Fair Values of Financial Instruments - Estimated Fair Value of Outstanding Debt Balances (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Carrying Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total debt	$ 1,227,400	$ 1,233,795
Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total debt	$ 1,254,341	1,223,899
3.95% Senior Notes Due 2028
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt interest rate	3.95%
3.95% Senior Notes Due 2028 | Carrying Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total debt	$ 482,505	482,505
3.95% Senior Notes Due 2028 | Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total debt	$ 477,694	461,720
5.15% Senior Notes Due 2029
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt interest rate	5.15%
5.15% Senior Notes Due 2029 | Carrying Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total debt	$ 344,895	344,895
5.15% Senior Notes Due 2029 | Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total debt	$ 348,032	336,490
7.15% Senior Notes Due 2033
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt interest rate	7.15%
7.15% Senior Notes Due 2033 | Carrying Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total debt	$ 400,000	400,000
7.15% Senior Notes Due 2033 | Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total debt	428,615	419,265
Equipment Loans Due 2025 (1) | Carrying Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total debt	0	6,395
Equipment Loans Due 2025 (1) | Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total debt	$ 0	$ 6,424