Fair Value Measurements (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands |
Jun. 30, 2022 |
Dec. 31, 2021 |
|---|---|---|
| Fair Value Measurements | $ 521,857 | $ 601,011 |
| Mutual funds | ||
| Fair Value Measurements | 102,514 | 110,006 |
| U.S. Treasury notes | ||
| Fair Value Measurements | 205,816 | 223,896 |
| Corporate debt securities | ||
| Fair Value Measurements | 205,254 | 155,796 |
| Money market mutual fund | ||
| Fair Value Measurements | 8,273 | 111,313 |
| Fair Value, Inputs, Level 1 [Member] | ||
| Fair Value Measurements | 521,857 | 601,011 |
| Fair Value, Inputs, Level 1 [Member] | Mutual funds | ||
| Fair Value Measurements | 102,514 | 110,006 |
| Fair Value, Inputs, Level 1 [Member] | U.S. Treasury notes | ||
| Fair Value Measurements | 205,816 | 223,896 |
| Fair Value, Inputs, Level 1 [Member] | Corporate debt securities | ||
| Fair Value Measurements | 205,254 | 155,796 |
| Fair Value, Inputs, Level 1 [Member] | Money market mutual fund | ||
| Fair Value Measurements | $ 8,273 | $ 111,313 |