CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 46,379	$ 94,250
Trade accounts and other receivables, net	131,551	125,179
Inventories:
Finished goods	89,567	87,218
Raw materials and supplies	41,382	47,042
Total inventories	130,949	134,260
Prepaid expenses and other current assets	8,756	5,442
Prepaid income taxes	4,334	1,888
Deferred income taxes	9,382	10,363
Total current assets	331,351	371,382
Property, plant and equipment:
Land and land improvements	36,422	31,163
Land-use and mineral rights	17,735	12,751
Buildings	77,694	72,702
Machinery and equipment	645,418	535,529
Construction in progress	71,717	109,735
Total	848,986	761,880
Less accumulated depreciation and amortization	304,243	283,345
Net property, plant and equipment	544,743	478,535
Goodwill	12,164	12,164
Intangible and other assets, net	17,103	16,870
Total assets	905,361	878,951
Current liabilities:
Accounts payable	29,796	24,570
Accrued payroll and benefits	9,208	13,650
Other accrued expenses	18,271	18,468
Total current liabilities	57,275	56,688
Deferred income taxes	54,473	53,676
Shareholders' equity:
Preferred stock, par value $0.01 per share, 5,000 shares authorized, none outstanding	0	0
Common stock, par value $0.01 per share, 80,000,000 shares authorized; 23,104,325 and 23,080,632 shares issued and outstanding at June 30, 2014 and December 31, 2013, respectively	231	231
Additional paid-in capital	57,267	56,782
Retained earnings	740,686	714,835
Accumulated other comprehensive loss	(4,571)	(3,261)
Total shareholders' equity	793,613	768,587
Total liabilities and shareholders' equity	$ 905,361	$ 878,951