Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounts receivable and other receivables
Reserves deducted from asset accounts:
Balance at Beginning of Year	$ 10,636	$ 10,636
Charged to Other Accounts			$ 10,636
Balance at End of Year	10,636	10,636	10,636
Current assets - supplies and inventory
Reserves deducted from asset accounts:
Balance at Beginning of Year	574	2,216	648
Additions (Reductions) Charged to Costs and Expenses	1,860	477	1,737
Charged to Other Accounts		(137)	(35)
Deductions	185	1,982	134
Balance at End of Year	2,249	574	2,216
Deferred income taxes
Reserves deducted from asset accounts:
Balance at Beginning of Year	573,995	506,316	530,612
Additions (Reductions) Charged to Costs and Expenses	(69,603)	76,524	(24,296)
Charged to Other Accounts		(8,845)
Balance at End of Year	$ 504,392	$ 573,995	$ 506,316