CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 80,723	$ 78,866
Trade accounts and other receivables, net	21,914	48,596
Inventories:
Finished goods	81,390	77,537
Raw materials and supplies	22,771	27,021
Total inventories	104,161	104,558
Prepaid expenses and other current assets	4,430	3,762
Prepaid income taxes	116
Deferred income taxes		49,495
Total current assets	211,344	285,277
Property, plant and equipment:
Land and land improvements	45,529	45,774
Land-use and mineral rights	19,696	19,877
Buildings	87,132	83,500
Machinery and equipment	645,695	642,396
Construction in progress	93,899	96,084
Total property, plant and equipment	891,951	887,631
Less accumulated depreciation and amortization	374,792	349,900
Net property, plant and equipment	517,159	537,731
Goodwill	3,500	3,500
Intangible and other assets, net	10,675	9,861
Total assets	742,678	836,369
Current liabilities:
Long-term debt, current portion	12,566	33,000
Notes payable	1,468
Accounts payable	4,921	10,709
Accrued payroll and benefits	2,645	6,003
Accrued freight	409	3,068
Accrued utilities	1,310	2,414
Accrued income taxes		139
Derivative instruments	4,014	6,240
Other accrued expenses	6,753	8,717
Total current liabilities	34,086	70,290
Deferred income taxes	28,428	63,858
Long-term debt	48,780	55,000
Notes payable, related parties	25,000
Other long-term liabilities	3,553	4,915
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; 23,498,241 and 23,280,696 shares issued and outstanding at June 30, 2016 and December 31, 2015, respectively	235	233
Additional paid-in capital	69,137	65,067
Retained earnings	568,591	614,708
Accumulated other comprehensive loss	(35,132)	(37,702)
Total shareholders' equity	602,831	642,306
Total liabilities and shareholders' equity	$ 742,678	$ 836,369