Inventories (Tables)

6 Months Ended

Jun. 30, 2018

Inventory Disclosure [Abstract]

Schedule of Major Components of Inventories

The major components of inventories were as follows:

	June 30, 2018		December 31, 2017
Petroleum products	$	5,490	$	8,731
Crude oil	29,930		29,873
Caustic soda	6,964		5,755
NaHS	13,040		8,277
Raw materials - Alkali operations	4,396		4,550
Work-in-process - Alkali operations	11,114		7,355
Finished goods, net - Alkali operations	11,182		14,075
Materials and supplies, net - Alkali operations	10,403		10,030
Other	1		7
Total	$	92,520	$	88,653