CWP and Workers Comp (Details) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Net periodic (benefit) cost	$ 16,687,000	$ 93,799,000	$ 52,446,000
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Actuarial Net (Gains) Losses	46,155,000	86,481,000	106,299,000
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax	(272,621,000)	(367,610,000)
Coal Workers Pneumoconiosis [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Curtailments	0	49,652,000
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	5,674,000	8,168,000	7,711,000
Interest cost	5,537,000	7,031,000	7,964,000
Amortization of actuarial gain	6,196,000	16,384,000	19,338,000
State administrative fees and insurance bond premiums	0	0	0
Defined Benefit Plan, Net Periodic Benefit Cost	0	(119,881,000)	0
Legal and administrative costs	5,674,000	8,168,000
Net periodic (benefit) cost	5,015,000	(121,066,000)	(4,058,000)
Legal and administrative costs	5,674,000	8,168,000
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation	126,098,000	121,183,000	184,079,000
Defined Benefit Plan, Actuarial Net (Gains) Losses	5,578,000	(18,020,000)
Defined Benefit Plan, Benefits Paid	(11,874,000)	(10,423,000)
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Fair Value of Plan Assets	0	0
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent	(116,942,000)	(111,972,000)
Defined Benefit Plan, Amounts Recognized in Balance Sheet	(126,098,000)	(121,183,000)
Pension and Other Postretirement Defined Benefit Plans, Current Liabilities	(9,156,000)	(9,211,000)
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax	(68,588,000)	(80,363,000)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax	(68,588,000)	(80,363,000)
Defined Benefit Plan, Amount to be Amortized from Accumulated Other Comprehensive Income (Loss) Next Fiscal Year [Abstract]
Defined Benefit Plan, Amortization of Net Gains (Losses)	(5,576,000)
Defined Benefit Plan, Amortization of Net Prior Service Cost (Credit)	0	0	(395,000)
Defined Benefit Plan, Assumptions Used in Calculations [Abstract]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	4.75%	4.03%	4.46%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	4.21%	4.75%	4.03%
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	9,156,000
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	7,483,000
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	6,802,000
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	6,402,000
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	6,207,000
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	29,376,000
Defined Benefit Plan, Effect of .25% Increase on OPEB costs	(95,000)
defined benefit plan, effect of .25% decrease on OPEB expense	102,000
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax		43,892,000
Deferred Income Taxes and Tax Credits		26,337,000
Workers Compensation [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Curtailments	347,000	105,308,000
Defined Benefit Plan, Effect of .25% increase on Pension Benefit Costs	(134,000)
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	9,781,000	15,943,000	17,126,000
Interest cost	3,577,000	6,401,000	7,113,000
Amortization of actuarial gain	382,000	2,630,000	3,944,000
State administrative fees and insurance bond premiums	3,352,000	5,324,000	6,727,000
Defined Benefit Plan, Net Periodic Benefit Cost	0	(121,838,000)	0
Legal and administrative costs	9,781,000	15,943,000
Net periodic (benefit) cost	16,328,000	(96,800,000)	27,022,000
Legal and administrative costs	9,781,000	15,943,000
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation	89,741,000	85,096,000	179,589,000
Defined Benefit Plan, Actuarial Net (Gains) Losses	3,805,000	11,806,000
Defined Benefit Plan, Benefits Paid	(15,523,000)	(28,659,000)
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Fair Value of Plan Assets	1,327,000	1,386,000
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent	(75,946,000)	(71,468,000)
Defined Benefit Plan, Amounts Recognized in Balance Sheet	(89,741,000)	(85,096,000)
Pension and Other Postretirement Defined Benefit Plans, Current Liabilities	(15,122,000)	(15,014,000)
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax	(9,382,000)	(13,569,000)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax	(9,382,000)	(13,569,000)
Defined Benefit Plan, Amount to be Amortized from Accumulated Other Comprehensive Income (Loss) Next Fiscal Year [Abstract]
Defined Benefit Plan, Amortization of Net Gains (Losses)	(30,000)
Defined Benefit Plan, Amortization of Net Prior Service Cost (Credit)	0	0	0
Defined Benefit Plan, Assumptions Used in Calculations [Abstract]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	4.57%	3.95%	4.40%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	3.84%	4.57%	3.95%
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	17,101,000
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	17,027,000
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	17,123,000
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	17,287,000
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	17,443,000
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	91,222,000
Defined Benefit Plan, Effect of .25% Decrease on Pension Benefit Costs	138,000
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax		13,768,000
Deferred Income Taxes and Tax Credits		8,262,000
Workers Compensation [Member] \| Actuarial Benefits [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	13,795,000
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	13,639,000
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	13,650,000
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	13,727,000
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	13,794,000
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	71,563,000
Workers Compensation [Member] \| Other Workers Comp benefits [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	3,306,000
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	3,388,000
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	3,473,000
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	3,560,000
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	3,649,000
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	19,659,000
Discontinued Operations [Member] \| Coal Workers Pneumoconiosis [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan, Net Periodic Benefit Cost			(2,374,000)
Net periodic (benefit) cost		(120,496,000)
Discontinued Operations [Member] \| Workers Compensation [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Net periodic (benefit) cost		$ (113,097,000)	$ 10,132,000

defined benefit plan, effect of .25% decrease on OPEB expense

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Defined Benefit Plan, Effect of .25% Decrease on Pension Benefit Costs

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Post Employment Benefit Plan, State Administrative Fees and Insurance Bond Premiums

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Service Legal and Administrative Costs

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Amount of deferred income tax expense (benefit) and income tax credits.

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The pretax total of net gain (loss), prior service cost (credit), and transition assets (obligations), as well as minimum pension liability if still remaining, included in accumulated other comprehensive income associated with a defined benefit pension or other postretirement plan(s) because they have yet to be recognized as components of net periodic benefit cost.

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The pretax net amount of gains and losses that are not yet recognized as a component of net periodic benefit cost, and that are recognized as increases or decreases in other comprehensive income as they arise. Gains and losses are due to changes in the value of either the benefit obligation or the plan assets resulting from experience different from that assumed or from a change in an actuarial assumption, or the consequence of a decision to temporarily deviate from the substantive plan.

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Amount of gain (loss) related to change in benefit obligation resulting from changes in actuarial assumptions, for example, but not limited to, interest, mortality, employee turnover, salary, and temporary deviation from the substantive plan.

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The amount of gains or losses recognized in net periodic benefit cost.

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The aggregate net amount recognized in the balance sheet associated with the defined benefit plan(s). Will normally be the same as the Defined Benefit Plan, Funded Status of Plan, Total.

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The interest rate used to adjust for the time value of money for the plan.

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The interest rate used to adjust for the time value of money.

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1) For defined benefit pension plans, the benefit obligation is the projected benefit obligation, which is the actuarial present value as of a date of all benefits attributed by the pension benefit formula to employee service rendered prior to that date. 2) For other postretirement defined benefit plans, the benefit obligation is the accumulated postretirement benefit obligation, which is the actuarial present value of benefits attributed to employee service rendered to a particular date.

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The amount of payments made for which participants are entitled under a pension plan, including pension benefits, death benefits, and benefits due on termination of employment. Also includes payments made under a postretirement benefit plan, including prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. This item represents a periodic decrease to the plan obligations and a decrease to plan assets.

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The amount of decrease that is related to an event that significantly reduces the expected years of future service of present employees or eliminates for a significant number of employees the accrual of defined benefits for some or all of their future services.

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Amount of benefits expected to be paid in the five fiscal years after the fifth fiscal year following the latest fiscal year from a defined benefit plan.

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Amount of benefits expected to be paid in the next fiscal year following the latest fiscal year from a defined benefit plan.

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Amount of benefits expected to be paid in the fifth fiscal year following the latest fiscal year from a defined benefit plan.

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Amount of benefits expected to be paid in the fourth fiscal year following the latest fiscal year from a defined benefit plan.

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Amount of benefits expected to be paid in the third fiscal year following the latest fiscal year from a defined benefit plan.

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Amount of benefits expected to be paid in the second fiscal year following the latest fiscal year from a defined benefit plan.

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Amount included in accumulated other comprehensive income (AOCI) related to gain (loss) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position.

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Amount included in accumulated other comprehensive income (AOCI) related to prior service cost (credit) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position.

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The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time.

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If aggregate disclosures are presented, the aggregate fair value of plan assets for pension plans with accumulated benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 20

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Amount of net gain (loss) recognized in net periodic benefit cost as a result of an irrevocable action that relieves the employer (or the plan) of primary responsibility for a benefit obligation and eliminates significant risks related to the obligation and the assets used to effect the settlement. Examples of transactions that constitute a settlement include, but are not limited to, lump-sum cash payments to plan participants in exchange for their rights to receive specified benefits and purchasing nonparticipating annuity contracts to cover vested benefits.

+ References

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The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan.

+ References

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-Glossary Service Cost (Component of Net Periodic Pension Cost)

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Amount after tax and reclassification adjustments, of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans.

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For a classified balance sheet, the amount recognized in balance sheet as a current liability associated with an underfunded defined benefit plan.

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Current Liabilities

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This represents the noncurrent liability for underfunded plans recognized in the balance sheet that is associated with the defined benefit pension plans and other postretirement defined benefit plans.

+ References

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

-Publisher FASB

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-Topic 210

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-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.24)

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