Income Taxes (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Change in unrecognized tax benefits
Balance as of January 1	$ 83,950,000	$ 68,848,000	$ 81,174,000
Additions based on tax positions related to the current year	145,000	922,000	1,850,000
Additions for tax positions of prior years	3,360,000	16,372,000	11,748,000
Reductions for tax positions of prior years	(30,320,000)	(1,174,000)	(11,082,000)
Settlements	(9,583,000)	(1,018,000)	(14,842,000)
Balance as of December 31	47,552,000	83,950,000	68,848,000
Reductions for tax positions for prior years related to settlements in Mexico, Canada and Algeria	21,600,000
Reductions for tax positions for prior years due to expiration of statutes	8,700,000
Interest and penalties on unrecognized tax benefits	20,600,000	42,800,000	28,200,000
Liability related to unrecognized tax benefit for accrued interest and penalties	5,200,000	2,700,000	4,600,000
Mexico Audit Assessment
Change in unrecognized tax benefits
Addition to unrecognized tax benefits	$ 10,400,000