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Debt (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Line of Credit Facility [Line Items]    
2022 $ 2.7  
2023 0.1  
2024 0.1  
Line of Credit    
Line of Credit Facility [Line Items]    
Unsecured line of credit - maximum 150.0 $ 150.0
Letter of Credit    
Line of Credit Facility [Line Items]    
Unsecured line of credit - maximum $ 30.0 $ 30.0
Wells Fargo | London Interbank Offered Rate (LIBOR)    
Line of Credit Facility [Line Items]    
Additional rate over base, percentage 0.75%  
Unused facility fee as a percentage of line of credit 0.125%