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Fair Value Disclosure (Narrative) (Details) - Level 1 - Fair value measurements, recurring - USD ($) $ in Thousands | 3 Months Ended |  |  |
--- | --- | --- | --- | ---
Mar. 31, 2021 | Mar. 31, 2020 | Dec. 31, 2020 | Jun. 30, 2020 | Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Equity securities | $ 14,005 |  | $ 13,164 |  |
Unrealized gain (loss) on equity securities | 500 |  |  |  |
Bellaire |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Unrealized gain (loss) on equity securities | $ 300 | $ (1,200) |  |  |
Carrying Value |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Equity securities |  |  |  | $ 2,000 |
Carrying Value | Bellaire |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Equity securities |  |  |  |  | $ 5,000

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