Discontinued Operations Financial Infomration for Discontinued Operations (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Discontinued Operations and Disposal Groups [Abstract]
Coal Revenue			$ 1,067,841
Other Outside Sales			60,066
Freight-Outside Coal			66,297
Miscellaneous Other Income			73,645
Total Revenue and Other Income			1,267,849
Total Costs			1,147,254
Income from Operations Before Income Taxes			120,595
Income Tax Expense			23,984
Less: Net Income Attributable to Noncontrolling Interest			10,903
Income from Discontinued Operations, net	$ 0	$ 0	$ 85,708

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Amount of tax expense (benefit) related to a discontinued operation. Includes, but is not limited to, tax expense (benefit) related to income (loss) from operations during the phase-out period, tax expense (benefit) related to gain (loss) on disposal, tax expense (benefit) related to gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and tax expense (benefit) related to adjustments of a prior period gain (loss) on disposal.

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