Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Net revenue:
Managed care and other	$ 775,031	$ 751,589	$ 699,861	$ 676,461	$ 863,506	$ 809,249	$ 776,240	$ 748,650	$ 2,902,942		$ 3,197,645		$ 2,968,374
PBM and dispensing	488,354	540,543	464,484	440,561	405,237	380,833	381,367	232,318	1,933,942		1,399,755		791,744
Total net revenue	1,263,385	1,292,132	1,164,345	1,117,022	1,268,743	1,190,082	1,157,607	980,968	4,836,884		4,597,400		3,760,118
Costs and expenses:
Cost of care	472,211	480,243	472,529	457,631	587,816	596,323	568,288	522,328	1,882,614		2,274,755		2,088,595
Cost of goods sold	456,658	509,673	436,930	415,459	381,817	360,444	361,409	218,207	1,818,720		1,321,877		732,949
Direct service costs and other operating expenses	240,985	229,094	214,077	192,456	205,901	220,586	191,455	204,450	876,612	[1],[2],[3]	822,392	[1],[2],[3]	723,498	[1],[2],[3]
Depreciation and amortization	28,574	26,885	25,580	25,007	27,605	26,721	25,022	23,496	106,046		102,844		91,070
Interest expense	3,413	3,038	1,994	1,748	1,648	1,654	1,653	1,626	10,193		6,581		7,387
Interest and other income	(702)	(741)	(692)	(683)	(568)	(631)	(500)	(466)	(2,818)		(2,165)		(1,301)
Total costs and expenses	1,201,139	1,248,192	1,150,418	1,091,618	1,204,219	1,205,097	1,147,327	969,641	4,691,367		4,526,284		3,642,198
Income (loss) before income taxes	62,246	43,940	13,927	25,404	64,524	(15,015)	10,280	11,327	145,517		71,116		117,920
Provision (benefit) for income taxes	26,469	18,631	12,615	12,013	39,543	(7,254)	5,987	4,133	69,728		42,409		43,689
Net income (loss)	35,777	25,309	1,312	13,391	24,981	(7,761)	4,293	7,194	75,789		28,707		74,231
Less: net income (loss) attributable to non-controlling interest	602	(200)	(2,646)	154	(2,309)	47	(350)	(94)	(2,090)		(2,706)		(5,173)
Net income (loss) attributable to Magellan Health, Inc.	$ 35,175	$ 25,509	$ 3,958	$ 13,237	$ 27,290	$ (7,808)	$ 4,643	$ 7,288	$ 77,879		$ 31,413		$ 79,404
Weighted average number of common shares outstanding-basic	22,556	23,052	23,516	23,631	23,582	24,892	25,684	25,319	23,181		24,865		26,689
Weighted average number of common shares outstanding-diluted	23,493	24,009	24,643	24,511	24,402	24,892	26,776	26,399	24,156		25,877		27,355
Net (loss) income attributable to Magellan Health, Inc. per common share-basic (in dollars per share)	$ 1.56	$ 1.11	$ 0.17	$ 0.56	$ 1.16	$ (0.31)	$ 0.18	$ 0.29	$ 3.36		$ 1.26		$ 2.98
Net (loss) income attributable to Magellan Health, Inc. per common share-diluted (in dollars per share)	$ 1.50	$ 1.06	$ 0.16	$ 0.54	$ 1.12	$ (0.31)	$ 0.17	$ 0.28	$ 3.22		$ 1.21		$ 2.90
Stock compensation expense	$ 9,849	$ 9,176	$ 9,510	$ 8,887	$ 9,791	$ 12,897	$ 13,795	$ 13,901	$ 37,422		$ 50,384		$ 40,584
Changes in fair value of contingent consideration	$ (614)	$ 313	463	$ (266)	$ (3,017)	$ 29,738	$ 2,567	$ 14,969	(104)		$ 44,257		$ 6,172
Impairment of intangible assets			$ 4,800						$ 4,800

[1] Includes changes in fair value of contingent consideration of $6,172, $44,257 and $(104) for the years ended December 31, 2014, 2015 and 2016, respectively.

[2] Includes impairment of intangible assets of $4,800 for the year ended December 31, 2016.

[3] Includes stock compensation expense of $40,584, $50,384 and $37,422 for the years ended December 31, 2014, 2015 and 2016, respectively.