Property Plant Equipment and Mineral Rights and Reserves (Tables)

12 Months Ended

Dec. 31, 2011

Property Plant Equipment and Mineral Rights and Reserves [Abstract]

Property plant equipment and mineral rights and reserves

Property, plant, equipment and mineral rights and reserves consisted of the following:

	December 31,
	2011 Restated		2010 Restated
Mineral rights and reserves	$	52,482	$	65,018
Land		12,103		10,875
Buildings and improvements		97,503		86,410
Machinery and equipment		362,043		350,952
Construction in progress		25,207		15,285
		549,338		528,540

Range of useful lives to depreciate plant and equipment

The range of useful lives to depreciate plant and equipment is as follows:

Buildings and improvements	3-50 years
Machinery and equipment	1-25 years

Depreciation and depletion charged to income

Depreciation and depletion were charged to income as follows:

	2011 Restated		2010 Restated		2009 Restated
Depreciation expense	$	35,036	$	30,106	$	28,932
Depletion expense		2,574		1,180		883
		37,610		31,286		29,815