Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 7,918	$ 8,799
Restricted cash (Note 12)	4,734	4,512
Certificates of deposit		245
Accounts receivable	12,703	25,580
Prepaid income taxes	981	1,562
Inventory (Note 3)	37,410	28,297
Parts and supplies, net of allowance of $274	10,886	11,775
Prepaid expenses	1,519	1,678
Total current assets	76,151	82,448
Property, plant and equipment, at cost:
Land and mineral rights	114,994	114,722
Building and equipment	358,488	351,614
Mine development	86,165	84,160
Total property, plant and equipment, at cost	559,647	550,496
Less - accumulated DD&A	(231,370)	(220,780)
Total property, plant and equipment, net	328,277	329,716
Investment in subsidiaries (Note 15)	3,306	3,139
Other long-term assets (Note 4)	7,955	10,324
Total assets	415,689	425,627
Current liabilities:
Current portion of bank debt, net (Note 5)	34,882	33,044
Accounts payable and accrued liabilities (Note 6)	38,247	31,800
Total current liabilities	73,129	64,844
Long-term liabilities:
Bank debt, net (Note 5)	127,123	140,594
Deferred income taxes	3,233	4,619
Asset retirement obligations (ARO)	15,993	15,694
Other	5,258	4,346
Total long-term liabilities	151,607	165,253
Total liabilities	224,736	230,097
Redeemable noncontrolling interests (Note 2)	4,000	4,000
Stockholders' equity:
Preferred stock, $.10 par value, 10,000 shares authorized; none issued
Common stock, $.01 par value, 100,000 shares authorized; 30,420 and 30,245 issued and outstanding, respectively	304	304
Additional paid-in capital	102,534	102,215
Retained earnings	84,115	89,011
Total stockholders' equity	186,953	191,530
Total liabilities , redeemable noncontrolling interests, and stockholders' equity	$ 415,689	$ 425,627