Fixed Assets and Asset Retirement Obligations (Schedule of Fixed Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	$ 5,173,475	$ 5,540,596
Less: Accumulated depreciation	(1,322,141)	(1,246,121)
Net fixed assets	3,851,334	4,294,475
Crude oil pipelines and natural gas pipelines and related assets
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	2,811,030	2,891,489
Onshore facilities, machinery, and equipment
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	267,810	640,376
Onshore facilities, machinery, and equipment | Alkali Business
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	622,598	591,547
Transportation equipment
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	19,470	19,864
Marine vessels
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	998,553	979,171
Land, buildings and improvements
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	219,382	238,451
Office equipment, furniture and fixtures
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	22,001	22,645
Construction in progress
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	170,740	115,162
Other
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	$ 41,891	$ 41,891