Fixed Assets and Asset Retirement Obligations (Schedule of Reconciliation of Liability for Asset Retirement Obligations) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset retirement obligations, beginning balance	$ 243,708,000	$ 228,573,000	$ 220,906,000
Accretion expense	11,107,000	12,040,000	13,092,000
Revisions in timing and estimated costs of AROs		3,185,000	11,216,000
Settlements	(406,000)	(90,000)	(16,641,000)
Asset retirement obligations, ending balance	$ 254,409,000	$ 243,708,000	$ 228,573,000