Fixed Assets, Mineral Leaseholds, and Asset Retirement Obligations (Fixed Assets, Net) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	$ 5,312,157	$ 5,173,475
Less: Accumulated depreciation	(1,437,510)	(1,322,141)
Net fixed assets	3,874,647	3,851,334
Crude oil pipelines and natural gas pipelines and related assets
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	2,821,996	2,811,030
Onshore facilities, machinery, and equipment
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	268,689	267,810
Onshore facilities, machinery, and equipment | Alkali Business
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	641,619	622,598
Transportation equipment
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	21,348	19,470
Marine vessels
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	1,011,171	998,553
Land, buildings and improvements
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	221,146	219,382
Office equipment, furniture and fixtures
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	22,185	22,001
Construction in progress
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	260,742	170,740
Other
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	$ 43,261	$ 41,891