Short-Term Borrowing - Additional Information (Detail)	3 Months Ended	12 Months Ended
	Dec. 31, 2025 USD ($)	Dec. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)
Short-term Debt [Line Items]
Short-term borrowings	$ 158,000,000.0	$ 158,000,000.0	$ 196,500,000
Number Of Unsecured Bank Credit Facilities		3
Short-term Debt, Weighted Average Interest Rate, at Point in Time	4.73%	4.73%	5.06%
Long-term debt including current maturities	$ 1,500,000,000	$ 1,500,000,000	$ 1,300,000,000
Line of Credit Facility, Remaining Borrowing Capacity	287,200,000	287,200,000
Notional Amount of Nonderivative Instruments	$ 50,000,000.0	$ 50,000,000.0
Debt Instrument, Interest Rate, Stated Percentage	6.54%	6.54%
Amount of letter of credit to our current primary insurance company		$ 4,800,000
Revolving Credit Facility [Member]
Short-term Debt [Line Items]
Line of Credit Facility, Aggregate Borrowing Capacity	$ 450,000,000.0	$ 450,000,000.0
Interest Rate Swap Rate, High Range [Member]
Short-term Debt [Line Items]
Fixed Swap Rate	3.97%	3.98%
Revolving Line of Credit, Short-term
Short-term Debt [Line Items]
Aggregate Investment, Maximum	$ 250,000,000.0	$ 250,000,000.0
Interest Rate Credit Adjustment	10	10
Line of Credit Facility, Interest Rate Description		1.05 percent
Line of Credit Facility, Increase Request	$ 50,000,000.0	$ 50,000,000.0
Revolving Line of Credit, Long-term
Short-term Debt [Line Items]
Interest Rate Credit Adjustment	10	10
Revolving Line of Credit, 5 year
Short-term Debt [Line Items]
Aggregate Investment, Maximum	$ 200,000,000.0	$ 200,000,000.0
Line of Credit Facility, Interest Rate Description		1.25 percent
Line of Credit Facility, Increase Request	$ 100,000,000.0	$ 100,000,000.0