Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt (Details)

v3.20.1
Long-Term Debt (Details) - USD ($)
3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Mar. 19, 2019
Debt Instrument [Line Items]      
Common stock, par value (in dollars per share) $ 0.01    
Securities Repurchase Plan, Remaining Authorized Repurchase Amount $ 113,100,000    
Debt extinguishment losses, net (319,000) $ (793,000)  
Repayments of long-term debt 18,144,000 $ 31,396,000  
Letters of credit outstanding, amount $ 1,200,000    
Interest rate earned on guarantees 0.50%    
SEACOR Marine Holdings Inc.      
Debt Instrument [Line Items]      
Guarantor obligations, maximum exposure, undiscounted $ 18,500,000    
Three Point Zero Percentage Convertible Notes      
Debt Instrument [Line Items]      
Debt instrument, interest rate, stated percentage 3.00%    
Two Point Five Percentage Convertible Notes      
Debt Instrument [Line Items]      
Debt instrument, interest rate, stated percentage 2.50%    
Three Point Two Five Percentage Convertible Notes      
Debt Instrument [Line Items]      
Debt instrument, interest rate, stated percentage 3.25%    
Convertible Debt | Three Point Zero Percentage Convertible Notes      
Debt Instrument [Line Items]      
Debt instrument, interest rate, stated percentage 3.00%    
Debt instrument, repurchased face amount $ 15,600,000    
Repayments of Long-term Debt and Payments for Conversion Option in Convertible Debt 15,400,000    
Debt extinguishment losses, net (300,000)    
Long-term Debt, Gross $ 34,500,000    
Convertible Debt | Two Point Five Percentage Convertible Notes      
Debt Instrument [Line Items]      
Debt instrument, interest rate, stated percentage 2.50%    
Convertible Debt | Three Point Two Five Percentage Convertible Notes      
Debt Instrument [Line Items]      
Debt instrument, interest rate, stated percentage 3.25%    
Line of Credit | Revolving Credit Facility | SEACOR Revolving Credit Facility      
Debt Instrument [Line Items]      
Line of Credit Facility, Maximum Borrowing Capacity     $ 125,000,000.0
Line of credit facility, remaining borrowing capacity $ 125,000,000.0    
Line of Credit | Revolving Credit Facility | SEA-Vista 2019 Credit Facility      
Debt Instrument [Line Items]      
Line of Credit Facility, Maximum Borrowing Capacity 100,000,000.0    
Line of Credit | Secured Debt | SEA-Vista 2019 Credit Facility, Term Loan      
Debt Instrument [Line Items]      
Repayments of long-term debt 2,500,000    
Notes Payable, Other Payables      
Debt Instrument [Line Items]      
Repayments of long-term debt $ 200,000