Fixed Assets, Mineral Leaseholds, and Asset Retirement Obligations (Fixed Assets, Net) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	$ 5,567,710	$ 5,540,596
Less: Accumulated depreciation	(1,311,219)	(1,246,121)
Net fixed assets	4,256,491	4,294,475
Crude oil pipelines and natural gas pipelines and related assets
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	2,892,342	2,891,489
Onshore facilities, machinery, and equipment
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	641,135	640,376
Onshore facilities, machinery, and equipment | Alkali Business
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	594,263	591,547
Transportation equipment
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	19,662	19,864
Marine vessels
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	994,730	979,171
Land, buildings and improvements
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	238,992	238,451
Office equipment, furniture and fixtures
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	22,659	22,645
Construction in progress
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	122,036	115,162
Other
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	$ 41,891	$ 41,891