Annual report pursuant to Section 13 and 15(d)

SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details)

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SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details)
12 Months Ended
Sep. 18, 2020
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Property, Plant and Equipment [Line Items]        
Reverse stock split ratio 0.1      
Allowance for doubtful accounts   $ 3,900,000 $ 4,600,000  
Provision for doubtful accounts   300,000 0 $ 0
Charged against the allowance for doubtful accounts   $ 1,000,000.0 700,000  
Period for advance payments to be applied against joint interest billings   90 days    
Impairment losses on non-crude oil and natural gas long-lived assets   $ 0 6,398,000 0
Minimum percentage of proved reserves sold to be considered a significant alteration   25.00%    
Discount rate   10.00%    
Impairment losses on oil and gas properties   $ 1,066,668,000 0 0
Capitalized costs related to expired leases subject to depletion   2,900,000 3,600,000 9,400,000
Valuation allowance against deferred tax assets   337,494,000 144,198,000  
Impairment of other long-lived assets   $ 0   0
Maximum percentage of annual contributions per employee   100.00%    
Vested percentage   100.00%    
Oil        
Property, Plant and Equipment [Line Items]        
Revenues   $ 305,200,000 574,600,000 450,100,000
Natural Gas and NGL        
Property, Plant and Equipment [Line Items]        
Revenues   18,800,000 26,600,000 43,800,000
Oil and Gas Sales        
Property, Plant and Equipment [Line Items]        
Revenues   $ 324,052,000 $ 601,218,000 $ 493,909,000
Oil and Gas Sales | Top Four Operators | Revenue Benchmark | Operator Concentration Risk        
Property, Plant and Equipment [Line Items]        
Concentration risk percentage   49.00% 51.00% 55.00%
Minimum        
Property, Plant and Equipment [Line Items]        
Property and equipment, estimated useful lives   3 years    
Maximum        
Property, Plant and Equipment [Line Items]        
Property and equipment, estimated useful lives   7 years    
Other Noncurrent Assets        
Property, Plant and Equipment [Line Items]        
Accounts receivable   $ 4,400,000 $ 4,700,000