Fixed Assets, Mineral Leaseholds, and Asset Retirement Obligations (Fixed Assets, Net) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	$ 5,206,508	$ 5,173,475
Less: Accumulated depreciation	(1,381,384)	(1,322,141)
Net fixed assets	3,825,124	3,851,334
Crude oil pipelines and natural gas pipelines and related assets
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	2,810,931	2,811,030
Onshore facilities, machinery, and equipment
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	268,571	267,810
Onshore facilities, machinery, and equipment | Alkali Business
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	635,446	622,598
Transportation equipment
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	19,520	19,470
Marine vessels
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	1,002,601	998,553
Land, buildings and improvements
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	220,454	219,382
Office equipment, furniture and fixtures
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	22,096	22,001
Construction in progress
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	183,628	170,740
Other
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	$ 43,261	$ 41,891