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Financing Agreements - Financing Agreements (Details) $ in Thousands |  | 3 Months Ended |
--- | --- | --- | ---
Apr. 04, 2022 | Mar. 31, 2022 USD ($) | Mar. 31, 2021 | Dec. 31, 2021 USD ($)
Financing Agreements [Line Items] |  |  |  |
Unpaid Principal Balance |  | $ 7,093,448 |  | $ 6,377,370
Fair value / Carrying Value |  | $ 7,028,211 |  | 6,378,782
Stock split ratio, common stock |  | 0.25 | 0.25 |
Subsequent Event |  |  |  |
Financing Agreements [Line Items] |  |  |  |
Stock split ratio, common stock | 0.25 |  |  |
6.25% Convertible Senior Notes | Convertible Debt | Subsequent Event |  |  |  |
Financing Agreements [Line Items] |  |  |  |
Stock split ratio, common stock | 0.25 |  |  |
Fair Value |  |  |  |
Financing Agreements [Line Items] |  |  |  |
Unpaid Principal Balance |  | $ 3,860,415 |  | 3,254,300
Amortized Cost Balance |  | 3,870,222 |  | 3,267,981
Fair value / Carrying Value |  | 3,804,906 |  | 3,266,773
Carrying Value |  |  |  |
Financing Agreements [Line Items] |  |  |  |
Unpaid Principal Balance |  | 3,233,033 |  | 3,123,070
Fair value / Carrying Value |  | 3,223,305 |  | 3,112,009
Agreements with mark-to-market collateral provisions | Fair Value |  |  |  |
Financing Agreements [Line Items] |  |  |  |
Unpaid Principal Balance |  | 1,555,250 |  | 627,026
Amortized Cost Balance |  | 1,555,250 |  | 627,026
Fair value / Carrying Value |  | 1,555,250 |  | 628,280
Agreements with mark-to-market collateral provisions | Carrying Value |  |  |  |
Financing Agreements [Line Items] |  |  |  |
Unpaid Principal Balance |  | 1,386,009 |  | 1,240,510
Fair value / Carrying Value |  | 1,385,685 |  | 1,239,937
Financing agreements with non-mark-to-market collateral provisions | Fair Value |  |  |  |
Financing Agreements [Line Items] |  |  |  |
Unpaid Principal Balance |  | 563,860 |  | 1,322,362
Amortized Cost Balance |  | 563,860 |  | 1,322,362
Fair value / Carrying Value |  | 563,860 |  | 1,322,362
Financing agreements with non-mark-to-market collateral provisions | Carrying Value |  |  |  |
Financing Agreements [Line Items] |  |  |  |
Unpaid Principal Balance |  | 438,374 |  | 311,977
Fair value / Carrying Value |  | 437,548 |  | 311,260
Securitized debt | Fair Value |  |  |  |
Financing Agreements [Line Items] |  |  |  |
Unpaid Principal Balance |  | 1,741,305 |  | 1,304,912
Amortized Cost Balance |  | 1,751,112 |  | 1,318,593
Fair value / Carrying Value |  | 1,685,796 |  | 1,316,131
Securitized debt | Carrying Value |  |  |  |
Financing Agreements [Line Items] |  |  |  |
Unpaid Principal Balance |  | 1,178,650 |  | 1,340,583
Fair value / Carrying Value |  | 1,173,265 |  | 1,334,342
Convertible senior notes | Carrying Value |  |  |  |
Financing Agreements [Line Items] |  |  |  |
Unpaid Principal Balance |  | 230,000 |  | 230,000
Fair value / Carrying Value |  | $ 226,807 |  | $ 226,470

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