Long-Term Debt And Other Long-Term Liabilities (Other Long-Term Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Dec. 31, 2020
Debt Disclosure [Abstract]
Asset retirement obligation (ARO) liability	$ 22,518	$ 25,688	$ 26,372	$ 23,356
Workers' compensation	7,435	7,925	$ 11,313	$ 10,164
Contract liability	421	1,788
Separation benefit plans	1,437	2,022
Gas balancing liability	4,256	1,090
Other liabilities	36,067	38,513
Current portion of other long-term liabilities	4,144	5,574
Total other long-term liabilities	$ 31,923	$ 32,939