Property, Plant And Equipment (Net Changes in Capitalized Exploratory Well Costs) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant And Equipment [Abstract]
Beginning balance at January 1	$ 120,455,000	$ 393,030,000	$ 445,697,000
Additions to capitalized exploratory well costs pending the determination of proved reserves	64,578,000	2,874,000	57,716,000
Reclassifications to proved properties based on the determination of proved reserves		(91,236,000)	(93,936,000)
Reduction of capitalized exploratory well costs due to partial asset sale in Malaysia		(122,175,000)
Capitalized exploratory well costs charged to expense	(54,519,000)	(62,038,000)	(16,447,000)
Ending balance at December 31	$ 130,514,000	$ 120,455,000	$ 393,030,000