Summary of Significant Accounting Policies (Details Textual) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 Division Segment Share Region Units	Dec. 31, 2010	Dec. 31, 2009	Nov. 01, 2011 Units
Summary of Significant Accounting Policies (Textual)
Fixed exchange ratio of shares	0.50
Legal, professional and other costs incurred in response to unsolicited tender offer	$ 2,227	$ 0	$ 0
Period considered to treat investments as cash equivalent	3 months or less
Accounts and notes receivable, credit period	30 days
Bad debt expense	1,644	3,100	4,173
Write-offs of accounts receivables	2,651	4,317	4,162
Financing receivable	7,471	8,043
Allowances recorded for financing receivables	0	0
Capitalized software costs	12,910	11,662
Capitalized software costs during the year	3,746	1,167	12,825
Depreciated capitalized software costs	2,520	2,895	2,563
Total gain (losses) of the Rabbi Trust investment	(3,292)	1,425
Gains (losses) related to investments still held by Rabbi Trust	(3,370)	1,455
Loss on impairment of long-lived assets		3,936	0
Goodwill	3,086,716	3,097,016	3,096,300
Percentage of goodwill in total assets	38.00%	37.00%
Number of operating segments	4
Number of reporting units based on geographic location	13
Goodwill impairment charges	0	0	0
Reporting unit goodwill				1,815,094
Number of reporting units where fair value of goodwill exceeded carrying value				1
Percentage by which fair value of goodwill exceeded carrying value				8.00%
Growth period for volumes, pricing and variable costs to produce	20 years
Inflation-adjusted (real) average annual rates of volumes	4.80%
Inflation-adjusted (real) average annual rates of pricing	0.90%
Inflation-adjusted (real) average annual rates of variable costs to produce	0.70%
Estimated future cash flows, discount rate	9.50%
Percentage of net property, plant & equipment in total assets	42.00%
Percentage of other intangible assets, net in total assets	8.00%
Stripping costs included in cost of inventory	40,049	40,842	40,810
Pre-production stripping costs capitalized	17,860	17,347
Research and development costs for continuing operations	1,109	1,582	1,541
Excess tax benefits from share-based compensation	121	808	2,072
Carrying value of reclamation obligations	153,979	162,730
Minimum retention period for employees	60 days
Number of divisions approved by restructuring plan to consolidate	8
Number of operating regions	4
Severance and related charges due to consolidation	8,906
Decrease in other accrued liabilities	4,065
Information technology costs paid in period	2,970
Spread between the amount accrued and the maximum environmental loss	4,109
Maximum self-insurance coverage per occurrence for losses related to workers' compensation	2,000
Maximum self-insurance coverage per occurrence for automotive and general/product liability	3,000
Amount of decrease in other accrued liabilities	23,653
Payment to Illinois Department of Transportation (IDOT)	$ 20,000
Accounting Standards Codification Topic 740 - Income Taxes recognition threshold for uncertain tax positions	50.00%
Antidilutive common stock equivalents	304,000	415,000
Basis of determining impairment test	a likelihood of more than 50%
Machinery and equipment [Member]
Summary of Significant Accounting Policies (Textual)
Estimated service life, minimum	3
Estimated service life, maximum	30
Buildings [Member]
Summary of Significant Accounting Policies (Textual)
Estimated service life, minimum	10
Estimated service life, maximum	20
Land improvements [Member]
Summary of Significant Accounting Policies (Textual)
Estimated service life, minimum	7
Estimated service life, maximum	20