Annual report pursuant to Section 13 and 15(d)

VARIABLE INTEREST ENTITIES AND OTHER INVESTMENTS IN SIGNIFICANT AFFILIATES - Narrative (Details)

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VARIABLE INTEREST ENTITIES AND OTHER INVESTMENTS IN SIGNIFICANT AFFILIATES - Narrative (Details)
$ in Thousands, £ in Millions
1 Months Ended 5 Months Ended 7 Months Ended 12 Months Ended
May 10, 2019
GBP (£)
Aug. 31, 2019
USD ($)
Jun. 30, 2019
USD ($)
Apr. 30, 2019
USD ($)
Mar. 31, 2020
USD ($)
Oct. 31, 2019
USD ($)
Mar. 31, 2021
USD ($)
affiliates
jointVenture
Mar. 31, 2019
USD ($)
Variable Interest Entity [Line Items]                
Number of variable interest entities | affiliates             6  
Loss on sale of subsidiaries         $ 0 $ 55,883 $ 0 $ 0
Number of joint ventures | jointVenture             2  
Sale of subsidiaries           5,612    
BNAS Holdings | VIE, primary beneficiary                
Variable Interest Entity [Line Items]                
Ownership percentage in Variable Interest Entity             49.00%  
BNAS                
Variable Interest Entity [Line Items]                
Ownership percentage in Variable Interest Entity             100.00%  
Bristow Aviation Holdings Limited | VIE, primary beneficiary                
Variable Interest Entity [Line Items]                
Ownership percentage in Variable Interest Entity             49.00%  
Bristow Helicopters Nigeria Ltd | VIE, primary beneficiary                
Variable Interest Entity [Line Items]                
Ownership percentage in Variable Interest Entity             48.00%  
Pan African Airlines Nigeria Ltd | VIE, primary beneficiary                
Variable Interest Entity [Line Items]                
Ownership percentage in Variable Interest Entity             50.17%  
Eastern Airways                
Variable Interest Entity [Line Items]                
Contributions to noncontrolling interest | £ £ 17.1              
Loss on sale of subsidiaries           46,900    
Write off of net assets           35,000    
Write off of cumulative translation adjustment           11,900    
European Union (“EU”) National | BNAS Holdings | VIE, primary beneficiary                
Variable Interest Entity [Line Items]                
Ownership percentage in Variable Interest Entity             51.00%  
Bristow Aviation Holdings Limited | Aviashelf Aviation Co.                
Variable Interest Entity [Line Items]                
Ownership percentage               48.50%
Impigra Aviation Holdings Limited | Bristow Aviation Holdings Limited                
Variable Interest Entity [Line Items]                
Ownership percentage in Variable Interest Entity             51.00%  
Nigerian Company | Bristow Helicopters Nigeria Ltd                
Variable Interest Entity [Line Items]                
Ownership percentage in Variable Interest Entity             50.00%  
Nigerian Employees | Nigerian Company                
Variable Interest Entity [Line Items]                
Noncontrolling ownership percentage             100.00%  
Employee Trust Fund | Bristow Helicopters Nigeria Ltd                
Variable Interest Entity [Line Items]                
Ownership percentage in Variable Interest Entity             2.00%  
Old Bristow | Aviashelf Aviation Co.                
Variable Interest Entity [Line Items]                
Loss on sale of subsidiaries           $ 9,000    
Option to acquire additional interest   8.50%           8.50%
Sale of noncontrolling interest, percentage     48.50%          
Sale of subsidiaries   $ 400 $ 2,600          
Old Bristow | BHLL                
Variable Interest Entity [Line Items]                
Ownership percentage               60.00%
Sale of noncontrolling interest, percentage       60.00%        
Sale of subsidiaries       $ 1,400        
Old Bristow | Sakhalin Bristow Air Services Ltd                
Variable Interest Entity [Line Items]                
Ownership percentage               60.00%