Income Taxes (Details 6) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Change in unrecognized tax benefits
Balance as of January 1	$ 203,707	$ 47,552	$ 83,950
Additions based on tax positions related to the current year	384	167,107	145
Additions for tax positions of prior years		1,744	3,360
Reductions for tax positions of prior years	(7,163)	(4,473)	(30,320)
Settlements	(5,027)	(8,223)	(9,583)
Balance as of December 31	191,901	203,707	47,552
Additions based on tax positions related to the current year due to internal restructuring	166,000
Interest and penalties on unrecognized tax benefits	3,900	16,900	20,600
Liability related to unrecognized tax benefit for accrued interest and penalties	1,400	$ 6,100	$ 5,200
Canada, Trinidad and U.S
Change in unrecognized tax benefits
Settlements	6,000
Reductions for tax positions for prior years due to expiration of statutes	1,100
Colombia, Ecuador, Canada and Montana
Change in unrecognized tax benefits
Settlements	5,000
Algeria Canada And Oman Settlements
Change in unrecognized tax benefits
Settlements	7,600
Mexico, Canada and Algeria
Change in unrecognized tax benefits
Reductions for tax positions for prior years related to settlements in Mexico, Canada and Algeria	21,600
Reductions for tax positions for prior years due to expiration of statutes	$ 8,700