Document and Entity Information
6 Months Ended
Jun. 30, 2019
$ / shares
Document Information [Line Items]  
Entity Central Index Key 0000019411
Document Type 10-Q
Document Quarterly Report true
Document Period End Date Jun. 30, 2019
Document Transition Report false
Entity File Number 1-6639
Entity Registrant Name MAGELLAN HEALTH, INC.
Entity Incorporation, State or Country Code DE
Entity Tax Identification Number 58-1076937
Entity Address, Address Line One 4800 N. Scottsdale Rd
Entity Address, Address Line Two Suite 4400
Entity Address, City or Town Scottsdale
Entity Address, State or Province AZ
Entity Address, Postal Zip Code 85251
City Area Code 602
Local Phone Number 572-6050
Entity Current Reporting Status Yes
Entity Interactive Data Current Yes
Entity Filer Category Large Accelerated Filer
Entity Small Business false
Entity Emerging Growth Company false
Entity Shell Company false
Entity Listing, Par Value Per Share | $ / shares $ 0.01
Title of 12(b) Security Common Stock, par value $0.01 per share
Trading Symbol MGLN
Security Exchange Name NASDAQ
Entity Common Stock, Shares Outstanding | shares 24,400,553
Current Fiscal Year End Date --12-31
Document Fiscal Year Focus 2019
Document Fiscal Period Focus Q2
Amendment Flag false