Annual report pursuant to Section 13 and 15(d)

Note 16 - Related Party Transactions (Details Textual)

v3.19.1
Note 16 - Related Party Transactions (Details Textual)
12 Months Ended
Jan. 25, 2019
USD ($)
Jan. 25, 2019
GBP (£)
Nov. 30, 2015
USD ($)
Dec. 31, 2018
USD ($)
shares
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Related Party Transaction, Rate       0.50%    
Interest Expense, Related Party       $ 300,000 $ 300,000 $ 400,000
Related Party Transaction, Amounts of Transaction       $ 11,214,000 12,655,000
Windcat Workboats [Member]            
Business Acquisition, Percentage of Voting Interests Acquired         12.50%  
OSV Partners [Member]            
Revenue from Related Parties       600,000 $ 600,000 500,000
Proceeds from Sale of Interest in Partnership Unit       $ 7,500,000    
Equity Method Investment, Ownership Percentage       30.40%    
OSV Partners [Member] | General Partner [Member]            
Equity Method Investment, Ownership Percentage       38.60%    
OSV Partners [Member] | Series A Preferred Stock [Member]            
Proceeds from Issuance of Redeemable Preferred Stock       $ 2,500,000    
Equity Method Investment, Ownership Percentage       43.00%    
OSV Partners [Member] | Second Lien Debt [Member]            
Proceeds from Issuance of Debt       $ 5,000,000    
Equity Method Investment, Ownership Percentage       43.00%    
Restricted Stock [Member]            
Adjustments to Additional Paid in Capital, Other       $ 2,700,000    
Stock Issued During Period, Shares, Restricted Stock Award, Gross | shares       120,693    
Share Distribution [Member]            
Related Party Transaction, Amounts of Transaction       $ 6,700,000    
SEACOR Holdings [Member]            
Related Party Transaction, Amounts of Transaction       9,400,000    
Officer [Member] | OSV Partners [Member] | Limited Partner [Member] | Fabrikant [Member]            
Limited Partners' Capital Account, Total       300,000    
Officer [Member] | OSV Partners [Member] | Limited Partner [Member] | Gellert [Member]            
Limited Partners' Capital Account, Total       $ 400,000    
Officer [Member] | OSV Partners [Member] | Limited Partner [Member] | Fabrikant and Gellert [Member]            
Equity Method Investment, Ownership Percentage       31.70%    
Officer [Member] | OSV Partners [Member] | Series A Preferred Stock [Member] | General Partner [Member]            
Equity Method Investment, Ownership Percentage       3.90%    
General Partners' Capital Account, Total       $ 100,000    
Officer [Member] | OSV Partners [Member] | Second Lien Debt [Member] | General Partner [Member]            
Equity Method Investment, Ownership Percentage       3.90%    
General Partners' Capital Account, Total       $ 200,000    
Transition Services Agreement [Member]            
Related Party Transaction, Amounts of Transaction       4,500,000 3,300,000  
Management Services [Member]            
Related Party Transaction, Amounts of Transaction       1,932,000 4,365,000
General and Administrative Expense [Member]            
Related Party Transaction, Amounts of Transaction     $ 3,400,000      
Maximum [Member] | Officer [Member] | OSV Partners [Member]            
Limited Partners' Capital Account, Total       $ 1,500,000    
Maximum [Member] | Officer [Member] | OSV Partners [Member] | Limited Partner [Member]            
Equity Method Investment, Ownership Percentage       3.90%    
Maximum [Member] | Officer [Member] | OSV Partners [Member] | General Partner [Member]            
Equity Method Investment, Ownership Percentage       5.00%    
General Partners' Capital Account, Total       $ 300,000    
Maximum [Member] | Transition Services Agreement [Member]            
Related Party Transaction, Amounts of Transaction       6,300,000    
Maximum [Member] | Management Services [Member]            
Related Party Transaction, Amounts of Transaction       7,700,000    
Restructuring Charges [Member]            
Related Party Transaction, Amounts of Transaction       6,000,000    
Restructuring Charges [Member] | Maximum [Member]            
Related Party Transaction, Amounts of Transaction       3,000,000    
Employee Severance [Member]            
Related Party Transaction, Amounts of Transaction       0 700,000  
SEACOR Holdings [Member]            
Revenue from Related Parties         100,000 $ 100,000
Guarantor Obligations, Maximum Exposure, Undiscounted       40,600,000 $ 69,100,000  
Allocated Share-based Compensation Expense, Total       $ 1,700,000    
Seabulk Overseas [Member] | Subsequent Event [Member] | Windcat Workboats [Member]            
Ownership Percentage 100.00% 100.00%        
Seabulk Overseas [Member] | Windcat Workboats [Member] | Subsequent Event [Member]            
Business Acquisition, Percentage of Voting Interests Acquired 6.25% 6.25%        
Business Combination, Consideration Transferred, Total $ 2,000,000 £ 1,552,780