Segment Reporting - Revenue from Segments to Consolidated (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues		$ 222,471	$ 239,572	$ 659,599	$ 678,103
Adjusted EBITDA		13,765	13,783	42,018	28,178
Evolent Health Services
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues		63,315	100,168	223,924	284,383
Adjusted EBITDA		(3,353)	24,645	9,120	36,361
Clinical Solutions
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues		159,614	140,071	437,031	395,723
Adjusted EBITDA		23,883	(974)	53,456	18,269
Intersegment Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues		(458)	(667)	(1,356)	(2,003)
Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues		222,471	239,572	659,599	678,103
Adjusted EBITDA		20,530	23,671	62,576	54,630
Corporate
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues		0	0	0	0
Adjusted EBITDA		(6,765)	(9,888)	(20,558)	(26,452)
Transformation services
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	[1]	2,075	4,807	4,984	10,800
Transformation services | Evolent Health Services
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues		2,075	4,807	4,984	10,800
Transformation services | Clinical Solutions
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues		0	0	0	0
Transformation services | Intersegment Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues		0	0	0	0
Transformation services | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues		2,075	4,807	4,984	10,800
Transformation services | Corporate
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues		0	0	0	0
Platform and operations services
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	[1]	220,396	234,765	654,615	667,303
Platform and operations services | Evolent Health Services
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues		61,240	95,361	218,940	273,583
Platform and operations services | Clinical Solutions
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues		159,614	140,071	437,031	395,723
Platform and operations services | Intersegment Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues		(458)	(667)	(1,356)	(2,003)
Platform and operations services | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues		220,396	234,765	654,615	667,303
Platform and operations services | Corporate
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues		$ 0	$ 0	$ 0	$ 0

[1] See Note 19 for amounts attributable to unconsolidated related parties included in these line items.