Concentrations of Credit Risk (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Concentration Risk [Line Items]
Management fee amounts	$ 735,589	$ 707,060
Receivables from Erie insurance exchange, allowance for credit loss	700	700
Affiliated Entity
Concentration Risk [Line Items]
Management fee amounts	$ 735,600	$ 707,100
Affiliated Entity | Exchange And Affiliates | Accounts Receivable | Credit Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	21.90%	24.50%