Share-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for issuance	788,495
Number of Shares, Granted	1,000
Number of shares withheld	8,000	14,000	20,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount	$ 7.2
SICP Awards to Non-employee directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to the awards to Non employee directors	$ 0.3
Weighted average grant-date fair value of awards granted	$ 134.05	$ 110.53
SICP Awards to Key Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	$ 129.76	$ 103.95
Number of Shares, Granted	100,000	110,000
Weighted average grant-date fair value of awards granted	$ 125.56	$ 105.21
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested	$ 36.2	$ 30.8	$ 22.5
Stock and Incentive Compensation Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for issuance	488,457