Unpaid Claims - Additional information (Details) $ in Thousands |
6 Months Ended | 9 Months Ended | 12 Months Ended | |||
|---|---|---|---|---|---|---|
|
Sep. 30, 2021
USD ($)
|
Sep. 30, 2021
USD ($)
|
Sep. 30, 2020
USD ($)
|
Dec. 31, 2020
USD ($)
|
Dec. 31, 2019
USD ($)
|
Dec. 31, 2018
USD ($)
|
|
| Liability for Unpaid Claims and Claims Adjustment Expense, Activity in Liability [Abstract] | ||||||
| Unpaid claims | $ 140,210 | $ 140,210 | $ 93,615 | $ 103,976 | $ 77,886 | $ 41,660 |
| Incurred claims paid | 1,073,141 | 394,811 | 564,378 | 414,419 | ||
| Favorable development | $ (17,095) | $ 15,401 | $ 13,715 | $ 2,778 | ||
| Ratio of current year medical claims paid as a percent of current year net medical claims | 0.882 | 0.796 | 0.830 | 0.831 | ||
| Direct Contracting Model, percentage of incurred claims | 42.40% | |||||