v3.26.1
Summary of Significant Accounting Policies - Fair Value of Marketable Securities (Detail) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Jun. 30, 2025
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Trading Securities $ 6.4 $ 6.7 $ 6.1
Deferred Compensation Plan [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Trading Securities 4.5 3.5 2.9
Fair Value, Inputs, Level 1      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Trading Securities 6.4 6.7 6.1
Fair Value, Inputs, Level 1 | Deferred Compensation Plan [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Trading Securities 4.5 3.5 2.9
Fair Value, Inputs, Level 1 | Equity Funds | Deferred Compensation Plan [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Trading Securities 3.9 3.1 2.7
Fair Value, Inputs, Level 1 | Fixed Income Funds [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Trading Securities 4.2 3.5 4.2
Fair Value, Inputs, Level 1 | Fixed Income Funds [Member] | Deferred Compensation Plan [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Trading Securities 0.5 0.3 0.1
Fair Value, Inputs, Level 1 | Money Market Funds      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Trading Securities 2.2 3.2 1.9
Fair Value, Inputs, Level 1 | Money Market Funds | Deferred Compensation Plan [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Trading Securities $ 0.1 $ 0.1 $ 0.1