Losses and LAE - Reserve for Losses and LAE by Segment (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Liability for Claims and Claims Adjustment Expense [Line Items]
Total reserve for losses and LAE	$ 405,651	$ 426,843
Mortgage insurance
Liability for Claims and Claims Adjustment Expense [Line Items]
Total reserve for losses and LAE	399,850	420,955	$ 721,510	$ 823,136
Title insurance
Liability for Claims and Claims Adjustment Expense [Line Items]
Total reserve for losses and LAE	5,801	5,888
Primary case | Mortgage insurance
Liability for Claims and Claims Adjustment Expense [Line Items]
Total reserve for losses and LAE	378,992	398,874
Primary IBNR and LAE | Mortgage insurance
Liability for Claims and Claims Adjustment Expense [Line Items]
Total reserve for losses and LAE	11,307	12,169
Pool and other | Mortgage insurance
Liability for Claims and Claims Adjustment Expense [Line Items]
Total reserve for losses and LAE	$ 9,551	$ 9,912