Consolidated Balance Sheets (USD $)	Dec. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 98,020,000	$ 124,929,000
Restricted cash	31,000	31,000
Short-term investments		10,005,000
Accounts receivable, net	82,801,000	87,351,000
Inventories	64,973,000	59,506,000
Supplies, prepaid items and other:
Prepaid insurance	10,049,000	5,953,000
Precious metals	13,528,000	17,777,000
Supplies	9,855,000	7,513,000
Fair value of derivatives and other	170,000	53,000
Prepaid income taxes		8,679,000
Other	2,096,000	2,034,000
Total supplies, prepaid items and other	35,698,000	42,009,000
Deferred income taxes	3,224,000	4,275,000
Total current assets	284,747,000	328,106,000
Property, plant and equipment, net	281,871,000	164,547,000
Other assets:
Investment in affiliate	1,809,000	2,910,000
Goodwill	1,724,000	1,724,000
Other, net	6,461,000	4,722,000
Total other assets	9,994,000	9,356,000
Total assets	576,612,000	502,009,000
Current liabilities:
Accounts payable	68,333,000	57,891,000
Short-term financing	9,254,000	5,646,000
Accrued and other liabilities	34,698,000	28,677,000
Current portion of long-term debt	4,798,000	4,935,000
Total current liabilities	117,083,000	97,149,000
Long-term debt	67,643,000	74,525,000
Noncurrent accrued and other liabilities	16,369,000	15,239,000
Deferred income taxes	21,020,000	21,826,000
Commitments and contingencies (Note 12)
Stockholders' equity:
Common stock, $.10 par value; 75,000,000 shares authorized, 26,731,360 shares issued (26,638,285 shares at December 31, 2011)	2,673,000	2,664,000
Capital in excess of par value	165,006,000	162,092,000
Retained earnings	212,192,000	153,888,000
Stockholders equity including treasury stock	382,871,000	321,644,000
Less treasury stock, at cost:
Common stock, 4,320,462 shares	28,374,000	28,374,000
Total stockholders' equity	354,497,000	293,270,000
Total Liabilities and Stockholders' equity	576,612,000	502,009,000
Series B Preferred Stock [Member]
Stockholders' equity:
Preferred stock, value	2,000,000	2,000,000
Series D Preferred Stock [Member]
Stockholders' equity:
Preferred stock, value	$ 1,000,000	$ 1,000,000