Unpaid Loss and Loss Adjustment Expense - Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Claims Development [Line Items]
Current accident year incurred loss and LAE	$ 73.2	$ 54.8
Rollforward table, current year, paid	49.2	44.6
Favorable (unfavorable) development on net loss and LAE reserves	(1.3)	(0.1)
Rollforward table, prior year, paid	7.5	9.8
2021 Current Accident Year
Claims Development [Line Items]
Current accident year incurred loss and LAE	73.2
Rollforward table, current year, paid	49.2
Development table, current year, incurred	69.4
Development table, current year, paid	45.4
Variance, current year, incurred	3.8
Variance, current year, paid	3.8
Unallocated loss adjustment expense, incurred	3.8
Unallocated loss adjustment expense, paid	3.8
2021 Prior Accident Year
Claims Development [Line Items]
Favorable (unfavorable) development on net loss and LAE reserves	(1.3)
Rollforward table, prior year, paid	7.5
Development table, prior year, incurred	(1.3)
Development table, prior year, paid	7.5
Variance, prior year, incurred	0.0
Variance, prior year, paid	0.0
Home
Claims Development [Line Items]
Development table, current year, incurred	172.5
Development table, current year, paid	149.2
Home | 2021 Current Accident Year
Claims Development [Line Items]
Current accident year incurred loss and LAE	62.2
Rollforward table, current year, paid	40.6
Development table, current year, incurred	59.4
Development table, current year, paid	37.9
Home | 2021 Prior Accident Year
Claims Development [Line Items]
Favorable (unfavorable) development on net loss and LAE reserves	(1.2)
Rollforward table, prior year, paid	7.2
Development table, current year, incurred	51.8	53.2
Development table, current year, paid	50.0	42.9
Development table, prior year, incurred	(1.2)
Development table, prior year, paid	7.2
Pet
Claims Development [Line Items]
Development table, current year, incurred	10.2
Development table, current year, paid	8.2
Pet | 2021 Current Accident Year
Claims Development [Line Items]
Current accident year incurred loss and LAE	10.9
Rollforward table, current year, paid	8.5
Development table, current year, incurred	10.0
Development table, current year, paid	7.5
Pet | 2021 Prior Accident Year
Claims Development [Line Items]
Favorable (unfavorable) development on net loss and LAE reserves	(0.1)
Rollforward table, prior year, paid	0.3
Development table, current year, incurred	0.2	0.3
Development table, current year, paid	0.7	$ 0.4
Development table, prior year, incurred	(0.1)
Development table, prior year, paid	0.3
Car | 2021 Current Accident Year
Claims Development [Line Items]
Current accident year incurred loss and LAE	0.1
Rollforward table, current year, paid	0.1
Car | 2021 Prior Accident Year
Claims Development [Line Items]
Favorable (unfavorable) development on net loss and LAE reserves	0.0
Rollforward table, prior year, paid	0.0
Others | 2021 Current Accident Year
Claims Development [Line Items]
Development table, current year, incurred	0.0
Development table, current year, paid	0.0
Others | 2021 Prior Accident Year
Claims Development [Line Items]
Development table, prior year, incurred	0.0
Development table, prior year, paid	$ 0.0