Fair Values of Financial Instruments - Estimated Fair Value of Outstanding Debt Balances (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Carrying Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total debt	$ 1,242,061	$ 1,246,086
Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total debt	1,242,680	1,223,284
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	459,274	450,540
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	337,487	329,032
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	430,206	424,946
Equipment Loans Due 2025 | Carrying Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total debt	14,661	18,686
Equipment Loans Due 2025 | Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total debt	$ 15,713	$ 18,766