Net Income per Common Share Attributable to Magellan Helath Services, Inc (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Numerator:
Net income attributable to Magellan Health, Inc.	$ 4,643	$ 4,986	$ 11,931	$ 30,706
Denominator:
Weighted average number of common shares outstanding-basic (in shares)	25,684	27,144	25,502	27,257
Common stock equivalents-stock options (in shares)	362	554	406	574
Common stock equivalents-RSAs (in shares)	654	66	584	49
Common stock equivalents-RSUs (in shares)	26		36	27
Common stock equivalents- PSUs( in shares)	49		58
Common stock equivalents-employee stock purchase plan (in shares)	1	1	2	1
Weighted average number of common shares outstanding-diluted (in shares)	26,776	27,765	26,588	27,908
Net income attributable to Magellan Health, Inc. per common share-basic (in dollars per share)	$ 0.18	$ 0.18	$ 0.47	$ 1.13
Net income attributable to Magellan Health, Inc. per common share-diluted (in dollars per share)	$ 0.17	$ 0.18	$ 0.45	$ 1.10
Potential dilutive securities excluded from computation of dilutive securities (in shares)	800	700	900	500