Reinsurance - Quota Share Agreement Terms (Details)	9 Months Ended
Sep. 30, 2021
2015 QSR
Effects of Reinsurance [Line Items]
Quota share for all policies covered (as a percent)	15.00%
Loss ratio threshold for profit commissions (as a percent)	68.00%
2017 QSR
Effects of Reinsurance [Line Items]
Quota share for all policies covered (as a percent)	30.00%
Loss ratio threshold for profit commissions (as a percent)	60.00%
2018 QSR
Effects of Reinsurance [Line Items]
Quota share for all policies covered (as a percent)	30.00%
Loss ratio threshold for profit commissions (as a percent)	62.00%
2019 QSR
Effects of Reinsurance [Line Items]
Quota share for all policies covered (as a percent)	30.00%
Loss ratio threshold for profit commissions (as a percent)	62.00%
Cede rate, option 1 (as a percent)	25.00%
Cede rate, option 2 (as a percent)	20.00%
2020 QSR
Effects of Reinsurance [Line Items]
Quota share for all policies covered (as a percent)	12.50%
Loss ratio threshold for profit commissions (as a percent)	62.00%
Cede rate, option 1 (as a percent)	10.50%
Cede rate, option 2 (as a percent)	8.00%
2020 QSR and 2021 QSR
Effects of Reinsurance [Line Items]
Quota share for all policies covered (as a percent)	17.50%
Loss ratio threshold for profit commissions (as a percent)	62.00%
Cede rate, option 1 (as a percent)	14.50%
Cede rate, option 2 (as a percent)	12.00%
2021 QSR
Effects of Reinsurance [Line Items]
Quota share for all policies covered (as a percent)	12.50%
Loss ratio threshold for profit commissions (as a percent)	57.50%
Cede rate, option 1 (as a percent)	10.50%
Cede rate, option 2 (as a percent)	8.00%
2022 QSR
Effects of Reinsurance [Line Items]
Quota share for all policies covered (as a percent)	15.00%
Loss ratio threshold for profit commissions (as a percent)	57.50%
Cede rate, option 1 (as a percent)	12.50%
Cede rate, option 2 (as a percent)	10.00%
Credit Union QSR
Effects of Reinsurance [Line Items]
Quota share for all policies covered (as a percent)	65.00%
Loss ratio threshold for profit commissions (as a percent)	50.00%

Reinsurance, Quota Share Reinsurance Agreement, Terms, Ceding Rate, Percent, Option One

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Reinsurance, Quota Share Reinsurance Agreement, Terms, Ceding Rate, Percent, Option Two

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Reinsurance, Quota Share Reinsurance Agreement, Terms, Quota Share, Percent

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Ratio of non-life losses and loss expenses to non-life net premiums earned.

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