Document and Entity Information
3 Months Ended
Mar. 31, 2019
Document and Entity Information  
Entity Registrant Name MAGELLAN HEALTH INC
Entity Central Index Key 0000019411
Document Type 10-Q
Document Period End Date Mar. 31, 2019
Amendment Flag false
Current Fiscal Year End Date --12-31
Entity Current Reporting Status Yes
Entity Filer Category Large Accelerated Filer
Entity Small Business false
Entity Emerging Growth Company false
Entity Common Stock, Shares Outstanding 24,032,629
Document Fiscal Year Focus 2019
Document Fiscal Period Focus Q1