| Pay vs Performance Disclosure - USD ($) | 12 Months Ended |
| Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020 |
| Pay vs Performance Disclosure [Table] | | | |
| Named Executive Officers, Footnote [Text Block] | Messrs. Blazer, Pierce and George Wilson and Ms. Painter were the non-PEO NEOs (named executive officers) for 2020 and 2021. For 2022, Mmes. Perry and Cunningham were added and Mr. Wilson was removed as a non-PEO NEO. | | |
| PEO Total Compensation Amount | $ 8,420,365 | $ 9,546,278 | $ 6,606,311 |
| PEO Actually Paid Compensation Amount | $ 335,421 | 17,317,167 | 13,102,307 |
| Adjustment To PEO Compensation, Footnote [Text Block] | The amounts disclosed in the "Compensation Actually Paid" columns do not reflect the actual amount of compensation earned or paid during the applicable year, instead they address the changes in valuation of the equity portions of named executive officers' compensation during the relevant year. The following adjustments were made to the amounts reported in the Summary Compensation Table to determine the amounts set forth in the "Compensation Actually Paid" columns (no other adjustments were required to be made in accordance with SEC rules): | | |
| Non-PEO NEO Average Total Compensation Amount | $ 3,831,938 | 3,453,255 | 2,731,636 |
| Non-PEO NEO Average Compensation Actually Paid Amount | $ 1,992,201 | 6,642,446 | 4,779,907 |
| Total Shareholder Return Vs Peer Group [Text Block] | Each year reflects what the cumulative value of $100 would be, including reinvestment of dividends, if such amount were invested on December 31, 2019. For the relevant fiscal year, represents the cumulative TSR of the peer group. | | |
| Total Shareholder Return Amount | $ 114.79 | 173.88 | 117.70 |
| Peer Group Total Shareholder Return Amount | 105.54 | 146.72 | 107.65 |
| Net Income (Loss) | $ 268,074,181 | $ 409,869,968 | $ 200,316,020 |
| Company Selected Measure Amount | 550,885,433 | 470,355,274 | 438,547,098 |
| PEO Name | Mr. Hanson was our PEO (principal executive officer) for all three years. | | |
| Additional 402(v) Disclosure [Text Block] | Net income for the years ended December 31, 2022, 2021 and 2020 include $1.2 million, $178.1 million and $22.7 million related to discontinued operations, respectively. The 2021 discontinued operations include the gain on sale of the Oxford business. | | |
| PEO [Member] | Deduct Equity Awards [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | $ 4,710,065 | $ 6,244,850 | $ 4,298,408 |
| PEO [Member] | Add Year End Value of Unvested Equity Granted in Year [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 4,781,920 | 7,040,684 | 10,437,773 |
| PEO [Member] | Add Change in Value of Unvested Awards Granted in Prior Years [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | (7,842,978) | 6,855,018 | 557,664 |
| PEO [Member] | Add Change in Value of Vested Equity Granted in Prior Years [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | (313,821) | 120,037 | (201,033) |
| Non-PEO NEO [Member] | Deduct Equity Awards [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 2,115,574 | 1,744,256 | 1,364,926 |
| Non-PEO NEO [Member] | Add Year End Value of Unvested Equity Granted in Year [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 1,972,340 | 2,217,104 | 3,068,672 |
| Non-PEO NEO [Member] | Add Change in Value of Unvested Awards Granted in Prior Years [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | (1,522,906) | 2,684,273 | 426,023 |
| Non-PEO NEO [Member] | Add Change in Value of Vested Equity Granted in Prior Years [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | $ (173,597) | $ 32,070 | $ (81,498) |
