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
Oct. 22, 2018
Document And Entity Information [Abstract]    
Entity Registrant Name SEACOR HOLDINGS INC /NEW/  
Entity Central Index Key 0000859598  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
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 Emerging Growth Company false  
Entity Small Business false  
Entity Common Stock, Shares Outstanding   18,246,825