Long-Term Debt - Outstanding Long-Term Debt (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Long-term Debt	$ 1,500,000	$ 1,300,000
Less: debt issuance costs	(3,600)	(3,600)
Long-term Debt and Lease Obligation	1,461,700	1,287,200
Less: current maturities	(134,600)	(25,500)
Total long-term debt, net of current maturities	$ 1,327,100	1,261,700
Debt Instrument, Interest Rate, Stated Percentage	6.54%
Proceeds from issuance of long-term debt	$ 199,100	99,500	$ 627,000
Proceeds from Issuance of Senior Long-Term Debt	550,000
Common Stock [Member]
Debt Instrument [Line Items]
Proceeds from Issuance of Senior Long-Term Debt	4,400
5.68% note, due June 30, 2026
Debt Instrument [Line Items]
Long-term Debt	$ 2,900	5,800
Debt Instrument, Interest Rate, Stated Percentage	5.68%
6.43% note, due May 2, 2028
Debt Instrument [Line Items]
Long-term Debt	$ 2,100	2,800
Debt Instrument, Interest Rate, Stated Percentage	6.43%
3.73% note, due December 16, 2028
Debt Instrument [Line Items]
Long-term Debt	$ 6,000	8,000
Debt Instrument, Interest Rate, Stated Percentage	3.73%
3.88% note, due May 15, 2029
Debt Instrument [Line Items]
Long-term Debt	$ 20,000	25,000
Debt Instrument, Interest Rate, Stated Percentage	3.88%
Uncollateralized Senior Note Due April Two Thousand Thirty Two [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 45,500	52,500
Debt Instrument, Interest Rate, Stated Percentage	3.25%
Uncollateralized Senior Note Due May Two Thousand Thirty Eight [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 50,000	70,000
Debt Instrument, Interest Rate, Stated Percentage	3.48%
Uncollateralized Senior Note Due November Two Thousand Thirty Eight [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 50,000	50,000
Debt Instrument, Interest Rate, Stated Percentage	3.58%
Uncollateralized Senior Note Due August Two Thousand Thirty Nine [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.98%
Uncollateralized Senior Note Due December Two Thousand Thirty Four [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 63,000	50,000
Debt Instrument, Interest Rate, Stated Percentage	2.98%
Uncollateralized Senior Note Due March 15, 2042
Debt Instrument [Line Items]
Long-term Debt	$ 50,000	50,000
Debt Instrument, Interest Rate, Stated Percentage	2.95%
Uncollateralized Senior Note Due March 14, 2038 [Abstract]
Debt Instrument [Line Items]
Long-term Debt	$ 80,000	80,000
Debt Instrument, Interest Rate, Stated Percentage	5.43%
Uncollateralized Senior Note Due December 2026
Debt Instrument [Line Items]
Long-term Debt	$ 100,000	100,000
Debt Instrument, Interest Rate, Stated Percentage	6.39%
Uncollateralized Senior Note Due December 2027
Debt Instrument [Line Items]
Long-term Debt	$ 100,000	100,000
Debt Instrument, Interest Rate, Stated Percentage	6.44%
Uncollateralized Senior Note Due December 2028
Debt Instrument [Line Items]
Long-term Debt	$ 100,000	100,000
Debt Instrument, Interest Rate, Stated Percentage	6.45%
Uncollateralized Senior Note Due December 2030
Debt Instrument [Line Items]
Long-term Debt	$ 100,000	100,000
Debt Instrument, Interest Rate, Stated Percentage	6.62%
Uncollateralized Senior Note Due December 2033
Debt Instrument [Line Items]
Long-term Debt	$ 100,000	100,000
Debt Instrument, Interest Rate, Stated Percentage	6.71%
Uncollateralized Senior Note Due December 2038
Debt Instrument [Line Items]
Long-term Debt	$ 50,000	50,000
Debt Instrument, Interest Rate, Stated Percentage	6.73%
Uncollateralized Senior Note Due July Two Thousand Thirty Five
Debt Instrument [Line Items]
Long-term Debt	$ 50,000	50,000
Debt Instrument, Interest Rate, Stated Percentage	3.00%
Uncollateralized Senior Note Due August Two Thousand Thirty Five
Debt Instrument [Line Items]
Long-term Debt	$ 40,000	100,000
Debt Instrument, Interest Rate, Stated Percentage	2.96%
Uncollateralized Senior Note Due January Two Thousand Thirty Seven
Debt Instrument [Line Items]
Long-term Debt	$ 50,000	50,000
Debt Instrument, Interest Rate, Stated Percentage	2.49%
Uncollateralized Senior Note Due November Two Thousand Thirty Nine
Debt Instrument [Line Items]
Long-term Debt	$ 100,000	40,000
Equipment Security Note
Debt Instrument [Line Items]
Long-term Debt	$ 5,800	6,700
Debt Instrument, Interest Rate, Stated Percentage	2.46%
Uncollateralized Senior Notes Due On October 2029
Debt Instrument [Line Items]
Long-term Debt	$ 100,000	$ 100,000
Debt Instrument, Interest Rate, Stated Percentage	5.20%
Uncollateralized Senior Note Due August 2028
Debt Instrument [Line Items]
Long-term Debt	$ 60,000
Debt Instrument, Interest Rate, Stated Percentage	4.88%
Uncollateralized Senior Note Due August 2028 | Prudential [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 60,000
Uncollateralized Senior Note Due September 2030
Debt Instrument [Line Items]
Long-term Debt	$ 50,000
Debt Instrument, Interest Rate, Stated Percentage	5.02%
Uncollateralized Senior Note Due September 2030 | Prudential [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 50,000
Uncollateralized Senior Note Due August 2031
Debt Instrument [Line Items]
Long-term Debt	$ 90,000
Debt Instrument, Interest Rate, Stated Percentage	5.16%
Uncollateralized Senior Note Due August 2031 | Prudential [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 90,000