Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accrued liabilities not currently deductible:
Employee compensation and benefits	$ 116,162	$ 106,147
Project and non-project reserves	60,768	59,043
Revenue recognition	0	9,808
Net operating loss carryforward	357,803	190,591
Tax basis of investment in excess of book basis	88,255	0
U.S. foreign tax credit carryforward	226,845	189,193
Other comprehensive loss	67,258	82,726
Other	85,059	69,898
Total deferred tax assets	1,002,150	707,406
Valuation allowance for deferred tax assets	(910,336)	(178,678)
Deferred tax assets, net	91,814	528,728
Deferred tax liabilities:
Revenue recognition	(1,787)	0
Book basis of property, equipment and other capital costs in excess of tax basis	(29,846)	(77,574)
Book basis of investments in excess of tax basis	0	(10,835)
Dividend withholding on unremitted non-U.S. earnings	(49,663)	(39,687)
Other	(31,125)	(22,530)
Total deferred tax liabilities	(112,421)	(150,626)
Deferred tax liabilities, net of deferred tax assets	$ (20,607)
Deferred tax assets, net of deferred tax liabilities		$ 378,102