Reinsurance - Excess of Loss Reinsurance (Details) - USD ($) $ in Thousands								3 Months Ended	12 Months Ended
	Apr. 26, 2022	Apr. 01, 2022	Aug. 03, 2021	Feb. 02, 2021	Oct. 29, 2020	May 25, 2019	Oct. 30, 2018	Mar. 31, 2023	Dec. 31, 2022
2022 Traditional XOL
Effects of Reinsurance [Line Items]
Amortization period excess of loss reinsurance coverage		10 years
Initial first layer retention		$ 82,523
Remaining first layer retention								$ 82,509	$ 82,517
Excess of loss reinsurance coverage, initial and remaining		$ 142,642						142,642	142,642
Home Re 2022-1
Effects of Reinsurance [Line Items]
Term of mortgage insurance-linked notes	12 years 6 months
Initial first layer retention	$ 325,589
Remaining first layer retention								325,520	325,576
Excess of loss reinsurance coverage, initial and remaining	$ 473,575							473,575	473,575
Home Re 2021-2
Effects of Reinsurance [Line Items]
Term of mortgage insurance-linked notes			12 years 6 months
Initial first layer retention			$ 190,159
Remaining first layer retention								190,016	190,097
Excess of loss reinsurance coverage, initial and remaining			$ 398,429					327,346	352,084
Home Re 2021-1
Effects of Reinsurance [Line Items]
Term of mortgage insurance-linked notes				12 years 6 months
Initial first layer retention				$ 211,159
Remaining first layer retention								211,055	211,102
Excess of loss reinsurance coverage, initial and remaining				$ 398,848				251,942	277,053
Home Re 2020-1
Effects of Reinsurance [Line Items]
Term of mortgage insurance-linked notes					10 years
Initial first layer retention					$ 275,283
Remaining first layer retention								274,979	274,871
Excess of loss reinsurance coverage, initial and remaining					$ 412,917			92,648	113,247
Home Re 2019-1
Effects of Reinsurance [Line Items]
Term of mortgage insurance-linked notes						10 years
Initial first layer retention						$ 185,730
Remaining first layer retention								183,351	183,540
Excess of loss reinsurance coverage, initial and remaining						$ 315,739		208,146	208,146
Home Re 2018-1
Effects of Reinsurance [Line Items]
Term of mortgage insurance-linked notes							10 years
Initial first layer retention							$ 168,691
Remaining first layer retention								164,708	164,849
Excess of loss reinsurance coverage, initial and remaining							$ 318,636	$ 121,513	$ 140,993