Investments In Securities - Weighted Average Lives of Trading Securities (Details) - USD ($) $ in Thousands |
Sep. 30, 2020 |
Dec. 31, 2019 |
|---|---|---|
| Fair Value | ||
| ≥ 1 year and 3 years | $ 488,744 | $ 389,883 |
| ≥ 3 years and 5 years | 1,351,241 | 407,656 |
| ≥ 5 years | 1,553,183 | 86,062 |
| Securities, trading | 3,393,168 | 883,601 |
| Amortized Cost | ||
| ≥ 1 year and 3 years | 488,823 | 369,600 |
| ≥ 3 years and 5 years | 1,339,604 | 375,030 |
| Greater than or equal to five years | 1,543,547 | 80,214 |
| Amortized Cost | $ 3,371,974 | $ 824,844 |