v3.25.2
Financial Instruments - Financial Instruments not Carried at Fair Value but which Require Fair Value Disclosure (Detail) - USD ($)
$ in Millions
Jun. 30, 2025
Mar. 31, 2025
Dec. 31, 2024
Carrying amount      
Financial Instrument At Fair Value [Line Items]      
Cash, cash equivalents and restricted cash $ 27.7   $ 114.7
Revolving credit facility 37.0   10.0
Fair value      
Financial Instrument At Fair Value [Line Items]      
Cash, cash equivalents and restricted cash 27.7   114.7
Revolving credit facility $ 37.0   $ 10.0
9.50% Senior Secured Notes due 2029      
Financial Instrument At Fair Value [Line Items]      
Debt instrument interest rate 9.50% 9.50% 9.50%
9.50% Senior Secured Notes due 2029 | Carrying amount      
Financial Instrument At Fair Value [Line Items]      
Long-term debt - Fixed rate $ 410.7   $ 365.4
9.50% Senior Secured Notes due 2029 | Fair value      
Financial Instrument At Fair Value [Line Items]      
Long-term debt - Fixed rate $ 444.3   $ 403.4
3.75% Senior Secured Notes due 2025      
Financial Instrument At Fair Value [Line Items]      
Debt instrument interest rate 3.75% 3.75% 3.75%
3.75% Senior Secured Notes due 2025 | Carrying amount      
Financial Instrument At Fair Value [Line Items]      
Long-term debt - Fixed rate $ 87.9   $ 78.3
3.75% Senior Secured Notes due 2025 | Fair value      
Financial Instrument At Fair Value [Line Items]      
Long-term debt - Fixed rate $ 87.8   $ 77.9