Quarterly report pursuant to Section 13 or 15(d)

Document And Entity Information

v3.10.0.1
Document And Entity Information - shares
9 Months Ended
Sep. 30, 2018
Nov. 09, 2018
Document Information [Line Items]    
Entity Registrant Name SEACOR Marine Holdings Inc.  
Entity Central Index Key 0001690334  
Trading Symbol smhi  
Current Fiscal Year End Date --12-31  
Entity Filer Category Non-accelerated Filer  
Entity Current Reporting Status Yes  
Entity Emerging Growth Company true  
Entity Small Business false  
Entity Common Stock, Shares Outstanding (in shares)   20,437,818
Document Type 10-Q  
Document Period End Date Sep. 30, 2018  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q3  
Amendment Flag false  
Entity Ex Transition Period true