Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 90,635	$ 41,270
Trade accounts and other receivables, net	103,258	112,014
Inventories:
Finished goods	102,625	105,233
Raw materials and supplies	38,061	26,783
Total inventories	140,686	132,016
Prepaid expenses and other current assets	4,293	4,023
Prepaid income taxes		3,279
Deferred income taxes	11,045	9,963
Total current assets	349,917	302,565
Property, plant and equipment:
Land and land improvements	19,700	14,512
Land-use and mineral rights	9,559	8,610
Buildings	67,866	67,120
Machinery and equipment	530,129	455,563
Construction in progress	39,564	48,778
Total	666,818	594,583
Less accumulated depreciation and amortization	240,586	201,924
Net property, plant and equipment	426,232	392,659
Goodwill	12,164	12,164
Intangible and other assets, net	20,565	33,477
Total assets	808,878	740,865
Current liabilities:
Accounts payable	20,078	38,192
Accrued payroll and benefits	13,986	17,237
Accrued freight	4,925	10,911
Accrued utilities	3,707	3,704
Accrued income taxes	727
Other accrued expenses	7,407	9,022
Total current liabilities	50,830	79,066
Deferred income taxes	44,970	31,641
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 and 40,000,000 shares authorized at December 31, 2012 and 2011, respectively; 23,092,906 and 23,106,358 shares issued and outstanding at December 31, 2012 and 2011, respectively	231	231
Additional paid-in capital	57,364	56,539
Retained earnings	657,423	577,253
Accumulated other comprehensive loss	(1,940)	(3,865)
Total shareholders' equity	713,078	630,158
Total liabilities and shareholders' equity	$ 808,878	$ 740,865