Unpaid Loss and Loss Adjustment Expense - Claims Development Information, Paid Losses (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Claims Development [Line Items]
Total unpaid loss and ALAE reserves, net	$ 169.3
Ceded unpaid loss and LAE	133.8	$ 149.5	$ 120.2	$ 124.6
Gross unpaid loss and ALAE	303.1	298.1	262.3	256.2
Home and renters
Claims Development [Line Items]
Total paid losses and ALAE, net	612.9
Total unpaid loss and ALAE reserves, net	105.4
Ceded unpaid loss and LAE	88.1
Gross unpaid loss and ALAE	193.5
Cumulative paid loss and ALAE, net of reinsurance	0.1	0.1	0.1	0.1	$ 0.1	$ 0.1	$ 0.1		$ 0.1	$ 0.1
Pet
Claims Development [Line Items]
Total paid losses and ALAE, net	275.0
Total unpaid loss and ALAE reserves, net	10.8
Ceded unpaid loss and LAE	6.6
Gross unpaid loss and ALAE	17.4
Car
Claims Development [Line Items]
Total paid losses and ALAE, net	437.9
Total unpaid loss and ALAE reserves, net	53.1
Ceded unpaid loss and ALAE	39.1
Total unpaid loss and ALAE reserves, net	53.1
Ceded unpaid loss and LAE	39.1
Gross unpaid loss and ALAE	92.2
Fair value adjustment on insurance contract intangible liability	0.2
2016 | Home and renters
Claims Development [Line Items]
Total paid losses and ALAE, net	0.0	0.0	0.0	0.0	0.0	0.0	0.0	$ 0.0	0.0	0.0
2016 | Car
Claims Development [Line Items]
Total paid losses and ALAE, net	3.3	3.3	2.2	1.9	1.7	1.6	1.6	1.5	1.2	$ 0.2
2017 | Home and renters
Claims Development [Line Items]
Total paid losses and ALAE, net	1.8	1.7	1.7	1.7	1.7	1.7	1.7	1.7	1.6
2017 | Car
Claims Development [Line Items]
Total paid losses and ALAE, net	38.3	38.3	24.6	31.7	30.8	30.1	28.1	24.3	$ 17.3
2018 | Home and renters
Claims Development [Line Items]
Total paid losses and ALAE, net	13.4	13.4	13.4	13.4	13.4	13.4	13.3	13.2
2018 | Car
Claims Development [Line Items]
Total paid losses and ALAE, net	41.8	41.7	25.1	30.2	27.6	28.2	24.4	$ 16.8
2019 | Home and renters
Claims Development [Line Items]
Total paid losses and ALAE, net	46.2	46.2	46.2	46.3	46.3	46.1	36.4
2019 | Car
Claims Development [Line Items]
Total paid losses and ALAE, net	31.0	30.7	22.3	18.8	14.5	18.7	$ 13.5
2020 | Home and renters
Claims Development [Line Items]
Total paid losses and ALAE, net	52.5	52.1	52.0	51.3	50.2	43.1
2020 | Pet
Claims Development [Line Items]
Total paid losses and ALAE, net	0.7	0.7	0.7	0.7	0.6	0.4
2020 | Car
Claims Development [Line Items]
Total paid losses and ALAE, net	14.4	14.0	15.0	5.6	(0.9)	$ 5.2
2021 | Home and renters
Claims Development [Line Items]
Total paid losses and ALAE, net	58.2	57.8	56.7	53.4	37.8
2021 | Pet
Claims Development [Line Items]
Total paid losses and ALAE, net	9.5	9.5	9.5	9.4	7.6
2021 | Car
Claims Development [Line Items]
Total paid losses and ALAE, net	81.5	80.2	77.1	58.9	$ 38.4
2022 | Home and renters
Claims Development [Line Items]
Total paid losses and ALAE, net	92.7	90.7	85.5	52.7
2022 | Pet
Claims Development [Line Items]
Total paid losses and ALAE, net	25.1	25.1	25.1	21.8
2022 | Car
Claims Development [Line Items]
Total paid losses and ALAE, net	85.7	81.4	74.0	$ 45.4
2023 | Home and renters
Claims Development [Line Items]
Total paid losses and ALAE, net	128.3	122.3	88.9
2023 | Pet
Claims Development [Line Items]
Total paid losses and ALAE, net	49.0	48.9	45.8
2023 | Car
Claims Development [Line Items]
Total paid losses and ALAE, net	60.3	58.4	$ 43.2
2024 | Home and renters
Claims Development [Line Items]
Total paid losses and ALAE, net	123.6	89.1
2024 | Pet
Claims Development [Line Items]
Total paid losses and ALAE, net	71.8	67.6
2024 | Car
Claims Development [Line Items]
Total paid losses and ALAE, net	49.9	$ 31.8
2025 | Home and renters
Claims Development [Line Items]
Total paid losses and ALAE, net	96.2
2025 | Pet
Claims Development [Line Items]
Total paid losses and ALAE, net	118.9
2025 | Car
Claims Development [Line Items]
Total paid losses and ALAE, net	$ 31.7