Summary of Significant Accounting Policies - Additional Information (Details)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($) Segment Entity	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Accounting Policies [Line Items]
Number of consolidated variable interest entities | Entity			3
Number of reporting segments | Segment			1
Number of operating segments | Segment			1
Assets, fair value disclosure	$ 2,348,000		$ 2,348,000		$ 1,440,000
Net loss attributable to noncontrolling interest	0		0
Federal deposit insurance corporation premium expense			$ 493,826,000		205,882,000
Industry tax		$ 2,795,000		$ 6,138,000
Award requisite service period			4 years
Revenues	308,739,000	$ 243,956,000	$ 575,739,000	$ 468,222,000
Level 3
Accounting Policies [Line Items]
Assets, fair value disclosure	0		0		0
Liabilities, fair value disclosure	0		0
Directly from CMS
Accounting Policies [Line Items]
Revenues	13,452,000		13,452,000
Medicare Advantage Plan
Accounting Policies [Line Items]
Minimum loss ratio amounts payable	$ 0		$ 0		$ 0
Percentage of consumer discounts on brand name			75.00%
Medicare Advantage Plan | Minimum
Accounting Policies [Line Items]
Loss ratio			85.00%