters of credit under the Credit Agreement. The 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 Credit Agreement provides for certain mandatory prepayments, including a provision pursuant to which, 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 Credit Agreement. Interest under the 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 Credit Agreement, which are included as a component of interest expense. At September 30, 2021, the weighted average interest rate on the outstanding principal balance under the Credit Agreement was 3.8%. The 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. The Credit Agreement also restricts the Company’s ability to make any dividend payments or distributions of cash on its common stock except to the extent that the Company has distributable free cash flow and (i) has at least 20% of available borrowing capacity, (ii) has 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 Credit Agreement. These restrictions apply to all of the Company’s restricted subsidiaries and are calculated in accordance with definitions contained in the Credit Agreement. The amended Credit Agreement requires the Company, as of the last day of any quarter, to maintain commodity hedges covering a minimum of 50% of its projected production for the succeeding twelve months, as reflected in the reserves report most recently provided by the Company to the lenders under the Credit Agreement. If the Company’s consolidated net leverage ratio equals or exceeds 1.0 to 1.0 as of the last day of any fiscal quarter, the Company will also be required to hedge 35% of its projected production for the next succeeding twelve months. The Company is also limited to hedging a maximum of 85% of its production from proved reserves. The Credit Agreement requires the Company 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 September 30, 2021, the Company was in compliance with the covenants under the Credit Agreement. The obligations of Whiting Oil and Gas under the Credit Agreement are secured by a first lien on substantially all of the Company’s and certain of its subsidiaries’ properties. The Company has also guaranteed the obligations of Whiting Oil and Gas under the Credit Agreement and has pledged the stock of certain of its subsidiaries as security for its guarantee. Senior Notes and Convertible Senior Notes (Predecessor) Prior to the Emergence Date, the Company had outstanding notes consisting of $774 million 5.75% Senior Notes due 2021, $408 million 6.25% Senior Notes due 2023 and $1.0 billion 6.625% Senior Notes due 2026 (collectively, the “Senior Notes”) and $187 million of 1.25% Convertible Senior Notes due 2020 (the “Convertible Senior Notes”). 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 condensed consolidated statements of operations. Refer to the “Chapter 11 Emergence” and “Fresh Start Accounting” footnotes for more information. In March 2020, the Company 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 Predecessor 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. There was no deferred tax impact associated with this reduction due to the full valuation allowance in effect as of March 31, 2020.

ASSET RETIREMENT OBLIGATIONS

ASSET RETIREMENT OBLIGATIONS	9 Months Ended
	Sep. 30, 2021
ASSET RETIREMENT OBLIGATIONS [Abstract]
ASSET RETIREMENT OBLIGATIONS	7. 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 September 30, 2021 and December 31, 2020 (Successor) were $7 million and $6 million, respectively, and have been included in accrued liabilities and other in the condensed consolidated balance sheets. The following table provides a reconciliation of the Company’s asset retirement obligations for the nine months ended September 30, 2021 (in thousands): ​ ​ ​ ​ ​ Asset retirement obligation at January 1, 2021 (Successor) ​ $ 98,130 Additional liability incurred or assumed ​ ​ 3,402 Revisions to estimated cash flows ​ ​ 17,363 Accretion expense ​ ​ 6,241 Obligations on sold properties ​ ​ (29,244) Liabilities settled ​ ​ (3,387) Asset retirement obligation at September 30, 2021 (Successor) ​ $ 92,505 ​

DERIVATIVE FINANCIAL INSTRUMENT

DERIVATIVE FINANCIAL INSTRUMENTS	9 Months Ended
	Sep. 30, 2021
DERIVATIVE FINANCIAL INSTRUMENTS [Abstract]
DERIVATIVE FINANCIAL INSTRUMENTS	8. 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. Commodity Derivative Contracts — Crude Oil, Natural Gas and Natural Gas Liquids Swaps and Collars, Natural Gas Basis Swaps and Crude Oil Differential Swaps. The table below details the Successor’s swap and collar derivatives entered into to hedge forecasted crude oil, NGL and natural gas production revenues as of September 30, 2021. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Average Settlement Period ​ Index ​ Derivative Instrument ​ Total Volumes ​ Units ​ Swap Price ​ Floor ​ Ceiling Crude Oil ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ NYMEX WTI ​ Fixed Price Swaps ​ 2,162,000 ​ Bbl ​ $44.90 ​ - ​ - 2021 ​ NYMEX WTI ​ Two-way Collars ​ 1,150,000 ​ Bbl ​ - ​ $42.48 ​ $51.80 Q1 2022 ​ NYMEX WTI ​ Fixed Price Swaps ​ 630,000 ​ Bbl ​ $54.30 ​ - ​ - 2022 ​ NYMEX WTI ​ Two-way Collars ​ 9,559,000 ​ Bbl ​ - ​ $43.23 ​ $53.73 Q1-Q3 2023 ​ NYMEX WTI ​ Two-way Collars ​ 3,443,500 ​ Bbl ​ - ​ $46.75 ​ $58.87 ​ ​ ​ ​ Total ​ 16,944,500 ​ ​ ​ ​ ​ ​ ​ ​ Crude Oil Differentials (1) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ UHC Clearbrook to NYMEX ​ Fixed Price Swaps ​ 30,500 ​ Bbl ​ -$1.95 ​ - ​ - ​ ​ ​ ​ Total ​ 30,500 ​ ​ ​ ​ ​ ​ ​ ​ Natural Gas ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ NYMEX Henry Hub ​ Fixed Price Swaps ​ 5,290,000 ​ MMBtu ​ $3.16 ​ - ​ - 2021 ​ NYMEX Henry Hub ​ Two-way Collars ​ 2,760,000 ​ MMBtu ​ - ​ $2.60 ​ $2.79 Q1-Q3 2022 ​ NYMEX Henry Hub ​ Fixed Price Swaps ​ 5,259,000 ​ MMBtu ​ $2.81 ​ - ​ - 2022 ​ NYMEX Henry Hub ​ Two-way Collars ​ 17,304,000 ​ MMBtu ​ - ​ $2.70 ​ $3.32 Q1-Q3 2023 ​ NYMEX Henry Hub ​ Two-way Collars ​ 6,999,000 ​ MMBtu ​ - ​ $2.42 ​ $2.94 ​ ​ ​ ​ Total ​ 37,612,000 ​ ​ ​ ​ ​ ​ ​ ​ Natural Gas Basis (2) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ NNG Ventura to NYMEX ​ Fixed Price Swaps ​ 2,760,000 ​ MMBtu ​ -$0.07 ​ - ​ - Q1-Q2 2022 ​ NNG Ventura to NYMEX ​ Fixed Price Swaps ​ 5,330,000 ​ MMBtu ​ $0.43 ​ - ​ - Q1-Q2 2023 ​ NNG Ventura to NYMEX ​ Fixed Price Swaps ​ 4,740,000 ​ MMBtu ​ $0.20 ​ - ​ - ​ ​ ​ ​ Total ​ 12,830,000 ​ ​ ​ ​ ​ ​ ​ ​ NGL - Propane ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ Mont Belvieu ​ Fixed Price Swaps ​ 9,660,000 ​ Gallons ​ $0.78 ​ - ​ - 2021 ​ Conway ​ Fixed Price Swaps ​ 7,728,000 ​ Gallons ​ $1.31 ​ - ​ - Q1 2022 ​ Mont Belvieu ​ Fixed Price Swaps ​ 3,780,000 ​ Gallons ​ $0.81 ​ - ​ - Q1 2022 ​ Conway ​ Fixed Price Swaps ​ 3,780,000 ​ Gallons ​ $1.20 ​ - ​ - ​ ​ ​ ​ Total ​ 24,948,000 ​ ​ ​ ​ ​ ​ ​ ​ (1) The weighted average price associated with the crude oil differential swaps shown in the table above represents the average fixed differential to NYMEX as stated in the related contracts, which is compared to the NE2 Canadian Monthly Index for UHC Clearbrook (“UHC Clearbrook”) for each period. If NYMEX combined with the fixed differential as stated in each contract is higher than the UHC Clearbrook index price at any settlement date, the Company receives the difference. Conversely, if the UHC Clearbrook index price is higher than NYMEX combined with the fixed differential, the Company pays the difference. (2) The weighted average price associated with the natural gas basis swaps shown in the table above represents the average fixed differential to NYMEX as stated in the related contracts, which is compared to the Northern Natural Gas Ventura Index (“NNG Ventura”) for each period. If NYMEX combined with the fixed differential as stated in each contract is higher than the NNG Ventura index price at any settlement date, the Company receives the difference. Conversely, if the NNG Ventura index price is higher than NYMEX combined with the fixed differential, the Company pays the difference. Subsequent to September 30, 2021, the Company entered into additional crude oil, natural gas, natural gas basis and propane swaps and collars for 2022. The table below details the Company’s additional swap and collar derivatives entered into during October 2021. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Average Settlement Period ​ Index ​ Derivative Instrument ​ Total Volumes ​ Units ​ Swap Price ​ Floor ​ Ceiling Crude Oil ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 ​ NYMEX WTI ​ Fixed Price Swaps ​ 1,645,000 ​ Bbl ​ $75.12 ​ - ​ - 2022 ​ NYMEX WTI ​ Two-way Collars ​ 1,645,000 ​ Bbl ​ - ​ $69.43 ​ $80.00 ​ ​ ​ ​ Total ​ 3,290,000 ​ ​ ​ ​ ​ ​ ​ ​ Natural Gas ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Q2-Q4 2022 ​ NYMEX Henry Hub ​ Fixed Price Swaps ​ 2,750,000 ​ MMBtu ​ $4.07 ​ - ​ - ​ ​ ​ ​ Total ​ 2,750,000 ​ ​ ​ ​ ​ ​ ​ ​ Natural Gas Basis ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Q1 2022 ​ NNG Ventura to NYMEX ​ Fixed Price Swaps ​ 900,000 ​ MMBtu ​ $1.00 ​ - ​ - ​ ​ ​ ​ Total ​ 900,000 ​ ​ ​ ​ ​ ​ ​ ​ NGL - Propane ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 ​ Mont Belvieu ​ Fixed Price Swaps ​ 15,330,000 ​ Gallons ​ $1.15 ​ - ​ - 2022 ​ Conway ​ Fixed Price Swaps ​ 15,330,000 ​ Gallons ​ $1.16 ​ - ​ - ​ ​ ​ ​ Total ​ 30,660,000 ​ ​ ​ ​ ​ ​ ​ ​ ​ Effect of Chapter 11 Cases Derivative Instrument Reporting Offsetting of Derivative Assets and Liabilities. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2021 (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 ​ $ 9,407 ​ $ (9,407) ​ $ - Commodity contracts - non-current ​ Other long-term assets ​ ​ 19,209 ​ ​ (19,209) ​ ​ - Total derivative assets ​ ​ ​ $ 28,616 ​ $ (28,616) ​ $ - Derivative liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commodity contracts - current ​ Derivative liabilities ​ $ 309,009 ​ $ (9,407) ​ $ 299,602 Commodity contracts - non-current ​ Long-term derivative liabilities ​ ​ 102,564 ​ ​ (19,209) ​ ​ 83,355 Total derivative liabilities ​ ​ ​ $ 411,573 ​ $ (28,616) ​ $ 382,957 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 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 ​ Long-term derivative liabilities ​ ​ 29,741 ​ ​ (19,991) ​ ​ 9,750 Total derivative liabilities ​ ​ ​ $ 93,513 ​ $ (34,278) ​ $ 59,235 (1) All of the counterparties to the Company’s financial derivative contracts subject to master netting arrangements are lenders under the 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	9 Months Ended
	Sep. 30, 2021
FAIR VALUE MEASUREMENTS [Abstract]
FAIR VALUE MEASUREMENTS	9. 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 Credit Agreement has a recorded value that approximates its fair value since its variable interest rate is tied to current market rates and the applicable margins represent market rates. 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 September 30, 2021 and December 31, 2020 (Successor), and indicate the fair value hierarchy of the valuation techniques utilized by the Company to determine such fair values (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Fair Value ​ Level 1 Level 2 Level 3 September 30, 2021 Financial Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commodity derivatives – current ​ $ - ​ $ 299,602 ​ $ - ​ $ 299,602 Commodity derivatives – non-current ​ ​ - ​ ​ 83,355 ​ ​ - ​ ​ 83,355 Total financial liabilities ​ $ - ​ $ 382,957 ​ $ - ​ $ 382,957 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 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 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 ​ ​ Net Carrying ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Value as of ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loss (Before Tax) ​ ​ March 31, ​ Fair Value Measurements Using ​ Three Months Ended ​ 2020 Level 1 Level 2 Level 3 March 31, 2020 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 as of March 31, 2020. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Predecessor ​ ​ Net Carrying ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Value as of ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loss (Before Tax) ​ ​ June 30, ​ Fair Value Measurements Using ​ Six Months Ended ​ 2020 Level 1 Level 2 Level 3 June 30, 2020 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 as of June 30, 2020. Predecessor Proved Property Impairments Williston Basin Acquisition.

REVENUE RECOGNITION

REVENUE RECOGNITION	9 Months Ended
	Sep. 30, 2021
REVENUE RECOGNITION [Abstract]
REVENUE RECOGNITION	10. REVENUE RECOGNITION The Company recognizes revenue in accordance with FASB ASC Topic 606 – Revenue from Contracts with Customers ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor OPERATING REVENUES ​ Three Months Ended September 30, 2021 ​ One Month Ended September 30, 2020 ​ ​ Two Months Ended August 31, 2020 Oil sales ​ $ 316,914 ​ $ 60,392 ​ ​ $ 116,971 NGL and natural gas sales ​ ​ 77,419 ​ ​ 692 ​ ​ ​ 5,587 Oil, NGL and natural gas sales ​ ​ 394,333 ​ ​ 61,084 ​ ​ ​ 122,558 Purchased gas sales ​ ​ 6,704 ​ ​ - ​ ​ ​ - Total operating revenues ​ $ 401,037 ​ $ 61,084 ​ ​ $ 122,558 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor OPERATING REVENUES ​ Nine Months Ended September 30, 2021 ​ One Month Ended September 30, 2020 ​ ​ Eight Months Ended August 31, 2020 Oil sales ​ $ 882,040 ​ $ 60,392 ​ ​ $ 440,820 NGL and natural gas sales ​ ​ 166,955 ​ ​ 692 ​ ​ ​ 18,184 Oil, NGL and natural gas sales ​ ​ 1,048,995 ​ ​ 61,084 ​ ​ ​ 459,004 Purchased gas sales ​ ​ 11,079 ​ ​ - ​ ​ ​ - Total operating revenues ​ $ 1,060,074 ​ $ 61,084 ​ ​ $ 459,004 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	9 Months Ended
	Sep. 30, 2021
SHAREHOLDERS' EQUITY
SHAREHOLDERS' EQUITY	11. SHAREHOLDERS’ EQUITY Common Stock — Upon emergence from the Chapter 11 Cases on the Emergence Date, 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” footnote 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 acquire 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 acquire 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”). In the event that a holder of Warrants elects to exercise their option to acquire shares of New Common Stock, the Company shall issue a net number of exercised shares of New Common Stock. The net number of exercised shares is calculated as (i) the number of Warrants exercised multiplied by (ii) the difference between the 30 day average price of the New Common Stock leading up to the exercise date (the “Current Market Price”) and the relevant exercise price, calculated as a percentage of the Current Market Price on the exercise date. 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. Settlement of Bankruptcy Claims — As discussed in the “Chapter 11 Emergence” footnote, an additional 2,121,304 shares of New Common Stock remain reserved as of September 30, 2021 for potential future distribution to certain general unsecured claimants whose claim values are pending resolution in the Bankruptcy Court.

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	9 Months Ended
	Sep. 30, 2021
STOCK-BASED COMPENSATION [Abstract]
STOCK-BASED COMPENSATION	12. 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 two three Successor Awards During September and October 2020, 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. In September 2020, 189,900 shares of market-based RSUs were granted to executive officers under the 2020 Equity Plan. The awards 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% vested when the VWAP exceeded $32.57 per share, an additional 25% vested when the daily VWAP exceeded $48.86 per share and the final 25% will vest if the daily VWAP exceeds $65.14 per share. The Company recognizes compensation expense based on the fair value as determined by a Monte Carlo valuation model (the “Monte Carlo Model”) over the expected vesting period, which was estimated to be between 1.8 and 3.8 years at the grant date. Upon vesting, any unrecognized compensation expense related to the shares is accelerated and recognized. The weighted average grant date fair value of these RSUs was $6.54 per share. More information on the inputs to the Monte Carlo Model are explained below. During the nine months ended September 30, 2021, the first 75% of these awards vested as the Company’s VWAP exceeded both $32.57 and $48.86 per share for 20 consecutive trading days during the period. During the nine months ended , 2021, 360,017 shares of service-based RSUs were granted to executive officers and employees under the 2020 Equity Plan, which vest ratably over either a two or three-year service period. Additionally, during the nine months ended September 30, 2021, 117,607 shares of service-based RSUs were granted to executive officers under the 2020 Equity Plan, which cliff vest on the fifth anniversary of the grant date. Finally, during the nine months ended September The Company determines compensation expense for these share-settled awards using their fair value at the grant date, which is based on the closing bid price of the Company’s common stock on such date. The weighted average grant date fair value of serviced-based RSUs was $23.82 per share for the nine months ended September 30, 2021. During the nine months ended September 30, 2021, 232,150 shares of PSUs subject to certain market-based vesting criteria were granted to executive officers under the 2020 Equity Plan. These market-based awards vest at the end of the performance period, which is December 31, 2023, and the number of shares that vest at the end of the performance period is determined based on two performance goals: (i) 116,075 shares vest based on the Company’s annualized absolute total stockholder return (“ATSR”) over the performance period as compared to certain preestablished target returns and (ii) 116,075 shares vest based on the Company’s relative total stockholder return (“RTSR”) compared to the stockholder returns of a preestablished peer group of companies over the performance period. The number of awards earned could range from zero up to two times the number of shares initially granted, all of which will be settled in shares. The weighted average grant date fair value of the market-based awards was $29.32 per share and $32.33 per share for the ATSR and RTSR awards, respectively, as determined by the Monte Carlo Model, which is described further below. For awards subject to market conditions, the grant date fair value is estimated using the Monte Carlo Model, which ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ 2021 ​ RSUs PSUs Number of simulations 100,000 500,000 Expected volatility 40% ​ 81% Risk-free interest rate 0.66% ​ 0.17% Dividend yield - - ​ The following table shows a summary of the Company’s service-based and market-based awards activity for the nine months ended September 30, 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of Awards ​ Weighted Average ​ ​ Service ‑ Based ​ Market-Based ​ Market-Based ​ Grant Date ​ RSUs RSUs PSUs Fair Value Nonvested awards, January 1 89,021 189,900 ​ - ​ $ 10.03 Granted 501,354 - ​ 232,150 ​ 26.04 Vested (53,787) (142,425) ​ - ​ 9.54 Forfeited (8,411) - ​ - ​ 22.46 Nonvested awards, September 30 528,177 47,475 ​ 232,150 ​ $ 24.55 ​ The Company recognized $3 million and $8 million in stock-based compensation expense during the three and nine months ended September 30, 2021, respectively. Predecessor Awards During the eight months ended August 31, 2020, 53,198 shares of share-settled, service-based RSAs and RSUs were granted to 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 these service-based RSAs and RSUs was $4.94 per share for the eight months ended August 31, 2020. 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, 1,616,504 shares 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, 1,665,153 shares 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, however, 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. 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 in 2020. 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. The Company recognized $1 million and $2 million in total stock-based compensation expense during the Predecessor Period and the Predecessor YTD Period, respectively. 2020 Compensation Adjustments.

INCOME TAXES

INCOME TAXES	9 Months Ended
	Sep. 30, 2021
INCOME TAXES [Abstract]
INCOME TAXES	13. INCOME TAXES Income tax expense during interim periods is based on applying an estimated annual effective income tax rate to year-to-date income, plus any significant unusual or infrequently occurring items which are recorded in the interim period. The provisions for income taxes for the three and nine months ended September 30, 2021 (Successor) differ from the amounts that would be provided by applying the statutory U.S. federal income tax rate of 21% to pre-tax income primarily due to a full valuation allowance in effect on the Company’s U.S. deferred tax assets (“DTAs”), resulting in no U.S. income tax expense recognized for the periods presented and an effective U.S. tax rate of 0%. The provision for income taxes for the month ended September 30, 2020 and the eight months ended August 31, 2020 differ from the amount that would be provided by applying the statutory U.S. federal income tax rate of 21% to pre-tax income primarily as a result of a full valuation allowance on the DTAs and the revision of the Company’s Canadian deferred tax liability (“DTL”) related to its outside basis difference in Whiting Canadian Holding Company ULC discussed below. The Company also recognized a $1 million U.S. income tax benefit during the eight months ended August 31, 2020 related to an alternative minimum tax refund received. As a result of the full valuation on the DTAs as of September 30, 2020 (Successor) and August 31, 2020 (Predecessor), no additional U.S. tax benefit or expense was recognized during the periods presented. During the Prior Successor Period, the Company partially executed a legal entity restructuring plan to reduce administrative expenses and burden with a simplified corporate structure. Several steps of the restructuring plan were executed during the Prior Successor Period, with the remaining steps completed in the fourth quarter of 2020, which ultimately resulted in Whiting Oil and 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 Predecessor YTD Period. As a result of the restructuring, the Company reduced its deferred tax liability and recorded a tax benefit of $15 million during the Prior Successor Period. In assessing the realizability of 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. The Company assesses the appropriateness of its valuation allowance on a quarterly basis. At September 30, 2021 and December 31, 2020 (Successor), the Company had a full valuation allowance on its DTAs. The computation of the annual estimated effective tax rate at each interim period requires certain estimates and significant judgment including, but not limited to, the expected operating income for the year, projections of the proportion of income earned and taxed in various jurisdictions, permanent and temporary differences, and the likelihood of recovering DTAs generated in the current year. The accounting estimates used to compute the provision for income taxes may change as new events occur, more experience is obtained, additional information becomes known or as the tax environment changes. Internal Revenue Code (“IRC”) Section 382 addresses tax impacts of an ownership change and specifically limits the utilization of net operating loss carryforwards (“NOLs”) and certain other deductions for tax periods 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. The ownership change and resulting annual limitation on the Company’s NOL usage will result in the expiration of certain NOLs and other tax attributes otherwise available, with a corresponding decrease in the Company’s valuation allowance. As of December 31, 2020, the Company had federal NOLs of $3 billion which are subject to limitation under IRC Section 382. Due to the annual IRC Section 382 limitation, certain other attribute reductions and the carryforward period of NOLs, approximately $2.4 billion of these federal NOLs will expire before they are able to be used. The remaining non-expiring NOLs are subject to a full valuation allowance as of September 30, 2021 and December 31, 2020.

EARNINGS PER SHARE

EARNINGS PER SHARE	9 Months Ended
	Sep. 30, 2021
EARNINGS PER SHARE [Abstract]
EARNINGS PER SHARE	14. EARNINGS PER SHARE The reconciliations between basic and diluted earnings (loss) per share are as follows (in thousands, except per share data): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ ​ Three Months Ended September 30, 2021 ​ One Month Ended September 30, 2020 ​ ​ Two Months Ended August 31, 2020 Basic earnings per share ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income ​ $ 198,162 ​ $ 40,270 ​ ​ $ 237,425 Weighted average shares outstanding, basic ​ ​ 39,121 ​ ​ 38,051 ​ ​ ​ 91,464 Earnings per common share, basic ​ $ 5.07 ​ $ 1.06 ​ ​ $ 2.60 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Diluted earnings per share ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income ​ $ 198,162 ​ $ 40,270 ​ ​ $ 237,425 Weighted average shares outstanding, basic ​ ​ 39,121 ​ ​ 38,051 ​ ​ ​ 91,464 Service-based awards and market-based awards ​ ​ 501 ​ ​ - ​ ​ ​ - Weighted average shares outstanding, diluted ​ ​ 39,622 ​ ​ 38,051 ​ ​ ​ 91,464 Earnings per common share, diluted ​ $ 5.00 ​ $ 1.06 ​ ​ $ 2.60 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ ​ Nine Months Ended September 30, 2021 ​ One Month Ended September 30, 2020 ​ ​ Eight Months Ended August 31, 2020 Basic earnings (loss) per share ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income (loss) ​ $ 135,727 ​ $ 40,270 ​ ​ $ (3,965,461) Weighted average shares outstanding, basic ​ ​ 38,963 ​ ​ 38,051 ​ ​ ​ 91,423 Earnings (loss) per common share, basic ​ $ 3.48 ​ $ 1.06 ​ ​ $ (43.37) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Diluted earnings (loss) per share ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income (loss) ​ $ 135,727 ​ $ 40,270 ​ ​ $ (3,965,461) Weighted average shares outstanding, basic ​ ​ 38,963 ​ ​ 38,051 ​ ​ ​ 91,423 Service-based awards and market-based awards ​ ​ 516 ​ ​ - ​ ​ ​ - Weighted average shares outstanding, diluted ​ ​ 39,479 ​ ​ 38,051 ​ ​ ​ 91,423 Earnings (loss) per common share, diluted ​ $ 3.44 ​ $ 1.06 ​ ​ $ (43.37) ​ Successor During the Current Successor Quarter, Current Successor YTD Period and Prior Successor Period, the diluted earnings per share calculations exclude the effect of common shares that may be issued pursuant to the Series A Warrants and Series B Warrants, as such Warrants were out-of-the-money as of September 30, 2021 and September 30, 2020. During the Current Successor Quarter and Current Successor YTD Period, the diluted earnings per share calculations also exclude the effect of 47,475 shares of market-based awards that did not meet the market-based vesting criteria as of September 30, 2021 and 2,121,304 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 September 30, 2021. During the Prior Successor Period, the diluted earnings per share calculation also excludes the effect of 189,900 shares of market-based awards that did not meet the market-based vesting criteria as of September 30, 2020, 87,171 shares of service-based awards that were anti-dilutive and 3,070,201 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 September 30, 2020. Refer to the “Stock-Based Compensation” footnote for more information on the Company’s service-based and market-based awards. Predecessor During the Predecessor Period, although the Company had net income, the treasury stock method resulted in a larger number of shares assumed to be reacquired by the Company than weighted average unvested awards outstanding. Thus, the diluted earnings per share calculation excludes the anti-dilutive effect of 239,186 shares of service-based awards. During the Predecessor YTD Period, the Company had a net loss and therefore the diluted earnings per share calculations excludes the anti-dilutive effect of 314,896 shares of service-based awards. In addition, the diluted earnings per share calculations exclude the effect of 18,310 and 29,465 common shares for the Predecessor Period and the Predecessor YTD Period, respectively, for stock options that were out of the money as of August 31, 2020. 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	9 Months Ended
	Sep. 30, 2021
COMMITMENTS AND CONTINGENCIES [Abstract]
COMMITMENTS AND CONTINGENCIES	15. COMMITMENTS AND CONTINGENCIES Chapter 11 Cases — However, it is reasonably possible that as a result of the legal proceedings associated with the bankruptcy claims administration process or the matter detailed below, the Bankruptcy Court may rule, or it may be determined, that (i) the applicable contracts cannot be rejected, 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 rejected the related contracts pursuant to the Plan. On October 1, 2020, 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 were 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 alleged 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. On February 18, 2021, WOG entered into a stipulation and agreed order with the United States Department of the Interior, Bureau of Safety & Environmental Enforcement (“BSEE”) pursuant to which the BSEE withdrew its proofs of claims against Whiting Petroleum Corporation and WOG and acknowledged their respective rights and obligations pursuant to the Plan. On March 26, 2021, the FMOG Entities withdrew their administrative claim for the recovery of Whiting’s proportionate share of costs incurred after August 31, 2020 to fulfill obligations owed to the U.S. Government on the basis of subrogation to the Government’s economic rights. The FMOG Entities continue to assert certain other administrative claims and have reserved the right to assert claims for the recovery of Whiting’s share of the decommissioning costs incurred after August 31, 2020 based on the theory of equitable subrogation. On September 14, 2021, Whiting Petroleum Corporation and WOG filed an objection in the Bankruptcy Court, seeking an order partially disallowing the FMOG Entities’ claims. The Bankruptcy Court has not issued a ruling on the damages for rejection of the Point Arguello Agreements and it is possible that a settlement with the FMOG Entities could be reached outside of the Bankruptcy Court’s claim resolution process. Although WOG intends to vigorously pursue its objection in this legal proceeding, if the FMOG Entities were to prevail on certain of their respective claims (including the reserved claims) on the merits, we enter into a settlement agreement or the U.S. government were to bring claims against WOG, Whiting could be liable for claims that must be paid or otherwise satisfied under and pursuant to the Plan, including through an equity issuance, cash payment or otherwise. 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 recorded $3 million of additional litigation settlement expense in general and administrative expenses in the condensed consolidated statements of operations for the 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 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 September 30, 2021 (Successor).

COMPANY RESTRUCTURING

COMPANY RESTRUCTURING	9 Months Ended
	Sep. 30, 2021
COMPANY RESTRUCTURING [Abstract]
COMPANY RESTRUCTURING	16. COMPANY RESTRUCTURING During September 2020, the Company executed a workforce reduction 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. The Company incurred one-time net charges related to this restructuring of $7 million in net restructuring costs associated with one-time employee termination benefits. These charges were recorded to general and administrative expenses during the Prior Successor Period in the condensed consolidated statement of operations. ​

BASIS OF PRESENTATION (Policies

BASIS OF PRESENTATION (Policies)	9 Months Ended
	Sep. 30, 2021
BASIS OF PRESENTATION [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 Predecessor YTD Period, the Company applied ASC 852 in preparing the condensed consolidated financial statements, which requires distinguishing transactions associated with the reorganization separate from activities related to the ongoing operations of the business. Accordingly, 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 indebtedness, were recorded as reorganization items, net in the condensed consolidated statements of operations for the Predecessor periods.
Condensed Consolidated Financial Statements	Condensed Consolidated Financial Statements operating results for the periods presented are not necessarily indicative of the results that may be expected for the full year. The condensed consolidated financial statements and related notes included in this Quarterly Report on Form 10-Q should be read in conjunction with Whiting’s consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the period ended December 31, 2020. Except as disclosed herein, there have been no material changes to the information disclosed in the notes to consolidated financial statements included in the Company’s Annual Report on Form 10-K for the period ending December 31, 2020.
Reclassifications	Reclassifications —
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted Cash — ​ Restricted cash as of December 31, 2020 consisted 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 following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the condensed consolidated balance sheets and statements of cash flows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ September 30, ​ December 31, ​ ​ 2021 ​ 2020 Cash and cash equivalents ​ $ 12,909 ​ $ 25,607 Restricted cash ​ ​ - ​ ​ 2,760 Total cash, cash equivalents and restricted cash ​ $ 12,909 ​ $ 28,367 ​
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 September 30, 2021 and December 31, 2020 (Successor), the Company had immaterial allowances for credit losses.

BASIS OF PRESENTATION (Tables)

BASIS OF PRESENTATION (Tables)	9 Months Ended
	Sep. 30, 2021
BASIS OF PRESENTATION [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 condensed consolidated balance sheets and statements of cash flows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ September 30, ​ December 31, ​ ​ 2021 ​ 2020 Cash and cash equivalents ​ $ 12,909 ​ $ 25,607 Restricted cash ​ ​ - ​ ​ 2,760 Total cash, cash equivalents and restricted cash ​ $ 12,909 ​ $ 28,367

FRESH START ACCOUNTING (Tables)

FRESH START ACCOUNTING (Tables)	9 Months Ended
	Sep. 30, 2021
FRESH START ACCOUNTING [Abstract]
Schedule of components of reorganization items	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ ​ One Month Ended September 30, 2020 ​ ​ Two Months Ended August 31, 2020 ​ Eight Months Ended August 31, 2020 Legal and professional advisory fees ​ $ - ​ ​ $ 30,502 ​ $ 57,170 Net gain on liabilities subject to compromise ​ ​ - ​ ​ ​ (1,324,940) ​ ​ (1,324,940) Fresh start adjustments, net ​ ​ - ​ ​ ​ 1,025,742 ​ ​ 1,025,742 Write-off of unamortized debt issuance costs and premium (1) ​ ​ - ​ ​ ​ - ​ ​ 15,145 Other items, net ​ ​ - ​ ​ ​ 9,464 ​ ​ 9,464 Total reorganization items, net ​ $ - ​ ​ $ (259,232) ​ $ (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)	9 Months Ended
	Sep. 30, 2021
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 September 30, 2021 and December 31, 2020 are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ September 30, ​ December 31, ​ 2021 ​ 2020 Proved oil and gas properties ​ $ 1,905,535 ​ $ 1,701,163 Unproved leasehold costs ​ ​ 197,525 ​ ​ 105,073 Wells and facilities in progress ​ ​ 63,319 ​ ​ 6,365 Total oil and gas properties, successful efforts method ​ ​ 2,166,379 ​ ​ 1,812,601 Accumulated depletion ​ ​ (198,604) ​ ​ (71,064) Oil and gas properties, net ​ $ 1,967,775 ​ $ 1,741,537
Schedule of impairment expense	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ ​ Three Months Ended September 30, 2021 ​ One Month Ended September 30, 2020 ​ ​ Two Months Ended August 31, 2020 Impairment expense for unproved properties ​ $ 836 ​ $ - ​ ​ $ 83 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ ​ Nine Months Ended September 30, 2021 ​ One Month Ended September 30, 2020 ​ ​ Eight Months Ended August 31, 2020 Impairment expense for unproved properties ​ $ 2,487 ​ $ - ​ ​ $ 12,566

ACQUISITIONS AND DIVESTITURES (

ACQUISITIONS AND DIVESTITURES (Tables)	9 Months Ended
	Sep. 30, 2021
Williston Basin [Member]
Business Acquisition [Line Items]
Schedule of purchase price allocation	​ ​ ​ ​ ​ Cash consideration ​ $ 270,800 ​ ​ ​ ​ Fair value of assets acquired: ​ ​ ​ Prepaid expenses and other ​ $ 730 Oil and gas properties, successful efforts method: ​ ​ ​ Proved oil and gas properties ​ ​ 167,435 Unproved leasehold costs ​ ​ 105,950 Total fair value of assets acquired ​ ​ 274,115 ​ ​ ​ ​ Fair value of liabilities assumed: ​ ​ ​ Asset retirement obligations ​ ​ 2,242 Revenue and royalties payable ​ ​ 1,073 Total fair value of liabilities assumed ​ ​ 3,315 ​ ​ ​ ​ Total fair value of assets acquired and liabilities assumed ​ $ 270,800

ASSET RETIREMENT OBLIGATIONS (T

ASSET RETIREMENT OBLIGATIONS (Tables)	9 Months Ended
	Sep. 30, 2021
ASSET RETIREMENT OBLIGATIONS [Abstract]
Schedule of reconciliation of the Company's asset retirement obligations	​ ​ ​ ​ ​ Asset retirement obligation at January 1, 2021 (Successor) ​ $ 98,130 Additional liability incurred or assumed ​ ​ 3,402 Revisions to estimated cash flows ​ ​ 17,363 Accretion expense ​ ​ 6,241 Obligations on sold properties ​ ​ (29,244) Liabilities settled ​ ​ (3,387) Asset retirement obligation at September 30, 2021 (Successor) ​ $ 92,505

DERIVATIVE FINANCIAL INSTRUME_2

DERIVATIVE FINANCIAL INSTRUMENTS (Tables)	9 Months Ended
	Sep. 30, 2021
DERIVATIVE FINANCIAL INSTRUMENTS [Abstract]
Derivative instruments	The table below details the Successor’s swap and collar derivatives entered into to hedge forecasted crude oil, NGL and natural gas production revenues as of September 30, 2021. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Average Settlement Period ​ Index ​ Derivative Instrument ​ Total Volumes ​ Units ​ Swap Price ​ Floor ​ Ceiling Crude Oil ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ NYMEX WTI ​ Fixed Price Swaps ​ 2,162,000 ​ Bbl ​ $44.90 ​ - ​ - 2021 ​ NYMEX WTI ​ Two-way Collars ​ 1,150,000 ​ Bbl ​ - ​ $42.48 ​ $51.80 Q1 2022 ​ NYMEX WTI ​ Fixed Price Swaps ​ 630,000 ​ Bbl ​ $54.30 ​ - ​ - 2022 ​ NYMEX WTI ​ Two-way Collars ​ 9,559,000 ​ Bbl ​ - ​ $43.23 ​ $53.73 Q1-Q3 2023 ​ NYMEX WTI ​ Two-way Collars ​ 3,443,500 ​ Bbl ​ - ​ $46.75 ​ $58.87 ​ ​ ​ ​ Total ​ 16,944,500 ​ ​ ​ ​ ​ ​ ​ ​ Crude Oil Differentials (1) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ UHC Clearbrook to NYMEX ​ Fixed Price Swaps ​ 30,500 ​ Bbl ​ -$1.95 ​ - ​ - ​ ​ ​ ​ Total ​ 30,500 ​ ​ ​ ​ ​ ​ ​ ​ Natural Gas ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ NYMEX Henry Hub ​ Fixed Price Swaps ​ 5,290,000 ​ MMBtu ​ $3.16 ​ - ​ - 2021 ​ NYMEX Henry Hub ​ Two-way Collars ​ 2,760,000 ​ MMBtu ​ - ​ $2.60 ​ $2.79 Q1-Q3 2022 ​ NYMEX Henry Hub ​ Fixed Price Swaps ​ 5,259,000 ​ MMBtu ​ $2.81 ​ - ​ - 2022 ​ NYMEX Henry Hub ​ Two-way Collars ​ 17,304,000 ​ MMBtu ​ - ​ $2.70 ​ $3.32 Q1-Q3 2023 ​ NYMEX Henry Hub ​ Two-way Collars ​ 6,999,000 ​ MMBtu ​ - ​ $2.42 ​ $2.94 ​ ​ ​ ​ Total ​ 37,612,000 ​ ​ ​ ​ ​ ​ ​ ​ Natural Gas Basis (2) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ NNG Ventura to NYMEX ​ Fixed Price Swaps ​ 2,760,000 ​ MMBtu ​ -$0.07 ​ - ​ - Q1-Q2 2022 ​ NNG Ventura to NYMEX ​ Fixed Price Swaps ​ 5,330,000 ​ MMBtu ​ $0.43 ​ - ​ - Q1-Q2 2023 ​ NNG Ventura to NYMEX ​ Fixed Price Swaps ​ 4,740,000 ​ MMBtu ​ $0.20 ​ - ​ - ​ ​ ​ ​ Total ​ 12,830,000 ​ ​ ​ ​ ​ ​ ​ ​ NGL - Propane ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ Mont Belvieu ​ Fixed Price Swaps ​ 9,660,000 ​ Gallons ​ $0.78 ​ - ​ - 2021 ​ Conway ​ Fixed Price Swaps ​ 7,728,000 ​ Gallons ​ $1.31 ​ - ​ - Q1 2022 ​ Mont Belvieu ​ Fixed Price Swaps ​ 3,780,000 ​ Gallons ​ $0.81 ​ - ​ - Q1 2022 ​ Conway ​ Fixed Price Swaps ​ 3,780,000 ​ Gallons ​ $1.20 ​ - ​ - ​ ​ ​ ​ Total ​ 24,948,000 ​ ​ ​ ​ ​ ​ ​ ​ (1) The weighted average price associated with the crude oil differential swaps shown in the table above represents the average fixed differential to NYMEX as stated in the related contracts, which is compared to the NE2 Canadian Monthly Index for UHC Clearbrook (“UHC Clearbrook”) for each period. If NYMEX combined with the fixed differential as stated in each contract is higher than the UHC Clearbrook index price at any settlement date, the Company receives the difference. Conversely, if the UHC Clearbrook index price is higher than NYMEX combined with the fixed differential, the Company pays the difference. (2) The weighted average price associated with the natural gas basis swaps shown in the table above represents the average fixed differential to NYMEX as stated in the related contracts, which is compared to the Northern Natural Gas Ventura Index (“NNG Ventura”) for each period. If NYMEX combined with the fixed differential as stated in each contract is higher than the NNG Ventura index price at any settlement date, the Company receives the difference. Conversely, if the NNG Ventura index price is higher than NYMEX combined with the fixed differential, the Company pays the difference. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Average Settlement Period ​ Index ​ Derivative Instrument ​ Total Volumes ​ Units ​ Swap Price ​ Floor ​ Ceiling Crude Oil ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 ​ NYMEX WTI ​ Fixed Price Swaps ​ 1,645,000 ​ Bbl ​ $75.12 ​ - ​ - 2022 ​ NYMEX WTI ​ Two-way Collars ​ 1,645,000 ​ Bbl ​ - ​ $69.43 ​ $80.00 ​ ​ ​ ​ Total ​ 3,290,000 ​ ​ ​ ​ ​ ​ ​ ​ Natural Gas ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Q2-Q4 2022 ​ NYMEX Henry Hub ​ Fixed Price Swaps ​ 2,750,000 ​ MMBtu ​ $4.07 ​ - ​ - ​ ​ ​ ​ Total ​ 2,750,000 ​ ​ ​ ​ ​ ​ ​ ​ Natural Gas Basis ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Q1 2022 ​ NNG Ventura to NYMEX ​ Fixed Price Swaps ​ 900,000 ​ MMBtu ​ $1.00 ​ - ​ - ​ ​ ​ ​ Total ​ 900,000 ​ ​ ​ ​ ​ ​ ​ ​ NGL - Propane ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 ​ Mont Belvieu ​ Fixed Price Swaps ​ 15,330,000 ​ Gallons ​ $1.15 ​ - ​ - 2022 ​ Conway ​ Fixed Price Swaps ​ 15,330,000 ​ Gallons ​ $1.16 ​ - ​ - ​ ​ ​ ​ Total ​ 30,660,000 ​ ​ ​ ​ ​ ​ ​ ​
Location and fair value of derivative instruments	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2021 (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 ​ $ 9,407 ​ $ (9,407) ​ $ - Commodity contracts - non-current ​ Other long-term assets ​ ​ 19,209 ​ ​ (19,209) ​ ​ - Total derivative assets ​ ​ ​ $ 28,616 ​ $ (28,616) ​ $ - Derivative liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commodity contracts - current ​ Derivative liabilities ​ $ 309,009 ​ $ (9,407) ​ $ 299,602 Commodity contracts - non-current ​ Long-term derivative liabilities ​ ​ 102,564 ​ ​ (19,209) ​ ​ 83,355 Total derivative liabilities ​ ​ ​ $ 411,573 ​ $ (28,616) ​ $ 382,957 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 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 ​ Long-term derivative liabilities ​ ​ 29,741 ​ ​ (19,991) ​ ​ 9,750 Total derivative liabilities ​ ​ ​ $ 93,513 ​ $ (34,278) ​ $ 59,235 (1) All of the counterparties to the Company’s financial derivative contracts subject to master netting arrangements are lenders under the 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)	9 Months Ended
	Sep. 30, 2021
FAIR VALUE MEASUREMENTS [Abstract]
Fair value assets and liabilities measured on a recurring basis	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Fair Value ​ Level 1 Level 2 Level 3 September 30, 2021 Financial Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commodity derivatives – current ​ $ - ​ $ 299,602 ​ $ - ​ $ 299,602 Commodity derivatives – non-current ​ ​ - ​ ​ 83,355 ​ ​ - ​ ​ 83,355 Total financial liabilities ​ $ - ​ $ 382,957 ​ $ - ​ $ 382,957 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 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
Non-financial assets and liabilities measured at fair value on a nonrecurring basis	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Predecessor ​ ​ Net Carrying ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Value as of ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loss (Before Tax) ​ ​ March 31, ​ Fair Value Measurements Using ​ Three Months Ended ​ 2020 Level 1 Level 2 Level 3 March 31, 2020 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 as of March 31, 2020. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Predecessor ​ ​ Net Carrying ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Value as of ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loss (Before Tax) ​ ​ June 30, ​ Fair Value Measurements Using ​ Six Months Ended ​ 2020 Level 1 Level 2 Level 3 June 30, 2020 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 as of June 30, 2020.

REVENUE RECOGNITION (Tables)

REVENUE RECOGNITION (Tables)	9 Months Ended
	Sep. 30, 2021
REVENUE RECOGNITION [Abstract]
Summary of revenue disaggregation	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor OPERATING REVENUES ​ Three Months Ended September 30, 2021 ​ One Month Ended September 30, 2020 ​ ​ Two Months Ended August 31, 2020 Oil sales ​ $ 316,914 ​ $ 60,392 ​ ​ $ 116,971 NGL and natural gas sales ​ ​ 77,419 ​ ​ 692 ​ ​ ​ 5,587 Oil, NGL and natural gas sales ​ ​ 394,333 ​ ​ 61,084 ​ ​ ​ 122,558 Purchased gas sales ​ ​ 6,704 ​ ​ - ​ ​ ​ - Total operating revenues ​ $ 401,037 ​ $ 61,084 ​ ​ $ 122,558 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor OPERATING REVENUES ​ Nine Months Ended September 30, 2021 ​ One Month Ended September 30, 2020 ​ ​ Eight Months Ended August 31, 2020 Oil sales ​ $ 882,040 ​ $ 60,392 ​ ​ $ 440,820 NGL and natural gas sales ​ ​ 166,955 ​ ​ 692 ​ ​ ​ 18,184 Oil, NGL and natural gas sales ​ ​ 1,048,995 ​ ​ 61,084 ​ ​ ​ 459,004 Purchased gas sales ​ ​ 11,079 ​ ​ - ​ ​ ​ - Total operating revenues ​ $ 1,060,074 ​ $ 61,084 ​ ​ $ 459,004

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	9 Months Ended
	Sep. 30, 2021
STOCK-BASED COMPENSATION [Abstract]
Assumption for valuing market based awards	​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ 2021 ​ RSUs PSUs Number of simulations 100,000 500,000 Expected volatility 40% ​ 81% Risk-free interest rate 0.66% ​ 0.17% Dividend yield - -
Summary of nonvested shares	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of Awards ​ Weighted Average ​ ​ Service ‑ Based ​ Market-Based ​ Market-Based ​ Grant Date ​ RSUs RSUs PSUs Fair Value Nonvested awards, January 1 89,021 189,900 ​ - ​ $ 10.03 Granted 501,354 - ​ 232,150 ​ 26.04 Vested (53,787) (142,425) ​ - ​ 9.54 Forfeited (8,411) - ​ - ​ 22.46 Nonvested awards, September 30 528,177 47,475 ​ 232,150 ​ $ 24.55

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	9 Months Ended
	Sep. 30, 2021
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 ​ ​ Three Months Ended September 30, 2021 ​ One Month Ended September 30, 2020 ​ ​ Two Months Ended August 31, 2020 Basic earnings per share ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income ​ $ 198,162 ​ $ 40,270 ​ ​ $ 237,425 Weighted average shares outstanding, basic ​ ​ 39,121 ​ ​ 38,051 ​ ​ ​ 91,464 Earnings per common share, basic ​ $ 5.07 ​ $ 1.06 ​ ​ $ 2.60 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Diluted earnings per share ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income ​ $ 198,162 ​ $ 40,270 ​ ​ $ 237,425 Weighted average shares outstanding, basic ​ ​ 39,121 ​ ​ 38,051 ​ ​ ​ 91,464 Service-based awards and market-based awards ​ ​ 501 ​ ​ - ​ ​ ​ - Weighted average shares outstanding, diluted ​ ​ 39,622 ​ ​ 38,051 ​ ​ ​ 91,464 Earnings per common share, diluted ​ $ 5.00 ​ $ 1.06 ​ ​ $ 2.60 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Successor ​ ​ Predecessor ​ ​ Nine Months Ended September 30, 2021 ​ One Month Ended September 30, 2020 ​ ​ Eight Months Ended August 31, 2020 Basic earnings (loss) per share ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income (loss) ​ $ 135,727 ​ $ 40,270 ​ ​ $ (3,965,461) Weighted average shares outstanding, basic ​ ​ 38,963 ​ ​ 38,051 ​ ​ ​ 91,423 Earnings (loss) per common share, basic ​ $ 3.48 ​ $ 1.06 ​ ​ $ (43.37) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Diluted earnings (loss) per share ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income (loss) ​ $ 135,727 ​ $ 40,270 ​ ​ $ (3,965,461) Weighted average shares outstanding, basic ​ ​ 38,963 ​ ​ 38,051 ​ ​ ​ 91,423 Service-based awards and market-based awards ​ ​ 516 ​ ​ - ​ ​ ​ - Weighted average shares outstanding, diluted ​ ​ 39,479 ​ ​ 38,051 ​ ​ ​ 91,423 Earnings (loss) per common share, diluted ​ $ 3.44 ​ $ 1.06 ​ ​ $ (43.37)

BASIS OF PRESENTATION (Reconcil

BASIS OF PRESENTATION (Reconciliation) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Aug. 31, 2020	Dec. 31, 2019
BASIS OF PRESENTATION [Abstract]
Cash and cash equivalents	$ 12,909	$ 25,607
Restricted cash		2,760
Total cash, cash equivalents and restricted cash	$ 12,909	$ 28,367	$ 26,935	$ 49,407	$ 8,652

CHAPTER 11 EMERGENCE (Details)

CHAPTER 11 EMERGENCE (Details) - USD ($) $ in Millions	Sep. 01, 2020	Aug. 31, 2020	Feb. 28, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 15, 2021
Chapter 11 Cases
Financial Designation, Predecessor and Successor [Fixed List]	Successor	Predecessor
Common stock issued	38,051,125
Number of shares authorized upon shareholder's approval	4,035,885
Interest expense not recognized				$ 57
Credit Agreement [Member]
Chapter 11 Cases
Maximum borrowing capacity of credit facility	$ 750				$ 750	$ 750
Additional contingent borrowings	$ 750					$ 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
Common stock issued	36,817,630
Existing Stockholders [Member]
Chapter 11 Cases
Common stock issued	1,233,495
General Unsecured Claimants [Member]
Chapter 11 Cases
Common stock issued			948,897
Reserved for future issuance (in shares)	3,070,201				2,121,304

FRESH START ACCOUNTING - Reorga

FRESH START ACCOUNTING - Reorganization Items, Net (Details) - USD ($) $ in Thousands	2 Months Ended	8 Months Ended
	Aug. 31, 2020	Aug. 31, 2020
FRESH START ACCOUNTING [Abstract]
Legal and professional advisory fees	$ 30,502	$ 57,170
Net gain on liabilities subject to compromise	(1,324,940)	(1,324,940)
Fresh start adjustments, net	1,025,742	1,025,742
Write-off of unamortized debt issuance costs and premium		15,145
Other items, net	9,464	9,464
Total reorganization items, net	$ (259,232)	$ (217,419)

OIL AND GAS PROPERTIES (Details

OIL AND GAS PROPERTIES (Details) - USD ($) $ in Thousands	2 Months Ended	3 Months Ended	8 Months Ended	9 Months Ended
	Aug. 31, 2020	Sep. 30, 2021	Aug. 31, 2020	Sep. 30, 2021	Dec. 31, 2020
Oil and gas properties
Proved oil and gas properties		$ 1,905,535		$ 1,905,535	$ 1,701,163
Unproved leasehold costs		197,525		197,525	105,073
Wells and facilities in progress		63,319		63,319	6,365
Total oil and gas properties, successful efforts method		2,166,379		2,166,379	1,812,601
Accumulated depletion		(198,604)		(198,604)	(71,064)
Oil and gas properties, net		1,967,775		1,967,775	$ 1,741,537
Unproved Properties [Member]
Oil and gas properties
Impairment of properties	$ 83	$ 836	$ 12,566	$ 2,487

ACQUISITIONS AND DIVESTITURES_2

ACQUISITIONS AND DIVESTITURES (Acquisition) (Details) $ in Thousands	Sep. 14, 2021USD ($)itemarea	Sep. 30, 2020USD ($)	Aug. 31, 2020USD ($)	Sep. 30, 2021USD ($)
Business Acquisition [Line Items]
Cash consideration		$ 162	$ 493	$ 272,043
Williston Basin [Member]
Business Acquisition [Line Items]
Aggregate purchase price	$ 271,000
Net acquisition area | area	8,750
Number of producing wells, gross | item	76
Number of producing wells, net | item	50.2
Number of drilled and uncompleted wells, gross | item	5
Number of drilled and uncompleted wells, net | item	2.4
Cash consideration	$ 270,800
Fair value of assets acquired:
Prepaid expenses and other	730
Oil and gas properties, successful efforts method:
Proved oil and gas properties	167,435
Unproved leasehold costs	105,950
Total fair value of assets acquired	274,115
Fair value of liabilities assumed:
Asset retirement obligations	2,242
Revenue and royalties payable	1,073
Total fair value of liabilities assumed	3,315
Total fair value of assets acquired and liabilities assumed	$ 270,800

ACQUISITIONS AND DIVESTITURES_3

ACQUISITIONS AND DIVESTITURES (Divestitures) (Details) - Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] $ in Millions	Sep. 23, 2021USD ($)	Jan. 09, 2020USD ($)item
Redtail Field, Denver-Julesburg Basin of Weld County, Colorado [Member]
Dispositions
Proceeds from sale of properties	$ 171
Pre-tax gain (loss) on sale	90
Finance lease right-of use assets terminated	16
Finance lease right-of use assets accumulated depreciation terminated	3
Finance lease obligations terminated	12
Assets and liabilities classified as held for sale
Asset retirement obligations	$ 20
McKenzie, Mountrail And Williams Counties [Member]
Dispositions
Number of well sold | item		30
Proceeds from sale of properties		$ 25

LONG-TERM DEBT (Schedule of lon

LONG-TERM DEBT (Schedule of long-term debt) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Long-term debt	$ 72,000	$ 360,000
Credit Agreement [Member]
Debt Instrument [Line Items]
Long-term debt	$ 72,000	$ 360,000

LONG-TERM DEBT (Credit agreemen

LONG-TERM DEBT (Credit agreement) (Details) - USD ($) $ in Millions	Sep. 01, 2020	Sep. 30, 2021	Sep. 15, 2021	Sep. 14, 2021
Credit Agreement [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity of credit facility	$ 750	$ 750	$ 750
Borrowing capacity of credit facility, net of letter of credit		676
Outstanding borrowings under credit facility		72
Letters of credit borrowings outstanding		$ 2
Additional contingent borrowings	750		$ 750
Maximum cash balance prior to mandatory repayment	$ 75
Commitment fees (as a percent)	0.50%
Weighted average interest rate		3.80%
Debt threshold, dividend payments and distributions (as a percent)			20.00%
Leverage ratio			2
Current year production covered by hedges (as a percent)			50.00%	65.00%
Maximum percentage of production from proved reserves (as a percent)			85.00%
Minimum consolidated current assets to consolidated current liabilities ratio			1
Total debt to EBITDAX ratio			3.5
Credit Agreement [Member] | Base Rate [Member] | Minimum [Member]
Debt Instrument [Line Items]
Basis points added to reference rate (as a percent)	1.75%
Credit Agreement [Member] | Base Rate [Member] | Maximum [Member]
Debt Instrument [Line Items]
Basis points added to reference rate (as a percent)	2.75%
Credit Agreement [Member] | Fed Funds Rate [Member]
Debt Instrument [Line Items]
Basis points added to reference rate (as a percent)	0.50%
Credit Agreement [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Basis points added to reference rate (as a percent)	1.00%
Credit Agreement [Member] | Eurodollar [Member] | Minimum [Member]
Debt Instrument [Line Items]
Basis points added to reference rate (as a percent)	2.75%
Credit Agreement [Member] | Eurodollar [Member] | Maximum [Member]
Debt Instrument [Line Items]
Basis points added to reference rate (as a percent)	3.75%
Credit Agreement [Member] | Less than 1.0 [Member]
Debt Instrument [Line Items]
Leverage ratio			1
Credit Agreement [Member] | Greater than 1.0 [Member]
Debt Instrument [Line Items]
Leverage ratio			1
Subsequent year production covered by hedges (as a percent)			35.00%
Letter of Credit [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity of credit facility			$ 50
Borrowing capacity of credit facility, net of letter of credit		$ 48

LONG-TERM DEBT (Senior notes) (

LONG-TERM DEBT (Senior notes) (Details) - USD ($) $ in Thousands	Sep. 01, 2020	Mar. 31, 2020	Mar. 31, 2020	Aug. 31, 2020	Sep. 30, 2020
Debt Instrument [Line Items]
Common stock issued (in shares)	38,051,125
Gain (loss) on extinguishment of debt				$ 25,883
Adjustment to equity component of 2020 Convertible Senior Notes			$ 3,461
Senior Notes [Member]
Debt Instrument [Line Items]
Common stock issued (in shares)	36,817,630
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%
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%
6.625% Senior Notes due 2026 [Member]
Debt Instrument [Line Items]
Notes Issued				$ 1,000,000
Interest rate on debt instrument (as a percent)				6.625%
1.25% Convertible Senior Notes due 2020 [Member]
Debt Instrument [Line Items]
Notes Issued				$ 187,000
Interest rate on debt instrument (as a percent)				1.25%	1.25%
Notes repurchased, principal amount		$ 73,000	$ 73,000
Principal amount of debt redeemed (as a percent)		72.50%
Gain (loss) on extinguishment of debt		$ 23,000
Repurchase of notes		53,000
Adjustment to equity component of 2020 Convertible Senior Notes		3,000
Non cash charges		$ 200

ASSET RETIREMENT OBLIGATIONS (D

ASSET RETIREMENT OBLIGATIONS (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Asset Retirement Obligations
Asset retirement obligations, current portion	$ 7,000	$ 6,000
Reconciliation of the Company's asset retirement obligations
Balance at the beginning of the period	98,130
Additional liability incurred or assumed	3,402
Revisions to estimated cash flows	17,363
Accretion expense	6,241
Obligations on sold properties	(29,244)
Liabilities settled	(3,387)
Balance at the end of the period	$ 92,505

DERIVATIVE FINANCIAL INSTRUME_3

DERIVATIVE FINANCIAL INSTRUMENTS (Instruments) (Details) $ in Thousands	1 Months Ended		2 Months Ended	3 Months Ended	8 Months Ended	9 Months Ended
	Sep. 30, 2020USD ($)	Apr. 30, 2020USD ($)	Aug. 31, 2020USD ($)	Sep. 30, 2021USD ($)item$ / item	Aug. 31, 2020USD ($)	Sep. 30, 2021USD ($)item$ / item	Oct. 31, 2021item$ / item
Derivative Financial Instruments [Line Items]
Derivative settlement | $		$ 145,000
Derivative gain (loss), net | $	$ 30,594	$ 13,000	$ (43,125)	$ (122,559)	$ 181,614	$ (524,661)
Derivative instrument proceeds held in escrow | $	$ 23,000
Crude Oil [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives | item				16,944,500		16,944,500	3,290,000
Crude Oil [Member] | 2021 [Member] | Fixed Price Swaps [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives | item				2,162,000		2,162,000
Swap Price (in dollars per unit)				44.90		44.90
Crude Oil [Member] | 2021 [Member] | Two-way Collars [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives | item				1,150,000		1,150,000
Floor Price (in dollars per unit)				42.48		42.48
Ceiling Price (in dollars per unit)				51.80		51.80
Crude Oil [Member] | 2022 [Member] | Fixed Price Swaps [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives | item				630,000		630,000	1,645,000
Swap Price (in dollars per unit)				54.30		54.30	75.12
Crude Oil [Member] | 2022 [Member] | Two-way Collars [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives | item				9,559,000		9,559,000	1,645,000
Floor Price (in dollars per unit)				43.23		43.23	69.43
Ceiling Price (in dollars per unit)				53.73		53.73	80
Crude Oil [Member] | 2023 [Member] | Two-way Collars [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives | item				3,443,500		3,443,500
Floor Price (in dollars per unit)				46.75		46.75
Ceiling Price (in dollars per unit)				58.87		58.87
Crude Oil Differentials [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives | item				30,500		30,500
Crude Oil Differentials [Member] | 2021 [Member] | Fixed Price Swaps [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives | item				30,500		30,500
Swap Price (in dollars per unit)				1.95		1.95
Natural Gas [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives | item				37,612,000		37,612,000	2,750,000
Natural Gas [Member] | 2021 [Member] | Fixed Price Swaps [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives | item				5,290,000		5,290,000
Swap Price (in dollars per unit)				3.16		3.16
Natural Gas [Member] | 2021 [Member] | Two-way Collars [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives | item				2,760,000		2,760,000
Floor Price (in dollars per unit)				2.60		2.60
Ceiling Price (in dollars per unit)				2.79		2.79
Natural Gas [Member] | 2022 [Member] | Fixed Price Swaps [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives | item				5,259,000		5,259,000	2,750,000
Swap Price (in dollars per unit)				2.81		2.81	4.07
Natural Gas [Member] | 2022 [Member] | Two-way Collars [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives | item				17,304,000		17,304,000
Floor Price (in dollars per unit)				2.70		2.70
Ceiling Price (in dollars per unit)				3.32		3.32
Natural Gas [Member] | 2023 [Member] | Two-way Collars [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives | item				6,999,000		6,999,000
Floor Price (in dollars per unit)				2.42		2.42
Ceiling Price (in dollars per unit)				2.94		2.94
Natural Gas Basis [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives | item				12,830,000		12,830,000	900,000
Natural Gas Basis [Member] | 2021 [Member] | Fixed Price Swaps [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives | item				2,760,000		2,760,000
Swap Price (in dollars per unit)				0.07		0.07
Natural Gas Basis [Member] | 2022 [Member] | Fixed Price Swaps [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives | item				5,330,000		5,330,000	900,000
Swap Price (in dollars per unit)				0.43		0.43	1
Natural Gas Basis [Member] | 2023 [Member] | Fixed Price Swaps [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives | item				4,740,000		4,740,000
Swap Price (in dollars per unit)				0.20		0.20
NGL - Propane [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives | item				24,948,000		24,948,000	30,660,000
NGL - Propane [Member] | 2021 [Member] | Mont Belvieu [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives | item				9,660,000		9,660,000
Swap Price (in dollars per unit)				0.78		0.78
NGL - Propane [Member] | 2021 [Member] | Conway [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives | item				7,728,000		7,728,000
Swap Price (in dollars per unit)				1.31		1.31
NGL - Propane [Member] | 2022 [Member] | Mont Belvieu [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives | item				3,780,000		3,780,000	15,330,000
Swap Price (in dollars per unit)				0.81		0.81	1.15
NGL - Propane [Member] | 2022 [Member] | Conway [Member]
Derivative Financial Instruments [Line Items]
Aggregate notional amount of price risk derivatives | item				3,780,000		3,780,000	15,330,000
Swap Price (in dollars per unit)				1.20		1.20	1.16

DERIVATIVE FINANCIAL INSTRUME_4

DERIVATIVE FINANCIAL INSTRUMENTS (Asset location) (Details) - Commodity contracts [Member] - Not Designated as ASC 815 Hedges [Member] - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Gross amounts of derivative assets and gross amounts offset [Line Items]
Gross Amounts of Recognized Assets	$ 28,616	$ 34,278
Gross Amounts Offset	(28,616)	(34,278)
Prepaid Expenses and Other [Member]
Gross amounts of derivative assets and gross amounts offset [Line Items]
Gross Amounts of Recognized Assets	9,407	14,287
Gross Amounts Offset	(9,407)	(14,287)
Other Long Term Assets [Member]
Gross amounts of derivative assets and gross amounts offset [Line Items]
Gross Amounts of Recognized Assets	19,209	19,991
Gross Amounts Offset	$ (19,209)	$ (19,991)

DERIVATIVE FINANCIAL INSTRUME_5

DERIVATIVE FINANCIAL INSTRUMENTS (Liability location) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Gross amounts of derivative liabilities and gross amounts offset [Line Items]
Total financial liabilities	$ 382,957	$ 59,235
Commodity contracts [Member] | Not Designated as ASC 815 Hedges [Member]
Gross amounts of derivative liabilities and gross amounts offset [Line Items]
Gross Amounts of Recognized Liabilities	411,573	93,513
Gross Amounts Offset	(28,616)	(34,278)
Total financial liabilities	382,957	59,235
Commodity contracts [Member] | Accrued liabilities and other [Member] | Not Designated as ASC 815 Hedges [Member]
Gross amounts of derivative liabilities and gross amounts offset [Line Items]
Gross Amounts of Recognized Liabilities	309,009	63,772
Gross Amounts Offset	(9,407)	(14,287)
Total financial liabilities	299,602	49,485
Commodity contracts [Member] | Long-term Derivative Liabilities [Member] | Not Designated as ASC 815 Hedges [Member]
Gross amounts of derivative liabilities and gross amounts offset [Line Items]
Gross Amounts of Recognized Liabilities	102,564	29,741
Gross Amounts Offset	(19,209)	(19,991)
Total financial liabilities	$ 83,355	$ 9,750

FAIR VALUE MEASUREMENTS (Recurr

FAIR VALUE MEASUREMENTS (Recurring basis) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Financial Liabilities
Total financial liabilities	$ 382,957	$ 59,235
Commodity contracts [Member]
Financial Liabilities
Financial liabilities - current	299,602	49,485
Financial liabilities - non-current	83,355	9,750
Level 2 [Member]
Financial Liabilities
Total financial liabilities	382,957	59,235
Level 2 [Member] | Commodity contracts [Member]
Financial Liabilities
Financial liabilities - current	299,602	49,485
Financial liabilities - non-current	$ 83,355	$ 9,750

FAIR VALUE MEASUREMENTS (Non-re

FAIR VALUE MEASUREMENTS (Non-recurring) (Details) - Proved Properties [Member] - USD ($) $ in Thousands	Sep. 14, 2021	Sep. 30, 2020	Mar. 31, 2020	Jun. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Proved property			$ 494,000	$ 85,000
Non-recurring assets at fair value, impairment loss (before tax)			$ 3,700,000	$ 409,000
Measurement Input, Discount Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Value of measurement input	11.00%	17.00%	16.00%
Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Proved property		$ 85,418	$ 816,234		$ 85,418	$ 4,500,000
Non-recurring assets at fair value, impairment loss (before tax)			3,732,096		409,079
Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Proved property		$ 85,418	$ 816,234		$ 85,418

REVENUE RECOGNITION (Revenue Re

REVENUE RECOGNITION (Revenue Reclassification) (Details) - USD ($) $ in Thousands	1 Months Ended	2 Months Ended	3 Months Ended	8 Months Ended	9 Months Ended
	Sep. 30, 2020	Aug. 31, 2020	Sep. 30, 2021	Aug. 31, 2020	Sep. 30, 2021
Revenue
Sales	$ 61,084	$ 122,558	$ 401,037	$ 459,004	$ 1,060,074
Oil, NGL and natural gas sales [Member]
Revenue
Sales	61,084	122,558	394,333	459,004	1,048,995
Oil sales [Member]
Revenue
Sales	60,392	116,971	316,914	440,820	882,040
NGL and natural gas sales [Member]
Revenue
Sales	$ 692	$ 5,587	77,419	$ 18,184	166,955
Purchased gas sales [Member]
Revenue
Sales			$ 6,704		$ 11,079

REVENUE RECOGNITION (Narrative)

REVENUE RECOGNITION (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Revenue
Receivable balance	$ 139	$ 88
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) - USD ($) $ / shares in Units, $ in Millions	Sep. 01, 2020	Feb. 28, 2021	Sep. 30, 2021	Dec. 31, 2020
Class of Stock [Line Items]
Capital stock, shares authorized	550,000,000
Common stock, shares authorized	500,000,000		500,000,000	500,000,000
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
Common stock issued (in shares)	38,051,125
General Unsecured Claimants [Member]
Class of Stock [Line Items]
Common stock issued (in shares)		948,897
Bankruptcy claims, amount paid		$ 2
Reserved for future issuance (in shares)	3,070,201		2,121,304
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. 01, 2020USD ($)shares	Sep. 30, 2020D$ / sharesshares	Oct. 31, 2020$ / sharesshares	Aug. 31, 2020USD ($)	Sep. 30, 2021USD ($)$ / sharesshares	Mar. 31, 2020USD ($)	Aug. 31, 2020USD ($)$ / sharesshares	Sep. 30, 2021USD ($)itemD$ / sharesshares
Share-based compensation disclosures
Common stock issued (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					3,031,871			3,031,871
Granted (in dollars per share) | $ / shares								$ 26.04
Stock compensation expense | $				$ 1,000,000	$ 3,000,000		$ 2,000,000	$ 8,000,000
Service-based [Member]
Share-based compensation disclosures
Granted (in shares)							53,198
Granted (in dollars per share) | $ / shares							$ 4.94
Service-based [Member] | Share-based Payment Arrangement, Employee [Member] | Vesting Period, Scenario 1 [Member]
Share-based compensation disclosures
Vesting (service) period								2 years
Service-based [Member] | Share-based Payment Arrangement, Employee [Member] | Vesting Period, Scenario 2 [Member]
Share-based compensation disclosures
Vesting (service) period								3 years
Service-based [Member] | Share-based Payment Arrangement, Employee [Member] | Vesting Period, Scenario 3 [Member]
Share-based compensation disclosures
Vesting (service) period								5 years
Service-based [Member] | Share-based Payment Arrangement, Nonemployee [Member]
Share-based compensation disclosures
Vesting (service) period								1 year
Cash Retention Incentives [Member]
Share-based compensation disclosures
Replacement award fair value | $				$ 12,000,000			$ 12,000,000
Cash bonus paid taxes | $						$ 9,000,000
Restricted Stock Units [Member]
Share-based compensation disclosures
Granted (in shares)							1,616,504
Service Based Restricted Stock [Member]
Share-based compensation disclosures
Granted (in shares)			89,021					501,354
Granted (in dollars per share) | $ / shares			$ 17.47					$ 23.82
Service Based Restricted Stock [Member] | Share-based Payment Arrangement, Employee [Member]
Share-based compensation disclosures
Granted (in shares)								360,017
Service Based Restricted Stock [Member] | Share-based Payment Arrangement, Employee [Member] | Minimum [Member]
Share-based compensation disclosures
Vesting (service) period								2 years
Service Based Restricted Stock [Member] | Share-based Payment Arrangement, Employee [Member] | Maximum [Member]
Share-based compensation disclosures
Vesting (service) period								3 years
Service Based Restricted Stock [Member] | Executive officers [Member]
Share-based compensation disclosures
Granted (in shares)								117,607
Service Based Restricted Stock [Member] | Director [Member]
Share-based compensation disclosures
Vesting (service) period								1 year
Granted (in shares)								23,730
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						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%						75.00%
Share price (in dollars per share) | $ / shares		$ 32.57			$ 32.57			$ 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			$ 48.86			$ 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
PSAs and PSUs [Member]
Share-based compensation disclosures
Vesting (service) period								3 years
Granted (in shares)							1,665,153
Granted (in dollars per share) | $ / shares							$ 4.31
PSU [Member]
Share-based compensation disclosures
Granted (in shares)								232,150
PSU [Member] | Minimum [Member]
Share-based compensation disclosures
Possible multiplier of shares earned | item								0
PSU [Member] | Maximum [Member]
Share-based compensation disclosures
Possible multiplier of shares earned | item								2
PSU [Member] | ATSR PSUs [Member]
Share-based compensation disclosures
Granted (in shares)								116,075
Granted (in dollars per share) | $ / shares								$ 29.32
PSU [Member] | RTSR PSUs [Member]
Share-based compensation disclosures
Granted (in shares)								116,075
Granted (in dollars per share) | $ / shares								$ 32.33
Existing Stockholders [Member]
Share-based compensation disclosures
Common stock issued (in shares)	1,233,495

STOCK-BASED COMPENSATION (Assum

STOCK-BASED COMPENSATION (Assumptions) (Details) - item	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Restricted Stock Units [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%
PSU [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of simulations	500,000
Expected volatility (as a percent)	81.00%
Risk-free interest rate (as a percent)	0.17%
Dividend yield (as a percent)	0.00%

STOCK-BASED COMPENSATION (Nonve

STOCK-BASED COMPENSATION (Nonvested awards) (Details) - $ / shares	1 Months Ended	2 Months Ended	9 Months Ended
	Sep. 30, 2020	Oct. 31, 2020	Sep. 30, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance at the beginning of the period (in dollars per share)			$ 10.03
Granted (in dollars per share)			26.04
Vested (in dollars per share)			9.54
Forfeited (in dollars per share)			22.46
Balance at the end of the period (in dollars per share)			$ 24.55
Service Based Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance at the beginning of the period (in shares)			89,021
Granted (in shares)		89,021	501,354
Vested (in shares)			(53,787)
Forfeited (in shares)			(8,411)
Balance at the end of the period (in shares)			528,177
Granted (in dollars per share)		$ 17.47	$ 23.82
Market Based Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance at the beginning of the period (in shares)			189,900
Granted (in shares)	189,900
Vested (in shares)			(142,425)
Balance at the end of the period (in shares)			47,475
Granted (in dollars per share)	$ 6.54
PSU [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)			232,150
Balance at the end of the period (in shares)			232,150

INCOME TAXES (Narrative) (Detai

INCOME TAXES (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended	2 Months Ended	3 Months Ended	8 Months Ended	9 Months Ended
	Sep. 30, 2020	Aug. 31, 2020	Sep. 30, 2021	Aug. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Operating Loss Carryforwards [Line Items]
U.S. statutory income tax rate (as a percent)			21.00%		21.00%	21.00%
Income tax benefit (expense)	$ (12,185)	$ (55,346)	$ 0	$ (56,374)	$ 0
Tax refund				1,000
Effective tax rate			0.00%		0.00%
Deferred	(14,501)	$ (55,346)		(59,092)
Federal operating loss carryforwards							$ 3,000,000
Carryforwards expected to expire							$ 2,400,000
CANADA
Operating Loss Carryforwards [Line Items]
Income tax benefit (expense)	$ (15,000)			$ (55,000)

EARNINGS PER SHARE (Reconciliat

EARNINGS PER SHARE (Reconciliation) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	1 Months Ended	2 Months Ended	3 Months Ended					8 Months Ended	9 Months Ended
	Sep. 30, 2020	Aug. 31, 2020	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Aug. 31, 2020	Sep. 30, 2021
Basic earnings (loss) per share
Net income (loss)	$ 40,270	$ 237,425	$ 198,162	$ (61,489)	$ (946)	$ (574,315)	$ (3,628,571)	$ (3,965,461)	$ 135,727
Weighted average shares outstanding, basic (in shares)	38,051	91,464	39,121					91,423	38,963
Earnings (loss) per common share, basic (in dollars per share)	$ 1.06	$ 2.60	$ 5.07					$ (43.37)	$ 3.48
Diluted earnings (loss) per share
Net income (loss)	$ 40,270	$ 237,425	$ 198,162	$ (61,489)	$ (946)	$ (574,315)	$ (3,628,571)	$ (3,965,461)	$ 135,727
Weighted average shares outstanding, basic (in shares)	38,051	91,464	39,121					91,423	38,963
Service-based awards and market-based awards (in shares)			501						516
Weighted average shares outstanding, diluted (in shares)	38,051	91,464	39,622					91,423	39,479
Earnings (loss) per common share, diluted (in dollars per share)	$ 1.06	$ 2.60	$ 5					$ (43.37)	$ 3.44

EARNINGS PER SHARE (Narrative)

EARNINGS PER SHARE (Narrative) (Details) - shares	1 Months Ended	2 Months Ended	3 Months Ended	8 Months Ended	9 Months Ended
	Sep. 30, 2020	Aug. 31, 2020	Sep. 30, 2021	Aug. 31, 2020	Sep. 30, 2021
Contingently Issuable Shares [Member]
Shares excluded from Earnings Per Share calculation [Line Items]
Antidilutive securities excluded from computation of earnings per share	3,070,201		2,121,304		2,121,304
Service Based Restricted Stock [Member]
Shares excluded from Earnings Per Share calculation [Line Items]
Antidilutive securities excluded from computation of earnings per share	87,171
Market Based Restricted Stock [Member]
Shares excluded from Earnings Per Share calculation [Line Items]
Antidilutive securities excluded from computation of earnings per share	189,900		47,475		47,475
Service-based [Member]
Shares excluded from Earnings Per Share calculation [Line Items]
Antidilutive securities excluded from computation of earnings per share		239,186		314,896
Stock Option [Member]
Shares excluded from Earnings Per Share calculation [Line Items]
Antidilutive securities excluded from computation of earnings per share		18,310		29,465

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Narrative) (Details) - USD ($) $ in Millions	Oct. 01, 2020	Jun. 30, 2020	Aug. 31, 2020	Jun. 30, 2020
Commitments
Payment made		$ 14
Indemnity amount			$ 25
General and Administrative Expense [Member]
Commitments
Additional litigation settlement expense			$ 3	$ 3
US Government [Member]
Commitments
Bankruptcy Claims, Amount of Claims Filed	$ 25
FMOG Entities [Member]
Commitments
Bankruptcy Claims, Amount of Claims Filed	$ 60

COMPANY RESTRUCTURING (Details)

COMPANY RESTRUCTURING (Details) $ in Millions	1 Months Ended
	Sep. 30, 2020USD ($)
One-time employee termination benefits [Member]
Restructuring
Restructuring costs incurred	$ 7