CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Less:
Lower of cost or net realizable value inventory adjustments		$ 1,810	$ 1,711	$ 6,379
Gross Margin (Deficit)		43,478	38,271	11,888
Selling and administrative		23,556	20,438	18,915
Accretion of asset retirement obligation		1,793	1,668	1,558
Restructuring expense				266
Care and maintenance expense		549	530	1,687
Other operating expense (income)		1,220	141	3,523
Operating Income (Loss)		16,360	15,494	(14,061)
Other Income (Expense)
Interest expense, net		(3,031)	(3,855)	(11,692)
Other income		355	252	403
Income (Loss) Before Income Taxes		13,684	11,891	(25,350)
Income Tax (Expense) Benefit		(53)	(108)	2,783
Net Income (Loss)		$ 13,631	$ 11,783	$ (22,567)
Weighted Average Shares Outstanding:
Basic (in shares)		129,049,168	128,070,702	115,708,859
Diluted (in shares)		131,050,920	130,985,919	115,708,859
Income (Loss) Per Share:
Basic (dollar per share)		$ 0.11	$ 0.09	$ (0.20)
Diluted (dollar per share)		$ 0.10	$ 0.09	$ (0.20)
Mineral [Member]
Sales	[1]	$ 220,075	$ 208,270	$ 177,915
Cost of goods and services sold		126,110	121,955	117,962
Freight costs [Member]
Cost of goods and services sold		40,056	37,052	32,016
Warehouse and handling costs [Member]
Cost of goods and services sold		$ 8,621	$ 9,281	$ 9,670

[1] Segment sales include the sales of byproducts generated during the production of potash and Trio®.