CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 68,169	$ 91,680
Restricted cash	6,935
Trade accounts and other receivables, net	37,705	23,622
Inventories:
Finished goods	59,519	74,133
Raw materials and supplies	19,480	23,041
Total inventories	78,999	97,174
Prepaid expenses and other current assets	3,989	3,548
Prepaid income taxes		1,199
Total current assets	195,797	217,223
Restricted cash	3,281
Income tax receivable	2,389
Property, plant and equipment:
Land and land improvements	41,590	45,530
Land-use and mineral rights	19,696	19,696
Buildings	72,427	87,318
Machinery and equipment	455,863	647,753
Construction in progress	36,138	92,704
Total property, plant and equipment	625,714	893,001
Less accumulated depreciation and amortization	301,528	398,898
Net property, plant and equipment	324,186	494,103
Goodwill	3,500	3,500
Intangible and other assets, net	11,445	8,631
Total assets	540,598	723,457
Current liabilities:
Long-term debt, current portion		13,000
Accounts payable	19,417	7,782
Accrued payroll and benefits	6,056	3,434
Accrued freight	2,292	593
Accrued utilities	1,552	1,169
Derivative instruments	2,537	1,599
Other accrued expenses	10,577	7,227
Total current liabilities	42,431	34,804
Deferred income taxes	230	1,236
Long-term debt, net	60,698	42,404
Notes payable, related parties	27,040	25,000
Other long-term liabilities	4,434	3,443
Shareholders’ equity:
Preferred stock, par value $0.01 per share, 5,000 shares authorized, none outstanding
Common stock, par value $0.01 per share, 80,000,000 shares authorized; 27,133,614 and 26,881,066 shares issued and outstanding at December 31, 2017 and 2016, respectively	271	269
Additional paid-in capital	125,715	117,192
Retained earnings	279,779	533,435
Accumulated other comprehensive loss		(34,326)
Total shareholders’ equity	405,765	616,570
Total liabilities and shareholders’ equity	$ 540,598	$ 723,457