Long-Term Debt And Other Long-Term Liabilities (Other Long-Term Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Debt Disclosure [Abstract]
Asset retirement obligation (ARO) liability	$ 23,919	$ 23,440	$ 24,939	$ 25,688
Workers' compensation	8,112	8,344	$ 7,673	$ 7,925
Contract liability	1,016	200
Separation benefit plans	1,074	1,110
Gas balancing liability	4,256	4,257
Dividend equivalents payable	1,635	0
Other liabilities	40,012	37,351
Current portion of other long-term liabilities	5,280	3,989
Total other long-term liabilities	$ 34,732	$ 33,362