v3.26.1
Regulatory Information - Schedule of Statutory Net Income (loss), Surplus, Contingency Reserve and Risk-to-Capital Ratio (Details) - NMIC and Re One combined
$ in Thousands
Jun. 30, 2026
USD ($)
Dec. 31, 2025
USD ($)
Statutory Accounting Practices [Line Items]    
Statutory surplus $ 985,575 $ 1,010,274
Contingency reserve 2,409,569 2,245,272
Statutory capital $ 3,395,144 $ 3,255,546
Risk-to-capital 12.9 13.0