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Significant Accounting Policies - Investment in Marketable Securities (Narrative) (Details) | 12 Months Ended
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Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($) security | Dec. 31, 2021 USD ($) marketableSecurity security
Real Estate [Line Items] |  |  |
Proceeds from sale of marketable securities |  | $ 7,800,000 | $ 0
Number of marketable securities sold | security |  | 1 |
Proceeds from the repayment of debt marketable securities |  | $ 3,700,000 | $ 4,500,000
Number of securities repaid | security |  | 1 | 1
Equity marketable securities | $ 0 | $ 0 |
Number of securities sold | marketableSecurity |  |  | 1
Proceeds from sale of equity marketable securities | 4,200,000 |  | $ 0
Marketable securities, realized loss |  | 6,500,000 |
Marketable securities, unrealized gain |  |  | $ 600,000
Commercial mortgage-backed securities |  |  |
Real Estate [Line Items] |  |  |
Cost basis of commercial mortgage backed securities | 11,500,000 | 11,500,000 |
Unrealized loss | 1,900,000 | 300,000 |
Fair value of security in a continuous unrealized loss position for less than 12 months | $ 9,600,000 | $ 11,200,000 |

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- Definition Amount of unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-2 + Details
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- Definition Amortized cost excluding accrued interest, after allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479130/326-30-45-1 + Details
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