Quarterly report pursuant to Section 13 or 15(d)

FAIR VALUE DISCLOSURES - Fair Value of Debt (Details)

v3.21.2
FAIR VALUE DISCLOSURES - Fair Value of Debt (Details) - USD ($)
$ in Thousands
Sep. 30, 2021
Mar. 31, 2021
Feb. 28, 2021
Senior Notes | 6.875% Senior Notes      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Stated interest rate 6.875%   6.875%
Carrying Value      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Long-term debt, fair value $ 531,815 $ 543,493  
Carrying Value | Senior Notes | 6.875% Senior Notes      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Long-term debt, fair value $ 391,613 391,550  
Stated interest rate 6.875%    
Carrying Value | Secured Debt | Lombard Debt      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Long-term debt, fair value $ 139,968 146,006  
Carrying Value | Secured Debt | Airnorth Debt      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Long-term debt, fair value   5,631  
Carrying Value | Secured Debt | Humberside Debt      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Long-term debt, fair value 234 306  
Level 1 | Fair Value      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Long-term debt, fair value 0 0  
Level 1 | Fair Value | Senior Notes | 6.875% Senior Notes      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Long-term debt, fair value 0 0  
Level 1 | Fair Value | Secured Debt | Lombard Debt      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Long-term debt, fair value 0 0  
Level 1 | Fair Value | Secured Debt | Airnorth Debt      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Long-term debt, fair value   0  
Level 1 | Fair Value | Secured Debt | Humberside Debt      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Long-term debt, fair value 0 0  
Level 2 | Fair Value      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Long-term debt, fair value 571,108 560,102  
Level 2 | Fair Value | Senior Notes | 6.875% Senior Notes      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Long-term debt, fair value 422,648 398,870  
Level 2 | Fair Value | Secured Debt | Lombard Debt      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Long-term debt, fair value 148,226 155,270  
Level 2 | Fair Value | Secured Debt | Airnorth Debt      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Long-term debt, fair value   5,656  
Level 2 | Fair Value | Secured Debt | Humberside Debt      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Long-term debt, fair value 234 306  
Level 3 | Fair Value      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Long-term debt, fair value 0 0  
Level 3 | Fair Value | Senior Notes | 6.875% Senior Notes      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Long-term debt, fair value 0 0  
Level 3 | Fair Value | Secured Debt | Lombard Debt      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Long-term debt, fair value 0 0  
Level 3 | Fair Value | Secured Debt | Airnorth Debt      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Long-term debt, fair value   0  
Level 3 | Fair Value | Secured Debt | Humberside Debt      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Long-term debt, fair value $ 0 $ 0