Income Taxes - Change in Unrecognized Tax Benefit (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Change in unrecognized tax benefits
Balance as of January 1	$ 33,203	$ 179,255	$ 188,376
Additions for tax positions of prior years	308	25,119	3,873
Reductions for tax positions of prior years	(7,800)	(171,171)	(11,547)
Settlements			(1,447)
Balance as of December 31	25,711	33,203	179,255
Unrecognized Tax Benefits, Decrease Resulting from Foreign Currency Translation			2,100
Interest and penalties on unrecognized tax benefits	6,700	9,700	9,200
Liability related to unrecognized tax benefit for accrued interest and penalties	1,000	500	600
Australia Algeria And Mexico
Change in unrecognized tax benefits
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations			7,200
Reductions for tax positions for prior years due to expiration of statutes			7,200
Trinidad
Change in unrecognized tax benefits
Settlements			$ (2,000)
U.S. Federal
Change in unrecognized tax benefits
Additions for tax positions of prior years		9,000
MEXICO
Change in unrecognized tax benefits
Reductions for tax positions of prior years	(4,800)
Saudi Arabia
Change in unrecognized tax benefits
Reductions for tax positions of prior years	(1,000)
EGYPT
Change in unrecognized tax benefits
Additions for tax positions of prior years		2,000
Reductions for tax positions of prior years	$ (2,000)
NORWAY
Change in unrecognized tax benefits
Additions for tax positions of prior years		$ 12,000