Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt (Details)

v3.20.2
Long-Term Debt (Details) - USD ($)
3 Months Ended 6 Months Ended
Jun. 30, 2020
Jun. 30, 2019
Jun. 30, 2020
Jun. 30, 2019
Debt Instrument [Line Items]        
Common stock, par value (in dollars per share) $ 0.01   $ 0.01  
Securities Repurchase Plan, Remaining Authorized Repurchase Amount $ 102,200,000   $ 102,200,000  
Debt extinguishment gains (losses), net 1,921,000 $ (503,000) 1,602,000 $ (1,296,000)
Repayments of long-term debt     31,828,000 $ 46,499,000
Letters of credit outstanding, amount 1,100,000   $ 1,100,000  
Interest rate earned on guarantees     0.50%  
SEACOR Marine Holdings Inc.        
Debt Instrument [Line Items]        
Guarantor obligations, maximum exposure, undiscounted $ 14,600,000   $ 14,600,000  
Three Point Zero Percentage Convertible Notes        
Debt Instrument [Line Items]        
Debt instrument, interest rate, stated percentage 3.00%   3.00%  
Two Point Five Percentage Convertible Notes        
Debt Instrument [Line Items]        
Debt instrument, interest rate, stated percentage 2.50%   2.50%  
Three Point Two Five Percentage Convertible Notes        
Debt Instrument [Line Items]        
Debt instrument, interest rate, stated percentage 3.25%   3.25%  
Convertible Debt | Three Point Zero Percentage Convertible Notes        
Debt Instrument [Line Items]        
Debt instrument, interest rate, stated percentage 3.00%   3.00%  
Debt instrument, repurchased face amount $ 15,600,000   $ 15,600,000  
Repayments of Long-term Debt and Payments for Conversion Option in Convertible Debt     15,400,000  
Debt extinguishment gains (losses), net     (300,000)  
Long-term Debt, Gross $ 34,500,000   $ 34,500,000  
Convertible Debt | Two Point Five Percentage Convertible Notes        
Debt Instrument [Line Items]        
Debt instrument, interest rate, stated percentage 2.50%   2.50%  
Debt instrument, repurchased face amount $ 12,900,000   $ 12,900,000  
Repayments of Long-term Debt and Payments for Conversion Option in Convertible Debt     10,900,000  
Debt extinguishment gains (losses), net     1,900,000  
Long-term Debt, Gross $ 51,600,000   $ 51,600,000  
Convertible Debt | Three Point Two Five Percentage Convertible Notes        
Debt Instrument [Line Items]        
Debt instrument, interest rate, stated percentage 3.25%   3.25%  
Line of Credit | Revolving Credit Facility | SEACOR Revolving Credit Facility        
Debt Instrument [Line Items]        
Line of credit facility, remaining borrowing capacity $ 125,000,000.0   $ 125,000,000.0  
Line of Credit | Revolving Credit Facility | SEA-Vista 2019 Credit Facility        
Debt Instrument [Line Items]        
Line of credit facility, remaining borrowing capacity $ 100,000,000.0   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     5,000,000.0  
Notes Payable, Other Payables        
Debt Instrument [Line Items]        
Repayments of long-term debt     $ 500,000