Net Income per Common Share Attributable to Magellan Helath, Inc (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Numerator:
Net income attributable to Magellan Health, Inc.	$ 3,958	$ 4,643	$ 17,195	$ 11,931
Denominator:
Weighted average number of common shares outstanding-basic (in shares)	23,516	25,684	23,570	25,502
Common stock equivalents-stock options (in shares)	355	362	306	406
Common stock equivalents-RSAs (in shares)	619	654	583	584
Common stock equivalents-RSUs (in shares)	23	26	27	36
Common stock equivalents- PSUs( in shares)	31	49	29	58
Common stock equivalents-employee stock purchase plan (in shares)	2	1	2	2
Weighted average number of common shares outstanding-diluted (in shares)	24,546	26,776	24,517	26,588
Net income attributable to Magellan Health, Inc. per common share-basic (in dollars per share)	$ 0.17	$ 0.18	$ 0.73	$ 0.47
Net income attributable to Magellan Health, Inc. per common share-diluted (in dollars per share)	$ 0.16	$ 0.17	$ 0.70	$ 0.45
Potential dilutive securities excluded from computation of dilutive securities (in shares)	1,200	800	1,100	900