Income Taxes Tax Examinations (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended	3 Months Ended
Jun. 30, 2014	Jun. 30, 2013	Mar. 31, 2009 Internal Revenue Service (IRS) [Member]	Mar. 31, 2008 Internal Revenue Service (IRS) [Member]
Income Tax Examination [Line Items]
Unrecognized Tax Benefits, Income Tax Penalties Expense	$ 4,464	$ 1,001
Income Tax Reconciliation, Nondeductible Expense, Depletion	20,480	25,471
Depletion	8,351		2,925	4,493
Effective Income Tax Rate Reconciliation, Deduction, Qualified Production Activity, Amount	$ 956		$ 1,402

The noncash expense charged against earnings to recognize the consumption of natural resources.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

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Amount of the difference between reported income tax expense (benefit) and the expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to deduction for qualified production activity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32687-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 13

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32698-109319

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to nondeductible depletion.

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Amount of expense for penalties related to a tax position claimed or expected to be claimed in the tax return.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319

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