Income Taxes - Analysis of Deferred Tax Assets and Deferred Tax Liabilities Showing Tax Effects of Significant Temporary Differences (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets
Property and leasehold costs	$ 242,467	$ 241,833
Liabilities for dismantlements	31,017	37,728
Postretirement and other employee benefits	86,798	114,790
U. S. net operating loss	442,699	577,531
Investment in partnership	11,595	39,396
Other deferred tax assets	111,212	135,838
Total gross deferred tax assets	925,788	1,147,116
Less valuation allowance	(136,008)	(111,259)
Net deferred tax assets	789,780	1,035,857
Deferred tax liabilities
Deferred tax on undistributed foreign earnings	(5,000)	(5,000)
Accumulated depreciation, depletion and amortization	(796,510)	(786,846)
Other deferred tax liabilities	(85,284)	(41,387)
Total gross deferred tax liabilities	(886,794)	(833,233)
Net deferred tax (liabilities) assets	$ (97,014)
Net deferred tax (liabilities) assets		$ 202,624