Assets Held for Sale and Discontinued Operations (Major Categories of Assets and Liabilities Reflected as Held for Sale) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current liabilities
Total current liabilities associated with assets held for sale	$ 0	$ 14,372
Discontinued operations, held-for-sale or disposed of by sale | Brunei Exploration And Production Operations
Current assets
Cash	0	10,185
Inventories	0	406
Property, plant, and equipment, net	40,820	307,704
Deferred income taxes and other assets	0	9,441
Total current assets associated with assets held for sale	40,820	327,736
Current liabilities
Accounts payable	0	5,306
Other accrued liabilities	0	45
Current maturities of long-term debt (finance lease)	0	737
Taxes payable	0	1,510
Long-term debt (finance lease)	0	6,513
Asset retirement obligation	0	261
Total current liabilities associated with assets held for sale	$ 0	$ 14,372