Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Net revenue:
Managed care and other	$ 863,506	$ 809,249	$ 776,240	$ 748,650	$ 753,489	$ 703,020	$ 682,274	$ 829,591	$ 3,197,645		$ 2,968,374		$ 3,063,049
PBM and dispensing	405,237	380,833	381,367	232,318	228,970	220,150	205,740	136,884	1,399,755		791,744		483,268
Total net revenue	1,268,743	1,190,082	1,157,607	980,968	982,459	923,170	888,014	966,475	4,597,400		3,760,118		3,546,317
Costs and expenses:
Cost of care	587,816	596,323	568,288	522,328	506,090	495,180	481,617	605,708	2,274,755		2,088,595		2,232,976
Cost of goods sold	381,817	360,444	361,409	218,207	212,905	202,180	192,566	125,298	1,321,877		732,949		455,601
Direct service costs and other operating expenses	205,901	220,586	191,455	204,450	202,814	176,928	179,034	164,722	822,392	[1],[2]	723,498	[1],[2]	619,546	[1],[2]
Depreciation and amortization	27,605	26,721	25,022	23,496	24,405	23,956	22,480	20,229	102,844		91,070		71,994
Interest expense	1,648	1,654	1,653	1,626	1,668	2,879	2,004	836	6,581		7,387		3,000
Interest and other income	(568)	(631)	(500)	(466)	(474)	(241)	(275)	(311)	(2,165)		(1,301)		(1,985)
Total costs and expenses	1,204,219	1,205,097	1,147,327	969,641	947,408	900,882	877,426	916,482	4,526,284		3,642,198		3,381,132
Income before income taxes	64,524	(15,015)	10,280	11,327	35,051	22,288	10,588	49,993	71,116		117,920		165,185
Provision for income taxes	39,543	(7,254)	5,987	4,133	15,305	(3,490)	6,261	25,613	42,409		43,689		39,924
Net income	24,981	(7,761)	4,293	7,194	19,746	25,778	4,327	24,380	28,707		74,231		125,261
Less: net income (loss) attributable to non-controlling interest	(2,309)	47	(350)	(94)	(1,819)	(1,355)	(659)	(1,340)	(2,706)		(5,173)
Net income attributable to Magellan Health, Inc.	$ 27,290	$ (7,808)	$ 4,643	$ 7,288	$ 21,565	$ 27,133	$ 4,986	$ 25,720	$ 31,413		$ 79,404		$ 125,261
Weighted average number of common shares outstanding-basic	23,582	24,892	25,684	25,319	25,558	26,703	27,144	27,370	24,865		26,689		27,054
Weighted average number of common shares outstanding-diluted	24,402	24,892	26,776	26,399	26,382	27,242	27,765	28,051	25,877		27,355		27,675
Net income attributable to Magellan Health, Inc. per common share-basic (in dollars per share)	$ 1.16	$ (0.31)	$ 0.18	$ 0.29	$ 0.84	$ 1.02	$ 0.18	$ 0.94	$ 1.26		$ 2.98		$ 4.63
Net income attributable to Magellan Health, Inc. per common share-diluted (in dollars per share)	$ 1.12	$ (0.31)	$ 0.17	$ 0.28	$ 0.82	$ 1.00	$ 0.18	$ 0.92	$ 1.21		$ 2.90		$ 4.53
Stock compensation expense	$ 9,791	$ 12,897	$ 13,795	$ 13,901	$ 14,601	$ 11,961	$ 9,550	$ 4,472	$ 50,384		$ 40,584		$ 21,252
Changes in fair value of contingent consideration	$ (3,017)	$ 29,738	$ 2,567	$ 14,969	$ 6,172				$ 44,257		$ 6,172

[1] Includes changes in fair value of contingent consideration of $6,172 and $44,257 for the years ended December 31, 2014 and 2015, respectively.

[2] Includes stock compensation expense of $21,252, $40,584 and $50,384 for the years ended December 31, 2013, 2014 and 2015, respectively.