v3.25.2
FAIR VALUE OF FINANCIAL INSTRUMENTS - Schedule of Fair Value of Assets and Liabilities (Details) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Assets    
Fixed maturities: $ 322.7 $ 306.8
Cash equivalents 349.5 342.4
Total assets at fair value 672.2 649.2
U.S. Treasury securities and agencies    
Assets    
Fixed maturities: 48.0 46.2
Municipal securities    
Assets    
Fixed maturities: 22.3 23.5
Corporate debt securities    
Assets    
Fixed maturities: 122.6 105.7
Asset-backed securities    
Assets    
Fixed maturities: 126.3 116.6
Total fixed maturities    
Assets    
Fixed maturities: 319.2 292.0
Short-term investments    
Assets    
Fixed maturities: 3.5 14.8
Level 1    
Assets    
Cash equivalents 349.5 342.4
Total assets at fair value 401.0 400.4
Level 1 | U.S. Treasury securities and agencies    
Assets    
Fixed maturities: 48.0 46.2
Level 1 | Municipal securities    
Assets    
Fixed maturities: 0.0 0.0
Level 1 | Corporate debt securities    
Assets    
Fixed maturities: 0.0 0.0
Level 1 | Asset-backed securities    
Assets    
Fixed maturities: 0.0 0.0
Level 1 | Total fixed maturities    
Assets    
Fixed maturities: 48.0 46.2
Level 1 | Short-term investments    
Assets    
Fixed maturities: 3.5 11.8
Level 2    
Assets    
Cash equivalents 0.0 0.0
Total assets at fair value 271.2 248.8
Level 2 | U.S. Treasury securities and agencies    
Assets    
Fixed maturities: 0.0 0.0
Level 2 | Municipal securities    
Assets    
Fixed maturities: 22.3 23.5
Level 2 | Corporate debt securities    
Assets    
Fixed maturities: 122.6 105.7
Level 2 | Asset-backed securities    
Assets    
Fixed maturities: 126.3 116.6
Level 2 | Total fixed maturities    
Assets    
Fixed maturities: 271.2 245.8
Level 2 | Short-term investments    
Assets    
Fixed maturities: 0.0 3.0
Level 3    
Assets    
Cash equivalents 0.0 0.0
Total assets at fair value 0.0 0.0
Level 3 | U.S. Treasury securities and agencies    
Assets    
Fixed maturities: 0.0 0.0
Level 3 | Municipal securities    
Assets    
Fixed maturities: 0.0 0.0
Level 3 | Corporate debt securities    
Assets    
Fixed maturities: 0.0 0.0
Level 3 | Asset-backed securities    
Assets    
Fixed maturities: 0.0 0.0
Level 3 | Total fixed maturities    
Assets    
Fixed maturities: 0.0 0.0
Level 3 | Short-term investments    
Assets    
Fixed maturities: $ 0.0 $ 0.0