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Fair Value of Financial Instruments - Carrying Values and Estimated Fair Values of Financial Instruments (Parenthetical) (Details)
Mar. 31, 2021
Dec. 31, 2020
Level 3 [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Percentage of coinsurance costs 10.00% 10.00%