Fixed Assets, Mineral Leaseholds, and Asset Retirement Obligations (Fixed Assets, Net) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	$ 5,505,360	$ 5,440,858
Less: Accumulated depreciation	(1,160,353)	(1,023,825)
Net fixed assets	4,345,007	4,417,033
Crude oil pipelines and natural gas pipelines and related assets
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	2,919,237	2,918,285
Onshore facilities, machinery, and equipment
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	640,129	639,023
Onshore facilities, machinery, and equipment | Alkali Business
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	542,919	533,924
Transportation equipment
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	19,573	20,102
Marine vessels
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	960,947	951,597
Land, buildings and improvements
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	223,341	222,242
Office equipment, furniture and fixtures
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	20,560	20,505
Construction in progress
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	136,763	94,025
Other
Property, Plant and Equipment [Line Items]
Fixed assets, at cost	$ 41,891	$ 41,155