Supplemental Cash Flow Information (Net Changes in Components of Operating Assets and Liabilities) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
(Increase) decrease in:
Accounts receivable	$ 17,511,000	$ 159,426,000	$ (261,849,000)
Inventories	38,824,000	(37,566,000)	2,087,000
Deferred charges	(14,742,000)	48,835,000	41,634,000
Other current assets	21,109,000	(2,110,000)	(6,971,000)
Increase (decrease) in:
Accounts payable	434,000	(135,289,000)	152,138,000
Accrued liabilities	(32,072,000)	(29,122,000)	(14,857,000)
Net changes in components of operating assets and liabilities	$ 31,064,000	$ 4,174,000	$ (87,818,000)