v3.26.1
Fair Value Accounting - Gains and Losses from Fair Value Changes Included in Consolidated Statement of Operations (Detail) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Changes included in OCI, net of tax $ (0.9) $ (4.1) $ 0.1 $ (3.0)
Junior Subordinated Debt        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Unrealized (losses) gains $ (1.2) $ (5.4) $ 0.1 $ (3.9)