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Fair Value Measurements - Assets and Liabilities Not Measured at Fair Value (Details) - USD ($) $ in Thousands | Dec. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Senior Notes | 5.75% Senior Notes due 2023 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Stated interest rate (in hundredths) | 5.75% |
9% Convertible Junior Subordinated Debentures due 2063 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Stated interest rate (in hundredths) | 9.00% |
Carrying Value |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Other invested assets | $ 3,100 | $ 3,100
FHLB Advance | 155,000 | 155,000
5.75% Notes | 420,867 | 419,713
9% Debentures | 256,872 | 256,872
Total financial liabilities | 832,739 | 831,585
Fair Value | Significant Other Observable Inputs (Level 2) |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Other invested assets | 3,100 | 3,100
FHLB Advance | 156,422 | 150,551
5.75% Notes | 471,827 | 425,791
9% Debentures | 346,289 | 338,069
Total financial liabilities | $ 974,538 | $ 914,411

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