Commitments and Contingencies - Additional Information (Details) - USD ($)	3 Months Ended			12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2019	Jun. 30, 2019
Restricted Cash and Cash Equivalents Items [Line Items]
Operating capital support commitment, maximum amount	$ 11,000,000.0			$ 4,000,000.0	$ 11,000,000.0
Restricted funds	160,823,000			28,340,000	160,823,000
Carrying amount	$ 221,041,000			293,667,000	221,041,000
Offering expenses				$ 0	$ 0	$ 1,500,000
Percent of tax savings to be paid				85.00%
New Mexico Health Connections
Restricted Cash and Cash Equivalents Items [Line Items]
Reinsurance arrangement, term	15 months
Reinsurance arrangement, capital amount		$ 10,000,000.0
Reinsurance arrangement, percentage of gross premiums ceded	90.00%				90.00%
Reinsurance arrangement, percentage of claims liability indemnified	90.00%				90.00%
Reinsurance arrangement, maximum amount of insurance risk as a percentage of premiums ceded	105.00%				105.00%
Restricted Cash For Letters Of Credit
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted funds				$ 1,800,000
Letters of credit for facility leases
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted funds	$ 3,710,000			3,610,000	$ 3,710,000
Collateral with financial institutions
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted funds	34,142,000			5,742,000	34,142,000
Restricted cash and investments	34,100,000			5,700,000	34,100,000
Letter of Credit | Line of Credit
Restricted Cash and Cash Equivalents Items [Line Items]
Maximum borrowing capacity			$ 5,000,000.0				$ 1,800,000
Line of credit, quarterly rental fee percentage			0.80%
Carrying amount	$ 0			$ 0	$ 0
Surety Bond
Restricted Cash and Cash Equivalents Items [Line Items]
Loss contingency, estimate of possible loss								$ 25,000,000.0