Losses and LAE - Schedule of Cumulative Paid Claims / Reconciliation of Outstanding Liabilities (Details) - USD ($) $ in Thousands	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	Dec. 31, 2015
Mortgage insurance
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Cumulative paid claims, net of reinsurance	$ 573,940
Mortgage insurance
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Liabilities for claims, net of reinsurance	308,290
Mortgage insurance | Mortgage insurance
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Liabilities for claims, net of reinsurance	308,290
2015 | Mortgage insurance
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Cumulative paid claims, net of reinsurance	177,883	$ 177,237	$ 176,823	$ 175,874	$ 174,812	$ 172,645	$ 163,916	$ 142,421	$ 84,271	$ 10,479
2016 | Mortgage insurance
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Cumulative paid claims, net of reinsurance	139,937	139,651	139,539	138,525	137,306	134,115	119,357	76,616	$ 11,061
2017 | Mortgage insurance
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Cumulative paid claims, net of reinsurance	113,497	113,027	112,445	111,458	108,484	99,678	66,585	$ 24,653
2018 | Mortgage insurance
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Cumulative paid claims, net of reinsurance	64,015	63,603	62,968	60,926	54,625	36,066	$ 5,584
2019 | Mortgage insurance
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Cumulative paid claims, net of reinsurance	39,082	37,960	35,594	28,896	18,703	$ 4,220
2020 | Mortgage insurance
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Cumulative paid claims, net of reinsurance	19,465	17,884	14,635	9,867	$ 4,148
2021 | Mortgage insurance
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Cumulative paid claims, net of reinsurance	6,043	4,409	2,561	$ 1,112
2022 | Mortgage insurance
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Cumulative paid claims, net of reinsurance	6,699	2,867	$ 498
2023 | Mortgage insurance
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Cumulative paid claims, net of reinsurance	6,201	$ 246
2024 | Mortgage insurance
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Cumulative paid claims, net of reinsurance	1,118
All outstanding liabilities before 2015, net of reinsurance | Mortgage insurance
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Cumulative paid claims, net of reinsurance	$ 7,411