Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies (Details Textual)

v3.21.2
Summary of Significant Accounting Policies (Details Textual)
3 Months Ended 9 Months Ended 12 Months Ended
Mar. 19, 2021
USD ($)
$ / shares
shares
Sep. 30, 2021
USD ($)
Sep. 30, 2020
USD ($)
Jun. 30, 2020
USD ($)
Mar. 31, 2020
USD ($)
Sep. 30, 2021
USD ($)
renewable_identification_number
shares
Sep. 30, 2020
USD ($)
Dec. 31, 2020
USD ($)
May 20, 2021
USD ($)
Feb. 29, 2020
USD ($)
Jan. 31, 2019
USD ($)
Jun. 30, 2016
USD ($)
Jun. 02, 2016
USD ($)
Business Acquisition [Line Items]                          
Restricted cash   $ 4,556,000 $ 3,000,000     $ 4,556,000 $ 3,000,000 $ 3,777,000          
Goodwill   16,080,000       16,080,000   16,080,000          
Impairment of goodwill   0       0   0          
Gain (loss) on debt extinguishment   0 18,000     (4,449,000) 1,809,000            
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt, Subsequent Adjustments     13,992,000 $ 20,860,000 $ 17,829,000                
Offering costs           19,970,000 0            
Biodiesel property, plant and equipment                          
Business Acquisition [Line Items]                          
Impairment charges   3,498,000 272,000     5,236,000 272,000            
Equipment                          
Business Acquisition [Line Items]                          
Impairment charges     18,984,000       18,984,000            
Equity Offering                          
Business Acquisition [Line Items]                          
Shares sold in offering (in shares) | shares 5,750,000                        
Offering price per share (in dollars per share) | $ / shares $ 67.00                        
Gross proceeds from offering $ 385,250,000                        
Offering costs 19,970,000                        
Net proceeds from offering $ 365,280,000                        
January 2019 Program                          
Business Acquisition [Line Items]                          
Security repurchase program, amount authorized to be repurchased                     $ 75,000,000    
February 2020 Program                          
Business Acquisition [Line Items]                          
Security repurchase program, amount authorized to be repurchased                   $ 100,000,000      
January 2019 Program and February 2020 Program                          
Business Acquisition [Line Items]                          
Security repurchase program, remaining amounts   91,914,000       91,914,000              
2036 Senior Convertible Notes Repurchases | Convertible Notes                          
Business Acquisition [Line Items]                          
Face amount                       $ 152,000,000 $ 152,000,000
Interest rate                       4.00% 4.00%
Principal amount of conversion           $ 59,619,000              
Debt conversion, shares issued (in shares) | shares           4,684,263              
Gain (loss) on debt extinguishment     18,000       1,809,000            
Convertible Notes Repurchases     18,086,000       75,890,000            
Principal amount of debt repurchased     5,000,000       30,008,000            
2036 Senior Convertible Notes Repurchases | Convertible Notes | January 2019 Program                          
Business Acquisition [Line Items]                          
Convertible Notes Repurchases     10,000,000       67,804,000            
2036 Senior Convertible Notes Repurchases | Convertible Notes | February 2020 Program                          
Business Acquisition [Line Items]                          
Convertible Notes Repurchases     8,086,000       8,086,000            
2028 Notes | Senior Notes                          
Business Acquisition [Line Items]                          
Face amount                 $ 550,000,000        
Interest rate                 5.875%        
Debt issuance costs                 $ 14,619,000        
Services                          
Business Acquisition [Line Items]                          
Goodwill   $ 16,080,000       $ 16,080,000   $ 16,080,000          
Minimum                          
Business Acquisition [Line Items]                          
RINs per gallon | renewable_identification_number           1.5              
Allowed RINs per gallon | renewable_identification_number           0              
Maximum                          
Business Acquisition [Line Items]                          
RINs per gallon | renewable_identification_number           1.7              
Allowed RINs per gallon | renewable_identification_number           2.5              
Common Stock - Additional Paid-in Capital                          
Business Acquisition [Line Items]                          
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt, Subsequent Adjustments     $ 13,992,000 $ 20,860,000 $ 17,829,000   $ 52,681,000