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Equity-Based Compensation (Details) - USD ($) shares in Millions |  | 5 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | --- | ---
Oct. 21, 2020 | Dec. 31, 2020 | Sep. 30, 2021 | Sep. 30, 2020 | Dec. 31, 2020 | Dec. 31, 2019
Equity-Based Compensation (Details) [Line Items] |  |  |  |  |  |
Authorized for issuance (in Shares) |  | 21.4 |  |  | 21.4 |
Incremental compensation cost | $ 1,500,000 |  |  |  |  |
Unit options exercisable and expected to vest |  | 9 years 7 months 28 days |  |  |  |
Unit options exercisable |  | 9 years 5 months 19 days |  |  |  |
Weighted average grant date fair value of unit options granted |  |  |  |  | $ 1.19 | $ 0
Intrinsic value of unit options exercised |  | $ 12,000 |  |  | 12,000 | 0
Total fair value of options vested |  | 2,200,000 |  |  | 2,200,000 | 97,000
Total compensation cost related to nonvested awards not yet recognized |  | $ 4,100,000 |  |  | 4,100,000 |
Equity-based compensation expense |  |  | $ 1,033,000 | $ 53,000 | 7,363,000 | 70,000
Weighted average grant date fair value of profits interest units granted |  |  |  |  | 1.27 | 0
Total fair value of units vested |  |  |  |  | 6,400,000 | 0
Total compensation cost related to nonvested profits interest units |  |  |  |  | $ 97,000 | $ 0
Weighted-average period over |  | 1 year 9 months 21 days |  |  | 1 year 9 months 21 days | 0 years
Equity based compensation expense |  |  |  |  | $ 859,000 | $ 0
Grant date fair value |  | $ 5,700,000 |  |  | 5,700,000 |
Total fair value of units vested upon grant and vested |  | 5,500,000 |  |  | 5,500,000 |
Total compensation cost |  | $ 211,000 |  |  | 211,000 |
Equity value |  |  |  |  | $ 525,034,000,000 |
Weighted average cost of capital |  | 38.00% |  |  | 38.00% |
Risk-free interest rate,percentage |  |  |  |  | 0.17% |
Percentage of traded common stock prices and the capital structure |  |  |  |  | 59.50% |
Stock Options [Member] |  |  |  |  |  |
Equity-Based Compensation (Details) [Line Items] |  |  |  |  |  |
Weighted-average period over |  | 3 years 7 months 20 days |  |  |  |
Equity-based compensation expense |  |  |  |  | $ 974,000 | $ 70,000
B-4s [Member] |  |  |  |  |  |
Equity-Based Compensation (Details) [Line Items] |  |  |  |  |  |
Equity-based compensation expense |  |  |  |  | $ 5,500,000 |
Weighted-average period over |  | 1 year 9 months 21 days |  |  | 1 year 9 months 21 days |
Equity value |  |  |  |  | $ 525,000,000 |

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