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Stock-Based Compensation Plans (Narrative) (Details) | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2021 USD ($) plan shares | Sep. 30, 2020 USD ($) | Jun. 30, 2020 USD ($) | Sep. 30, 2021 USD ($) plan shares | Sep. 30, 2020 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Compensation expense for share-based payments | $ 7,492,763 | $ 6,904,725 |  | $ 20,114,921 | $ 22,865,087
Employee Stock |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Shares issued under the Omnibus plan | shares |  |  |  | 1,463,744 |
Number of shares authorized | shares | 2,000,000 |  |  | 2,000,000 |
ESPP discount rate |  |  |  | 85.00% |
ESPP discount rate recognized as compensation expense |  |  |  | 15.00% |
Employee Severance |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Compensation expense for share-based payments |  |  | $ 4,173,710 |  |
Omnibus Incentive Plan |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Total grants in period (in shares) | shares |  |  |  | 6,156,962 |
Shares issued under the Omnibus plan | shares |  |  |  | 15,031,810 |
Number of shares authorized | shares | 45,000,000 |  |  | 45,000,000 |
Employee Stock Option Plan |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Unrecognized compensation cost | $ 9,556,647 |  |  | $ 9,556,647 |
Employee Stock Option Plan | Minimum |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Option vesting period |  |  |  | 1 year |
Option expiration period |  |  |  | 5 years |
Employee Stock Option Plan | Maximum |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Option vesting period |  |  |  | 5 years |
Option expiration period |  |  |  | 10 years |
Restricted Stock Plan |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Unrecognized compensation cost | 48,175,427 |  |  | $ 48,175,427 |
Restricted period, maximum |  |  |  | 10 years |
Amortization expense | $ 5,215,981 | 4,366,025 |  | $ 13,978,358 | 16,271,774
Restricted Stock Plan | Employee Severance |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Amortization expense |  |  | $ 4,148,477 |  |
Equity Incentive Plans |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Number of plans | plan | 2 |  |  | 2 |
Performance Shares |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Unrecognized compensation cost | $ 7,967,733 |  |  | $ 7,967,733 |
Amortization expense | $ 581,830 | $ 1,403,799 |  | $ 1,387,584 | $ 2,361,359

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