Net Income per Common Share Attributable to Magellan Helath, Inc (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Numerator:
Net income attributable to Magellan Health, Inc.	$ 13,237	$ 7,288
Denominator:
Weighted average number of common shares outstanding-basic (in shares)	23,631	25,319
Common stock equivalents-stock options (in shares)	257	450
Common stock equivalents-RSAs (in shares)	547	514
Common stock equivalents-RSUs (in shares)	30	46
Common stock equivalents- PSUs( in shares)	28	68
Common stock equivalents-employee stock purchase plan (in shares)	2	2
Weighted average number of common shares outstanding-diluted (in shares)	24,495	26,399
Net income attributable to Magellan Health, Inc. per common share-basic (in dollars per share)	$ 0.56	$ 0.29
Net income attributable to Magellan Health, Inc. per common share-diluted (in dollars per share)	$ 0.54	$ 0.28
Potential dilutive securities excluded from computation of dilutive securities (in shares)	1,500	1,000