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Equity and Debt Securities - Additional Information (Details) - USD ($)
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Schedule Of Available For Sale And Trading Securities [Line Items]    
Gross unrealized loss $ 4,300,000 $ 298,000
Credit losses 0  
Margin Account Borrowing    
Schedule Of Available For Sale And Trading Securities [Line Items]    
Marketable securities $ 499,400,000