Stockholders' Equity Reclassifications out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands  | 
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2021  | 
Dec. 31, 2020  | 
Dec. 31, 2019  | 
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| Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] | |||
| Other-than-temporary impairments on AFS securities | $ 0 | $ 0 | $ 14,312 | 
| Reclassification out of Accumulated Other Comprehensive Income [Member] | |||
| Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] | |||
| Other-than-temporary impairments on AFS securities | 0 | 0 | 14,312 | 
| Realized gains on sales of certain AFS securities, net of tax | 135,561 | 530,462 | 232,075 | 
| Amounts reclassified from accumulated other comprehensive income (loss), net of tax | $ (135,561) | $ (530,462) | $ (217,763) | 
| X | ||||||||||
- Definition Amount of realized gain (loss) on investment in marketable security, including other-than-temporary impairment (OTTI). No definition available. 
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- Definition Amount of realized gain (loss) on investment in marketable security, excluding other-than-temporary impairment (OTTI). No definition available. 
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| X | ||||||||||
- Definition Amount of other-than-temporary impairment (OTTI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), recognized in earnings. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available. 
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- Details 
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