Unaudited Condensed Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Income Statement [Abstract]
Revenues	$ 196,052	$ 173,679
Cost of sales	149,791	128,160
Gross profit	46,261	45,519
Earnings of unconsolidated mines	12,098	12,006
Operating expenses
Selling, general and administrative expenses	50,991	49,416
Loss on sale of assets	346	41
Operating Expenses	51,337	49,457
Operating profit	7,022	8,068
Other (income) expense
Interest expense	1,304	1,707
Income from other unconsolidated affiliates	(391)	(351)
Closed mine obligations	405	334
Other	(133)	(372)
Other (income) expense	1,185	1,318
Income from continuing operations before income tax provision	5,837	6,750
Income tax provision	1,415	2,038
Income from continuing operations, net of tax	4,422	4,712
Income from discontinued operations, net of tax expense of $6,425	0	20,538
Net income	$ 4,422	$ 25,250
Basic Earnings per Share:
Continuing operations	$ 0.53	$ 0.57
Discontinued operations	$ 0.00	$ 2.44
Basic earnings per share	$ 0.53	$ 3.01
Diluted Earnings per Share:
Continuing operations	$ 0.53	$ 0.57
Discontinued operations	$ 0.00	$ 2.43
Diluted earnings per share	$ 0.53	$ 3.00
Dividends per share	$ 0.2500	$ 0.5325
Basic Weighted Average Shares Outstanding	8,360	8,379
Diluted Weighted Average Shares Outstanding	8,399	8,394