Segment Reporting - Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total revenues	$ 319,418	$ 309,852
Net gains (losses) on investments and other financial instruments	490	5,585
All Other
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total revenues	34,406	25,076
Operating Segments | Mortgage Insurance revenues
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total revenues	285,023	279,366
Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net gains (losses) on investments and other financial instruments	107	5,505
Intersegment Eliminations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total revenues	$ (118)	$ (95)