Commitments (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Commitments and Contingencies Disclosure [Line Items]
Operating lease rental payments due in 2017	$ 71,335,000
Operating lease rental payments due in 2018	67,586,000
Operating lease rental payments due in 2019	54,672,000
Operating lease rental payments due in 2020	54,423,000
Operating lease rental payments due in 2021	54,622,000
Rental expenses for non-cancellable lease, including contingent payments	77,520,000	$ 111,425,000	$ 144,981,000
Commitments for capital expenditures	585,651,000
Malaysia [Member]
Commitments and Contingencies Disclosure [Line Items]
Commitments for capital expenditures	224,485,000
Kaybob Duvernay Lands, Alberta [Member]
Commitments and Contingencies Disclosure [Line Items]
Commitments for capital expenditures	156,984,000
Gulf Of Mexico [Member]
Commitments and Contingencies Disclosure [Line Items]
Commitments for capital expenditures	25,202,000
Eagle Ford Shale [Member]
Commitments and Contingencies Disclosure [Line Items]
Commitments for capital expenditures	107,002,000
Vietnam [Member]
Commitments and Contingencies Disclosure [Line Items]
Commitments for capital expenditures	27,178,000
Brunei [Member]
Commitments and Contingencies Disclosure [Line Items]
Commitments for capital expenditures	12,828,000
Drilling Rigs And Associated Equipment [Member]
Commitments and Contingencies Disclosure [Line Items]
Commitments for capital expenditures	45,042,000
Processing Production Handling and Transportation Services [Member]
Commitments and Contingencies Disclosure [Line Items]
Operating lease rental payments due in 2017	53,893,000
Operating lease rental payments due in 2018	48,962,000
Operating lease rental payments due in 2019	42,616,000
Operating lease rental payments due in 2020	46,597,000
Operating lease rental payments due in 2021	47,793,000
Processing and transportation charges	$ 50,300,000	$ 32,473,000	$ 34,597,000