Annual report pursuant to Section 13 and 15(d)

RELATED PARTY TRANSACTIONS Narrative (Details)

v3.10.0.1
RELATED PARTY TRANSACTIONS Narrative (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Jul. 31, 2011
Related Party Transaction [Line Items]        
Rental expense $ 4.1 $ 5.5 $ 5.7  
SEACOR        
Related Party Transaction [Line Items]        
Rental expense 0.4 0.4 0.4  
Training Services | Equity Method Investee        
Related Party Transaction [Line Items]        
Notes receivable to related party 3.6 3.7    
Dart Helicopter Services LLC and Dart Holding Company Ltd. | Products Purchased | Equity Method Investee        
Related Party Transaction [Line Items]        
Expenses from transactions with related party 2.0 2.0 1.9  
Dart Holding Company Ltd. | Equity Method Investee        
Related Party Transaction [Line Items]        
Notes receivable to related party 2.3 2.8   $ 5.1
Era Training Center        
Related Party Transaction [Line Items]        
Notes receivable to related party 0.4      
Era Training Center | Helicopter, Management and Other Services | Equity Method Investee        
Related Party Transaction [Line Items]        
Expenses from transactions with related party 0.1 0.2 0.2  
Era Training Center | Training Services | Equity Method Investee        
Related Party Transaction [Line Items]        
Expenses from transactions with related party $ 0.2 $ 0.5 $ 0.6