Arch Resources (ARCH) 10-K 11 Feb 20 2019 FY Annual report Financial data

Cover Page

Cover Page - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2019	Jan. 31, 2020	Jun. 30, 2019
Cover page.
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	1-13105
Entity Registrant Name	Arch Coal, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	43-0921172
Entity Central Index Key	0001037676
Entity Address, Address Line One	One CityPlace Drive
Entity Address, Address Line Two	Suite 300
Entity Address, City or Town	St. Louis
Entity Address, State or Province	MO
Entity Address, Postal Zip Code	63141
City Area Code	314
Local Phone Number	994-2700
Title of 12(b) Security	Common Stock, $.01 par value
Trading Symbol	ARCH
Security Exchange Name	NYSE
Entity Well Known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business Company	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 1.5
Entity Common Stock, Shares Outstanding (in shares)		15,131,573
Documents Incorporated by Reference	Portions of the registrant’s definitive proxy statement to be filed with the Securities and Exchange Commission in connection with the 2020 annual stockholders’ meeting are incorporated by reference into Part III of this Form 10-K.
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY

Consolidated Income Statements

Consolidated Income Statements - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues	$ 2,294,352	$ 2,451,787	$ 2,324,623
Costs, expenses and other operating
Cost of sales (exclusive of items shown separately below)	1,873,017	1,925,202	1,839,993
Depreciation, depletion and amortization	112,055	119,563	122,464
Accretion on asset retirement obligations	20,548	27,970	30,209
Amortization of sales contracts, net	(434)	11,107	53,985
Change in fair value of coal derivatives and coal trading activities, net	(18,601)	9,118	7,222
Selling, general and administrative expenses	95,781	100,300	87,952
Costs related to proposed joint venture with Peabody Energy	13,816	0	0
Preference Rights Lease Application settlement income	(39,000)	0	0
Other operating income, net	(19,012)	(20,611)	(30,241)
Costs, expenses and other operating	2,051,482	2,172,649	2,090,287
Income from operations	242,870	279,138	234,336
Interest expense, net
Interest expense	(16,485)	(20,471)	(26,905)
Interest and investment income	9,691	6,782	2,649
Interest expense, net	(6,794)	(13,689)	(24,256)
Income before nonoperating expenses	236,076	265,449	210,080
Nonoperating income (expense)
Non-service related pension and postretirement benefit costs	(2,053)	(3,202)	(1,940)
Net loss resulting from early retirement of debt and debt restructuring	0	(485)	(2,547)
Reorganization income (loss), net	24	(1,661)	(2,398)
Nonoperating income (expense)	(2,029)	(5,348)	(6,885)
Income before income taxes	234,047	260,101	203,195
Provision for (benefit from) income taxes	248	(52,476)	(35,255)
Net income	$ 233,799	$ 312,577	$ 238,450
Earnings per common share
Basic earnings per common share (in dollars per share)	$ 14.42	$ 15.90	$ 10.05
Diluted earnings per common share (in dollars per share)	$ 13.52	$ 15.15	$ 9.84
Weighted average shares outstanding
Basic weighted average shares outstanding (in shares)	16,218	19,663	23,725
Diluted weighted average shares outstanding (in shares)	17,298	20,629	24,240
Coal-Mac LLC
Costs, expenses and other operating
(Gain) loss on sale of disposal group	$ 9,008	$ 0	$ 0
Lone Mountain Processing, Inc.
Costs, expenses and other operating
(Gain) loss on sale of disposal group	$ 4,304	$ 0	$ (21,297)

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 233,799	$ 312,577	$ 238,450
Derivative instruments
Comprehensive income (loss) before tax	(5,892)	2,681	647
Income tax benefit (provision)	0	0	0
Derivative instruments, net of tax	(5,892)	2,681	647
Pension, postretirement and other post-employment benefits
Comprehensive income (loss) before tax	(32,038)	20,591	(4,347)
Income tax benefit (provision)	0	0	0
Pension, postretirement and other post-employment benefits, net of tax	(32,038)	20,591	(4,347)
Available-for-sale securities
Comprehensive income (loss) before tax	323	(343)	(387)
Income tax benefit (provision)	0	0	0
Available-for-sale securities, net of tax	323	(343)	(387)
Total other comprehensive income (loss)	(37,607)	22,929	(4,087)
Total comprehensive income	$ 196,192	$ 335,506	$ 234,363

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 153,020	$ 264,937
Short-term investments	135,667	162,797
Trade accounts receivable	168,125	200,904
Other receivables	21,143	48,926
Inventories	130,898	125,470
Other current assets	97,894	75,749
Total current assets	706,747	878,783
Property, plant and equipment
Coal lands and mineral rights	450,539	396,125
Plant and equipment	639,399	510,683
Deferred mine development	252,108	194,363
Property, plant and equipment, gross	1,342,046	1,101,171
Less accumulated depreciation, depletion and amortization	(357,537)	(266,343)
Property, plant and equipment, net	984,509	834,828
Other assets
Prepaid royalties	1,600	600
Deferred income taxes	82	170
Equity investments	105,588	104,676
Other noncurrent assets	69,230	68,003
Other Noncurrent Assets, Excluding Property, Plant And Equipment	176,500	173,449
Total assets	1,867,756	1,887,060
Current liabilities
Accounts payable	133,060	128,024
Accrued expenses and other current liabilities	157,167	183,514
Current maturities of debt	20,753	17,797
Total current liabilities	310,980	329,335
Long-term debt	290,066	300,186
Asset retirement obligations	242,432	230,304
Accrued pension benefits	5,476	16,147
Accrued postretirement benefits other than pension	80,567	83,163
Accrued workers’ compensation	215,599	174,303
Other noncurrent liabilities	82,100	48,801
Total liabilities	1,227,220	1,182,239
Stockholders' equity
Common stock, $0.01 par value, authorized 300,000 shares, issued 25,220 and 25,047 shares at December 31, 2019 and 2018, respectively	252	250
Paid-in capital	730,551	717,492
Treasury stock, 10,088 and 7,216 shares at December 31, 2019 and 2018, respectively, at cost	(827,381)	(583,883)
Retained earnings	731,425	527,666
Accumulated other comprehensive income	5,689	43,296
Total stockholders’ equity	640,536	704,821
Total liabilities and stockholders’ equity	$ 1,867,756	$ 1,887,060

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares issued (in shares)	25,220,000	25,047,000
Treasury stock, shares (in shares)	10,088,000	7,216,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating activities
Net income	$ 233,799	$ 312,577	$ 238,450
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Depreciation, depletion and amortization	112,055	119,563	122,464
Accretion on asset retirement obligations	20,548	27,970	30,209
Amortization of sales contracts, net	(434)	11,107	53,985
Prepaid royalties expensed	4,270	134	2,905
Deferred income taxes	13,501	18,701	(21,965)
Employee stock-based compensation expense	21,989	17,519	10,437
Loss (Gain) on disposals and divestitures	8,304	(625)	(24,327)
Amortization relating to financing activities	3,691	4,179	3,736
Preference Rights Lease Application settlement income	(39,000)	0	0
Net loss resulting from early retirement of debt and debt restructuring	0	485	2,547
Changes in:
Receivables	30,713	(22,903)	8,370
Inventories	(15,251)	3,490	(19,626)
Income taxes receivable/payable	38,152	(46,971)	(6,834)
Coal derivative assets and liabilities, including margin account	10,117	(779)	(7,342)
Accounts payable, accrued expenses and other current liabilities	(28,222)	(14,208)	17,173
Asset retirement obligations	(11,455)	(9,743)	(20,584)
Pension, postretirement and other postemployment benefits	(209)	(4,703)	(15,253)
Other	17,146	2,170	22,129
Cash provided by operating activities	419,714	417,963	396,474
Investing activities
Capital expenditures	(266,356)	(95,272)	(59,205)
Minimum royalty payments	(1,249)	(584)	(5,296)
Proceeds from disposals and divestitures	6,135	1,083	12,920
Purchases of short term investments	(205,216)	(143,328)	(258,948)
Proceeds from sales of short term investments	233,074	136,630	190,064
Investments in and advances to affiliates, net	(5,499)	(2,481)	(10,173)
Cash used in investing activities	(239,111)	(103,952)	(130,638)
Financing activities
Proceeds from issuance of term loan due 2024	0	0	298,500
Payments to extinguish term loan due 2021	0	0	(325,684)
Payments on term loan	(3,000)	(3,000)	(2,250)
Net payments on other debt	(5,373)	(6,077)	(694)
Debt financing costs	0	(1,257)	(10,149)
Dividends paid	(30,220)	(31,269)	(24,369)
Purchases of treasury stock	(244,998)	(280,871)	(301,512)
Payments for taxes related to net share settlement of equity awards	(8,961)	0	0
Expenses related to debt restructuring	0	(50)	(2,360)
Other	32	(152)	(138)
Cash provided by (used in) financing activities	(292,520)	(322,676)	(368,656)
Decrease in cash and cash equivalents, including restricted cash	(111,917)	(8,665)	(102,820)
Cash and cash equivalents, including restricted cash, beginning of period	264,937	273,602	376,422
Cash and cash equivalents, including restricted cash, end of period	153,020	264,937	273,602
SUPPLEMENTAL CASH FLOW INFORMATION
Cash paid during the period for interest	16,627	17,493	34,691
Cash refunded during the period for income taxes, net	$ 52,272	$ 24,330	$ 7,958

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Paid-in Capital	Treasury Stock, at cost	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)
Beginning Balance at Dec. 31, 2016	$ 746,577	$ 250	$ 688,424	$ 0	$ 33,449	$ 24,454
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends on common shares	(24,667)				(24,667)
Employee stock-based compensation expense	10,437		10,437
Issuance of shares of common stock under long-term incentive plan	1,244		1,244
Warrants exercised	20		20
Purchase of common stock under share repurchase program	(302,109)			(302,109)
Total comprehensive income (loss)	234,363				238,450	(4,087)
Ending Balance at Dec. 31, 2017	665,865	250	700,125	(302,109)	247,232	20,367
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends on common shares	(32,143)				(32,143)
Employee stock-based compensation expense	17,519		17,519
Warrants exercised	9		9
Purchase of common stock under share repurchase program	(281,774)			(281,774)
Common stock withheld related to net share settlement of equity awards	(161)		(161)
Total comprehensive income (loss)	335,506				312,577	22,929
Ending Balance at Dec. 31, 2018	704,821	250	717,492	(583,883)	527,666	43,296
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends on common shares	(30,040)				(30,040)
Employee stock-based compensation expense	21,989		21,989
Issuance of shares of common stock under long-term incentive plan	2	2
Warrants exercised	32		32
Purchase of common stock under share repurchase program	(243,498)			(243,498)
Common stock withheld related to net share settlement of equity awards	(8,962)		(8,962)
Total comprehensive income (loss)	196,192				233,799	(37,607)
Ending Balance at Dec. 31, 2019	$ 640,536	$ 252	$ 730,551	$ (827,381)	$ 731,425	$ 5,689

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Parenthetical) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Stockholders' Equity [Abstract]
Issuance of shares of common stock under long-term incentive plan (in shares)	172,720		17,233
Purchase of shares of common stock under share repurchase program (in shares)	2,872,548	3,238,615	3,977,215

Basis of Presentation

Basis of Presentation	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements include the accounts of Arch Coal, Inc. and its subsidiaries and controlled entities (the “Company”). Unless the context indicates otherwise, the terms “Arch” and the “Company” are used interchangeably in this Annual Report on Form 10-K. The Company’s primary business is the production of thermal and metallurgical coal from surface and underground mines located throughout the United States, for sale to utility, industrial and steel producers both in the United States and around the world. The Company currently operates mining complexes in West Virginia, Illinois, Wyoming and Colorado. All subsidiaries are wholly-owned. Intercompany transactions and accounts have been eliminated in consolidation.

Accounting Policies

Accounting Policies	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Accounting Policies	Accounting Policies The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States for financial reporting and U.S. Securities and Exchange Commission regulations. Accounting Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and revenues and expenses in the accompanying consolidated financial statements and the disclosure of contingent assets and liabilities. Actual results could differ from those estimates. Cash and Cash Equivalents Cash and cash equivalents are stated at cost. Cash equivalents consist of highly-liquid investments with an original maturity of three months or less when purchased. Accounts Receivable Accounts receivable are recorded at amounts that are expected to be collected, based on past collection history, the economic environment and specified risks identified in the receivables portfolio. Inventories Coal and supplies inventories are valued at the lower of average cost or market. Coal inventory costs include labor, supplies, equipment costs, transportation costs incurred prior to the transfer of title to customers and operating overhead. The costs of removing overburden, called stripping costs, incurred during the production phase of the mine are considered variable production costs and are included in the cost of the coal extracted during the period the stripping costs are incurred. Investments and Membership Interests in Joint Ventures Investments and membership interests in joint ventures are accounted for under the equity method of accounting if the Company has the ability to exercise significant influence, but not control, over the entity. The Company’s share of the entity’s income or loss is reflected in “ Other operating income, net ” in the Consolidated Income Statements. Information about investment activity is provided in Note 10 to the Consolidated Financial Statements, “ Equity Method Investments and Membership Interests in Joint Ventures .” Investments in debt securities and marketable equity securities that do not qualify for equity method accounting are classified as available-for-sale and are recorded at their fair values. Unrealized gains and losses on these investments are recorded in other comprehensive income or loss. A decline in the value of an investment that is considered other-than-temporary would be recognized in operating expenses. Sales Contracts Coal supply agreements (sales contracts) valued during fresh start accounting or acquired in a business combination are capitalized at their fair value and amortized over the tons of coal shipped during the term of the contract. The fair value of a sales contract is determined by discounting the cash flows attributable to the difference between the contract price and the prevailing forward prices for the tons under contract at the date of acquisition. Exploration Costs Costs to acquire permits for exploration activities are capitalized. Drilling and other costs related to locating coal deposits and evaluating the economic viability of such deposits are expensed as incurred. Prepaid Royalties Leased mineral rights are often acquired through royalty payments. When royalty payments represent prepayments recoupable against royalties owed on future revenues from the underlying coal, they are recorded as a prepaid asset, with amounts expected to be recouped within one year classified as current. When coal from these leases is sold, the royalties owed are recouped against the prepayment and charged to cost of sales. An impairment charge is recognized for prepaid royalties that are not expected to be recouped. Property, Plant and Equipment Plant and Equipment Plant and equipment were recorded at fair value at emergence during fresh start accounting; subsequent purchases of property, plant and equipment have been recorded at cost. Interest costs incurred during the construction period for major asset additions are capitalized. The Company capitalized $2.9 million and $0.3 million of interest costs during years ended December 31, 2019 and 2018 , respectively. Expenditures that extend the useful lives of existing plant and equipment or increase the productivity of the asset are capitalized. The cost of maintenance and repairs that do not extend the useful life or increase the productivity of the asset is expensed as incurred. Preparation plants and loadouts are depreciated using the units-of-production method over the estimated recoverable reserves, subject to a minimum level of depreciation. Other plant and equipment are depreciated principally using the straight-line method over the estimated useful lives of the assets, limited by the remaining life of the mine. The useful lives of mining equipment, including longwalls, draglines and shovels, range from 1 to 18 years. The useful lives of buildings and leasehold improvements generally range from 3 to 18 years. Deferred Mine Development Costs of developing new mines or significantly expanding the capacity of existing mines are capitalized and amortized using the units-of-production method over the estimated recoverable reserves that are associated with the property being benefited. Costs may include construction permits and licenses; mine design; construction of access roads, shafts, slopes and main entries; and removing overburden to access reserves in a new pit. Additionally, deferred mine development includes the asset cost associated with asset retirement obligations. Coal sales revenue related to incidental production during the development phase will be recorded as coal sales revenue with an offset to cost of coal sales based on the estimated cost per ton sold for the mine when the asset is in place for its intended use. Coal Lands and Mineral Rights Rights to coal reserves may be acquired directly through governmental or private entities. A significant portion of the Company’s coal reserves are controlled through leasing arrangements. Lease agreements are generally long-term in nature (original terms range from 10 to 50 years), and substantially all of the leases contain provisions that allow for automatic extension of the lease term providing certain requirements are met. Leases of mineral reserves and related land leases are exempt from the provisions of the leasing standard. The net book value of the Company’s coal interests was $360.9 million and $338.1 million at December 31, 2019 and 2018 , respectively. Payments to acquire royalty lease agreements and lease bonus payments are capitalized as a cost of the underlying mineral reserves and depleted over the life of proven and probable reserves. Coal lease rights are depleted using the units-of-production method, and the rights are assumed to have no residual value. The Company currently does not have any future lease bonus payments. Depreciation, depletion and amortization The depreciation, depletion and amortization related to long-lived assets is reflected in the income statement as a separate line item. No depreciation, depletion or amortization is included in any other operating cost categories. Impairment If facts and circumstances suggest that the carrying value of a long-lived asset or asset group may not be recoverable, the asset or asset group is reviewed for potential impairment. If this review indicates that the carrying amount of the asset will not be recoverable through projected undiscounted cash flows generated by the asset and its related asset group over its remaining life, then an impairment loss is recognized by reducing the carrying value of the asset to its fair value. The Company may, under certain circumstances, idle mining operations in response to market conditions or other factors. Because an idling is not a permanent closure, it is not considered an automatic indicator of impairment. Deferred Financing Costs The Company capitalizes costs incurred in connection with new borrowings, the establishment or enhancement of credit facilities and the issuance of debt securities. These costs are amortized as an adjustment to interest expense over the life of the borrowing or term of the credit facility using the interest method. Debt issuance costs related to a recognized liability are presented in the balance sheet as a direct reduction from the carrying amount of that liability whereas debt issuance costs related to a credit facility with no balance outstanding are shown as an asset. The unamortized balance of deferred financing costs shown as an asset was $3.0 million at December 31, 2019 , with $2.0 million classified as current; the unamortized balance of deferred financing costs shown as an asset at December 31, 2018 was $4.7 million with $2.2 million classified as current. The current amounts are classified within “Other current assets” and the noncurrent amounts are classified within “Other noncurrent assets.” For information on the unamortized balance of deferred financing fees related to outstanding debt, see Note 13 to the Consolidated Financial Statements, “ Debt and Financing Arrangements .” Revenue Recognition Revenues include sales to customers of coal produced at Company operations and coal purchased from third parties. The Company recognizes revenue at the time risk of loss passes to the customer at contracted amounts. Transportation costs are included in cost of sales and amounts billed by the Company to its customers for transportation are included in revenues. Other Operating Income, net Other operating income, net in the accompanying Consolidated Income Statements reflects income and expense from sources other than physical coal sales, including: bookouts, or the practice of offsetting purchase and sale contracts for shipping convenience purposes; contract settlements; royalties earned from properties leased to third parties; income from equity investments (Note 10 , “ Equity Method Investments and Membership Interests in Joint Ventures ”); non-material gains and losses from divestitures and dispositions of assets; and realized gains and losses on derivatives that do not qualify for hedge accounting and are not held for trading purposes (Note 11 , “ Derivatives ”); and land management expenses. Asset Retirement Obligations The Company’s legal obligations associated with the retirement of long-lived assets are recognized at fair value at the time the obligations are incurred. Accretion expense is recognized through the expected settlement date of the obligation. Obligations are incurred at the time development of a mine commences for underground and surface mines or construction begins for support facilities, refuse areas and slurry ponds. The obligation’s fair value is determined using a discounted cash flow technique and is based upon permit requirements and various estimates and assumptions that would be used by market participants, including estimates of disturbed acreage, reclamation costs and assumptions regarding equipment productivity. Upon initial recognition of a liability, a corresponding amount is capitalized as part of the carrying value of the related long-lived asset. The Company reviews its asset retirement obligation at least annually and makes necessary adjustments for permit changes as granted by state authorities and for revisions of estimates of the amount and timing of costs. For ongoing operations, adjustments to the liability result in an adjustment to the corresponding asset. For idle operations, adjustments to the liability are recognized as income or expense in the period the adjustment is recorded. Any difference between the recorded obligation and the actual cost of reclamation is recorded in profit or loss in the period the obligation is settled. See additional discussion in Note 15 , “ Asset Retirement Obligations .” Loss Contingencies The Company accrues for cost related to contingencies when a loss is probable and the amount is reasonably determinable. Disclosure of contingencies is included in the financial statements when it is at least reasonably possible that a material loss or an additional material loss in excess of amounts already accrued may be incurred. The amount accrued represents the Company’s best estimate of the loss, or, if no best estimate within a range of outcomes exists, the minimum amount in the range. Derivative Instruments The Company generally utilizes derivative instruments to manage exposures to commodity prices and interest rate risk on long-term debt. Additionally, the Company may hold certain coal derivative instruments for trading purposes. Derivative financial instruments are recognized on the balance sheet at fair value. Certain coal contracts may meet the definition of a derivative instrument, but because they provide for the physical purchase or sale of coal in quantities expected to be used or sold by the Company over a reasonable period in the normal course of business, they are not recognized on the balance sheet. Certain derivative instruments are designated as the hedge instrument in a hedging relationship. In a fair value hedge, the Company hedges the risk of changes in the fair value of a firm commitment, typically a fixed-price coal sales contract. Changes in both the hedged firm commitment and the fair value of a derivative used as a hedge instrument in a fair value hedge are recorded in earnings. In a cash flow hedge, the Company hedges the risk of changes in future cash flows related to the underlying item being hedged. Changes in the fair value of the derivative instrument used as a hedge instrument in a cash flow hedge are recorded in other comprehensive income or loss. Amounts in other comprehensive income or loss are reclassified to earnings when the hedged transaction affects earnings and are classified in a manner consistent with the transaction being hedged. The Company formally documents the relationships between hedging instruments and the respective hedged items, as well as its risk management objectives for hedge transactions. The Company evaluates the effectiveness of its hedging relationships both at the hedge’s inception and on an ongoing basis. Any ineffective portion of the change in fair value of a derivative instrument used as a hedge instrument in a fair value or cash flow hedge is recognized immediately in earnings. The ineffective portion is based on the extent to which exact offset is not achieved between the change in fair value of the hedge instrument and the cumulative change in expected future cash flows on the hedged transaction from inception of the hedge in a cash flow hedge or the change in the fair value. Ineffectiveness was insignificant for the periods disclosed within. See Note 11 , “ Derivatives ” for further disclosures related to the Company’s derivative instruments. Fair Value Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly hypothetical transaction between market participants at a given measurement date. Valuation techniques used must maximize the use of observable inputs and minimize the use of unobservable inputs. See Note 16 , “ Fair Value Measurements ” for further disclosures related to the Company’s recurring fair value estimates. Income Taxes Deferred income taxes are provided for temporary differences arising from differences between the financial statement and tax basis of assets and liabilities existing at each balance sheet date using enacted tax rates anticipated to be in effect when the related taxes are expected to be paid or recovered. A valuation allowance is established if it is more likely than not that a deferred tax asset will not be realized. Management reassesses the ability to realize its deferred tax assets annually in the fourth quarter or when circumstances indicate that the ability to realize deferred tax assets has changed. In determining the need for a valuation allowance, the Company considers projected realization of tax benefits based on expected levels of future taxable income, available tax planning strategies and the reversal of temporary differences. Benefits from tax positions that are uncertain are not recognized unless the Company concludes that it is more likely than not that the position would be sustained in a dispute with taxing authorities, should the dispute be taken to the court of last resort. The Company would measure any such benefit at the largest amount of benefit that is greater than 50 percent likely of being realized upon settlement with taxing authorities. See Note 14 , “ Taxes ” for further disclosures about income taxes. Benefit Plans The Company has non-contributory defined benefit pension plans covering most of its salaried and hourly employees. On January 1, 2015 the Company’s cash balance and excess pension plans were amended to freeze new service credits for any new or active employees. The Company also currently provides certain postretirement medical and life insurance coverage for eligible employees. The cost of providing these benefits is determined on an actuarial basis and accrued over the employees’ period of active service. The Company recognizes the overfunded or underfunded status of these plans as determined on an actuarial basis on the balance sheet and the changes in the funded status are recognized in other comprehensive income. The Company amortizes actuarial gains and losses over the remaining service attribution periods of the employees using the corridor method. See Note 20 , “ Employee Benefit Plans ” for additional disclosures relating to these obligations. Stock-Based Compensation The compensation cost of all stock-based awards is determined based on the grant-date fair value of the award, and is recognized over the requisite service period. The grant-date fair value of option awards and restricted stock awards with a market condition is determined using a Monte Carlo simulation. Compensation cost for an award with performance conditions is accrued if it is probable that the conditions will be met. The Company accounts for forfeitures as they occur. See further discussion in Note 18 , “ Stock-Based Compensation and Other Incentive Plans .” Recently Adopted Accounting Guidance In February 2016, the FASB established Topic 842, Leases, by issuing ASU 2016-02, “Leases” which requires lessees to recognize leases on-balance sheet and disclose key information about leasing arrangements. The ASU was subsequently amended by ASU 2018-01, “Land Easements Practical Expedient for Transition to Topic 842;” ASU 2018-10, “Codification Improvements to Topic 842, Leases;” and ASU 2018-11, “Targeted Improvements.” The new standard establishes a right-of-use (“ROU”) model that requires a lessee to recognize an ROU asset and lease liability on the balance sheet for all leases with a term longer than 12 months. The standard also requires a lessee to recognize a single lease cost, calculated so that the cost of the lease is allocated over the term of the lease, on a generally straight line basis. Leases of mineral reserves and related land leases have been exempted from the standard. The Company adopted ASU 2016-02 effective January 1, 2019 and elected the option to not restate comparative periods in transition and also elected the “package of practical expedients” within the standard which permits the Company not to reassess its prior conclusions about lease identification, lease classification and initial direct costs. Additionally, the Company made an election to not separate lease and non-lease components for all leases, and will not use hindsight. Finally, the Company will continue its current policy for accounting for land easements as executory contracts. The adoption of the standard had no impact on the Company’s consolidated income statement or statement of cash flows. In April 2017, the FASB issued ASU 2017-08, “Receivables-Nonrefundable Fees and Other Costs (Subtopic 310-20), Premium Amortization on Purchased Callable Debt Securities.” The new guidance shortens the amortization period for the premium on certain purchased callable debt securities to the earliest call date. The new guidance does not change the accounting for purchased callable debt securities held at a discount. The Company adopted ASU 2017-08 effective January 1, 2019 with no impact on the Company’s financial statements. In August 2017, the FASB issued ASU 2017-12, “Targeted Improvements to Accounting for Hedging Activities.” The new guidance provides targeted improvements to the accounting for hedging activities to better align an entity’s risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedging relationships and the presentation of hedging results. The Company adopted ASU 2017-12 effective January 1, 2019 with no impact on the Company’s financial statements. In February 2018, the FASB issued ASU 2018-02, “Income Statement-Reporting Comprehensive Income (Topic 220) Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” ASU 2018-02 provides an option to reclassify stranded tax effects within accumulated other comprehensive income to retained earnings due to the change in the U.S. federal tax rate in the Tax Cuts and Jobs Act of 2017. The Company adopted ASU 2018-02 effective January 1, 2019 with no impact on the Company’s financial statements. In June 2018, the FASB issued ASU 2018-07, “Compensation-Stock Compensation (Topic 718), Improvements to Non-employee Share-Based Payment Accounting.” ASU 2018-07 aligns the measurement and classification guidance for share-based payments to non-employees with the guidance for share-based payments to employees. The Company adopted ASU 2018-07 effective January 1, 2019 with no impact on the Company’s financial statements. In October 2018, the FASB issued ASU 2018-16, “Derivatives and Hedging (Topic 815), Inclusion of the Secured Overnight Financing Rate (SOFR) Overnight Index Swap (OIS) Rate as a Benchmark Interest Rate of Hedge Accounting Purposes.” The Company adopted ASU 2018-16 effective January 1, 2019 with no impact on the Company’s financial statements. Recent Accounting Guidance Issued Not Yet Effective In June 2016, the FASB issued ASU 2016-13, “Financial Instruments-Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments” and also issued subsequent amendments to the initial guidance under ASU 2018-19, ASU 2019-04 and ASU 2019-05. The standard modifies the measurement approach for credit losses on financial instruments, including trade receivables, from an incurred loss method to a current expected credit loss method, otherwise known as “CECL.” The standard requires the measurement of expected credit losses to be based on relevant information, including historical experience, current conditions and a forecast that is supportable. The standard is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years; early adoption is permitted. The standard must be adopted by applying a cumulative adjustment to retained earnings. The Company anticipates adopting the standard in the first quarter of 2020, although it does not expect a significant impact to the Company’s financial results. In August 2018, the FASB issued ASU 2018-13, “Fair Value Measurement (Topic 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement.” The primary focus of ASU 2018-13 is to improve the effectiveness of the disclosures for fair value measurements by requiring public entities to disclose certain new information while modifying some existing disclosure requirements. The FASB issued this ASU as part of its broader disclosure framework project, which aims to improve the effectiveness of disclosures in the notes to the financial statements by focusing on requirements that clearly communicate the most important information to users of the financial statements. The ASU is effective for public companies for fiscal years beginning after December 15, 2019, and interim periods therein with early adoption permitted. The Company does not expect a significant impact to the Company’s financial statements. In August 2018, the FASB issued ASU 2018-14, “Compensation-Retirement Benefits-Defined Benefit Plans-General (Subtopic 715-20), Disclosure Framework-Changes to the Disclosure Requirements for Defined Benefit Plans.” ASU 2018-14 makes minor changes to the disclosure requirements for employers that sponsor defined benefit pension and postretirement benefit plants. The new guidance eliminates requirements for certain disclosures that are no longer considered cost beneficial and adds new ones that the FASB considers pertinent. The FASB issued this ASU as part of its broader disclosure framework project, which aims to improve the effectiveness of disclosures in the notes to the financial statements by focusing on requirements that clearly communicate the most important information to users of the financial statements. The ASU is effective for public companies for fiscal years beginning after December 15, 2020, and interim periods therein with early adoption permitted. The Company does not expect a significant impact to the Company’s financial statements.

Emergence from Bankruptcy

Emergence from Bankruptcy	12 Months Ended
	Dec. 31, 2019
Reorganizations [Abstract]
Emergence from Bankruptcy	Emergence from Bankruptcy On January 11, 2016 (the “Petition Date”), Arch and substantially all of its wholly owned domestic subsidiaries (the “Filing Subsidiaries” and, together with Arch, the “Debtors”) filed voluntary petitions for reorganization (collectively, the “Bankruptcy Petitions”) under Chapter 11 of Title 11 of the U.S. Code (the “Bankruptcy Code”) in the United States Bankruptcy Court for the Eastern District of Missouri (the “Court”). The Debtor’s Chapter 11 Cases (collectively, the “Chapter 11 Cases”) were jointly administered under the caption In re Arch Coal, Inc., et al. Case No. 16-40120 (lead case). During the bankruptcy proceedings, each Debtor operated its business as a “debtor in possession” under the jurisdiction of the Court and in accordance with the applicable provisions of the Bankruptcy Code and the orders of the Court. For periods subsequent to filing the Bankruptcy Petitions, the Company applied the FASB Accounting Standards Codification (“ASC”) 852, “Reorganizations”, in preparing its consolidated financial statements. ASC 852 requires that financial statements distinguish transactions and events that are directly associated with the reorganization from the ongoing operations of the business. Accordingly, certain revenues, expenses, realized gains and losses and provisions for losses that are realized or incurred in the bankruptcy proceedings have been recorded in a reorganization line item on the Consolidated Income Statements. On September 13, 2016, the Bankruptcy Court entered an order, Docket No. 1324, confirming the Debtors’ Fourth Amended Joint Plan of Reorganization under Chapter 11 of the Bankruptcy Code dated as of September 11, 2016 (the “Plan”), which order was amended on September 15, 2016, Docket No. 1334. On October 5, 2016, Arch Coal satisfied the closing conditions contemplated by the Plan, which became effective on that date (the “Effective Date”). Reorganization Items, Net In accordance with ASC 852, the income statement shall portray the results of operations of the reporting entity while it is in Chapter 11. Revenues, expenses (including professional fees), realized gains and losses, and provisions for losses resulting from reorganization and restructuring of the business shall be reported separately as reorganization items. The Company’s reorganization items, net for the respective periods are as follows: Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 (In thousands) Professional fees $ 24 $ (1,661 ) $ (2,398 )

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Accumulated Other Comprehensive Income	Accumulated Other Comprehensive Income The following items are included in accumulated other comprehensive income: Pension, Postretirement Accumulated and Other Post- Other Derivative Employment Available-for- Comprehensive Instruments Benefits Sale Securities Income (Loss) (In thousands) January 1, 2018 $ 647 $ 19,720 $ — $ 20,367 Unrealized gains (losses) (4,359 ) 22,923 (319 ) 18,245 Amounts reclassified from accumulated other comprehensive income 7,040 (2,332 ) (24 ) 4,684 December 31, 2018 $ 3,328 $ 40,311 $ (343 ) $ 43,296 Unrealized gains (losses) 4,648 (27,692 ) 508 (22,536 ) Amounts reclassified from accumulated other comprehensive income (10,540 ) (4,346 ) (185 ) (15,071 ) December 31, 2019 $ (2,564 ) $ 8,273 $ (20 ) $ 5,689 The following amounts were reclassified out of accumulated other comprehensive income during the respective periods: Details about accumulated other comprehensive income components Year Ended December 31, 2019 Year Ended December 31, 2018 Line Item in the Consolidated Income Statements (in thousands) Derivative instruments Coal hedges $ 9,480 $ (8,206 ) Revenues Interest rate hedges 1,060 1,166 Interest expense — — Provision for (benefit from) income taxes $ 10,540 $ (7,040 ) Net of tax Pension, postretirement and other post-employment benefits Amortization of net actuarial gains (losses) 1 $ 3,020 $ — Settlement gains 1,326 2,332 $ 4,346 $ 2,332 Total before tax — — Provision for (benefit from) income taxes $ 4,346 $ 2,332 Net of tax Available-for-sale securities 2 $ 185 $ 24 Interest and investment income — — Provision for (benefit from) income taxes $ 185 $ 24 Net of tax 1 Production-related benefits and workers’ compensation costs are included in costs to produce coal. 2 The gains and losses on sales of available-for-sale-securities are determined on a specific identification basis.

Divestitures

Divestitures	12 Months Ended
	Dec. 31, 2019
Discontinued Operations and Disposal Groups [Abstract]
Divestitures	Divestitures On December 13, 2019, the Company sold Coal-Mac LLC, an operating mine complex within the Company’s Other Thermal segment to Condor Holdings, LLC. The Company received $2.3 million of proceeds offset by $0.2 million in closing fees; and recorded a loss of $9.0 million which is reflected as a separate line, “ Loss on sale of Coal-Mac LLC ,” within the Consolidated Income Statements. On September 14, 2017, the Company sold Lone Mountain Processing LLC, an operating mine complex within the Company’s metallurgical coal segment, and two idled mining companies, Cumberland River Coal LLC and Powell Mountain Energy LLC to Revelation Energy LLC. The Company received $8.3 million of proceeds offset by $1.4 million in disbursements related to landholder consent fees and professional fees; and recorded a gain of $21.3 million which is reflected as a separate line, “ (Gain) loss on sale of Lone Mountain Processing, Inc. ,” within the Consolidated Income Statements. The gain included a $4.7 million curtailment gain related to black lung liabilities accrued for active employees at these operations. Under the terms of the purchase agreement, Revelation assumed certain traumatic workers compensation claims and pneumoconiosis (occupational disease) benefits. On July 1, 2019, Blackjewel LLC and four affiliates, including Revelation Energy LLC, filed for Chapter 11 bankruptcy. As a result of the bankruptcy, the Company recorded a $4.3 million charge for these claims during the second quarter of 2019.

Joint Venture with Peabody Ener

Joint Venture with Peabody Energy Joint Venture with Peabody Energy	12 Months Ended
	Dec. 31, 2019
Equity Method Investments and Joint Ventures [Abstract]
Joint Venture with Peabody Energy	Joint Venture with Peabody Energy On June 18, 2019, Arch Coal entered into a definitive implementation agreement (the “Implementation Agreement”) with Peabody Energy Corporation (“Peabody”), to establish a joint venture that will combine the respective Powder River Basin and Colorado mining operations of Arch Coal and Peabody. Pursuant to the terms of the Implementation Agreement, Arch Coal will hold a 33.5% economic interest, and Peabody will hold a 66.5% economic interest in the joint venture. At the closing of the joint venture transaction, certain of the respective subsidiaries of Arch Coal and Peabody will enter into an Amended and Restated Limited Liability Company Agreement (the “LLC Agreement”). Under the terms of the LLC Agreement, the governance of the joint venture will be overseen by the joint venture’s board of managers, which will initially be comprised of three representatives appointed by Peabody and two representatives appointed by Arch. Decisions of the board of managers will be determined by a majority vote subject to certain specified matters set forth in the LLC Agreement that will require a supermajority vote. Peabody, or one of its affiliates, will initially be appointed as the operator of the joint venture and will manage the day-to-day operations of the joint venture, subject to the supervision of the joint venture’s board of managers. Formation of the joint venture is subject to customary closing conditions, including the termination or expiration of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, the receipt of certain other required regulatory approvals and the absence of injunctions or other legal restraints preventing the formation of the joint venture. Formation of the joint venture does not require approval of the respective stockholders of either Arch or Peabody. The Company has incurred expenses of $13.8 million during the year ended December 31, 2019 associated with the regulatory approval process of the joint venture. Equity Method Investments and Membership Interests in Joint Ventures The Company accounts for its investments and membership interests in joint ventures under the equity method of accounting if the Company has the ability to exercise significant influence, but not control, over the entity. Equity method investments are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the investments may not be recoverable. Below are the equity method investments reflected in the consolidated balance sheets: (In thousands) Knight Hawk DTA Total December 31, 2017 $ 90,166 $ 15,941 $ 106,107 Advances to (distributions from) affiliates, net (10,534 ) 2,481 (8,053 ) Equity in comprehensive income (loss) 10,389 (3,767 ) 6,622 December 31, 2018 $ 90,021 $ 14,655 $ 104,676 Sale of investment in affiliates (1,879 ) — (1,879 ) Advances to (distributions from) affiliates, net (5,884 ) 5,500 (384 ) Equity in comprehensive income (loss) 7,953 (4,778 ) 3,175 December 31, 2019 $ 90,211 $ 15,377 $ 105,588 In December 2019, the Company sold 1% of its ownership interest in Knight Hawk Holdings, LLC (“Knight Hawk”) to a third party for $2.0 million . After the transaction, the Company holds a 48% equity interest in Knight Hawk, a coal producer in the Illinois Basin. The Company holds a general partnership interest in Dominion Terminal Associates (“DTA”), which is accounted for under the equity method. In March 2017, the Company paid $7.2 million through an auction process held by one of the existing owners, increasing its ownership in DTA from 21.875% to 35% . DTA operates a ground storage-to-vessel coal transloading facility in Newport News, Virginia for use by the partners. Under the terms of a throughput and handling agreement with DTA, each partner is charged its share of cash operating and debt-service costs in exchange for the right to use the facility’s loading capacity and is required to make periodic cash advances to DTA to fund such costs.

Preference Rights Lease Applica

Preference Rights Lease Application (PRLA) Settlement Income	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Preference Rights Lease Application (PRLA) Settlement Income	Preference Rights Lease Application Settlement Income The Company recorded a $39.0 million gain during the third quarter of 2019 related to a settlement with the United States Department of Interior over a long-standing dispute, dating back to the 1970’s, on the valuation and disposition of Preference Rights Lease Application that Arch controlled in northwestern New Mexico with a joint venture partner. As part of the settlement, Arch received $67.0 million in the form of royalty credits on its federal coal leases which will be used to settle 50% of the Company’s monthly royalty obligations. Additionally, as part of the settlement, Arch made a one-time payment of $27.0 million to its’ partner in the venture for its ownership interest in the underlying mineral reserves, as well as paying $1.0 million in closing fees. The Company has utilized $13.3 million of the royalty credits as of December 31, 2019 , and based on current planned production levels and sales commitments, anticipates the majority of the remaining balance will be monetized by the end of the 2020 calendar year.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2019
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories consist of the following: December 31, 2019 December 31, 2018 (In thousands) Coal $ 46,815 $ 40,982 Repair parts and supplies 84,083 84,488 $ 130,898 $ 125,470 The repair parts and supplies are stated net of an allowance for slow-moving and obsolete inventories of $2.2 million at December 31, 2019 and $0.6 million at December 31, 2018 .

Investments in Available-for-Sa

Investments in Available-for-Sale Securities	12 Months Ended
	Dec. 31, 2019
Debt Securities, Available-for-sale [Abstract]
Investments in Available-for-Sale Securities	Investments in Available-for-Sale Securities The Company has invested in marketable debt securities, primarily highly liquid U.S Treasury securities and investment grade corporate bonds. These investments are held in the custody of a major financial institution. These securities are classified as available-for-sale securities and, accordingly, the unrealized gains and losses are recorded through other comprehensive income. The Company’s investments in available-for-sale marketable securities are as follows: December 31, 2019 Balance Sheet Gross Gross Classification Unrealized Unrealized Fair Short-Term Cost Basis Gains Losses Value Investments (In thousands) Available-for-sale: U.S. government and agency securities $ 35,044 $ 1 $ (16 ) $ 35,029 $ 35,029 Corporate notes and bonds 100,643 200 (205 ) 100,638 100,638 Total Investments $ 135,687 $ 201 $ (221 ) $ 135,667 $ 135,667 December 31, 2018 Balance Sheet Gross Gross Classification Unrealized Unrealized Fair Short-Term Cost Basis Gains Losses Value Investments (In thousands) Available-for-sale: U.S. government and agency securities $ 100,003 $ 11 $ (126 ) $ 99,888 $ 99,888 Corporate notes and bonds 63,137 4 (232 ) 62,909 62,909 Total Investments $ 163,140 $ 15 $ (358 ) $ 162,797 $ 162,797 The aggregate fair value of investments with unrealized losses that had been owned for less than a year was $72.3 million and $115.2 million at December 31, 2019 and 2018 , respectively. The aggregate fair value of investments with unrealized losses that have been owned for over a year was $0.0 million and $32.4 million at December 31, 2019 and 2018 , respectively. The debt securities outstanding at December 31, 2019 have maturity dates ranging from the first quarter of 2020 through the second quarter of 2021 . The Company classifies its investments as current based on the nature of the investments and their availability to provide cash for use in current operations, if needed.

Equity Method Investments and M

Equity Method Investments and Membership Interests in Joint Ventures	12 Months Ended
	Dec. 31, 2019
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investments and Membership Interests in Joint Ventures	Joint Venture with Peabody Energy On June 18, 2019, Arch Coal entered into a definitive implementation agreement (the “Implementation Agreement”) with Peabody Energy Corporation (“Peabody”), to establish a joint venture that will combine the respective Powder River Basin and Colorado mining operations of Arch Coal and Peabody. Pursuant to the terms of the Implementation Agreement, Arch Coal will hold a 33.5% economic interest, and Peabody will hold a 66.5% economic interest in the joint venture. At the closing of the joint venture transaction, certain of the respective subsidiaries of Arch Coal and Peabody will enter into an Amended and Restated Limited Liability Company Agreement (the “LLC Agreement”). Under the terms of the LLC Agreement, the governance of the joint venture will be overseen by the joint venture’s board of managers, which will initially be comprised of three representatives appointed by Peabody and two representatives appointed by Arch. Decisions of the board of managers will be determined by a majority vote subject to certain specified matters set forth in the LLC Agreement that will require a supermajority vote. Peabody, or one of its affiliates, will initially be appointed as the operator of the joint venture and will manage the day-to-day operations of the joint venture, subject to the supervision of the joint venture’s board of managers. Formation of the joint venture is subject to customary closing conditions, including the termination or expiration of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, the receipt of certain other required regulatory approvals and the absence of injunctions or other legal restraints preventing the formation of the joint venture. Formation of the joint venture does not require approval of the respective stockholders of either Arch or Peabody. The Company has incurred expenses of $13.8 million during the year ended December 31, 2019 associated with the regulatory approval process of the joint venture. Equity Method Investments and Membership Interests in Joint Ventures The Company accounts for its investments and membership interests in joint ventures under the equity method of accounting if the Company has the ability to exercise significant influence, but not control, over the entity. Equity method investments are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the investments may not be recoverable. Below are the equity method investments reflected in the consolidated balance sheets: (In thousands) Knight Hawk DTA Total December 31, 2017 $ 90,166 $ 15,941 $ 106,107 Advances to (distributions from) affiliates, net (10,534 ) 2,481 (8,053 ) Equity in comprehensive income (loss) 10,389 (3,767 ) 6,622 December 31, 2018 $ 90,021 $ 14,655 $ 104,676 Sale of investment in affiliates (1,879 ) — (1,879 ) Advances to (distributions from) affiliates, net (5,884 ) 5,500 (384 ) Equity in comprehensive income (loss) 7,953 (4,778 ) 3,175 December 31, 2019 $ 90,211 $ 15,377 $ 105,588 In December 2019, the Company sold 1% of its ownership interest in Knight Hawk Holdings, LLC (“Knight Hawk”) to a third party for $2.0 million . After the transaction, the Company holds a 48% equity interest in Knight Hawk, a coal producer in the Illinois Basin. The Company holds a general partnership interest in Dominion Terminal Associates (“DTA”), which is accounted for under the equity method. In March 2017, the Company paid $7.2 million through an auction process held by one of the existing owners, increasing its ownership in DTA from 21.875% to 35% . DTA operates a ground storage-to-vessel coal transloading facility in Newport News, Virginia for use by the partners. Under the terms of a throughput and handling agreement with DTA, each partner is charged its share of cash operating and debt-service costs in exchange for the right to use the facility’s loading capacity and is required to make periodic cash advances to DTA to fund such costs.

Derivatives

Derivatives	12 Months Ended
	Dec. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	Derivatives Interest rate risk management The Company has entered into interest rate swaps to reduce the variability of cash outflows associated with interest payments on its variable rate term loan. These swaps have been designated as cash flow hedges. For additional information on these arrangements, see Note 13 , “ Debt and Financing Arrangements ” in the Consolidated Financial Statements. Diesel fuel price risk management The Company is exposed to price risk with respect to diesel fuel purchased for use in its operations. The Company anticipates purchasing approximately 34 to 40 million gallons of diesel fuel for use in its operations during 2020 . To protect the Company’s cash flows from increases in the price of diesel fuel for its operations, the Company uses forward physical diesel purchase contracts and purchased heating oil call options. At December 31, 2019 , the Company had heating oil call options for approximately 10.1 million gallons at an average strike price of $2.28 . These positions are not designated as hedges for accounting purposes, and therefore, changes in the fair value are recorded immediately to earnings. Coal risk management positions The Company may sell or purchase forward contracts, swaps and options in the over-the-counter coal market in order to manage its exposure to coal prices. The Company has exposure to the risk of fluctuating coal prices related to forecasted sales or purchases of coal or to the risk of changes in the fair value of a fixed price physical sales contract. Certain derivative contracts may be designated as hedges of these risks. At December 31, 2019 , the Company held derivatives for risk management purposes that are expected to settle in the following years: (Tons in thousands) 2020 2021 Total Coal sales 668 — 668 Coal purchases 668 — 668 The Company may also enter into natural gas options to protect the Company from decreases in natural gas prices, which could impact thermal coal demand. These options are not designated as hedges. Coal trading positions The Company may sell or purchase forward contracts, swaps and options in the over-the-counter coal market for trading purposes. The Company is exposed to the risk of changes in coal prices on the value of its coal trading portfolio. The unrecognized losses of $0.5 million in the trading portfolio are expected to be realized in 2020 . Tabular derivatives disclosures The Company has master netting agreements with all of its counterparties which allow for the settlement of contracts in an asset position with contracts in a liability position in the event of default or termination. Such netting arrangements reduce the Company’s credit exposure related to these counterparties. For classification purposes, the Company records the net fair value of all the positions with a given counterparty as a net asset or liability in the consolidated balance sheets. The amounts shown in the table below represent the fair value position of individual contracts, and not the net position presented in the accompanying consolidated balance sheets. The fair value and location of derivatives reflected in the accompanying consolidated balance sheets are as follows: December 31, 2019 December 31, 2018 Fair Value of Derivatives Asset Liability Asset Liability (In thousands) Derivative Derivative Derivative Derivative Derivatives Designated as Hedging Instruments Coal $ 1,351 $ (962 ) $ 2,342 $ (805 ) Derivatives Not Designated as Hedging Instruments Heating oil -- diesel purchases 133 (112 ) 532 — Coal held for trading purposes, exchange traded swaps and futures 18,467 (18,940 ) 10,329 (10,701 ) Coal -- risk management 11,662 (5,856 ) 5,672 (19,579 ) Natural gas 3 — 4 (4 ) Total $ 30,265 (24,908 ) $ 16,537 $ (30,284 ) Total derivatives $ 31,616 $ (25,870 ) $ 18,879 $ (31,089 ) Effect of counterparty netting (25,759 ) 25,759 (17,801 ) 17,801 Net derivatives as classified in the balance sheets $ 5,857 $ (111 ) $ 5,746 $ 1,078 $ (13,288 ) $ (12,210 ) December 31, 2019 December 31, 2018 Net derivatives as reflected on the balance sheets Heating oil Other current assets $ 133 $ 532 Coal Other current assets 5,724 546 Accrued expenses and other current liabilities (111 ) (13,288 ) $ 5,746 $ (12,210 ) The Company had a current liability representing cash collateral owed to a margin account for derivative positions primarily related to coal derivatives of $4.4 million at December 31, 2019 and a current asset of $24.7 million at December 31, 2018 representing cash collateral posted to a margin account, respectively. These amounts are not included with the derivatives presented in the table above and are included in “accrued expenses and other current liabilities” and “other current assets” in the accompanying Consolidated Balance Sheets. The effects of derivatives on measures of financial performance are as follows: Derivatives used in Cash Flow Hedging Relationships (in thousands) For the noted periods, Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion) Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 Coal sales (1) $ 10,249 $ (7,517 ) $ (2,127 ) Coal purchases (2) (1,231 ) 1,348 942 $ 9,018 $ (6,169 ) $ (1,185 ) Gains (Losses) Reclassified from Other Comprehensive Income into Income Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 Coal sales $ 10,167 $ (10,912 ) $ — Coal purchases (686 ) 2,707 — $ 9,481 $ (8,205 ) $ — No ineffectiveness or amounts excluded from effectiveness testing relating to the Company’s cash flow hedging relationships were recognized in the results of operations in the respective periods. Derivatives Not Designated as Hedging Instruments (in thousands) For the noted periods, Gain (Loss) Recognized Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 Coal trading— realized and unrealized (3) $ (1,013 ) $ 135 $ (2,047 ) Coal risk management— unrealized (3) 19,713 (9,530 ) (4,648 ) Natural gas trading — realized and unrealized (3) (99 ) 277 (527 ) Change in fair value of coal derivatives and coal trading activities, net total $ 18,601 $ (9,118 ) $ (7,222 ) Coal risk management — realized (4) $ 487 $ (8,734 ) $ — Heating oil — diesel purchases (4) $ (2,291 ) $ (505 ) $ (1,057 ) Location in income statement: (1) — Revenues (2) — Cost of sales (3) — Change in fair value of coal derivatives and coal trading activities, net (4) — Other operating income, net Based on fair values at December 31, 2019 , amounts on derivative contracts designated as hedge instruments in cash flow hedges expected to be reclassified from other comprehensive income into earnings during the next twelve months are gains of $0.4 million .

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Dec. 31, 2019
Accrued Expenses and Other Current Liabilities [Abstract]
Accrued Expenses and Other Current Liabilities	Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consist of the following: December 31, 2019 December 31, 2018 (In thousands) Payroll and employee benefits $ 50,929 $ 57,166 Taxes other than income taxes 69,061 75,017 Interest 133 156 Workers’ compensation 16,119 20,044 Asset retirement obligations 10,366 13,113 Other 10,559 18,018 $ 157,167 $ 183,514

Debt and Financing Arrangements

Debt and Financing Arrangements	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Debt and Financing Arrangements	Debt and Financing Arrangements December 31, 2019 December 31, 2018 (In thousands) Term loan due 2024 ($291.8 and $294.8 million face value, respectively) $ 290,825 $ 293,626 Other 25,007 30,449 Debt issuance costs (5,013 ) (6,092 ) $ 310,819 $ 317,983 Less current maturities of debt 20,753 17,797 Long-term debt $ 290,066 $ 300,186 Term Loan Facility In 2017, the Company entered into a senior secured term loan credit agreement in an aggregate principal amount of $300 million (the “Term Loan Debt Facility”) with Credit Suisse AG, Cayman Islands Branch, as administrative agent and collateral agent (in such capacities, the “Agent”), and the other financial institutions from time to time party thereto (collectively, the “Lenders”). The Term Loan Debt Facility was issued at 99.50% of the face amount and will mature on March 7, 2024. The term loans provided under the Term Loan Debt Facility (the “Term Loans”) are subject to quarterly principal amortization payments in an amount equal to $750,000 . During 2018, the Company entered into the Second Amendment (the “Second Amendment”) to its Term Loan Debt Facility. The Second Amendment further reduced the interest rate on its Term Loan Debt Facility to, at the option of Arch Coal, either (i) the London interbank offered rate (“LIBOR”) plus an applicable margin of 2.75% , subject to a 1.00% LIBOR floor, or (ii) a base rate plus an applicable margin of 1.75% . The Second Amendment also resets the 1.00% call premium to apply to repricing events that occur on or prior to October 3, 2018. The LIBOR floor remains at 1.00% . There is no change to the maturities as a result of the Second Amendment. The Term Loan Debt Facility is guaranteed by all existing and future wholly owned domestic subsidiaries of the Company (collectively, the “Subsidiary Guarantors” and, together with Arch Coal, the “Loan Parties”), subject to customary exceptions, and is secured by first priority security interests on substantially all assets of the Loan Parties, including 100% of the voting equity interests of directly owned domestic subsidiaries and 65% of the voting equity interests of directly owned foreign subsidiaries, subject to customary exceptions. The Company has the right to prepay Term Loans at any time and from time to time in whole or in part without premium or penalty, upon written notice, except that any prepayment of Term Loans that bear interest at the LIBOR Rate other than at the end of the applicable interest periods therefor shall be made with reimbursement for any funding losses and redeployment costs of the Lenders resulting therefrom. The Term Loan Debt Facility is subject to certain usual and customary mandatory prepayment events, including 100% of net cash proceeds of (i) debt issuances (other than debt permitted to be incurred under the terms of the New Term Loan Debt Facility) and (ii) non-ordinary course asset sales or dispositions, subject to customary thresholds, exceptions and reinvestment rights. The Term Loan Debt Facility contains customary affirmative covenants and representations. The Term Loan Debt Facility also contains customary negative covenants, which, among other things, and subject to certain exceptions, include restrictions on (i) indebtedness, (ii) liens, (iii) liquidations, mergers, consolidations and acquisitions, (iv) disposition of assets or subsidiaries, (v) affiliate transactions, (vi) creation or ownership of certain subsidiaries, partnerships and joint ventures, (vii) continuation of or change in business, (viii) restricted payments, (ix) prepayment of subordinated and junior lien indebtedness, (x) restrictions in agreements on dividends, intercompany loans and granting liens on the collateral, (xi) loans and investments, (xii) sale and leaseback transactions, (xiii) changes in organizational documents and fiscal year and (xiv) transactions with respect to bonding subsidiaries. The New Term Loan Debt Facility does not contain any financial maintenance covenant. The Term Loan Debt Facility contains customary events of default, subject to customary thresholds and exceptions, including, among other things, (i) nonpayment of principal and nonpayment of interest and fees, (ii) a material inaccuracy of a representation or warranty at the time made, (iii) a failure to comply with any covenant, subject to customary grace periods in the case of certain affirmative covenants, (iv) cross-events of default to indebtedness of at least $50 million , (v) cross-events of default to surety, reclamation or similar bonds securing obligations with an aggregate face amount of at least $50 million , (vi) uninsured judgments in excess of $50 million , (vii) any loan document shall cease to be a legal, valid and binding agreement, (viii) uninsured losses or proceedings against assets with a value in excess of $50 million , (ix) certain ERISA events, (x) a change of control or (xi) bankruptcy or insolvency proceedings relating to the Company or any material subsidiary of the Company. Accounts Receivable Securitization Facility In 2018, the Company extended and amended its existing trade accounts receivable securitization facility provided to Arch Receivable Company, LLC, a special-purpose entity that is a wholly owned subsidiary of Arch Coal (“Arch Receivable”) (the “Extended Securitization Facility”), which supports the issuance of letters of credit and requests for cash advances. The amendment to the Extended Securitization Facility maintained the $160 million borrowing capacity and extended the maturity date to the date that is three years after the Securitization Facility Closing Date. Additionally, the amendment provided the Company the opportunity to use credit insurance to increase the pool of eligible receivables for borrowing. Pursuant to the Extended Securitization Facility, Arch Receivable also agreed to a revised schedule of fees payable to the administrator and the providers of the Extended Securitization Facility. The Extended Securitization Facility will terminate at the earliest of (i) three years from the Securitization Facility Closing Date, (ii) if the Liquidity (defined in the Extended Securitization Facility and consistent with the definition in the Inventory Facility) is less than $175 million for a period of 60 consecutive days, the date that is the 364 th day after the first day of such 60 consecutive day period and (iii) the occurrence of certain predefined events substantially consistent with the existing transaction documents. Under the Extended Securitization Facility, Arch Receivable, Arch Coal and certain of Arch Coal’s subsidiaries party to the Extended Securitization Facility have granted to the administrator of the Extended Securitization Facility a first priority security interest in eligible trade accounts receivable generated by such parties from the sale of coal and all proceeds thereof. As of December 31, 2019 , letters of credit totaling $15.5 million were outstanding under the facility with $108.9 million of additional availability for borrowings. Inventory-Based Revolving Credit Facility In 2017, the Company and certain subsidiaries of Arch Coal entered into a senior secured inventory-based revolving credit facility in an aggregate principal amount of $40 million (the “Inventory Facility”) with Regions Bank (“Regions”) as administrative agent and collateral agent, as lender and swingline lender (in such capacities, the “Lender”) and as letter of credit issuer. Availability under the Inventory Facility is subject to a borrowing base consisting of (i) 85% of the net orderly liquidation value of eligible coal inventory, (ii) the lesser of (x) 85% of the net orderly liquidation value of eligible parts and supplies inventory and (y) 35% of the amount determined pursuant to clause (i), and (iii) 100% of Arch Coal’s Eligible Cash (defined in the Inventory Facility), subject to reduction for reserves imposed by Regions. In 2018, the Company and certain subsidiaries of Arch Coal amended and extended the Inventory Facility by increasing the facility size by $10 million bringing the total aggregate principal amount available to $50 million , subject to borrowing base calculations described above. The commitments under the Inventory Facility will terminate on the date that is the earliest to occur of (i) the date, if any, that is 364 days following the first day that Liquidity (defined in the Inventory Facility and consistent with the definition in the Extended Securitization Facility (as defined below)) is less than $250 million for a period of 60 consecutive days and (ii) the date, if any, that is 60 days following the maturity, termination or repayment in full of the Extended Securitization Facility. Revolving loan borrowings under the Inventory Facility bear interest at a per annum rate equal to, at the option of Arch Coal, either the base rate or the London interbank offered rate plus, in each case, a margin ranging from 2.00% to 2.50% (in the case of LIBOR loans) and 1.00% to 1.50% (in the case of base rate loans) determined using a Liquidity-based grid. Letters of credit under the New Inventory Facility are subject to a fee in an amount equal to the applicable margin for LIBOR loans, plus customary fronting and issuance fees. All existing and future direct and indirect domestic subsidiaries of Arch Coal, subject to customary exceptions, will either constitute co-borrowers under or guarantors of the Inventory Facility (collectively with the Company, the “Loan Parties”). The Inventory Facility is secured by first priority security interests in the ABL Priority Collateral (defined in the Inventory Facility) of the Loan Parties and second priority security interests in substantially all other assets of the Loan Parties, subject to customary exceptions (including an exception for the collateral that secures the Extended Securitization Facility). Arch Coal has the right to prepay borrowings under the Inventory Facility at any time and from time to time in whole or in part without premium or penalty, upon written notice, except that any prepayment of such borrowings that bear interest at the LIBOR rate other than at the end of the applicable interest periods therefore shall be made with reimbursement for any funding losses and redeployment costs of the Lender resulting therefrom. The Inventory Facility is subject to certain usual and customary mandatory prepayment events, including non-ordinary course asset sales or dispositions, subject to customary thresholds, exceptions (including exceptions for required prepayments under the Arch Coal’s term loan facility) and reinvestment rights. The Inventory Facility contains certain customary affirmative and negative covenants; events of default, subject to customary thresholds and exceptions; and representations, including certain cash management and reporting requirements that are customary for asset-based credit facilities. The Inventory Facility also includes a requirement to maintain Liquidity equal to or exceeding $175 million at all times. As of December 31, 2019 , letters of credit totaling $35.9 million were outstanding under the facility with $14.1 million additional availability for borrowings. Interest Rate Swaps The Company has entered into a series of interest rate swaps to fix a portion of the LIBOR interest payments due under the term loan. The interest rate swaps qualify for cash flow hedge accounting treatment and as such, the change in the fair value of the interest rate swaps are recorded on the Company’s Consolidated Balance Sheet as an asset or liability with the effective portion of the gains or losses reported as a component of accumulated other comprehensive income and the ineffective portion reported in earnings. As interest payments are made on the term loan, amounts in accumulated other comprehensive income will be reclassified into earnings through interest expense to reflect a net interest on the term loan equal to the effective yield of the fixed rate of the swap plus 2.75% which is the spread on the revised LIBOR term loan. In the event that an interest rate swap is terminated prior to maturity, gains or losses in accumulated other comprehensive income will remain deferred and reclassified into earnings in the periods which the hedged forecasted transaction affects earnings. Below is a summary of the Company’s outstanding interest rate swap agreements designated as hedges as of December 31, 2019 : Notional Amount (in millions) Effective Date Fixed Rate Receive Rate Expiration Date $250.0 June 28, 2019 2.025% 1-month LIBOR June 30, 2020 $200.0 June 30, 2020 2.249% 1-month LIBOR June 30, 2021 $100.0 June 30, 2021 2.315% 1-month LIBOR June 30, 2023 The fair value of the interest rate swaps at December 31, 2019 is a liability of $3.0 million which is recorded within Other noncurrent liabilities with the offset to accumulated other comprehensive income on the Company’s Consolidated Balance Sheet. The Company realized $1.1 million and $1.2 million of gains , and $0.1 million of losses during the years ended December 31, 2019 , 2018 and 2017 , respectively, related to settlements of the interest rate swaps which were recorded to interest expense on the Company’s Consolidated Income Statements. The interest rate swaps are classified as level 2 within the fair value hierarchy. Debt Maturities The contractual maturities of debt as of December 31, 2019 are as follows: Year (In thousands) 2020 $ 21,863 2021 8,853 2022 3,130 2023 3,161 2024 279,750 Thereafter — $ 316,757 Financing Costs The Company paid financing costs of $0.0 million , $1.3 million and $10.1 million during the years ended December 31, 2019 , 2018 and 2017 , respectively.

Taxes

Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Taxes	Taxes The Company provides for deferred income taxes for temporary differences arising from differences between the financial statement and tax basis of assets and liabilities existing at each balance sheet date using enacted tax rates expected to be in effect when the related taxes are expected to be paid or recovered. The Company initially recognizes the effects of a tax position when it is more than 50 percent likely, based on the technical merits, that that position will be sustained upon examination, including resolution of the related appeals or litigation processes, if any. The Company’s determination of whether or not a tax position has met the recognition threshold considers the facts, circumstances, and information available at the reporting date. The Company reassesses our ability to realize deferred tax assets annually in the fourth quarter, during the annual budget process, or when circumstances indicate that the ability to realize deferred tax assets has changed. The assessment takes into account expectations of future taxable income or loss, available tax planning strategies and the reversal of temporary differences. The development of these expectations involves the use of estimates such as production levels, operating profitability, timing of development activities and the cost and timing of reclamation work. A valuation allowance may be recorded to reflect the amount of future tax benefits that the Company believes are not likely to be realized. A valuation allowance is difficult to avoid when a company is in a cumulative loss position. A cumulative loss position is defined as a cumulative pre-tax loss for the current and two preceding years. Because of the 2016 bankruptcy, the Company was in a cumulative loss position in 2017 and 2018. As a cumulative loss constitutes significant negative evidence with regards to future taxable income, in 2017 and 2018, the Company relied solely on the expected reversal of taxable temporary differences to support the future realization of our deferred tax assets. As of December 31, 2019, the Company is no longer in a cumulative loss position. In 2019, the Company’s assessment took into account expectations of future taxable income, available tax planning strategies and the reversal of temporary differences. Based on significant near-term uncertainty in market pricing and uncertainty surrounding other planned changes in our operating structure, the Company will not release the valuation allowance in 2019. As of December 31, 2019, the Company had a valuation allowance against its deferred tax assets of $506.3 million . If actual outcomes differ from our expectations, the Company may adjust its valuation allowance through income tax expense in the period such determination is made. Due to changes in ownership that occurred in connection with the Company’s emergence from bankruptcy in 2016, there was a change in ownership for purposes of IRC Section 382. Section 382 provides a combined annual limitation with respect to the ability of a corporation to use its NOLs, AMT credits and capital loss carryforwards generated before the ownership change against future taxable income. The Company’s annual limit under IRC section 382 is estimated to be $29.8 million . The Company had a net unrealized built-in gain, based on comparing the fair value and carryover tax basis in assets, at the time of the ownership change, therefore, certain built-in gains recognized within five years after the ownership change will increase the annual IRC section 382 limit for the five year recognition period beginning October 1, 2016 through September 30, 2021. There is uncertainty surrounding which assets with built-in gain will be realized within the five year period following the Company’s emergence from bankruptcy and allow the Company to realize the incremental net operating losses and credit in excess of the base 382 limitation. The Company is reflecting a deferred tax asset for the full amount of the net operating losses and credit carryforwards. If at some point in time it becomes evident that some portion of the deferred tax assets will not be realizable, the deferred tax asset, and offsetting valuation allowance will be reduced. During 2018, the IRS completed an audit of AMT NOL carryback claims the Company filed in prior periods. In addition, the Company filed an amended 2016 tax return which changed the amount of available tax attributes and the mix used to offset its bankruptcy CODI as of January 1, 2017. As a result, the Company increased available AMT credits and reduced other tax attributes as of that date. The AMT credits do not require a valuation allowance to be recorded against them due to the law changes enacted as part of the Tax Cut and Jobs Act of 2017 (“the Act”), while the Company’s other tax attributes are fully offset by a valuation allowance. The associated valuation allowance release related to the shift in attributes reflects what the Company believes will be realized upon audit of the amended tax return filing. The Company anticipates that all AMT credits will be converted to cash in the next three years as provided by The Act. In total, these changes resulted in a recorded benefit from income taxes of $48.8 million , which was net of a $26.6 million uncertain tax position charge. The Company is subject to U.S. federal income tax as well as income tax in multiple state jurisdictions. The tax years 2008 through 2019 remain open to examination for U.S. federal income tax matters and 1999 through 2019 remain open to examination for various state income tax matters. Significant components of the provision for (benefit from) income taxes are as follows: Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 (In thousands) Current: Federal $ (36 ) $ 86 $ 835 State 124 136 31 Total current $ 88 $ 222 $ 866 Deferred: Federal 667 (52,309 ) (36,162 ) State (507 ) (389 ) 41 Total deferred $ 160 $ (52,698 ) $ (36,121 ) $ 248 $ (52,476 ) $ (35,255 ) A reconciliation of the statutory federal income tax provision (benefit) at the statutory rate to the actual provision for (benefit from) income taxes follows: Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 (In thousands) Income tax provision (benefit) at statutory rate $ 49,150 $ 54,621 $ 71,118 Percentage depletion allowance (17,743 ) (17,725 ) (31,255 ) State taxes, net of effect of federal taxes (12,769 ) 4,480 7,002 Change in valuation allowance (24,206 ) (79,961 ) (410,983 ) Impact of Tax Cuts and Jobs Act of 2017 — (17,645 ) 332,345 Other, net 5,816 3,754 (3,482 ) Provision for (benefit from) income taxes $ 248 $ (52,476 ) $ (35,255 ) Significant components of the Company’s deferred tax assets and liabilities that result from carryforwards and temporary differences between the financial statement basis and tax basis of assets and liabilities are summarized as follows: December 31, 2019 December 31, 2018 (In thousands) Deferred tax assets: Tax loss carryforwards $ 294,535 $ 307,615 Tax credit carryforwards 5,297 5,394 Investment in partnerships 190,418 193,217 Other 20,387 28,747 Gross deferred tax assets $ 510,637 $ 534,973 Valuation allowance (506,316 ) (530,612 ) Total deferred tax assets $ 4,321 $ 4,361 Deferred tax liabilities: Plant and equipment 2,063 3,037 Other 2,178 1,154 Total deferred tax liabilities $ 4,241 $ 4,191 Net deferred tax asset $ 80 $ 170 The Company has gross federal NOL carryforwards for regular income tax purposes of $1.0 billion at December 31, 2019 that will expire between 2029 and 2037 . The future annual usage of NOLs will be limited under IRC section 382. On December 22, 2017, the Act was signed into law making significant changes to the Internal Revenue Code. The Company provided its best estimate of the impact of the Act at December 31, 2017 and during 2018 completed its analysis as provided by SAB 118. The Company has recorded the impact of the Act in its year-end income tax provision in accordance with the guidance and interpretations available. The following items have been impacted by the Act: • Remeasurement of deferred taxes: Deferred tax assets and liabilities attributable to the U.S. were remeasured from 35% to the reduced tax rate of 21%. The amount related to the remeasurement of certain deferred tax assets and liabilities based on the rates at which they are expected to reverse in the future was $330.9 million of income tax expense in 2017 and $16.7 million of income tax benefit in 2018, related to the 2016 amended return filing, with offsetting valuation allowance adjustments. • One-time transition tax on mandatory deemed repatriation of cumulative foreign earnings: The amount of income tax expense related to the mandatory deemed repatriation of foreign earnings was $1.5 million based on cumulative foreign earnings of $4.2 million . The deemed repatriation tax is completely offset with net operating loss carryforwards, with an offsetting valuation allowance adjustment and will not result in a cash tax liability. • Elimination of the corporate AMT regime: Existing AMT credits as of December 31, 2018 will be refunded during 2019 through 2022. The Company has determined that it will receive a refund of existing AMT credits of approximately $45.0 million , net of a $26.6 million uncertain tax position charge. The valuation allowance previously recorded against these credits was released in 2017. The credits were reflected as a deferred tax asset. In 2018, the credits were reclassified from a deferred tax asset to short term and long term receivables. • Elimination of executive compensation exemptions: The Act made changes to the $1 million limit on deductible compensation paid to certain “covered” employees. The Act eliminated exemptions for qualified performance based compensation and compensation paid after termination and expanded the number of employees to which the limit applies. The Company recorded an amount of $0.2 million of tax expense in 2017, $6.1 million of tax expense in 2018 and $3.9 million of tax expense in 2019, with an offsetting valuation allowance adjustment. • Other provisions in the Act such as global intangible low-taxed income “GILTI” rules covering foreign income earned in low-tax countries, base-erosion and anti-abuse tax “BEAT,” and the foreign derived intangible income “FDII” deduction will have no material impact on the company At December 31, 2017 additional tax losses were realized primarily as a result of the reversal of deductible temporary differences and percentage depletion. A $35.7 million benefit was recorded from the release of valuation allowance offsetting alternative minimum tax credits that have become refundable by the Act, as well as carryback claims filed in the fourth quarter related to specific liability losses that resulted in claims for refund of previously paid alternative minimum taxes. At December 31, 2017 a $610.6 million valuation allowance fully offsets all net deferred tax assets, other than alternative minimum tax credits. At December 31, 2018, the valuation allowance related to sequestration on the AMT credits has been released and the credits have been reclassified from deferred tax assets to short and long term receivables, as all AMT credits will be refunded between 2019 through 2022. The impact of the 2016 amended return and finalization of the AMT NOL 10-yr carryback claims also affects NOLs, AMT credits and the investment in partnerships. A $530.6 million valuation allowance fully offsets all net deferred tax assets. At December 31, 2019, a $24.2 million benefit was recorded from the release of valuation allowance offsetting federal and state net operating losses used to offset current year taxable income. A $506.3 million valuation allowance fully offsets all net deferred tax assets. A reconciliation of the beginning and ending amounts of gross unrecognized tax benefits follows: (In thousands) Balance at December 31, 2016 $ 7,455 Additions based on tax positions related to the current year — Additions for tax positions of prior years 3,928 Reductions as a result of lapses in the statute of limitations — Balance at December 31, 2017 11,383 Additions based on tax positions of prior years 28,387 Additions for tax positions related to the current year 3,228 Reductions for tax positions of prior years (634 ) Reductions as a result of lapses in the statute of limitations (3,271 ) Balance at December 31, 2018 39,093 Additions for tax positions related to the current year 2,980 Reductions for tax positions of prior years (1,970 ) Reductions as a result of lapses in the statute of limitations $ (374 ) Balance at December 31, 2019 $ 39,729 If recognized, the entire amount of the gross unrecognized tax benefits at December 31, 2019 would affect the effective tax rate. The Company recognizes interest and penalties related to unrecognized tax benefits in income tax expense. The Company had accrued interest and penalties of $0.8 million and $0.3 million at December 31, 2019 and 2018 , respectively. In the next 12 months, $0.5 million

Asset Retirement Obligations

Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2019
Asset Retirement Obligation [Abstract]
Asset Retirement Obligations	Asset Retirement Obligations The Company’s asset retirement obligations arise from the Federal Surface Mining Control and Reclamation Act of 1977 and similar state statutes, which require that mine property be restored in accordance with specified standards and an approved reclamation plan. The required reclamation activities to be performed are outlined in the Company’s mining permits. These activities include reclaiming the pit and support acreage at surface mines, sealing portals at underground mines, reclaiming refuse areas and slurry ponds and water treatment. The following table describes the changes to the Company’s asset retirement obligation liability: Year Ended December 31, 2019 Year Ended December 31, 2018 (In thousands) Balance at beginning of period (including current portion) $ 243,417 $ 328,695 Accretion expense 20,548 27,970 Obligations of divested operations (12,185 ) — Adjustments to the liability from changes in estimates 11,438 (100,728 ) Liabilities settled (10,420 ) (12,520 ) Balance at period end $ 252,798 $ 243,417 Current portion included in accrued expenses (10,366 ) (13,113 ) Noncurrent liability $ 242,432 $ 230,304 The reduction in the asset retirement obligation during the year ended December 31, 2018 primarily relates to a revised mining and reclamation plan at the Company’s Black Thunder Mine. The revised plan provides for accelerated mine reclamation during the ordinary mining process, which significantly reduces the size of the mine’s open pit at the time of final reclamation. The change reduced the asset retirement obligation, and corresponding deferred mine development asset on the Company’s balance sheet by $95.6 million . As of December 31, 2019 , the Company had $528.9 million in surety bonds outstanding and no letters of credit to secure reclamation bonding obligations. Additionally, the Company has posted $0.6 million

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The hierarchy of fair value measurements assigns a level to fair value measurements based on the inputs used in the respective valuation techniques. The levels of the hierarchy, as defined below, give the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. · Level 1 is defined as observable inputs such as quoted prices in active markets for identical assets. Level 1 assets include available-for-sale equity securities, U.S. Treasury securities, and coal swaps and futures that are submitted for clearing on the New York Mercantile Exchange. · Level 2 is defined as observable inputs other than Level 1 prices. These include quoted prices for similar assets or liabilities in an active market, quoted prices for identical assets and liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. The Company’s level 2 assets and liabilities include U.S. government agency securities, coal commodity contracts and interest rate swaps with fair values derived from quoted prices in over-the-counter markets or from prices received from direct broker quotes. · Level 3 is defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions. These include the Company’s commodity option contracts (coal and heating oil) valued using modeling techniques, such as Black-Scholes, that require the use of inputs, particularly volatility, that are rarely observable. Changes in the unobservable inputs would not have had a significant impact on the reported Level 3 fair values at December 31, 2019 and 2018 . The table below sets forth, by level, the Company’s financial assets and liabilities that are recorded at fair value in the accompanying consolidated balance sheet: Fair Value at December 31, 2019 Total Level 1 Level 2 Level 3 (In thousands) Assets: Investments in marketable securities $ 135,667 $ 35,029 $ 100,638 $ — Derivatives 5,857 5,269 527 61 Total assets $ 141,524 $ 40,298 $ 101,165 $ 61 Liabilities: Derivatives $ 3,065 $ — $ 3,065 $ — Fair Value at December 31, 2018 Total Level 1 Level 2 Level 3 (In thousands) Assets: Investments in marketable securities $ 162,797 $ 99,888 $ 62,909 $ — Derivatives 3,554 — 3,022 532 Total assets $ 166,351 $ 99,888 $ 65,931 $ 532 Liabilities: Derivatives $ 13,288 $ 13,252 $ 36 $ — The Company’s contracts with its counterparties allow for the settlement of contracts in an asset position with contracts in a liability position in the event of default or termination. For classification purposes, the Company records the net fair value of all the positions with these counterparties as a net asset or liability. Each level in the table above displays the underlying contracts according to their classification in the accompanying consolidated balance sheet, based on this counterparty netting. The following table summarizes the change in the fair values of financial instruments categorized as level 3. Year Ended December 31, 2019 Year Ended December 31, 2018 (In thousands) Balance, beginning of period $ 532 $ 5,426 Realized and unrealized (gains) losses recognized in earnings, net (1,893 ) (302 ) Purchases 1,597 3,420 Issuances (208 ) (724 ) Settlements 33 (7,288 ) Ending balance $ 61 $ 532 Net unrealized losses of $1.2 million were recognized during the year ended December 31, 2019 related to level 3 financial instruments held on December 31, 2019 . Cash and Cash Equivalents At December 31, 2019 and 2018 , the carrying amounts of cash and cash equivalents approximate their fair value. Fair Value of Long-Term Debt At December 31, 2019 and 2018 , the fair value of the Company’s debt, including amounts classified as current, was $308.0 million and $318.6 million

Capital Stock

Capital Stock	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Capital Stock	Capital Stock Dividends The Company declared and paid cash dividends per share during the periods presented below: 2019: Dividends per share Amount (in thousands) 1st quarter $ 0.45 $ 7,839 2nd quarter 0.45 7,425 3rd quarter 0.45 7,000 4th quarter 0.45 7,956 Total cash dividends declared and paid $ 1.80 $ 30,220 2018: Dividends per share Amount (in thousands) 1st quarter $ 0.40 $ 8,335 2nd quarter 0.40 7,998 3rd quarter 0.40 7,633 4th quarter 0.40 7,303 Total cash dividends declared and paid $ 1.60 $ 31,269 Future dividend declarations will be subject to ongoing Board review and authorization will be based on a number of factors, including business and market conditions, the Company’s future financial performance and other capital priorities. Share Repurchase Program During April 2019, the Board of Directors of Arch Coal, Inc. approved an incremental $250 million to the share repurchase program bringing the total authorization to $1.05 billion . Below is a table showing the share repurchase activity during the periods presented below: 2019: Number of Shares Average Repurchase Price per Share Amount (in thousands) 1st quarter 872,317 $ 89.70 $ 78,249 2nd quarter 697,255 90.92 63,393 3rd quarter 1,169,597 78.11 91,357 4th quarter 133,379 78.72 10,499 Total shares repurchased 2,872,548 $ 84.77 $ 243,498 2018: Number of Shares Average Repurchase Price per Share Amount (in thousands) 1st quarter 407,091 $ 94.79 $ 38,588 2nd quarter 960,105 81.54 78,287 3rd quarter 870,538 87.59 76,248 4th quarter 1,000,881 88.57 88,651 Total shares repurchased 3,238,615 $ 87.00 $ 281,774 The timing of any future share repurchases, and the ultimate number of shares purchased, will depend on a number of factors, including business and market conditions, the Company’s future financial performance and other capital priorities. The shares will be acquired in the open market or through private transactions in accordance with the Securities and Exchange Commission requirements. The share repurchase program has no termination date, but may be amended, suspended or discontinued at any time and does not commit the Company to repurchase shares of its common stock. The actual number and value of the shares to be purchased will depend on the performance of the Company’s stock price and other market conditions. Outstanding Warrants On the Effective Date, the Company entered into a warrant agreement (the “Warrant Agreement”) with American Stock Transfer & Trust Company, LLC as warrant agent and, pursuant to the terms of the Plan, issued warrants (“Warrants”) to purchase up to an aggregate of 1,914,856 shares of Class A Common Stock, par value $0.01 per share, of Arch Coal (the “Class A Common Stock”) to holders of claims arising under the Cancelled Notes (as defined below). Each Warrant expires on October 5, 2023, and is initially exercisable for one share of Class A Common Stock at an initial exercise price of $57.00 per share. The Warrants are exercisable by a holder paying the exercise price in cash or on a cashless basis, at the election of the holder. The Warrants contain anti-dilution adjustments for stock splits, reverse stock splits, stock dividends, dividends and distributions of cash, other securities or other property, spin-offs and tender and exchange offers by Arch Coal or its subsidiaries to purchase Class A Common Stock at above-market prices. If, in connection with a merger, recapitalization, business combination, transfer to a third party of substantially all of Arch Coal’s consolidated assets or other transaction that results in a change to the Class A Common Stock (each, a “Transaction”), (i) the Transaction is consummated prior to the fifth anniversary of the Effective Date and the Transaction consideration to holders of Class A Common Stock is 90% or more listed common stock or common stock of a company that provides publicly available financial reporting, and holds management calls regarding the same, no less than quarterly (“Reporting Stock”) or (ii) regardless of the consideration, the Transaction is consummated on or after the fifth anniversary of the Effective Date, the Warrants will be assumed by the surviving company and will become exercisable for the consideration that the holders of Class A Common Stock receive in such Transaction; provided that if the consideration such holders receive consists solely of cash, then upon the consummation of such Transaction, Arch Coal will pay for each Warrant an amount of cash equal to the greater of (i) (x) the amount of cash payable with respect to the number of shares of Class A Common Stock underlying the Warrant minus (y) the exercise price per share then in effect multiplied by the number of shares of Class A Common Stock underlying the Warrant and (ii) $0 . If a Transaction is consummated prior to the fifth anniversary of the Effective Date in which the Transaction consideration is less than 90% Reporting Stock, a portion of the Warrants corresponding to the portion of the Transaction consideration that is Reporting Stock will be assumed by the surviving company and will become exercisable for the Reporting Stock consideration that the holders of Class A Common Stock receive in such Transaction, and the portion of the Warrants corresponding to the portion of the Transaction consideration that is not Reporting Stock will, at the option of each holder, (i) be assumed by the surviving company and will become exercisable for the consideration that the holders of Class A Common Stock receive in such Transaction or (ii) be redeemed by Arch Coal for cash in an amount equal to the Black Scholes Payment (as defined in the Warrant Agreement). During 2019 , holders of warrants had exercised 386 of the warrants, leaving 1,845,568 warrants outstanding at December 31, 2019 . As provided in ASC 825-20, “Financial Instruments,” the warrants are considered equity because they can only be physically settled in Company shares, can be settled in unregistered shares, the Company has adequate authorized shares to settle the outstanding warrants and each warrant is fixed in terms of settlement to one share of Company stock subject only to remote contingency adjustment factors designed to assure the relative value in terms of shares remains fixed.

Stock-Based Compensation and Ot

Stock-Based Compensation and Other Incentive Plans	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement, Noncash Expense [Abstract]
Stock-Based Compensation And Other Incentive Plans	Stock-Based Compensation and Other Incentive Plans Under the Company’s 2016 Omnibus Incentive Plan (the “Incentive Plan”), 3.0 million shares of the Company’s common stock were reserved for awards to officers and other selected key management employees of the Company. The Incentive Plan provides the Board of Directors with the flexibility to grant stock options, stock appreciation rights, restricted stock awards, restricted stock units, performance stock or units, phantom stock awards and rights to acquire stock through purchase under a stock purchase program (“Awards”). Awards the Board of Directors elects to pay out in cash do not impact the shares authorized in the Incentive Plan. Shares available for award under the plan were 2.3 million at December 31, 2019 . Restricted Stock Unit Awards The Company may issue restricted stock and restricted stock units, which require no payment from the employee. Restricted stock cliff-vests at various dates and restricted stock units either vest ratably over or vest at the end of the award’s stated vesting period. Compensation expense is based on the fair value on the grant date and is recorded ratably over the vesting period utilizing the straight-line recognition method. The employee receives cash compensation equal to the amount of dividends that would have been paid on the underlying shares. During 2019 , the Company granted both time based awards and performance based awards. The time based awards vest over either a one or three year period and the performance based awards vest over a three year period. The time based awards’ grant date fair value was determined based on the stock price at the date of grant. The performance awards grant date fair value was determined using a Black-Scholes Monte Carlo simulation. A historical volatility 36% was selected for the performance-based award based on comparator companies, and the three-year risk free rate was derived from yields on U.S. Government bonds. Information regarding the restricted stock units activity and weighted average grant-date fair value follows: Time Based Awards Performance Based Awards Restricted Stock Units Weighted Average Grant-Date Fair Value Restricted Stock Units Weighted Average Grant-Date Fair Value (Shares in thousands) Outstanding at January 1, 2019 388 $ 84.11 415 $ 85.30 Granted 7 92.08 6 105.56 Forfeited/Canceled (1 ) 92.00 (89 ) 67.72 Vested (156 ) 79.25 (137 ) 67.34 Unvested outstanding at December 31, 2019 238 $ 87.50 195 $ 106.44 The Company recognized expense related to restricted stock units of $22.0 million , $17.5 million and $10.4 million for the years ended December 31, 2019 , 2018 and 2017 , respectively. As of December 31, 2019 , there was $19.2 million of unrecognized share-based compensation expense which is expected to be recognized over a weighted-average period of approximately three years . Long-Term Incentive Compensation The Company has a long-term incentive program that allows for the award of performance units. The total number of units earned by a participant is based on financial and operational performance measures, and may be paid out in cash or in shares of the Company’s common stock. The Company recognizes compensation expense over the three year term of the grant. The liabilities are remeasured quarterly. The Company recognized expense of $1.0 million , $2.7 million and $0.7 million for the years ended December 31, 2019 , 2018 and 2017 , respectively. The expense is included primarily in “Selling, general and administrative expenses” in the accompanying Consolidated Income Statements. Amounts accrued and unpaid for all grants under the plan totaled $3.0 million and $6.9 million as of December 31, 2019 and 2018 , respectively.

Workers' Compensation Expense

Workers' Compensation Expense	12 Months Ended
	Dec. 31, 2019
Compensation Related Costs [Abstract]
Workers' Compensation Expense	Workers’ Compensation Expense The Company is liable under the Federal Mine Safety and Health Act of 1969, as subsequently amended, to provide for pneumoconiosis (occupational disease) benefits to eligible employees, former employees and dependents. The Company currently provides for federal claims principally through a self-insurance program. The Company is also liable under various state workers’ compensation statutes for occupational disease benefits. The occupational disease benefit obligation represents the present value of the actuarially computed present and future liabilities for such benefits over the employees’ applicable years of service. In addition, the Company is liable for workers’ compensation benefits for traumatic injuries which are calculated using actuarially-based loss rates, loss development factors and discounted based on a risk free rate of 1.75% . Traumatic workers’ compensation claims are insured with varying retentions/deductibles, or through state-sponsored workers’ compensation programs. Workers’ compensation expense consists of the following components: Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 (In thousands) Self-insured occupational disease benefits: Service cost $ 6,677 $ 7,440 $ 6,320 Interest cost (1) 4,922 4,365 4,651 Net amortization (1) — — — Total occupational disease $ 11,599 $ 11,805 $ 10,971 Traumatic injury claims and assessments 13,050 5,395 3,208 Total workers’ compensation expense $ 24,649 $ 17,200 $ 14,179 (1) In accordance with the adoption of ASU 2017-07, “Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost,” these costs are recorded within Nonoperating expenses in the Consolidated Income Statements on the line item “Non-service related pension and postretirement benefit costs.” The table below reconciles changes in the occupational disease liability for the respective period. (In thousands) Year Ended December 31, 2019 Year Ended December 31, 2018 Beginning of period $ 118,900 $ 122,426 Service cost 6,677 7,440 Interest cost 4,922 4,365 Actuarial (gain) loss 35,993 (7,071 ) Benefit and administrative payments (8,167 ) (8,260 ) $ 158,325 $ 118,900 The following table provides the assumptions used to determine the projected occupational disease obligation: Year Ended December 31, 2019 Year Ended December 31, 2018 (Percentages) Discount rate 3.31 4.26 Summarized below is information about the amounts recognized in the accompanying consolidated balance sheets for workers’ compensation benefits: Year Ended December 31, 2019 Year Ended December 31, 2018 (In thousands) Occupational disease costs $ 158,325 $ 118,900 Traumatic and other workers’ compensation claims 73,393 75,447 Total obligations 231,718 194,347 Less amount included in accrued expenses 16,119 20,044 Noncurrent obligations $ 215,599 $ 174,303 As of December 31, 2019 , the Company had $121.7 million in surety bonds and letters of credit outstanding to secure workers’ compensation obligations. As of December 31, 2019 , the Company’s recorded liabilities include $13.6 million of obligations that are reimbursable under various insurance policies purchased by the company. These insurance receivables are recorded in the balance sheet line items “Other receivables” and “Other noncurrent assets” for $0.5 million and $13.1 million , respectively.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2019
Pension and Other Postretirement Benefits Cost (Reversal of Cost) [Abstract]
Employee Benefit Plans	Employee Benefit Plans Defined Benefit Pension and Other Postretirement Benefit Plans The Company provides funded and unfunded non-contributory defined benefit pension plans covering certain of its salaried and hourly employees. Benefits are generally based on the employee’s age and compensation. The Company funds the plans in an amount not less than the minimum statutory funding requirements or more than the maximum amount that can be deducted for U.S. federal income tax purposes. The Company also currently provides certain postretirement medical and life insurance coverage for eligible employees. Generally, covered employees who terminate employment after meeting eligibility requirements are eligible for postretirement coverage for themselves and their dependents. The Company offers a subsidy to eligible retirees based on age and years of service at retirement and contain other cost-sharing features such as deductibles and coinsurance. The Company’s current funding policy is to fund the cost of all postretirement benefits as they are paid. On January 1, 2015, the Company’s cash balance and excess plans were amended to freeze new service credits for any new or active employee. Obligations and Funded Status. Summaries of the changes in the benefit obligations, plan assets and funded status of the plans are as follows: Pension Benefits Other Postretirement Benefits Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2019 Year Ended December 31, 2018 (In thousands) CHANGE IN BENEFIT OBLIGATIONS Benefit obligations at beginning of period $ 228,873 $ 270,098 $ 88,563 $ 110,519 Service cost — — 480 558 Interest cost 8,141 9,269 3,505 3,674 Settlement gain (1,326 ) (2,332 ) — — Curtailments — — 30 — Benefits paid (34,918 ) (36,895 ) (7,304 ) (5,388 ) Other-primarily actuarial (gain) loss 16,778 (11,267 ) 2,593 (20,800 ) Benefit obligations at end of period $ 217,548 $ 228,873 $ 87,867 $ 88,563 CHANGE IN PLAN ASSETS Value of plan assets at beginning of period $ 212,506 $ 255,642 $ — $ — Actual return on plan assets 33,998 (6,463 ) — — Employer contributions 216 222 7,304 5,388 Benefits paid (34,918 ) (36,895 ) (7,304 ) (5,388 ) Value of plan assets at end of period $ 211,802 $ 212,506 $ — $ — Accrued benefit cost $ (5,746 ) $ (16,367 ) $ (87,867 ) $ (88,563 ) ITEMS NOT YET RECOGNIZED AS A COMPONENT OF NET PERIODIC BENEFIT COST Prior service credit $ 992 $ — $ — $ — Accumulated gain 14,537 8,899 20,333 25,936 $ 15,529 $ 8,899 $ 20,333 $ 25,936 BALANCE SHEET AMOUNTS Current liability $ (270 ) $ (220 ) $ (7,300 ) $ (5,400 ) Noncurrent liability (5,476 ) (16,147 ) (80,567 ) (83,163 ) $ (5,746 ) $ (16,367 ) $ (87,867 ) $ (88,563 ) Pension Benefits The accumulated benefit obligation for all pension plans was $217.5 million and $228.9 million at December 31, 2019 and 2018 , respectively. The Company uses the corridor method of amortizing actuarial gains (losses); it is anticipated there will be $0.1 million of prior service credit amortized from accumulated other comprehensive income into net periodic benefit cost during 2020 . Other Postretirement Benefits The Company uses the corridor method of amortizing actuarial gains (losses); it is anticipated there will be $2.1 million of gains amortized from accumulated other comprehensive income into net periodic benefit cost during 2020 . Components of Net Periodic Benefit Cost . The following table details the components of pension and postretirement benefit costs (credits): Pension Benefits Other Postretirement Benefits Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 (In thousands) Service cost $ — $ — $ — $ 480 $ 558 $ 671 Interest cost (1) 8,141 9,269 11,169 3,505 3,674 4,150 Curtailments — — — — — (520 ) Settlements (1) (1,326 ) (2,332 ) (1,532 ) — — — Expected return on plan assets (1) (10,555 ) (12,083 ) (16,498 ) — — — Amortization of prior service credits (1) (24 ) — — — — — Amortization of other actuarial losses (gains) (1) (11 ) — — (2,974 ) — — Net benefit cost (credit) $ (3,775 ) $ (5,146 ) $ (6,861 ) $ 1,011 $ 4,232 $ 4,301 (1) In accordance with the adoption of ASU 2017-07, “Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost,” these costs are recorded within Nonoperating expenses in the Consolidated Income Statements on the line item “Non-service related pension and postretirement benefit costs.” The differences generated from changes in assumed discount rates and returns on plan assets are amortized into earnings over the remaining service attribution periods of the employees using the corridor method. Assumptions. The following table provides the assumptions used to determine the actuarial present value of projected benefit obligations for the respective periods. Year Ended December 31, 2019 Year Ended December 31, 2018 (Percentages) Pension Benefits Discount rate 3.09/2.90 4.11/3.94 Other Postretirement Benefits Discount rate 3.09 4.12 The following table provides the weighted average assumptions used to determine net periodic benefit cost for the respective periods. Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 (Percentages) Pension Benefits Discount rate 3.65 3.82 3.77 Expected return on plan assets 5.10 5.30 6.20 Other Postretirement Benefits Discount rate 4.12 3.49 3.85 The discount rates used in 2019, 2018 and 2017 were reevaluated during the year for settlements and curtailments. The obligations are remeasured at an updated discount rate that impacts the benefit cost recognized subsequent to the remeasurement. The Company establishes the expected long-term rate of return at the beginning of each fiscal year based upon historical returns and projected returns on the underlying mix of invested assets. The Company utilizes modern portfolio theory modeling techniques in the development of its return assumptions. This technique projects rates of return that can be generated through various asset allocations that lie within the risk tolerance set forth by members of the Company’s pension committee (the “Pension Committee”). The risk assessment provides a link between a pension plan’s risk capacity, management’s willingness to accept investment risk and the asset allocation process, which ultimately leads to the return generated by the invested assets. The health care cost trend rate assumed for 2020 is 5.7% and is expected to reach an ultimate trend rate of 4.5% by 2038 . A one-percentage-point increase in the health care cost trend rate would increase the postretirement benefit obligation at December 31, 2019 by $8.7 million and the net periodic postretirement benefit cost for the year ended December 31, 2019 by $0.4 million . Plan Assets The Pension Committee is responsible for overseeing the investment of pension plan assets. The Pension Committee is responsible for determining and monitoring appropriate asset allocations and for selecting or replacing investment managers, trustees and custodians. The pension plan’s current investment targets are 27% equity and 73% fixed income securities. The Pension Committee reviews the actual asset allocation in light of these targets on a periodic basis and rebalances among investments as necessary. The Pension Committee evaluates the performance of investment managers as compared to the performance of specified benchmarks and peers and monitors the investment managers to ensure adherence to their stated investment style and to the plan’s investment guidelines. The Company’s pension plan assets at December 31, 2019 and 2018 , respectively, are categorized below according to the fair value hierarchy as defined in Note 16 , “ Fair Value Measurements ”: Total Level 1 Level 2 Level 3 2019 2018 2019 2018 2019 2018 2019 2018 (In thousands) Equity Securities: (A) U.S. small-cap $ 2,319 $ 2,751 $ 2,319 $ 2,751 $ — $ — $ — $ — U.S. mid-cap 1,397 1,182 1,397 1,182 — — — — U.S. large-cap — — — — — — — — Non-U.S. — — — — — — — — Fixed income securities: — U.S. government securities (B) 50,610 43,829 35,751 38,436 14,859 5,393 — — Non-U.S. government securities (C) 2,242 2,092 — — 2,242 2,092 — — U.S. government asset and mortgage backed securities (D) — 7,667 — — — 7,667 — — Corporate fixed income (E) 108,023 68,762 — — 108,023 68,762 — — State and local government securities (F) 2,653 3,480 — — 2,653 3,480 — — Other investments (I) — 5,223 — — — 5,223 — — Total $ 167,244 $ 134,986 $ 39,467 $ 42,369 $ 127,777 $ 92,617 $ — $ — Assets at net asset value (G) 53,418 82,765 Short-term investments (H) — 7,003 Other liabilities (J) (8,860 ) (12,248 ) $ 211,802 $ 212,506 (A) Equity securities includes investments in 1) common stock, 2) preferred stock and 3) mutual funds. Investments in common and preferred stocks are valued using quoted market prices multiplied by the number of shares owned. Investments in mutual funds are valued at the net asset value per share multiplied by the number of shares held as of the measurement date and are traded on listed exchanges. (B) U.S. government securities includes agency and treasury debt. These investments are valued using dealer quotes in an active market. (C) Non-U.S. government securities includes debt securities issued by foreign governments and are valued utilizing a price spread basis valuation technique with observable sources from investment dealers and research vendors. (D) U.S. government asset and mortgage backed securities includes government-backed mortgage funds which are valued utilizing an income approach that includes various valuation techniques and sources such as discounted cash flows models, benchmark yields and securities, reported trades, issuer trades and/or other applicable data. (E) Corporate fixed income is primarily comprised of corporate bonds and certain corporate asset-backed securities that are denominated in the U.S. dollar and are investment-grade securities. These investments are valued using dealer quotes. (F) State and local government securities include different U.S. state and local municipal bonds and asset backed securities, these investments are valued utilizing a market approach that includes various valuation techniques and sources such as value generation models, broker quotes, benchmark yields and securities, reported trades, issuer trades and/or other applicable data. (G) Investments that are measured at fair value using the net asset value per share practical expedient have not been classified in the fair value hierarchy in accordance with Accounting Standards Update 2015-07. These investments are primarily mutual funds that are highly liquid with no restrictions on ability to redeem the funds into cash. (H) Short-term investments include governmental agency funds, government repurchase agreements, commingled funds, and pooled funds and mutual funds. Governmental agency funds are valued utilizing an option adjusted spread valuation technique and sources such as interest rate generation processes, benchmark yields and broker quotes. Investments in governmental repurchase agreements, commingled funds and pooled funds and mutual funds are valued at the net asset value per share multiplied by the number of shares held as of the measurement date. (I) Other investments include cash, forward contracts, derivative instruments, credit default swaps, interest rate swaps and mutual funds. Investments in interest rate swaps are valued utilizing a market approach that includes various valuation techniques and sources such as value generation models, broker quotes in active and non-active markets, benchmark yields and securities, reported trades, issuer trades and/or other applicable data. Forward contracts and derivative instruments are valued at their exchange listed price or broker quote in an active market. The mutual funds are valued at the net asset value per share multiplied by the number of shares held as of the measurement date and are traded on listed exchanges. (J) Net payable amount due for pending securities purchased and sold due to broker/dealer. Cash Flows. The Company expects to make no contributions to the pension plans in 2020 . The following represents expected future benefit payments from the plan: Other Pension Postretirement Benefits Benefits (In thousands) 2020 $ 18,016 $ 12,043 2021 16,603 12,273 2022 15,257 12,071 2023 14,240 11,974 2024 13,640 11,836 Next 5 years 60,068 58,640 $ 137,824 $ 118,837 Other Plans The Company sponsors savings plans which were established to assist eligible employees in providing for their future retirement needs. The Company’s expense, representing its contributions to the plans, was $17.5 million , $17.9 million , and $18.0 million for the years ended December 31, 2019 , 2018 , and 2017 respectively.

Earnings Per Common Share

Earnings Per Common Share	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Earnings Per Common Share	Earnings Per Common Share The Company computes basic net income per share using the weighted average number of common shares outstanding during the period. Diluted net income per share is computed using the weighted average number of common shares and the effect of potentially dilutive securities outstanding during the period. Potentially dilutive securities may consist of warrants, restricted stock units or other contingently issuable shares. The dilutive effect of outstanding warrants, restricted stock units and other contingently issuable shares is reflected in diluted earnings per share by application of the treasury stock method. The following table provides the basis for basic and diluted EPS by reconciling the numerators and denominators of the computations: Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 (In Thousands) Weighted average shares outstanding: Basic weighted average shares outstanding 16,218 19,663 23,725 Effect of dilutive securities 1,080 966 515 Diluted weighted average shares outstanding 17,298 20,629 24,240

Leases

Leases	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Lessee, Operating Leases [Text Block]	Leases The Company has operating leases for mining equipment, office equipment and office space with remaining lease terms ranging from less than 1 year to approximately 8 years. Some of these leases include both lease and non-lease components which are accounted for as a single lease component as the Company has elected the practical expedient to combine these components for all leases. As most of the leases do not provide an implicit rate, the Company calculated the ROU assets and lease liabilities using its’ secured incremental borrowing rate at the lease commencement date. The Company currently does not have any finance leases outstanding. Information related to leases was as follows: Year Ended December 31, 2019 (In thousands) Operating lease information: Operating lease cost $ 3,921 Operating cash flows from operating leases 3,842 Weighted average remaining lease term in years 5.92 Weighted average discount rate 5.5 % Future minimum lease payments under non-cancellable leases as of December 31, 2019 were as follows: Year Amount (In thousands) 2020 $ 3,616 2021 3,367 2022 3,292 2023 3,261 2024 3,152 Thereafter 8,001 Total minimum lease payments $ 24,689 Less imputed interest (4,888 ) Total operating lease liability $ 19,801 As reflected on the balance sheet: Accrued expenses and other current liabilities $ 2,514 Other noncurrent liabilities 17,287 Total operating lease liability $ 19,801 At December 31, 2019 , the Company had a $19.2 million ROU operating lease asset recorded within “Other noncurrent assets” on the Consolidated Balance Sheet. The Company has no obligations for future minimum payments under capital leases for equipment at December 31, 2019 and 2018 . Rental expense, including amounts related to these operating leases and other shorter-term arrangements, amounted to $12.0 million in 2019 , $12.4 million in 2018 and $19.2 million in 2017 . Royalties are paid to lessors either as a fixed price per ton or as a percentage of the gross selling price of the mined coal. Royalties under the majority of the Company’s significant leases are paid on the percentage of gross selling price basis. Royalty expense, including production royalties, was $149.5 million in 2019 , $166.1 million in 2018 , and $167.4 million in 2017 . As of December 31, 2019 , certain of the Company’s lease obligations were secured by outstanding surety bonds totaling $29.5 million

Risk Concentrations

Risk Concentrations	12 Months Ended
	Dec. 31, 2019
Risks and Uncertainties [Abstract]
Risk Concentrations	Risk Concentrations Credit Risk and Major Customers The Company has a formal written credit policy that establishes procedures to determine creditworthiness and credit limits for trade customers and counterparties in the over-the-counter coal market. Generally, credit is extended based on an evaluation of the customer’s financial condition. Collateral is not generally required, unless credit cannot be established. Credit losses are provided for in the financial statements and historically have been minimal. The Company markets its thermal coal principally to domestic and foreign electric utilities and its metallurgical coal to domestic and foreign steel producers. As of December 31, 2019 and 2018 , accounts receivable from sales of thermal coal of $69.1 million and $73.9 million , respectively, represented 41% and 37% of total trade receivables at each date. As of December 31, 2019 and 2018 , accounts receivable from sales of metallurgical-quality coal of $98.6 million and $126.5 million , respectively, represented 59% and 63% of total trade receivables at each date. The Company uses shipping destination as the basis for attributing revenue to individual countries. Because title may transfer on brokered transactions at a point that does not reflect the end usage point, they are reflected as exports, and attributed to an end delivery point if that knowledge is known to the Company. The Company’s foreign revenues by geographical location as follows: Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 (In thousands) Europe $ 537,117 $ 559,165 $ 388,926 Asia 322,029 452,711 264,503 Central and South America 82,476 79,085 30,982 Africa 18,698 17,567 14,901 Brokered Sales — 2,372 3,150 Total $ 960,320 $ 1,110,900 $ 702,462 The Company is committed under long-term contracts to supply thermal coal that meets certain quality requirements at specified prices. These prices are generally adjusted based on market indices. Quantities sold under some of these contracts may vary from year to year within certain limits at the option of the customer based on their requirements. The Company sold approximately 90.3 million tons of coal in 2019 . Approximately 56% of this tonnage (representing approximately 50% of the Company’s revenues) was sold under long-term contracts (contracts having a term of greater than one year). Long-term contracts range in remaining life from one to four years . Third-party sources of coal The Company purchases coal from third parties that it sells to customers. Factors beyond the Company’s control could affect the availability of coal purchased by the Company. Disruptions in the quantities of coal purchased by the Company could impair its ability to fill customer orders or require it to purchase coal from other sources at prevailing market prices in order to satisfy those orders. Transportation

Revenue Recognition

Revenue Recognition	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue Recognition	Revenue Recognition ASC 606-10-50-5 requires that entities disclose disaggregated revenue information in categories (such as type of good or service, geography, market, type of contract, etc.) that depict how the nature, amount, timing, and uncertainty of revenue and cash flow are affected by economic factors. ASC 606-10-55-89 explains that the extent to which an entity’s revenue is disaggregated depends on the facts and circumstances that pertain to the entity’s contracts with customers and that some entities may need to use more than one type of category to meet the objective for disaggregating revenue. In general, the Company’s business segmentation is aligned according to the nature and economic characteristics of its coal and customer relationships and provides meaningful disaggregation of each segment’s results. The company has further disaggregated revenue between North America and Seaborne revenues which depicts the pricing and contract differences between the two. North America revenue is characterized by contracts with a term of one year or longer and typically the pricing is fixed; whereas Seaborne revenue generally is derived by spot or short term contracts with an indexed based pricing mechanism. PRB MET Other Thermal Corporate, Other and Eliminations Consolidated (in thousands) Year Ended December 31, 2019 North America revenues $ 915,750 $ 217,381 $ 190,051 $ 10,850 $ 1,334,032 Seaborne revenues — 773,169 187,151 — 960,320 Total revenues $ 915,750 $ 990,550 $ 377,202 $ 10,850 $ 2,294,352 Year Ended December 31, 2018 North America revenues $ 971,337 $ 160,969 $ 195,547 $ 13,034 $ 1,340,887 Seaborne revenues 1,911 875,652 233,337 — 1,110,900 Total revenues $ 973,248 $ 1,036,621 $ 428,884 $ 13,034 $ 2,451,787 Year Ended December 31, 2017 North America revenues $ 1,024,197 $ 312,874 $ 269,007 $ 16,083 $ 1,622,161 Seaborne revenues — 574,965 127,497 — 702,462 Total revenues $ 1,024,197 $ 887,839 $ 396,504 $ 16,083 $ 2,324,623 As of December 31, 2019 , the Company has outstanding performance obligations for approximately 67.4 million tons of coal for 2020 representing 61.6 million tons of fixed price contracts and 5.8 million tons of variable price contracts. Additionally, the Company has outstanding performance obligations of approximately 69.0 million tons in periods beyond 2020 comprised of 64.9 million tons of fixed price contracts and 4.1 million tons of variable price contracts.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies The Company accrues for cost related to contingencies when a loss is probable and the amount is reasonably determinable. Disclosure of contingencies is included in the financial statements when it is at least reasonably possible that a material loss or an additional material loss in excess of amounts already accrued may be incurred. The Company is a party to numerous claims and lawsuits with respect to various matters. As of December 31, 2019 and 2018 , the Company had accrued $0.2 million and $0.2 million , respectively, for all legal matters, all classified as current. The ultimate resolution of any such legal matter could result in outcomes which may be materially different from amounts the Company has accrued for such matters. The Company believes it has recorded adequate reserves for these matters. The Company has unconditional purchase obligations relating to purchases of coal, materials and supplies and capital commitments, other than reserve acquisitions, and is also a party to transportation capacity commitments. The future commitments under these agreements total $170.5 million in 2020

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Segment Information	Segment Information The Company’s reportable business segments are based on two distinct lines of business, metallurgical coal and thermal coal, and may include a number of mine complexes. The Company manages its coal sales by market, not by individual mining complex. Geology, coal transportation routes to customers, and regulatory environments also have a significant impact on the Company’s marketing and operations management. Mining operations are evaluated based on Adjusted EBITDA, per-ton cash operating costs (defined as including all mining costs except depreciation, depletion, amortization, accretion on asset retirement obligations, and pass-through transportation expenses), and on other non-financial measures, such as safety and environmental performance. Adjusted EBITDA is not a measure of financial performance in accordance with generally accepted accounting principles, and items excluded from Adjusted EBITDA are significant in understanding and assessing our financial condition. Therefore, Adjusted EBITDA should not be considered in isolation, nor as an alternative to net income, income from operations, cash flows from operations or as a measure of our profitability, liquidity or performance under generally accepted accounting principles. The Company uses Adjusted EBITDA to measure the operating performance of its segments and allocate resources to the segments. Furthermore, analogous measures are used by industry analysts and investors to evaluate the Company’s operating performance. Investors should be aware that the Company’s presentation of Adjusted EBITDA may not be comparable to similarly titled measures used by other companies. The Company reports its results of operations primarily through the following reportable segments: Powder River Basin (PRB) segment containing the Company’s primary thermal operations in Wyoming; the Metallurgical (MET) segment, containing the Company’s metallurgical operations in West Virginia and the Other Thermal segment containing the Company’s supplementary thermal operations in Colorado and Illinois. Periods presented in this note have been recast for comparability. On December 13, 2019, the Company closed on its’ definitive agreement to sell Coal-Mac LLC, an operating mine complex within the Company’s other thermal coal segment. Coal-Mac is included in the Other Thermal segment results below up to the date of divestiture. For further information on the divestiture, please see Note 5 , “ Divestitures ” to the Consolidated Financial Statements. On September 14, 2017, the Company closed on its’ definitive agreement to sell Lone Mountain Processing LLC, an operating mine complex within the Company’s Metallurgical coal segment. Through this transaction the Company divested all active operations in the states of Kentucky and Virginia. Lone Mountain is included in the MET segment results below up to the date of divestiture. For further information on the divestiture, please see Note 5 , “ Divestitures ” to the Consolidated Financial Statements. Operating segment results for the year ended December 31, 2019 , the year ended December 31, 2018 , and the year ended December 31, 2017 are presented below. The Company measures its segments based on “adjusted earnings before interest, taxes, depreciation, depletion, amortization, and accretion on asset retirements obligations (Adjusted EBITDA).” Adjusted EBITDA does not reflect mine closure or impairment costs, since those are not reflected in the operating income reviewed by management. The Corporate, Other and Eliminations grouping includes these charges, as well as the change in fair value of coal derivatives and coal trading activities, net; corporate overhead; land management activities; other support functions; and the elimination of intercompany transactions. (In thousands) PRB MET Other Thermal Corporate, Other and Eliminations Consolidated Year Ended December 31, 2019 Revenues $ 915,750 $ 990,550 $ 377,202 10,850 $ 2,294,352 Adjusted EBITDA 110,528 305,363 41,495 (94,219 ) 363,167 Depreciation, depletion and amortization 20,810 74,211 14,414 2,620 112,055 Accretion on asset retirement obligation 12,542 2,123 2,413 3,470 20,548 Total Assets 256,460 625,134 105,411 880,751 1,867,756 Capital expenditures 29,420 211,718 20,088 5,130 266,356 Year Ended December 31, 2018 Revenues $ 973,248 $ 1,036,621 $ 428,884 $ 13,034 $ 2,451,787 Adjusted EBITDA 126,525 349,524 68,620 (106,891 ) 437,778 Depreciation, depletion and amortization 33,120 69,560 14,699 2,184 119,563 Accretion on asset retirement obligation 19,541 1,874 2,261 4,294 27,970 Total assets 278,314 545,061 125,333 938,352 1,887,060 Capital expenditures 12,140 64,307 11,999 6,826 95,272 Year Ended December 31, 2017 Revenues $ 1,024,197 $ 887,839 $ 396,504 $ 16,083 $ 2,324,623 Adjusted EBITDA 158,882 243,616 102,006 (84,807 ) 419,697 Depreciation, depletion and amortization 36,349 70,896 13,588 1,631 122,464 Accretion on asset retirement obligation 20,160 2,000 2,161 5,888 30,209 Total assets 390,665 548,476 134,397 906,094 1,979,632 Capital expenditures 6,212 32,678 11,901 8,414 59,205 A reconciliation of segment Adjusted EBITDA to consolidated income (loss) from continuing operations before income taxes follows: (In thousands) Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 Income before income taxes $ 234,047 $ 260,101 $ 203,195 Interest expense, net 6,794 13,689 24,256 Depreciation, depletion and amortization 112,055 119,563 122,464 Accretion on asset retirement obligations 20,548 27,970 30,209 Amortization of sales contracts, net (434 ) 11,107 53,985 Costs related to proposed joint venture with Peabody Energy 13,816 — — Loss on sale of Coal-Mac LLC 9,008 — — Preference Rights Lease Application settlement income (39,000 ) — — Loss (gain) on sale of Lone Mountain Processing, Inc. 4,304 — (21,297 ) Net loss resulting from early retirement of debt and debt restructuring — 485 2,547 Non-service related postretirement benefit costs 2,053 3,202 1,940 Reorganization items, net (24 ) 1,661 2,398 Adjusted EBITDA $ 363,167 $ 437,778 $ 419,697

Quarterly Selected Financial Da

Quarterly Selected Financial Data (unaudited)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Quarterly Selected Financial Data (unaudited)	Quarterly Selected Financial Data (unaudited) Three Months Ended Year Ended December 31, 2019 March 31 June 30 September 30 December 31 (In thousands, except per share data) Revenues $ 555,183 $ 570,222 $ 619,467 $ 549,480 Gross profit $ 86,794 $ 88,032 $ 93,681 $ 23,144 Income (loss) from operations $ 76,779 $ 66,570 $ 106,481 $ (6,960 ) Reorganization items, net $ 87 $ (16 ) $ — $ (47 ) Net income (loss) $ 72,741 $ 62,840 $ 106,769 $ (8,551 ) Diluted income (loss) per common share $ 3.91 $ 3.53 $ 6.34 $ (0.57 ) Three Months Ended Year Ended December 31, 2018 March 31 June 30 September 30 December 31 (In thousands, except per share data) Revenues $ 575,295 $ 592,349 $ 633,180 $ 650,963 Gross profit $ 81,198 $ 77,663 $ 109,740 $ 101,396 Income from operations $ 65,167 $ 44,595 $ 82,886 $ 86,490 Reorganization items, net $ (301 ) $ (740 ) $ (560 ) $ (60 ) Net income $ 59,985 $ 43,306 $ 123,192 $ 86,094 Diluted income per common share $ 2.74 $ 2.06 $ 6.10 $ 4.44

Valuation and Qualifying Accoun

Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2019
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Valuation and Qualifying Accounts	Valuation and Qualifying Accounts Additions (Reductions) Balance at Charged to Charged to Balance at Beginning of Costs and Other End of Year Expenses Accounts Deductions (a) Year (In thousands) Year Ended December 31, 2019 Reserves deducted from asset accounts: Accounts receivable and other receivables $ — — 10,636 (b) — $ 10,636 Current assets — supplies and inventory 648 1,737 (35 ) (b) 134 2,216 Deferred income taxes 530,612 (24,296 ) — — 506,316 Year Ended December 31, 2018 Reserves deducted from asset accounts: Accounts receivable and other receivables $ — $ — $ — $ — $ — Current assets — supplies and inventory 261 1,247 — 860 648 Deferred income taxes 610,571 (79,959 ) — — 530,612 Year Ended December 31, 2017 Reserves deducted from asset accounts: Accounts receivable and other receivables $ — $ — $ — $ — $ — Current assets — supplies and inventory — 365 (17 ) (b) 87 261 Deferred income taxes 1,021,553 (410,982 ) — 610,571 (a) Reserves utilized, unless otherwise indicated. (b) Disposition of subsidiaries (c) Fresh start accounting adjustment

Accounting Policies (Policies)

Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Accounting Estimates	Accounting Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and revenues and expenses in the accompanying consolidated financial statements and the disclosure of contingent assets and liabilities. Actual results could differ from those estimates.
Cash and Cash Equivalents	Cash and Cash Equivalents
Accounts Receivable	Accounts Receivable
Inventories	Inventories
Investments and Membership Interests in Joint Ventures	Investments and Membership Interests in Joint Ventures Investments and membership interests in joint ventures are accounted for under the equity method of accounting if the Company has the ability to exercise significant influence, but not control, over the entity. The Company’s share of the entity’s income or loss is reflected in “ Other operating income, net ” in the Consolidated Income Statements. Information about investment activity is provided in Note 10 to the Consolidated Financial Statements, “ Equity Method Investments and Membership Interests in Joint Ventures .” Investments in debt securities and marketable equity securities that do not qualify for equity method accounting are classified as available-for-sale and are recorded at their fair values. Unrealized gains and losses on these investments are recorded in other comprehensive income or loss. A decline in the value of an investment that is considered other-than-temporary would be recognized in operating expenses.
Sales Contracts	Sales Contracts Coal supply agreements (sales contracts) valued during fresh start accounting or acquired in a business combination are capitalized at their fair value and amortized over the tons of coal shipped during the term of the contract. The fair value of a sales contract is determined by discounting the cash flows attributable to the difference between the contract price and the prevailing forward prices for the tons under contract at the date of acquisition.
Exploration Costs	Exploration Costs
Prepaid Royalties	Prepaid Royalties
Property, Plant and Equipment	Property, Plant and Equipment Plant and Equipment Plant and equipment were recorded at fair value at emergence during fresh start accounting; subsequent purchases of property, plant and equipment have been recorded at cost. Interest costs incurred during the construction period for major asset additions are capitalized. The Company capitalized $2.9 million and $0.3 million of interest costs during years ended December 31, 2019 and 2018 , respectively. Expenditures that extend the useful lives of existing plant and equipment or increase the productivity of the asset are capitalized. The cost of maintenance and repairs that do not extend the useful life or increase the productivity of the asset is expensed as incurred. Preparation plants and loadouts are depreciated using the units-of-production method over the estimated recoverable reserves, subject to a minimum level of depreciation. Other plant and equipment are depreciated principally using the straight-line method over the estimated useful lives of the assets, limited by the remaining life of the mine. The useful lives of mining equipment, including longwalls, draglines and shovels, range from 1 to 18 years. The useful lives of buildings and leasehold improvements generally range from 3 to 18 years. Deferred Mine Development Costs of developing new mines or significantly expanding the capacity of existing mines are capitalized and amortized using the units-of-production method over the estimated recoverable reserves that are associated with the property being benefited. Costs may include construction permits and licenses; mine design; construction of access roads, shafts, slopes and main entries; and removing overburden to access reserves in a new pit. Additionally, deferred mine development includes the asset cost associated with asset retirement obligations. Coal sales revenue related to incidental production during the development phase will be recorded as coal sales revenue with an offset to cost of coal sales based on the estimated cost per ton sold for the mine when the asset is in place for its intended use. Coal Lands and Mineral Rights Rights to coal reserves may be acquired directly through governmental or private entities. A significant portion of the Company’s coal reserves are controlled through leasing arrangements. Lease agreements are generally long-term in nature (original terms range from 10 to 50 years), and substantially all of the leases contain provisions that allow for automatic extension of the lease term providing certain requirements are met. Leases of mineral reserves and related land leases are exempt from the provisions of the leasing standard. The net book value of the Company’s coal interests was $360.9 million and $338.1 million at December 31, 2019 and 2018 , respectively. Payments to acquire royalty lease agreements and lease bonus payments are capitalized as a cost of the underlying mineral reserves and depleted over the life of proven and probable reserves. Coal lease rights are depleted using the units-of-production method, and the rights are assumed to have no residual value. The Company currently does not have any future lease bonus payments. Depreciation, depletion and amortization The depreciation, depletion and amortization related to long-lived assets is reflected in the income statement as a separate line item. No depreciation, depletion or amortization is included in any other operating cost categories. Impairment If facts and circumstances suggest that the carrying value of a long-lived asset or asset group may not be recoverable, the asset or asset group is reviewed for potential impairment. If this review indicates that the carrying amount of the asset will not be recoverable through projected undiscounted cash flows generated by the asset and its related asset group over its remaining life, then an impairment loss is recognized by reducing the carrying value of the asset to its fair value. The Company may, under certain circumstances, idle mining operations in response to market conditions or other factors. Because an idling is not a permanent closure, it is not considered an automatic indicator of impairment.
Deferred Financing Costs	Deferred Financing Costs The Company capitalizes costs incurred in connection with new borrowings, the establishment or enhancement of credit facilities and the issuance of debt securities. These costs are amortized as an adjustment to interest expense over the life of the borrowing or term of the credit facility using the interest method. Debt issuance costs related to a recognized liability are presented in the balance sheet as a direct reduction from the carrying amount of that liability whereas debt issuance costs related to a credit facility with no balance outstanding are shown as an asset. The unamortized balance of deferred financing costs shown as an asset was $3.0 million at December 31, 2019 , with $2.0 million classified as current; the unamortized balance of deferred financing costs shown as an asset at December 31, 2018 was $4.7 million with $2.2 million classified as current. The current amounts are classified within “Other current assets” and the noncurrent amounts are classified within “Other noncurrent assets.” For information on the unamortized balance of deferred financing fees related to outstanding debt, see Note 13 to the Consolidated Financial Statements, “ Debt and Financing Arrangements .”
Revenue Recognition	Revenue Recognition
Other Operating Income, net	Other Operating Income, net Other operating income, net in the accompanying Consolidated Income Statements reflects income and expense from sources other than physical coal sales, including: bookouts, or the practice of offsetting purchase and sale contracts for shipping convenience purposes; contract settlements; royalties earned from properties leased to third parties; income from equity investments (Note 10 , “ Equity Method Investments and Membership Interests in Joint Ventures ”); non-material gains and losses from divestitures and dispositions of assets; and realized gains and losses on derivatives that do not qualify for hedge accounting and are not held for trading purposes (Note 11 , “ Derivatives ”); and land management expenses.
Asset Retirement Obligations	Asset Retirement Obligations The Company’s legal obligations associated with the retirement of long-lived assets are recognized at fair value at the time the obligations are incurred. Accretion expense is recognized through the expected settlement date of the obligation. Obligations are incurred at the time development of a mine commences for underground and surface mines or construction begins for support facilities, refuse areas and slurry ponds. The obligation’s fair value is determined using a discounted cash flow technique and is based upon permit requirements and various estimates and assumptions that would be used by market participants, including estimates of disturbed acreage, reclamation costs and assumptions regarding equipment productivity. Upon initial recognition of a liability, a corresponding amount is capitalized as part of the carrying value of the related long-lived asset.
Loss Contingencies	Loss Contingencies The Company accrues for cost related to contingencies when a loss is probable and the amount is reasonably determinable. Disclosure of contingencies is included in the financial statements when it is at least reasonably possible that a material loss or an additional material loss in excess of amounts already accrued may be incurred. The amount accrued represents the Company’s best estimate of the loss, or, if no best estimate within a range of outcomes exists, the minimum amount in the range.
Derivative Instruments	Derivative Instruments The Company generally utilizes derivative instruments to manage exposures to commodity prices and interest rate risk on long-term debt. Additionally, the Company may hold certain coal derivative instruments for trading purposes. Derivative financial instruments are recognized on the balance sheet at fair value. Certain coal contracts may meet the definition of a derivative instrument, but because they provide for the physical purchase or sale of coal in quantities expected to be used or sold by the Company over a reasonable period in the normal course of business, they are not recognized on the balance sheet. Certain derivative instruments are designated as the hedge instrument in a hedging relationship. In a fair value hedge, the Company hedges the risk of changes in the fair value of a firm commitment, typically a fixed-price coal sales contract. Changes in both the hedged firm commitment and the fair value of a derivative used as a hedge instrument in a fair value hedge are recorded in earnings. In a cash flow hedge, the Company hedges the risk of changes in future cash flows related to the underlying item being hedged. Changes in the fair value of the derivative instrument used as a hedge instrument in a cash flow hedge are recorded in other comprehensive income or loss. Amounts in other comprehensive income or loss are reclassified to earnings when the hedged transaction affects earnings and are classified in a manner consistent with the transaction being hedged. The Company formally documents the relationships between hedging instruments and the respective hedged items, as well as its risk management objectives for hedge transactions. The Company evaluates the effectiveness of its hedging relationships both at the hedge’s inception and on an ongoing basis. Any ineffective portion of the change in fair value of a derivative instrument used as a hedge instrument in a fair value or cash flow hedge is recognized immediately in earnings. The ineffective portion is based on the extent to which exact offset is not achieved between the change in fair value of the hedge instrument and the cumulative change in expected future cash flows on the hedged transaction from inception of the hedge in a cash flow hedge or the change in the fair value. Ineffectiveness was insignificant for the periods disclosed within.
Fair Value	Fair Value Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly hypothetical transaction between market participants at a given measurement date. Valuation techniques used must maximize the use of observable inputs and minimize the use of unobservable inputs. See Note 16 , “ Fair Value Measurements ” for further disclosures related to the Company’s recurring fair value estimates.
Income Taxes	Income Taxes Deferred income taxes are provided for temporary differences arising from differences between the financial statement and tax basis of assets and liabilities existing at each balance sheet date using enacted tax rates anticipated to be in effect when the related taxes are expected to be paid or recovered. A valuation allowance is established if it is more likely than not that a deferred tax asset will not be realized. Management reassesses the ability to realize its deferred tax assets annually in the fourth quarter or when circumstances indicate that the ability to realize deferred tax assets has changed. In determining the need for a valuation allowance, the Company considers projected realization of tax benefits based on expected levels of future taxable income, available tax planning strategies and the reversal of temporary differences.
Benefit Plans	Benefit Plans The Company has non-contributory defined benefit pension plans covering most of its salaried and hourly employees. On January 1, 2015 the Company’s cash balance and excess pension plans were amended to freeze new service credits for any new or active employees. The Company also currently provides certain postretirement medical and life insurance coverage for eligible employees. The cost of providing these benefits is determined on an actuarial basis and accrued over the employees’ period of active service.
Stock-Based Compensation	Stock-Based Compensation
Recently Adopted Accounting Guidance and Recent Accounting Guidance Issued Not Yet Effective	Recently Adopted Accounting Guidance In February 2016, the FASB established Topic 842, Leases, by issuing ASU 2016-02, “Leases” which requires lessees to recognize leases on-balance sheet and disclose key information about leasing arrangements. The ASU was subsequently amended by ASU 2018-01, “Land Easements Practical Expedient for Transition to Topic 842;” ASU 2018-10, “Codification Improvements to Topic 842, Leases;” and ASU 2018-11, “Targeted Improvements.” The new standard establishes a right-of-use (“ROU”) model that requires a lessee to recognize an ROU asset and lease liability on the balance sheet for all leases with a term longer than 12 months. The standard also requires a lessee to recognize a single lease cost, calculated so that the cost of the lease is allocated over the term of the lease, on a generally straight line basis. Leases of mineral reserves and related land leases have been exempted from the standard. The Company adopted ASU 2016-02 effective January 1, 2019 and elected the option to not restate comparative periods in transition and also elected the “package of practical expedients” within the standard which permits the Company not to reassess its prior conclusions about lease identification, lease classification and initial direct costs. Additionally, the Company made an election to not separate lease and non-lease components for all leases, and will not use hindsight. Finally, the Company will continue its current policy for accounting for land easements as executory contracts. The adoption of the standard had no impact on the Company’s consolidated income statement or statement of cash flows. In April 2017, the FASB issued ASU 2017-08, “Receivables-Nonrefundable Fees and Other Costs (Subtopic 310-20), Premium Amortization on Purchased Callable Debt Securities.” The new guidance shortens the amortization period for the premium on certain purchased callable debt securities to the earliest call date. The new guidance does not change the accounting for purchased callable debt securities held at a discount. The Company adopted ASU 2017-08 effective January 1, 2019 with no impact on the Company’s financial statements. In August 2017, the FASB issued ASU 2017-12, “Targeted Improvements to Accounting for Hedging Activities.” The new guidance provides targeted improvements to the accounting for hedging activities to better align an entity’s risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedging relationships and the presentation of hedging results. The Company adopted ASU 2017-12 effective January 1, 2019 with no impact on the Company’s financial statements. In February 2018, the FASB issued ASU 2018-02, “Income Statement-Reporting Comprehensive Income (Topic 220) Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” ASU 2018-02 provides an option to reclassify stranded tax effects within accumulated other comprehensive income to retained earnings due to the change in the U.S. federal tax rate in the Tax Cuts and Jobs Act of 2017. The Company adopted ASU 2018-02 effective January 1, 2019 with no impact on the Company’s financial statements. In June 2018, the FASB issued ASU 2018-07, “Compensation-Stock Compensation (Topic 718), Improvements to Non-employee Share-Based Payment Accounting.” ASU 2018-07 aligns the measurement and classification guidance for share-based payments to non-employees with the guidance for share-based payments to employees. The Company adopted ASU 2018-07 effective January 1, 2019 with no impact on the Company’s financial statements. In October 2018, the FASB issued ASU 2018-16, “Derivatives and Hedging (Topic 815), Inclusion of the Secured Overnight Financing Rate (SOFR) Overnight Index Swap (OIS) Rate as a Benchmark Interest Rate of Hedge Accounting Purposes.” The Company adopted ASU 2018-16 effective January 1, 2019 with no impact on the Company’s financial statements. Recent Accounting Guidance Issued Not Yet Effective In June 2016, the FASB issued ASU 2016-13, “Financial Instruments-Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments” and also issued subsequent amendments to the initial guidance under ASU 2018-19, ASU 2019-04 and ASU 2019-05. The standard modifies the measurement approach for credit losses on financial instruments, including trade receivables, from an incurred loss method to a current expected credit loss method, otherwise known as “CECL.” The standard requires the measurement of expected credit losses to be based on relevant information, including historical experience, current conditions and a forecast that is supportable. The standard is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years; early adoption is permitted. The standard must be adopted by applying a cumulative adjustment to retained earnings. The Company anticipates adopting the standard in the first quarter of 2020, although it does not expect a significant impact to the Company’s financial results. In August 2018, the FASB issued ASU 2018-13, “Fair Value Measurement (Topic 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement.” The primary focus of ASU 2018-13 is to improve the effectiveness of the disclosures for fair value measurements by requiring public entities to disclose certain new information while modifying some existing disclosure requirements. The FASB issued this ASU as part of its broader disclosure framework project, which aims to improve the effectiveness of disclosures in the notes to the financial statements by focusing on requirements that clearly communicate the most important information to users of the financial statements. The ASU is effective for public companies for fiscal years beginning after December 15, 2019, and interim periods therein with early adoption permitted. The Company does not expect a significant impact to the Company’s financial statements. In August 2018, the FASB issued ASU 2018-14, “Compensation-Retirement Benefits-Defined Benefit Plans-General (Subtopic 715-20), Disclosure Framework-Changes to the Disclosure Requirements for Defined Benefit Plans.” ASU 2018-14 makes minor changes to the disclosure requirements for employers that sponsor defined benefit pension and postretirement benefit plants. The new guidance eliminates requirements for certain disclosures that are no longer considered cost beneficial and adds new ones that the FASB considers pertinent. The FASB issued this ASU as part of its broader disclosure framework project, which aims to improve the effectiveness of disclosures in the notes to the financial statements by focusing on requirements that clearly communicate the most important information to users of the financial statements. The ASU is effective for public companies for fiscal years beginning after December 15, 2020, and interim periods therein with early adoption permitted. The Company does not expect a significant impact to the Company’s financial statements.

Emergence from Bankruptcy (Tabl

Emergence from Bankruptcy (Tables)	12 Months Ended
	Dec. 31, 2019
Reorganizations [Abstract]
Schedule of Reorganization Items, Net	The Company’s reorganization items, net for the respective periods are as follows: Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 (In thousands) Professional fees $ 24 $ (1,661 ) $ (2,398 )

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following items are included in accumulated other comprehensive income: Pension, Postretirement Accumulated and Other Post- Other Derivative Employment Available-for- Comprehensive Instruments Benefits Sale Securities Income (Loss) (In thousands) January 1, 2018 $ 647 $ 19,720 $ — $ 20,367 Unrealized gains (losses) (4,359 ) 22,923 (319 ) 18,245 Amounts reclassified from accumulated other comprehensive income 7,040 (2,332 ) (24 ) 4,684 December 31, 2018 $ 3,328 $ 40,311 $ (343 ) $ 43,296 Unrealized gains (losses) 4,648 (27,692 ) 508 (22,536 ) Amounts reclassified from accumulated other comprehensive income (10,540 ) (4,346 ) (185 ) (15,071 ) December 31, 2019 $ (2,564 ) $ 8,273 $ (20 ) $ 5,689
Schedule of Comprehensive Income Reclassifications	The following amounts were reclassified out of accumulated other comprehensive income during the respective periods: Details about accumulated other comprehensive income components Year Ended December 31, 2019 Year Ended December 31, 2018 Line Item in the Consolidated Income Statements (in thousands) Derivative instruments Coal hedges $ 9,480 $ (8,206 ) Revenues Interest rate hedges 1,060 1,166 Interest expense — — Provision for (benefit from) income taxes $ 10,540 $ (7,040 ) Net of tax Pension, postretirement and other post-employment benefits Amortization of net actuarial gains (losses) 1 $ 3,020 $ — Settlement gains 1,326 2,332 $ 4,346 $ 2,332 Total before tax — — Provision for (benefit from) income taxes $ 4,346 $ 2,332 Net of tax Available-for-sale securities 2 $ 185 $ 24 Interest and investment income — — Provision for (benefit from) income taxes $ 185 $ 24 Net of tax 1 Production-related benefits and workers’ compensation costs are included in costs to produce coal. 2 The gains and losses on sales of available-for-sale-securities are determined on a specific identification basis.

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2019
Inventory Disclosure [Abstract]
Inventories	Inventories consist of the following: December 31, 2019 December 31, 2018 (In thousands) Coal $ 46,815 $ 40,982 Repair parts and supplies 84,083 84,488 $ 130,898 $ 125,470

Investments in Available-for-_2

Investments in Available-for-Sale Securities (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Securities, Available-for-sale [Abstract]
Available-for-sale Securities	The Company’s investments in available-for-sale marketable securities are as follows: December 31, 2019 Balance Sheet Gross Gross Classification Unrealized Unrealized Fair Short-Term Cost Basis Gains Losses Value Investments (In thousands) Available-for-sale: U.S. government and agency securities $ 35,044 $ 1 $ (16 ) $ 35,029 $ 35,029 Corporate notes and bonds 100,643 200 (205 ) 100,638 100,638 Total Investments $ 135,687 $ 201 $ (221 ) $ 135,667 $ 135,667 December 31, 2018 Balance Sheet Gross Gross Classification Unrealized Unrealized Fair Short-Term Cost Basis Gains Losses Value Investments (In thousands) Available-for-sale: U.S. government and agency securities $ 100,003 $ 11 $ (126 ) $ 99,888 $ 99,888 Corporate notes and bonds 63,137 4 (232 ) 62,909 62,909 Total Investments $ 163,140 $ 15 $ (358 ) $ 162,797 $ 162,797

Equity Method Investments and_2

Equity Method Investments and Membership Interests in Joint Ventures (Tables)	12 Months Ended
	Dec. 31, 2019
Equity Method Investments and Joint Ventures [Abstract]
Schedule Of Equity Method Investments	Below are the equity method investments reflected in the consolidated balance sheets: (In thousands) Knight Hawk DTA Total December 31, 2017 $ 90,166 $ 15,941 $ 106,107 Advances to (distributions from) affiliates, net (10,534 ) 2,481 (8,053 ) Equity in comprehensive income (loss) 10,389 (3,767 ) 6,622 December 31, 2018 $ 90,021 $ 14,655 $ 104,676 Sale of investment in affiliates (1,879 ) — (1,879 ) Advances to (distributions from) affiliates, net (5,884 ) 5,500 (384 ) Equity in comprehensive income (loss) 7,953 (4,778 ) 3,175 December 31, 2019 $ 90,211 $ 15,377 $ 105,588

Derivatives (Tables)

Derivatives (Tables)	12 Months Ended
	Dec. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Price Risk Derivatives	At December 31, 2019 , the Company held derivatives for risk management purposes that are expected to settle in the following years: (Tons in thousands) 2020 2021 Total Coal sales 668 — 668 Coal purchases 668 — 668
Disclosure Of Fair Value Of Derivatives	The fair value and location of derivatives reflected in the accompanying consolidated balance sheets are as follows: December 31, 2019 December 31, 2018 Fair Value of Derivatives Asset Liability Asset Liability (In thousands) Derivative Derivative Derivative Derivative Derivatives Designated as Hedging Instruments Coal $ 1,351 $ (962 ) $ 2,342 $ (805 ) Derivatives Not Designated as Hedging Instruments Heating oil -- diesel purchases 133 (112 ) 532 — Coal held for trading purposes, exchange traded swaps and futures 18,467 (18,940 ) 10,329 (10,701 ) Coal -- risk management 11,662 (5,856 ) 5,672 (19,579 ) Natural gas 3 — 4 (4 ) Total $ 30,265 (24,908 ) $ 16,537 $ (30,284 ) Total derivatives $ 31,616 $ (25,870 ) $ 18,879 $ (31,089 ) Effect of counterparty netting (25,759 ) 25,759 (17,801 ) 17,801 Net derivatives as classified in the balance sheets $ 5,857 $ (111 ) $ 5,746 $ 1,078 $ (13,288 ) $ (12,210 ) December 31, 2019 December 31, 2018 Net derivatives as reflected on the balance sheets Heating oil Other current assets $ 133 $ 532 Coal Other current assets 5,724 546 Accrued expenses and other current liabilities (111 ) (13,288 ) $ 5,746 $ (12,210 )
Effects Of Derivatives On Measures Of Financial Performance	The effects of derivatives on measures of financial performance are as follows: Derivatives used in Cash Flow Hedging Relationships (in thousands) For the noted periods, Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion) Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 Coal sales (1) $ 10,249 $ (7,517 ) $ (2,127 ) Coal purchases (2) (1,231 ) 1,348 942 $ 9,018 $ (6,169 ) $ (1,185 ) Gains (Losses) Reclassified from Other Comprehensive Income into Income Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 Coal sales $ 10,167 $ (10,912 ) $ — Coal purchases (686 ) 2,707 — $ 9,481 $ (8,205 ) $ — No ineffectiveness or amounts excluded from effectiveness testing relating to the Company’s cash flow hedging relationships were recognized in the results of operations in the respective periods. Derivatives Not Designated as Hedging Instruments (in thousands) For the noted periods, Gain (Loss) Recognized Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 Coal trading— realized and unrealized (3) $ (1,013 ) $ 135 $ (2,047 ) Coal risk management— unrealized (3) 19,713 (9,530 ) (4,648 ) Natural gas trading — realized and unrealized (3) (99 ) 277 (527 ) Change in fair value of coal derivatives and coal trading activities, net total $ 18,601 $ (9,118 ) $ (7,222 ) Coal risk management — realized (4) $ 487 $ (8,734 ) $ — Heating oil — diesel purchases (4) $ (2,291 ) $ (505 ) $ (1,057 ) Location in income statement: (1) — Revenues (2) — Cost of sales (3) — Change in fair value of coal derivatives and coal trading activities, net (4) — Other operating income, net

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2019
Accrued Expenses and Other Current Liabilities [Abstract]
Schedule of Accrued Liabilities	Accrued expenses and other current liabilities consist of the following: December 31, 2019 December 31, 2018 (In thousands) Payroll and employee benefits $ 50,929 $ 57,166 Taxes other than income taxes 69,061 75,017 Interest 133 156 Workers’ compensation 16,119 20,044 Asset retirement obligations 10,366 13,113 Other 10,559 18,018 $ 157,167 $ 183,514

Debt and Financing Arrangemen_2

Debt and Financing Arrangements (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Debt	December 31, 2019 December 31, 2018 (In thousands) Term loan due 2024 ($291.8 and $294.8 million face value, respectively) $ 290,825 $ 293,626 Other 25,007 30,449 Debt issuance costs (5,013 ) (6,092 ) $ 310,819 $ 317,983 Less current maturities of debt 20,753 17,797 Long-term debt $ 290,066 $ 300,186
Schedule of Interest Rate Swap Agreements	Below is a summary of the Company’s outstanding interest rate swap agreements designated as hedges as of December 31, 2019 : Notional Amount (in millions) Effective Date Fixed Rate Receive Rate Expiration Date $250.0 June 28, 2019 2.025% 1-month LIBOR June 30, 2020 $200.0 June 30, 2020 2.249% 1-month LIBOR June 30, 2021 $100.0 June 30, 2021 2.315% 1-month LIBOR June 30, 2023
Schedule of Maturities of Long-term Debt	The contractual maturities of debt as of December 31, 2019 are as follows: Year (In thousands) 2020 $ 21,863 2021 8,853 2022 3,130 2023 3,161 2024 279,750 Thereafter — $ 316,757

Taxes (Tables)

Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	Significant components of the provision for (benefit from) income taxes are as follows: Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 (In thousands) Current: Federal $ (36 ) $ 86 $ 835 State 124 136 31 Total current $ 88 $ 222 $ 866 Deferred: Federal 667 (52,309 ) (36,162 ) State (507 ) (389 ) 41 Total deferred $ 160 $ (52,698 ) $ (36,121 ) $ 248 $ (52,476 ) $ (35,255 )
Schedule of Effective Income Tax Rate Reconciliation	A reconciliation of the statutory federal income tax provision (benefit) at the statutory rate to the actual provision for (benefit from) income taxes follows: Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 (In thousands) Income tax provision (benefit) at statutory rate $ 49,150 $ 54,621 $ 71,118 Percentage depletion allowance (17,743 ) (17,725 ) (31,255 ) State taxes, net of effect of federal taxes (12,769 ) 4,480 7,002 Change in valuation allowance (24,206 ) (79,961 ) (410,983 ) Impact of Tax Cuts and Jobs Act of 2017 — (17,645 ) 332,345 Other, net 5,816 3,754 (3,482 ) Provision for (benefit from) income taxes $ 248 $ (52,476 ) $ (35,255 )
Schedule of Deferred Tax Assets and Liabilities	Significant components of the Company’s deferred tax assets and liabilities that result from carryforwards and temporary differences between the financial statement basis and tax basis of assets and liabilities are summarized as follows: December 31, 2019 December 31, 2018 (In thousands) Deferred tax assets: Tax loss carryforwards $ 294,535 $ 307,615 Tax credit carryforwards 5,297 5,394 Investment in partnerships 190,418 193,217 Other 20,387 28,747 Gross deferred tax assets $ 510,637 $ 534,973 Valuation allowance (506,316 ) (530,612 ) Total deferred tax assets $ 4,321 $ 4,361 Deferred tax liabilities: Plant and equipment 2,063 3,037 Other 2,178 1,154 Total deferred tax liabilities $ 4,241 $ 4,191 Net deferred tax asset $ 80 $ 170
Summary of Income Tax Contingencies	A reconciliation of the beginning and ending amounts of gross unrecognized tax benefits follows: (In thousands) Balance at December 31, 2016 $ 7,455 Additions based on tax positions related to the current year — Additions for tax positions of prior years 3,928 Reductions as a result of lapses in the statute of limitations — Balance at December 31, 2017 11,383 Additions based on tax positions of prior years 28,387 Additions for tax positions related to the current year 3,228 Reductions for tax positions of prior years (634 ) Reductions as a result of lapses in the statute of limitations (3,271 ) Balance at December 31, 2018 39,093 Additions for tax positions related to the current year 2,980 Reductions for tax positions of prior years (1,970 ) Reductions as a result of lapses in the statute of limitations $ (374 ) Balance at December 31, 2019 $ 39,729

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2019
Asset Retirement Obligation [Abstract]
Schedule of Change in Asset Retirement Obligation	The following table describes the changes to the Company’s asset retirement obligation liability: Year Ended December 31, 2019 Year Ended December 31, 2018 (In thousands) Balance at beginning of period (including current portion) $ 243,417 $ 328,695 Accretion expense 20,548 27,970 Obligations of divested operations (12,185 ) — Adjustments to the liability from changes in estimates 11,438 (100,728 ) Liabilities settled (10,420 ) (12,520 ) Balance at period end $ 252,798 $ 243,417 Current portion included in accrued expenses (10,366 ) (13,113 ) Noncurrent liability $ 242,432 $ 230,304

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Summary Of Financial Assets And Liabilities Accounted For At Fair Value	The table below sets forth, by level, the Company’s financial assets and liabilities that are recorded at fair value in the accompanying consolidated balance sheet: Fair Value at December 31, 2019 Total Level 1 Level 2 Level 3 (In thousands) Assets: Investments in marketable securities $ 135,667 $ 35,029 $ 100,638 $ — Derivatives 5,857 5,269 527 61 Total assets $ 141,524 $ 40,298 $ 101,165 $ 61 Liabilities: Derivatives $ 3,065 $ — $ 3,065 $ — Fair Value at December 31, 2018 Total Level 1 Level 2 Level 3 (In thousands) Assets: Investments in marketable securities $ 162,797 $ 99,888 $ 62,909 $ — Derivatives 3,554 — 3,022 532 Total assets $ 166,351 $ 99,888 $ 65,931 $ 532 Liabilities: Derivatives $ 13,288 $ 13,252 $ 36 $ —
Summary Of Change In The Fair Values Of Financial Instruments Categorized As Level 3	The following table summarizes the change in the fair values of financial instruments categorized as level 3. Year Ended December 31, 2019 Year Ended December 31, 2018 (In thousands) Balance, beginning of period $ 532 $ 5,426 Realized and unrealized (gains) losses recognized in earnings, net (1,893 ) (302 ) Purchases 1,597 3,420 Issuances (208 ) (724 ) Settlements 33 (7,288 ) Ending balance $ 61 $ 532

Capital Stock (Tables)

Capital Stock (Tables)	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Dividends declared and paid	The Company declared and paid cash dividends per share during the periods presented below: 2019: Dividends per share Amount (in thousands) 1st quarter $ 0.45 $ 7,839 2nd quarter 0.45 7,425 3rd quarter 0.45 7,000 4th quarter 0.45 7,956 Total cash dividends declared and paid $ 1.80 $ 30,220 2018: Dividends per share Amount (in thousands) 1st quarter $ 0.40 $ 8,335 2nd quarter 0.40 7,998 3rd quarter 0.40 7,633 4th quarter 0.40 7,303 Total cash dividends declared and paid $ 1.60 $ 31,269
Share repurchase activity	Below is a table showing the share repurchase activity during the periods presented below: 2019: Number of Shares Average Repurchase Price per Share Amount (in thousands) 1st quarter 872,317 $ 89.70 $ 78,249 2nd quarter 697,255 90.92 63,393 3rd quarter 1,169,597 78.11 91,357 4th quarter 133,379 78.72 10,499 Total shares repurchased 2,872,548 $ 84.77 $ 243,498 2018: Number of Shares Average Repurchase Price per Share Amount (in thousands) 1st quarter 407,091 $ 94.79 $ 38,588 2nd quarter 960,105 81.54 78,287 3rd quarter 870,538 87.59 76,248 4th quarter 1,000,881 88.57 88,651 Total shares repurchased 3,238,615 $ 87.00 $ 281,774

Stock-Based Compensation and _2

Stock-Based Compensation and Other Incentive Plans (Tables)	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement, Noncash Expense [Abstract]
Schedule of Restricted Stock Units Activity	Information regarding the restricted stock units activity and weighted average grant-date fair value follows: Time Based Awards Performance Based Awards Restricted Stock Units Weighted Average Grant-Date Fair Value Restricted Stock Units Weighted Average Grant-Date Fair Value (Shares in thousands) Outstanding at January 1, 2019 388 $ 84.11 415 $ 85.30 Granted 7 92.08 6 105.56 Forfeited/Canceled (1 ) 92.00 (89 ) 67.72 Vested (156 ) 79.25 (137 ) 67.34 Unvested outstanding at December 31, 2019 238 $ 87.50 195 $ 106.44

Workers' Compensation Expense (

Workers' Compensation Expense (Tables)	12 Months Ended
	Dec. 31, 2019
Compensation Related Costs [Abstract]
Workers' compensation expense	Workers’ compensation expense consists of the following components: Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 (In thousands) Self-insured occupational disease benefits: Service cost $ 6,677 $ 7,440 $ 6,320 Interest cost (1) 4,922 4,365 4,651 Net amortization (1) — — — Total occupational disease $ 11,599 $ 11,805 $ 10,971 Traumatic injury claims and assessments 13,050 5,395 3,208 Total workers’ compensation expense $ 24,649 $ 17,200 $ 14,179 (1) In accordance with the adoption of ASU 2017-07, “Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost,” these costs are recorded within Nonoperating expenses in the Consolidated Income Statements on the line item “Non-service related pension and postretirement benefit costs.”
Schedule of Changes in Occupational Disease Obligations	The table below reconciles changes in the occupational disease liability for the respective period. (In thousands) Year Ended December 31, 2019 Year Ended December 31, 2018 Beginning of period $ 118,900 $ 122,426 Service cost 6,677 7,440 Interest cost 4,922 4,365 Actuarial (gain) loss 35,993 (7,071 ) Benefit and administrative payments (8,167 ) (8,260 ) $ 158,325 $ 118,900
Schedule of Occupational Disease Obligation Assumptions Used	The following table provides the assumptions used to determine the projected occupational disease obligation: Year Ended December 31, 2019 Year Ended December 31, 2018 (Percentages) Discount rate 3.31 4.26
Workers' compensation liabilities	Summarized below is information about the amounts recognized in the accompanying consolidated balance sheets for workers’ compensation benefits: Year Ended December 31, 2019 Year Ended December 31, 2018 (In thousands) Occupational disease costs $ 158,325 $ 118,900 Traumatic and other workers’ compensation claims 73,393 75,447 Total obligations 231,718 194,347 Less amount included in accrued expenses 16,119 20,044 Noncurrent obligations $ 215,599 $ 174,303

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2019
Pension and Other Postretirement Benefits Cost (Reversal of Cost) [Abstract]
Pension Benefit Costs	Summaries of the changes in the benefit obligations, plan assets and funded status of the plans are as follows: Pension Benefits Other Postretirement Benefits Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2019 Year Ended December 31, 2018 (In thousands) CHANGE IN BENEFIT OBLIGATIONS Benefit obligations at beginning of period $ 228,873 $ 270,098 $ 88,563 $ 110,519 Service cost — — 480 558 Interest cost 8,141 9,269 3,505 3,674 Settlement gain (1,326 ) (2,332 ) — — Curtailments — — 30 — Benefits paid (34,918 ) (36,895 ) (7,304 ) (5,388 ) Other-primarily actuarial (gain) loss 16,778 (11,267 ) 2,593 (20,800 ) Benefit obligations at end of period $ 217,548 $ 228,873 $ 87,867 $ 88,563 CHANGE IN PLAN ASSETS Value of plan assets at beginning of period $ 212,506 $ 255,642 $ — $ — Actual return on plan assets 33,998 (6,463 ) — — Employer contributions 216 222 7,304 5,388 Benefits paid (34,918 ) (36,895 ) (7,304 ) (5,388 ) Value of plan assets at end of period $ 211,802 $ 212,506 $ — $ — Accrued benefit cost $ (5,746 ) $ (16,367 ) $ (87,867 ) $ (88,563 ) ITEMS NOT YET RECOGNIZED AS A COMPONENT OF NET PERIODIC BENEFIT COST Prior service credit $ 992 $ — $ — $ — Accumulated gain 14,537 8,899 20,333 25,936 $ 15,529 $ 8,899 $ 20,333 $ 25,936 BALANCE SHEET AMOUNTS Current liability $ (270 ) $ (220 ) $ (7,300 ) $ (5,400 ) Noncurrent liability (5,476 ) (16,147 ) (80,567 ) (83,163 ) $ (5,746 ) $ (16,367 ) $ (87,867 ) $ (88,563 )
Other Postretirement Benefit Costs	The following table details the components of pension and postretirement benefit costs (credits): Pension Benefits Other Postretirement Benefits Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 (In thousands) Service cost $ — $ — $ — $ 480 $ 558 $ 671 Interest cost (1) 8,141 9,269 11,169 3,505 3,674 4,150 Curtailments — — — — — (520 ) Settlements (1) (1,326 ) (2,332 ) (1,532 ) — — — Expected return on plan assets (1) (10,555 ) (12,083 ) (16,498 ) — — — Amortization of prior service credits (1) (24 ) — — — — — Amortization of other actuarial losses (gains) (1) (11 ) — — (2,974 ) — — Net benefit cost (credit) $ (3,775 ) $ (5,146 ) $ (6,861 ) $ 1,011 $ 4,232 $ 4,301 (1) In accordance with the adoption of ASU 2017-07, “Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost,” these costs are recorded within Nonoperating expenses in the Consolidated Income Statements on the line item “Non-service related pension and postretirement benefit costs.”
Schedule of Assumptions Used	The following table provides the assumptions used to determine the actuarial present value of projected benefit obligations for the respective periods. Year Ended December 31, 2019 Year Ended December 31, 2018 (Percentages) Pension Benefits Discount rate 3.09/2.90 4.11/3.94 Other Postretirement Benefits Discount rate 3.09 4.12 The following table provides the weighted average assumptions used to determine net periodic benefit cost for the respective periods. Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 (Percentages) Pension Benefits Discount rate 3.65 3.82 3.77 Expected return on plan assets 5.10 5.30 6.20 Other Postretirement Benefits Discount rate 4.12 3.49 3.85
Schedule of Allocation of Plan Assets	The Company’s pension plan assets at December 31, 2019 and 2018 , respectively, are categorized below according to the fair value hierarchy as defined in Note 16 , “ Fair Value Measurements ”: Total Level 1 Level 2 Level 3 2019 2018 2019 2018 2019 2018 2019 2018 (In thousands) Equity Securities: (A) U.S. small-cap $ 2,319 $ 2,751 $ 2,319 $ 2,751 $ — $ — $ — $ — U.S. mid-cap 1,397 1,182 1,397 1,182 — — — — U.S. large-cap — — — — — — — — Non-U.S. — — — — — — — — Fixed income securities: — U.S. government securities (B) 50,610 43,829 35,751 38,436 14,859 5,393 — — Non-U.S. government securities (C) 2,242 2,092 — — 2,242 2,092 — — U.S. government asset and mortgage backed securities (D) — 7,667 — — — 7,667 — — Corporate fixed income (E) 108,023 68,762 — — 108,023 68,762 — — State and local government securities (F) 2,653 3,480 — — 2,653 3,480 — — Other investments (I) — 5,223 — — — 5,223 — — Total $ 167,244 $ 134,986 $ 39,467 $ 42,369 $ 127,777 $ 92,617 $ — $ — Assets at net asset value (G) 53,418 82,765 Short-term investments (H) — 7,003 Other liabilities (J) (8,860 ) (12,248 ) $ 211,802 $ 212,506 (A) Equity securities includes investments in 1) common stock, 2) preferred stock and 3) mutual funds. Investments in common and preferred stocks are valued using quoted market prices multiplied by the number of shares owned. Investments in mutual funds are valued at the net asset value per share multiplied by the number of shares held as of the measurement date and are traded on listed exchanges. (B) U.S. government securities includes agency and treasury debt. These investments are valued using dealer quotes in an active market. (C) Non-U.S. government securities includes debt securities issued by foreign governments and are valued utilizing a price spread basis valuation technique with observable sources from investment dealers and research vendors. (D) U.S. government asset and mortgage backed securities includes government-backed mortgage funds which are valued utilizing an income approach that includes various valuation techniques and sources such as discounted cash flows models, benchmark yields and securities, reported trades, issuer trades and/or other applicable data. (E) Corporate fixed income is primarily comprised of corporate bonds and certain corporate asset-backed securities that are denominated in the U.S. dollar and are investment-grade securities. These investments are valued using dealer quotes. (F) State and local government securities include different U.S. state and local municipal bonds and asset backed securities, these investments are valued utilizing a market approach that includes various valuation techniques and sources such as value generation models, broker quotes, benchmark yields and securities, reported trades, issuer trades and/or other applicable data. (G) Investments that are measured at fair value using the net asset value per share practical expedient have not been classified in the fair value hierarchy in accordance with Accounting Standards Update 2015-07. These investments are primarily mutual funds that are highly liquid with no restrictions on ability to redeem the funds into cash. (H) Short-term investments include governmental agency funds, government repurchase agreements, commingled funds, and pooled funds and mutual funds. Governmental agency funds are valued utilizing an option adjusted spread valuation technique and sources such as interest rate generation processes, benchmark yields and broker quotes. Investments in governmental repurchase agreements, commingled funds and pooled funds and mutual funds are valued at the net asset value per share multiplied by the number of shares held as of the measurement date. (I) Other investments include cash, forward contracts, derivative instruments, credit default swaps, interest rate swaps and mutual funds. Investments in interest rate swaps are valued utilizing a market approach that includes various valuation techniques and sources such as value generation models, broker quotes in active and non-active markets, benchmark yields and securities, reported trades, issuer trades and/or other applicable data. Forward contracts and derivative instruments are valued at their exchange listed price or broker quote in an active market. The mutual funds are valued at the net asset value per share multiplied by the number of shares held as of the measurement date and are traded on listed exchanges. (J) Net payable amount due for pending securities purchased and sold due to broker/dealer.
Schedule of Expected Benefit Payments	The following represents expected future benefit payments from the plan: Other Pension Postretirement Benefits Benefits (In thousands) 2020 $ 18,016 $ 12,043 2021 16,603 12,273 2022 15,257 12,071 2023 14,240 11,974 2024 13,640 11,836 Next 5 years 60,068 58,640 $ 137,824 $ 118,837

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Schedule of Weighted Average Number of Shares	The following table provides the basis for basic and diluted EPS by reconciling the numerators and denominators of the computations: Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 (In Thousands) Weighted average shares outstanding: Basic weighted average shares outstanding 16,218 19,663 23,725 Effect of dilutive securities 1,080 966 515 Diluted weighted average shares outstanding 17,298 20,629 24,240

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Lease, Cost	Information related to leases was as follows: Year Ended December 31, 2019 (In thousands) Operating lease information: Operating lease cost $ 3,921 Operating cash flows from operating leases 3,842 Weighted average remaining lease term in years 5.92 Weighted average discount rate 5.5 %
Lessee, Operating Lease, Liability, Maturity	Future minimum lease payments under non-cancellable leases as of December 31, 2019 were as follows: Year Amount (In thousands) 2020 $ 3,616 2021 3,367 2022 3,292 2023 3,261 2024 3,152 Thereafter 8,001 Total minimum lease payments $ 24,689 Less imputed interest (4,888 ) Total operating lease liability $ 19,801 As reflected on the balance sheet: Accrued expenses and other current liabilities $ 2,514 Other noncurrent liabilities 17,287 Total operating lease liability $ 19,801

Risk Concentrations (Tables)

Risk Concentrations (Tables)	12 Months Ended
	Dec. 31, 2019
Risks and Uncertainties [Abstract]
Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas	The Company’s foreign revenues by geographical location as follows: Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 (In thousands) Europe $ 537,117 $ 559,165 $ 388,926 Asia 322,029 452,711 264,503 Central and South America 82,476 79,085 30,982 Africa 18,698 17,567 14,901 Brokered Sales — 2,372 3,150 Total $ 960,320 $ 1,110,900 $ 702,462

Revenue Recognition (Tables)

Revenue Recognition (Tables)	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Schedule of effects of revenue recognition	PRB MET Other Thermal Corporate, Other and Eliminations Consolidated (in thousands) Year Ended December 31, 2019 North America revenues $ 915,750 $ 217,381 $ 190,051 $ 10,850 $ 1,334,032 Seaborne revenues — 773,169 187,151 — 960,320 Total revenues $ 915,750 $ 990,550 $ 377,202 $ 10,850 $ 2,294,352 Year Ended December 31, 2018 North America revenues $ 971,337 $ 160,969 $ 195,547 $ 13,034 $ 1,340,887 Seaborne revenues 1,911 875,652 233,337 — 1,110,900 Total revenues $ 973,248 $ 1,036,621 $ 428,884 $ 13,034 $ 2,451,787 Year Ended December 31, 2017 North America revenues $ 1,024,197 $ 312,874 $ 269,007 $ 16,083 $ 1,622,161 Seaborne revenues — 574,965 127,497 — 702,462 Total revenues $ 1,024,197 $ 887,839 $ 396,504 $ 16,083 $ 2,324,623

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Schedule Of Operating Segment Results	(In thousands) PRB MET Other Thermal Corporate, Other and Eliminations Consolidated Year Ended December 31, 2019 Revenues $ 915,750 $ 990,550 $ 377,202 10,850 $ 2,294,352 Adjusted EBITDA 110,528 305,363 41,495 (94,219 ) 363,167 Depreciation, depletion and amortization 20,810 74,211 14,414 2,620 112,055 Accretion on asset retirement obligation 12,542 2,123 2,413 3,470 20,548 Total Assets 256,460 625,134 105,411 880,751 1,867,756 Capital expenditures 29,420 211,718 20,088 5,130 266,356 Year Ended December 31, 2018 Revenues $ 973,248 $ 1,036,621 $ 428,884 $ 13,034 $ 2,451,787 Adjusted EBITDA 126,525 349,524 68,620 (106,891 ) 437,778 Depreciation, depletion and amortization 33,120 69,560 14,699 2,184 119,563 Accretion on asset retirement obligation 19,541 1,874 2,261 4,294 27,970 Total assets 278,314 545,061 125,333 938,352 1,887,060 Capital expenditures 12,140 64,307 11,999 6,826 95,272 Year Ended December 31, 2017 Revenues $ 1,024,197 $ 887,839 $ 396,504 $ 16,083 $ 2,324,623 Adjusted EBITDA 158,882 243,616 102,006 (84,807 ) 419,697 Depreciation, depletion and amortization 36,349 70,896 13,588 1,631 122,464 Accretion on asset retirement obligation 20,160 2,000 2,161 5,888 30,209 Total assets 390,665 548,476 134,397 906,094 1,979,632 Capital expenditures 6,212 32,678 11,901 8,414 59,205
Reconciliation Statement Of Segment Income From Operations To Consolidated Income Before Income Taxes	A reconciliation of segment Adjusted EBITDA to consolidated income (loss) from continuing operations before income taxes follows: (In thousands) Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 Income before income taxes $ 234,047 $ 260,101 $ 203,195 Interest expense, net 6,794 13,689 24,256 Depreciation, depletion and amortization 112,055 119,563 122,464 Accretion on asset retirement obligations 20,548 27,970 30,209 Amortization of sales contracts, net (434 ) 11,107 53,985 Costs related to proposed joint venture with Peabody Energy 13,816 — — Loss on sale of Coal-Mac LLC 9,008 — — Preference Rights Lease Application settlement income (39,000 ) — — Loss (gain) on sale of Lone Mountain Processing, Inc. 4,304 — (21,297 ) Net loss resulting from early retirement of debt and debt restructuring — 485 2,547 Non-service related postretirement benefit costs 2,053 3,202 1,940 Reorganization items, net (24 ) 1,661 2,398 Adjusted EBITDA $ 363,167 $ 437,778 $ 419,697

Quarterly Selected Financial _2

Quarterly Selected Financial Data (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	Three Months Ended Year Ended December 31, 2019 March 31 June 30 September 30 December 31 (In thousands, except per share data) Revenues $ 555,183 $ 570,222 $ 619,467 $ 549,480 Gross profit $ 86,794 $ 88,032 $ 93,681 $ 23,144 Income (loss) from operations $ 76,779 $ 66,570 $ 106,481 $ (6,960 ) Reorganization items, net $ 87 $ (16 ) $ — $ (47 ) Net income (loss) $ 72,741 $ 62,840 $ 106,769 $ (8,551 ) Diluted income (loss) per common share $ 3.91 $ 3.53 $ 6.34 $ (0.57 ) Three Months Ended Year Ended December 31, 2018 March 31 June 30 September 30 December 31 (In thousands, except per share data) Revenues $ 575,295 $ 592,349 $ 633,180 $ 650,963 Gross profit $ 81,198 $ 77,663 $ 109,740 $ 101,396 Income from operations $ 65,167 $ 44,595 $ 82,886 $ 86,490 Reorganization items, net $ (301 ) $ (740 ) $ (560 ) $ (60 ) Net income $ 59,985 $ 43,306 $ 123,192 $ 86,094 Diluted income per common share $ 2.74 $ 2.06 $ 6.10 $ 4.44

Accounting Policies (Details)

Accounting Policies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Statutory Accounting Practices
Interest costs capitalized	$ 2.9	$ 0.3
Mineral rights	360.9	338.1
Deferred finance costs, net	3	4.7
Deferred finance costs, current	$ 2	$ 2.2
Exploration and production equipment | Minimum
Statutory Accounting Practices
Estimated useful life	1 year
Exploration and production equipment | Maximum
Statutory Accounting Practices
Estimated useful life	18 years
Building and building improvements | Minimum
Statutory Accounting Practices
Estimated useful life	3 years
Building and building improvements | Maximum
Statutory Accounting Practices
Estimated useful life	18 years
Mining properties and mineral rights | Minimum
Statutory Accounting Practices
Term of contract	10 years
Mining properties and mineral rights | Maximum
Statutory Accounting Practices
Term of contract	50 years

Emergence from Bankruptcy (Deta

Emergence from Bankruptcy (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reorganizations [Abstract]
Professional fees	$ 24	$ (1,661)	$ (2,398)

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Schedule of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Unrealized gains (losses)	$ (22,536)	$ 18,245
Amounts reclassified from accumulated other comprehensive income	(15,071)	4,684
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Beginning balance	43,296	20,367
Ending balance	5,689	43,296
Derivative Instruments
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Beginning balance	3,328	647
Unrealized gains (losses)	4,648	(4,359)
Amounts reclassified from accumulated other comprehensive income	(10,540)	7,040
Ending balance	(2,564)	3,328
Pension, Postretirement and Other Post-Employment Benefits
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Beginning balance	40,311	19,720
Unrealized gains (losses)	(27,692)	22,923
Amounts reclassified from accumulated other comprehensive income	(4,346)	(2,332)
Ending balance	8,273	40,311
Available-for-Sale Securities
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Beginning balance	(343)	0
Unrealized gains (losses)	508	(319)
Amounts reclassified from accumulated other comprehensive income	(185)	(24)
Ending balance	$ (20)	$ (343)

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Income (Schedule of Reclassifications) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Revenues	$ 549,480	$ 619,467	$ 570,222	$ 555,183	$ 650,963	$ 633,180	$ 592,349	$ 575,295	$ 2,294,352	$ 2,451,787	$ 2,324,623
Interest expense									(16,485)	(20,471)	(26,905)
Provision for (benefit from) income taxes									(248)	52,476	35,255
Total before tax									234,047	260,101	203,195
Interest and investment income									9,691	6,782	2,649
Net of tax	$ (8,551)	$ 106,769	$ 62,840	$ 72,741	$ 86,094	$ 123,192	$ 43,306	$ 59,985	233,799	312,577	$ 238,450
Pension, Postretirement and Other Post-Employment Benefits
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of net actuarial gains (losses)									3,020	0
Reclassification out of accumulated other comprehensive income | Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Revenues									9,480	(8,206)
Interest expense									1,060	1,166
Provision for (benefit from) income taxes									0	0
Net of tax									10,540	(7,040)
Reclassification out of accumulated other comprehensive income | Pension, Postretirement and Other Post-Employment Benefits
Accumulated Other Comprehensive Income (Loss) [Line Items]
Provision for (benefit from) income taxes									0	0
Settlement gains									1,326	2,332
Total before tax									4,346	2,332
Net of tax									4,346	2,332
Reclassification out of accumulated other comprehensive income | Available-for-Sale Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Provision for (benefit from) income taxes									0	0
Interest and investment income									185	24
Net of tax									$ 185	$ 24

Divestitures (Details)

Divestitures (Details) $ in Thousands	Dec. 13, 2019USD ($)	Sep. 14, 2017USD ($)company	Jun. 30, 2019USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Charge for bankruptcy claims			$ 4,300
Coal-Mac LLC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
(Gain) loss on sale of disposal group				$ 9,008	$ 0	$ 0
Coal-Mac LLC | Discontinued operations, disposed of by sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale	$ 2,300
Disbursements related to landholder consent fees and professional fees	200
(Gain) loss on sale of disposal group	$ 9,000
Lone Mountain Processing LLC | Discontinued operations, disposed of by sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale		$ 8,300
Disbursements related to landholder consent fees and professional fees		$ 1,400
Number of mining companies | company		2
(Gain) loss on sale of disposal group		$ (21,300)
Pension Benefits
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Curtailment gains				$ 0	$ 0	$ 0
Pension Benefits | Lone Mountain Processing LLC | Discontinued operations, disposed of by sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Curtailment gains		$ 4,700

Joint Venture with Peabody En_2

Joint Venture with Peabody Energy (Details) - Implementation Agreement - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Jun. 18, 2019
Schedule of Equity Method Investments [Line Items]
Economic interest held		33.50%
Incurred expenses related to regulatory approval process	$ 13.8
Peabody Energy Corporation
Schedule of Equity Method Investments [Line Items]
Economic interest held		66.50%

Preference Rights Lease Appli_2

Preference Rights Lease Application (PRLA) Settlement Income (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Gain Contingencies [Line Items]
Gain related to settlement		$ 39,000	$ 0	$ 0
Company utilization of royalty credits		13,300
Preference Rights Lease Application
Gain Contingencies [Line Items]
Gain related to settlement	$ 39,000
Royalty credits to be received due to settlement		$ 67,000
Royalty credits to be received due to settlement, percentage of royalty obligations		50.00%
One-time payment for ownership interest		$ 27,000
Payment to acquire investment, closing fees		$ 1,000

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Coal	$ 46,815	$ 40,982
Repair parts and supplies	84,083	84,488
Inventories	130,898	125,470
Allowance for slow-moving and obsolete inventories	$ 2,200	$ 600

Investments in Available-for-_3

Investments in Available-for-Sale Securities (Cost Basis to Fair Value Reconciliation) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Cost Basis	$ 135,687	$ 163,140
Gross Unrealized Gains	201	15
Gross Unrealized Losses	(221)	(358)
Fair Value	135,667	162,797
U.S. government and agency securities
Debt Securities, Available-for-sale [Line Items]
Cost Basis	35,044	100,003
Gross Unrealized Gains	1	11
Gross Unrealized Losses	(16)	(126)
Fair Value	35,029	99,888
Corporate notes and bonds
Debt Securities, Available-for-sale [Line Items]
Cost Basis	100,643	63,137
Gross Unrealized Gains	200	4
Gross Unrealized Losses	(205)	(232)
Fair Value	100,638	62,909
Short-term investments
Debt Securities, Available-for-sale [Line Items]
Fair Value	135,667	162,797
Short-term investments | U.S. government and agency securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	35,029	99,888
Short-term investments | Corporate notes and bonds
Debt Securities, Available-for-sale [Line Items]
Fair Value	$ 100,638	$ 62,909

Investments in Available-for-_4

Investments in Available-for-Sale Securities (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Abstract]
Continuous unrealized loss position for less than a year	$ 72.3	$ 115.2
Continuous unrealized loss position for over a year	$ 0	$ 32.4

Equity Method Investments and_3

Equity Method Investments and Membership Interests in Joint Ventures (Schedule of Equity Method Investments) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Beginning Balance	$ 104,676	$ 106,107
Sale of investment in affiliates	(1,879)
Advances to (distributions from) affiliates, net	(384)	(8,053)
Equity in comprehensive income (loss)	3,175	6,622
Ending Balance	105,588	104,676
Knight Hawk
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Beginning Balance	90,021	90,166
Sale of investment in affiliates	(1,879)
Advances to (distributions from) affiliates, net	(5,884)	(10,534)
Equity in comprehensive income (loss)	7,953	10,389
Ending Balance	90,211	90,021
DTA
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Beginning Balance	14,655	15,941
Advances to (distributions from) affiliates, net	5,500	2,481
Equity in comprehensive income (loss)	(4,778)	(3,767)
Ending Balance	$ 15,377	$ 14,655

Equity Method Investments and_4

Equity Method Investments and Membership Interests in Joint Ventures (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2019	Mar. 01, 2017
Knight Hawk | Sale
Schedule of Equity Method Investments [Line Items]
Ownership interest sold		1.00%
Ownership interest sold, value		$ 2
Ownership interest		48.00%
DTA
Schedule of Equity Method Investments [Line Items]
Ownership interest	35.00%		21.875%
Payments to auction house to increase ownership	$ 7.2

Derivatives (Narrative) (Detail

Derivatives (Narrative) (Details) $ in Thousands, gal in Millions	12 Months Ended
	Dec. 31, 2019USD ($)$ / optiongal	Dec. 31, 2018USD ($)
Derivative [Line Items]
Cash collateral, liability	$ 25,759	$ 17,801
Right to reclaim cash collateral, asset	25,759	17,801
Derivative contracts expected to be reclassified from OCI into earnings	400
2019
Derivative [Line Items]
Value of trading portfolio realized	$ (500)
Diesel purchases | Heating oil
Derivative [Line Items]
Quantities under derivative contracts | gal	10.1
Average strike price (in dollars per option) | $ / option	2.28
Diesel purchases | Minimum
Derivative [Line Items]
Gallons of diesel fuel purchased annually | gal	34
Diesel purchases | Maximum
Derivative [Line Items]
Gallons of diesel fuel purchased annually | gal	40
Other Current Liabilities
Derivative [Line Items]
Cash collateral, liability	$ 4,400
Other current assets
Derivative [Line Items]
Right to reclaim cash collateral, asset		$ 24,700

Derivatives (Schedule of Price

Derivatives (Schedule of Price Risk Derivatives) (Details) T in Thousands	12 Months Ended
	Dec. 31, 2019T
Coal sales
Derivative [Line Items]
Derivatives Held	668
Coal purchases
Derivative [Line Items]
Derivatives Held	668
2019 | Coal sales
Derivative [Line Items]
Derivatives Held	668
2019 | Coal purchases
Derivative [Line Items]
Derivatives Held	668
2020 | Coal sales
Derivative [Line Items]
Derivatives Held	0
2020 | Coal purchases
Derivative [Line Items]
Derivatives Held	0

Derivatives (Disclosure of Fair

Derivatives (Disclosure of Fair Value of Derivatives) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Derivative Assets	$ 31,616	$ 18,879
Derivative liabilities	(25,870)	(31,089)
Effect of counterparty netting in derivative assets	(25,759)	(17,801)
Effect of counterparty netting in derivative liabilities	25,759	17,801
Net derivative assets as classified in the balance sheet	5,857	1,078
Net derivative liabilities as classified in the balance sheet	(111)	(13,288)
Net derivatives as classified in the balance sheet	5,746	(12,210)
Derivatives Not Designated as Hedging Instruments
Derivative [Line Items]
Derivative Assets	30,265	16,537
Derivative liabilities	(24,908)	(30,284)
Derivatives Not Designated as Hedging Instruments | Coal held for trading purposes, exchange traded swaps and futures
Derivative [Line Items]
Derivative Assets	18,467	10,329
Derivative liabilities	(18,940)	(10,701)
Coal | Derivatives Designated as Hedging Instruments
Derivative [Line Items]
Derivative Assets	1,351	2,342
Derivative liabilities	(962)	(805)
Coal | Derivatives Not Designated as Hedging Instruments
Derivative [Line Items]
Derivative Assets	11,662	5,672
Derivative liabilities	(5,856)	(19,579)
Heating oil -- diesel purchases | Derivatives Not Designated as Hedging Instruments
Derivative [Line Items]
Derivative Assets	133	532
Derivative liabilities	(112)	0
Natural gas | Derivatives Not Designated as Hedging Instruments
Derivative [Line Items]
Derivative Assets	3	4
Derivative liabilities	$ 0	$ (4)

Derivatives (Net Derivatives as

Derivatives (Net Derivatives as Reflected on the Balance Sheets) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Net derivatives as classified in the balance sheet	$ 5,746	$ (12,210)
Other current assets | Heating oil
Derivatives, Fair Value [Line Items]
Net derivatives as classified in the balance sheet	133	532
Other current assets | Coal
Derivatives, Fair Value [Line Items]
Net derivatives as classified in the balance sheet	5,724	546
Accrued expenses and other current liabilities | Coal
Derivatives, Fair Value [Line Items]
Net derivatives as classified in the balance sheet	$ (111)	$ (13,288)

Derivatives (Effects of Derivat

Derivatives (Effects of Derivatives on Measures of Financial Performance) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Change In Fair Value Of Coal Derivatives And Coal Trading Activities, Net	$ 18,601	$ (9,118)	$ (7,222)
Derivatives Not Designated as Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Change In Fair Value Of Coal Derivatives And Coal Trading Activities, Net	18,601	(9,118)	(7,222)
Coal contract | Derivatives Designated as Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion)	9,018	(6,169)	(1,185)
Gains (Losses) Reclassified from Other Comprehensive Income into Income (Effective Portion)	9,481	(8,205)	0
Coal contract | Derivatives Not Designated as Hedging Instruments | Change in Fair Value of Coal Derivatives and Coal Trading Activity, Net
Derivative Instruments, Gain (Loss) [Line Items]
Trading - realized and unrealized	(1,013)	135	(2,047)
Coal risk management— unrealized	19,713	(9,530)	(4,648)
Coal risk management — realized	487	(8,734)
Natural gas | Derivatives Not Designated as Hedging Instruments | Change in Fair Value of Coal Derivatives and Coal Trading Activity, Net
Derivative Instruments, Gain (Loss) [Line Items]
Trading - realized and unrealized	(99)	277	(527)
Heating oil -- diesel purchases | Derivatives Not Designated as Hedging Instruments | Other Operating Income (Expense)
Derivative Instruments, Gain (Loss) [Line Items]
Heating oil — diesel purchases	(2,291)	(505)	(1,057)
Short | Coal contract | Derivatives Designated as Hedging Instruments | Sales Revenue, net
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion)	10,249	(7,517)	(2,127)
Gains (Losses) Reclassified from Other Comprehensive Income into Income (Effective Portion)	10,167	(10,912)	0
Long | Coal contract | Derivatives Designated as Hedging Instruments | Cost of Sales
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion)	(1,231)	1,348	942
Gains (Losses) Reclassified from Other Comprehensive Income into Income (Effective Portion)	$ (686)	$ 2,707	$ 0

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accrued Expenses and Other Current Liabilities [Abstract]
Payroll and employee benefits	$ 50,929	$ 57,166
Taxes other than income taxes	69,061	75,017
Interest	133	156
Workers’ compensation	16,119	20,044
Asset retirement obligations	10,366	13,113
Other	10,559	18,018
Accrued expenses and other current liabilities	$ 157,167	$ 183,514

Debt and Financing Arrangemen_3

Debt and Financing Arrangements (Debt Outstanding) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Term loan	$ 290,825	$ 293,626
Other	25,007	30,449
Debt issuance costs	(5,013)	(6,092)
Total	310,819	317,983
Less current maturities of debt	20,753	17,797
Long-term debt	290,066	300,186
Term loan due 2024 ($291.8 and $294.8 million face value, respectively)
Debt Instrument [Line Items]
Term loan, face value	$ 291,800	$ 294,800

Debt and Financing Arrangemen_4

Debt and Financing Arrangements (Company Debt Narrative) (Details) - USD ($)	Apr. 27, 2018	Mar. 07, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Apr. 27, 2017
Debt Instrument [Line Items]
Letters of credit outstanding			$ 0
Additional availability for borrowings			14,100,000
Derivative liabilities			25,870,000	$ 31,089,000
Debt financing costs			0	$ 1,257,000	$ 10,149,000
Senior notes | Term loan debt facility
Debt Instrument [Line Items]
Mandatory prepayment amount		100.00%
Default to indebtedness amount		$ 50,000,000
Default to surety, reclamation, or similar bonds securing obligations		50,000,000
Default to uninsured judgements		50,000,000
Uninsured losses or proceedings against minimum amount		50,000,000
Line of credit | Secured debt
Debt Instrument [Line Items]
Letters of credit outstanding			$ 15,500,000
Term loan debt facility | Senior notes
Debt Instrument [Line Items]
Amount of debt instrument		$ 300,000,000
Percent of face amount of debt issued		99.50%
Quarterly principal amortization payments		$ 750,000
Voting interests of directly owned subsidiaries		100.00%
Voting equity interests of directly owned foreign subsidiaries		65.00%
Term loan debt facility | Senior notes | LIBOR
Debt Instrument [Line Items]
Applicable margin on interest rate			2.75%
Term loan debt facility | Line of credit
Debt Instrument [Line Items]
Call premium				1.00%
Term loan debt facility | Line of credit | LIBOR
Debt Instrument [Line Items]
Applicable margin on interest rate				2.75%
Term loan debt facility | Line of credit | LIBOR | Minimum
Debt Instrument [Line Items]
Applicable margin on interest rate				1.00%
Term loan debt facility | Line of credit | Base rate
Debt Instrument [Line Items]
Applicable margin on interest rate				1.75%
Regions Bank | Line of credit | Secured debt
Debt Instrument [Line Items]
Amount of debt instrument					40,000,000
Maximum borrowing capacity				$ 50,000,000
Current borrowing capacity				160,000,000
Liquidity amount minimum					$ 175,000,000	$ 175,000,000
Letters of credit outstanding			$ 35,900,000
Borrowing base percentage, coal inventory					85.00%
Borrowing base percentage, parts and supplies inventory					85.00%
Borrowing base, percentage of clause					35.00%
Percent of eligible cash					100.00%
Increase to line of credit facility				10,000,000
Covenant amount					$ 250,000,000
Regions Bank | Line of credit | Secured debt | LIBOR | Minimum
Debt Instrument [Line Items]
Applicable margin on interest rate					2.00%
Regions Bank | Line of credit | Secured debt | LIBOR | Maximum
Debt Instrument [Line Items]
Borrowing base, percentage of clause					2.50%
Regions Bank | Line of credit | Secured debt | Base rate | Minimum
Debt Instrument [Line Items]
Applicable margin on interest rate					1.00%
Regions Bank | Line of credit | Secured debt | Base rate | Maximum
Debt Instrument [Line Items]
Applicable margin on interest rate					1.50%
Arch Receivable Company, LLC | Line of credit | Secured debt | Accounts Receivable Securitization Facility
Debt Instrument [Line Items]
Current borrowing capacity			108,900,000
Maturity date	3 years
Liquidity threshold, consecutive days	60 days
Liquidity threshold	364 days
Liquidity threshold, expiration period	60 days
Interest rate swap
Debt Instrument [Line Items]
Derivative liabilities			3,000,000
Gain (loss) on interest rate swap			$ 1,100,000	$ 1,200,000	$ (100,000)

Debt and Financing Arrangemen_5

Debt and Financing Arrangements (Interest Rate Derivatives) (Details)	Dec. 31, 2019USD ($)
June 28, 2019
Derivative [Line Items]
Notional Amount	$ 250,000,000
Fixed Rate	2.025%
June 30, 2020
Derivative [Line Items]
Notional Amount	$ 200,000,000
Fixed Rate	2.249%
June 30, 2021
Derivative [Line Items]
Notional Amount	$ 100,000,000
Fixed Rate	2.315%

Debt and Financing Arrangemen_6

Debt and Financing Arrangements (Debt Maturities) (Details) $ in Thousands	Dec. 31, 2019USD ($)
Debt Disclosure [Abstract]
2020	$ 21,863
2021	8,853
2022	3,130
2023	3,161
2024	279,750
Thereafter	0
Total	$ 316,757

Taxes (Narrative) (Details)

Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2020	Dec. 31, 2016
Operating Loss Carryforwards [Line Items]
Valuation allowance	$ 506,316	$ 506,316	$ 530,612	$ 610,600
Annual limitation on operating loss use	29,800	29,800
Income tax benefit from cumulative adjustments		48,800
Change in uncertain tax positions		26,600
Operating loss carryforwards	1,000,000	1,000,000
Tax Cuts and Jobs Act of 2017, Income tax expense (benefit)			16,700	(330,900)
Repatriation of foreign earnings		1,500
Cumulative foreign earnings		4,200
Tax Cuts and Jobs Act of 2017, Income tax expense (benefit) related to valuation allowance	(45,000)
Tax Cuts and Jobs Act of 2017, Provisional income tax expense (benefit) related to change in limit on deductible for covered employees		3,900	6,100	200
Decrease in valuation allowance		24,200		35,700
Interest and penalties accrued related to unrecognized tax benefits	800	800	300
Gross unrecognized tax benefits	$ 39,729	$ 39,729	$ 39,093	$ 11,383		$ 7,455
Scenario, forecast
Operating Loss Carryforwards [Line Items]
Gross unrecognized tax benefits					$ 500

Taxes (Schedule of Components o

Taxes (Schedule of Components of Income Tax) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
Federal	$ (36)	$ 86	$ 835
State	124	136	31
Total current	88	222	866
Deferred:
Federal	667	(52,309)	(36,162)
State	(507)	(389)	41
Total deferred	160	(52,698)	(36,121)
Provision for (benefit from) income taxes	$ 248	$ (52,476)	$ (35,255)

Taxes (Schedule of Effective In

Taxes (Schedule of Effective Income Tax Rate Reconciliation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income tax provision (benefit) at statutory rate	$ 49,150	$ 54,621	$ 71,118
Percentage depletion allowance	(17,743)	(17,725)	(31,255)
State taxes, net of effect of federal taxes	(12,769)	4,480	7,002
Change in valuation allowance	(24,206)	(79,961)	(410,983)
Impact of Tax Cuts and Jobs Act of 2017	0	(17,645)	332,345
Other, net	5,816	3,754	(3,482)
Provision for (benefit from) income taxes	$ 248	$ (52,476)	$ (35,255)

Taxes (Schedule of Deferred Tax

Taxes (Schedule of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Tax loss carryforwards	$ 294,535	$ 307,615
Tax credit carryforwards	5,297	5,394
Investment in partnerships	190,418	193,217
Other	20,387	28,747
Gross deferred tax assets	510,637	534,973
Valuation allowance	(506,316)	(530,612)	$ (610,600)
Total deferred tax assets	4,321	4,361
Deferred tax liabilities:
Plant and equipment	2,063	3,037
Other	2,178	1,154
Total deferred tax liabilities	4,241	4,191
Net deferred tax asset	$ 80	$ 170

Taxes (Schedule of Gross Unreco

Taxes (Schedule of Gross Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning Balance	$ 39,093	$ 11,383	$ 7,455
Additions based on tax positions related to the current year	2,980	3,228	0
Additions for tax positions of prior years		28,387	3,928
Reductions for tax positions of prior years	(1,970)	(634)
Reductions as a result of lapses in the statute of limitations	(374)	(3,271)	0
Ending Balance	$ 39,729	$ 39,093	$ 11,383

Asset Retirement Obligations (R

Asset Retirement Obligations (Rollforward) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning Balance	$ 243,417	$ 328,695
Accretion expense	20,548	27,970	$ 30,209
Obligations of divested operations	(12,185)	0
Adjustments to the liability from changes in estimates	11,438	(100,728)
Liabilities settled	(10,420)	(12,520)
Ending Balance	252,798	243,417	$ 328,695
Current portion included in accrued expenses	(10,366)	(13,113)
Noncurrent liability	$ 242,432	$ 230,304

Asset Retirement Obligations (N

Asset Retirement Obligations (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
asset retirement obligations [Line Items]
Adjustments to the liability from changes in estimates	$ (11,438,000)	$ 100,728,000
Surety bonds outstanding	29,500,000
Letters of credit outstanding	0
Cash collateral for surety bond	600,000
Asset retirement obligations
asset retirement obligations [Line Items]
Surety bonds outstanding	528,900,000
Black Thunder Mine
asset retirement obligations [Line Items]
Adjustments to the liability from changes in estimates	$ 95,600,000

Fair Value Measurements (Financ

Fair Value Measurements (Financial Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Assets:
Investments in marketable securities	$ 135,667	$ 162,797
Derivatives	5,857	3,554
Total assets	141,524	166,351
Liabilities:
Derivatives	3,065	13,288
Level 1
Assets:
Investments in marketable securities	35,029	99,888
Derivatives	5,269	0
Total assets	40,298	99,888
Liabilities:
Derivatives		13,252
Level 2
Assets:
Investments in marketable securities	100,638	62,909
Derivatives	527	3,022
Total assets	101,165	65,931
Liabilities:
Derivatives	3,065	36
Level 3
Assets:
Investments in marketable securities	0	0
Derivatives	61	532
Total assets	61	532
Liabilities:
Derivatives	$ 0	$ 0

Fair Value Measurements (Change

Fair Value Measurements (Change in Instruments Categorized as Level 3) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	$ 532	$ 5,426
Realized and unrealized (gains) losses recognized in earnings, net	(1,893)	(302)
Purchases	1,597	3,420
Issuances	(208)	(724)
Settlements	33	(7,288)
Ending balance	$ 61	$ 532

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Net unrealized (losses) related to level 3 instruments	$ (1.2)
Fair value of senior notes and other long-term debt, including amounts classified as current	$ 308	$ 318.6

Capital Stock (Dividends) (Deta

Capital Stock (Dividends) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Equity [Abstract]
Dividends (in dollars per share)	$ 0.45	$ 0.45	$ 0.45	$ 0.45	$ 0.40	$ 0.40	$ 0.40	$ 0.40	$ 1.80	$ 1.60
Amount (in thousands)	$ 7,956	$ 7,000	$ 7,425	$ 7,839	$ 7,303	$ 7,633	$ 7,998	$ 8,335	$ 30,220	$ 31,269

Capital Stock (Narrative) (Deta

Capital Stock (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Apr. 30, 2019	Dec. 31, 2018	Oct. 05, 2016
Class of Stock [Line Items]
Incremental increase to authorized amount of share repurchase program		$ 250
Authorized amount of share repurchase program		$ 1,050
Warrants issued (in shares)	1,845,568
Common stock, par value (in dollars per share)	$ 0.01		$ 0.01
Percentage of common stock in transaction	90.00%
Warrants, repurchase amount (in dollars per share)	$ 0
Warrants exercised (in shares)	386
Common Class A
Class of Stock [Line Items]
Warrants issued (in shares)				1,914,856
Common stock, par value (in dollars per share)				$ 0.01
Warrant exercise price (in dollars per share)				$ 57

Capital Stock (Share Repurchase

Capital Stock (Share Repurchase Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Equity [Abstract]
Number of Shares (in shares)	133,379	1,169,597	697,255	872,317	1,000,881	870,538	960,105	407,091	2,872,548	3,238,615
Average Repurchase Price per Share (in dollars per share)	$ 78.72	$ 78.11	$ 90.92	$ 89.70	$ 88.57	$ 87.59	$ 81.54	$ 94.79	$ 84.77	$ 87
Amount (in thousands)	$ 10,499	$ 91,357	$ 63,393	$ 78,249	$ 88,651	$ 76,248	$ 78,287	$ 38,588	$ 243,498	$ 281,774	$ 302,109

Stock-Based Compensation and _3

Stock-Based Compensation and Other Incentive Plans (Narrative) (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 22	$ 17.5	$ 10.4
Unrecognized share-based compensation expense	$ 19.2
Weighted-average period for recognition of unrecognized share-based compensation expense	3 years
Time Based Restricted Stock Units (RSUs) | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year
Time Based Restricted Stock Units (RSUs) | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Performance Based Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Volatility rate	36.00%
2016 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for incentive plan (in shares)	3
Number of shares available for grant (in shares)	2.3
Long Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Requisite service period	3 years
Compensation expense	$ 1	2.7	$ 0.7
Amounts unpaid under long term incentive plan	$ 3	$ 6.9

Stock-Based Compensation and _4

Stock-Based Compensation and Other Incentive Plans (Restricted Stock Unit Activity) (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2019$ / sharesshares
Time Based Awards
Restricted Stock Common Shares
Outstanding at beginning of period (in shares) | shares	388
Granted (in shares) | shares	7
Forfeited/Canceled (in shares) | shares	(1)
Vested (in shares) | shares	(156)
Outstanding at end of period (in shares) | shares	238
Weighted Average Grant Date Fair Value
Outstanding weighted average grant date fair value at beginning of period (in dollars per share) | $ / shares	$ 84.11
Granted (in dollars per share) | $ / shares	$ 92.08
Forfeited/Canceled (in dollars per share) | $ / shares	92
Vested (in dollars per share) | $ / shares	$ 79.25
Outstanding weighted average grant date fair value at end of period (in dollars per share) | $ / shares	$ 87.50
Performance Based Awards
Restricted Stock Common Shares
Outstanding at beginning of period (in shares) | shares	415
Granted (in shares) | shares	6
Forfeited/Canceled (in shares) | shares	(89)
Vested (in shares) | shares	(137)
Outstanding at end of period (in shares) | shares	195
Weighted Average Grant Date Fair Value
Outstanding weighted average grant date fair value at beginning of period (in dollars per share) | $ / shares	$ 85.30
Granted (in dollars per share) | $ / shares	$ 105.56
Forfeited/Canceled (in dollars per share) | $ / shares	67.72
Vested (in dollars per share) | $ / shares	$ 67.34
Outstanding weighted average grant date fair value at end of period (in dollars per share) | $ / shares	$ 106.44

Workers' Compensation Expense_2

Workers' Compensation Expense (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Defined Benefit Plan Disclosure [Line Items]
Reimbursable liabilities	$ 13.6
Insurance receivable, current	0.5
Insurance receivable, noncurrent	13.1
Traumatic and other workers’ compensation claims
Defined Benefit Plan Disclosure [Line Items]
Surety bonds and letters of credit outstanding	$ 121.7
Risk Free Interest Rate | Traumatic and other workers’ compensation claims
Defined Benefit Plan Disclosure [Line Items]
Discount rate	0.0175

Workers' Compensation Expense_3

Workers' Compensation Expense (Worker's Compensation Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accrued Workers' Compensation [Line Items]
Service cost	$ 6,677	$ 7,440	$ 6,320
Interest cost	4,922	4,365	4,651
Net amortization	0	0	0
Traumatic and other workers’ compensation claims
Accrued Workers' Compensation [Line Items]
Total workers’ compensation expense	24,649	17,200	14,179
Total occupational disease
Accrued Workers' Compensation [Line Items]
Service cost	6,677	7,440
Interest cost	4,922	4,365
Total occupational disease	11,599	11,805	10,971
Traumatic injury claims and assessments
Accrued Workers' Compensation [Line Items]
Traumatic injury claims and assessments	$ 13,050	$ 5,395	$ 3,208

Workers' Compensation Expense_4

Workers' Compensation Expense (Occupational Disease Costs Activity and Assumptions) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Self Insurance Reserve [Roll Forward]
Service cost	$ 6,677	$ 7,440	$ 6,320
Interest cost	$ 4,922	$ 4,365	4,651
Discount Rate
Self Insurance Reserve [Roll Forward]
Discount rate	0.0331	0.0426
Occupational disease costs
Self Insurance Reserve [Roll Forward]
Beginning of period	$ 118,900	$ 122,426
Service cost	6,677	7,440
Interest cost	4,922	4,365
Actuarial (gain) loss	35,993	(7,071)
Benefit and administrative payments	(8,167)	(8,260)
End of period	$ 158,325	$ 118,900	$ 122,426

Workers' Compensation Expense_5

Workers' Compensation Expense (Schedule of Amounts Recognized in Balance Sheet) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accrued Workers' Compensation [Line Items]
Total obligations	$ 231,718	$ 194,347
Less amount included in accrued expenses	16,119	20,044
Noncurrent obligations	215,599	174,303
Occupational disease costs
Accrued Workers' Compensation [Line Items]
Occupational disease costs	158,325	118,900	$ 122,426
Traumatic and other workers’ compensation claims
Accrued Workers' Compensation [Line Items]
Occupational disease costs	$ 73,393	$ 75,447

Employee Benefit Plans (Schedul

Employee Benefit Plans (Schedule of Defined Benefit Plans Disclosures) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Service cost	$ 6,677	$ 7,440	$ 6,320
Interest cost	4,922	4,365	4,651
CHANGE IN PLAN ASSETS
Value of Plan Assets at beginning of year	212,506
Value of Plan Assets at end of year	211,802	212,506
Pension Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligations at beginning of year	228,873	270,098
Service cost	0	0	0
Interest cost	8,141	9,269	11,169
Settlement gain	(1,326)	(2,332)
Curtailments	0	0
Benefits paid	(34,918)	(36,895)
Other-primarily actuarial (gain) loss	16,778	(11,267)
Benefit Obligations at end of year	217,548	228,873	270,098
CHANGE IN PLAN ASSETS
Value of Plan Assets at beginning of year	212,506	255,642
Actual return on plan assets	33,998	(6,463)
Employer contributions	216	222
Benefits paid	(34,918)	(36,895)
Value of Plan Assets at end of year	211,802	212,506	255,642
Accrued benefit cost	(5,746)	(16,367)
ITEMS NOT YET RECOGNIZED AS A COMPONENT OF NET PERIODIC BENEFIT COST
Prior service credit	992	0
Accumulated gain	14,537	8,899
Total not yet recognized as a component of net periodic benefit cost	15,529	8,899
BALANCE SHEET AMOUNTS
Current liability	(270)	(220)
Noncurrent liability	(5,476)	(16,147)
Liability, Defined Benefit Plan	(5,746)	(16,367)
Other Postretirement Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligations at beginning of year	88,563	110,519
Service cost	480	558	671
Interest cost	3,505	3,674	4,150
Settlement gain	0	0
Curtailments	30	0
Benefits paid	(7,304)	(5,388)
Other-primarily actuarial (gain) loss	2,593	(20,800)
Benefit Obligations at end of year	87,867	88,563	110,519
CHANGE IN PLAN ASSETS
Value of Plan Assets at beginning of year	0	0
Actual return on plan assets		0
Employer contributions	7,304	5,388
Benefits paid	(7,304)	(5,388)
Value of Plan Assets at end of year	0	0	$ 0
Accrued benefit cost	(87,867)	(88,563)
ITEMS NOT YET RECOGNIZED AS A COMPONENT OF NET PERIODIC BENEFIT COST
Prior service credit	0	0
Accumulated gain	20,333	25,936
Total not yet recognized as a component of net periodic benefit cost	20,333	25,936
BALANCE SHEET AMOUNTS
Current liability	(7,300)	(5,400)
Noncurrent liability	(80,567)	(83,163)
Liability, Defined Benefit Plan	$ (87,867)	$ (88,563)

Employee Benefit Plans (Narrati

Employee Benefit Plans (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate assumed	5.70%
Ultimate trend rate	4.50%
Effect of one percentage point increase on postretirement benefit obligation	$ 8,700,000
Effect of one percentage point increase on postretirement benefit cost	$ 400,000
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations (percent)	27.00%
Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations (percent)	73.00%
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation of pension plans	$ 217,500,000	$ 228,900,000
Expected amortization of prior service credit, next fiscal year	100,000
Pension contributions planned for next fiscal year	0
Other postretirement benefits payments	17,500,000	$ 17,900,000	$ 18,000,000
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Expected amortization of gain, next fiscal year	$ 2,100,000

Employee Benefit Plans (Sched_2

Employee Benefit Plans (Schedule of Net Benefit Costs) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 6,677	$ 7,440	$ 6,320
Interest cost	4,922	4,365	4,651
Amortization of other actuarial losses (gains)	0	0	0
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0
Interest cost	8,141	9,269	11,169
Curtailments	0	0	0
Settlements	(1,326)	(2,332)	(1,532)
Expected return on plan assets	(10,555)	(12,083)	(16,498)
Amortization of prior service credits	(24)	0	0
Amortization of other actuarial losses (gains)	(11)	0	0
Total occupational disease	(3,775)	(5,146)	(6,861)
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	480	558	671
Interest cost	3,505	3,674	4,150
Curtailments	0	0	(520)
Settlements	0	0	0
Expected return on plan assets	0	0	0
Amortization of prior service credits	0	0	0
Amortization of other actuarial losses (gains)	(2,974)	0	0
Total occupational disease	$ 1,011	$ 4,232	$ 4,301

Employee Benefit Plans (Sched_3

Employee Benefit Plans (Schedule of Assumptions Used to Calculate Benefit Obligations) (Details)	Dec. 31, 2019	Dec. 31, 2018
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	3.09%	4.12%
Excess Plan | Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	2.90%	3.94%
Cash Balance | Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	3.09%	4.11%

Employee Benefit Plans (Sched_4

Employee Benefit Plans (Schedule of Assumptions Used) (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	3.65%	3.82%	3.77%
Expected return on plan assets	5.10%	5.30%	6.20%
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	4.12%	3.49%	3.85%

Employee Benefit Plans (Sched_5

Employee Benefit Plans (Schedule of Allocation of Plan Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	$ 211,802	$ 212,506
Other liabilities	(8,860)	(12,248)
Total
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	167,244	134,986
Total | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	39,467	42,369
Total | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	127,777	92,617
Total | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
U.S. small-cap
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	2,319	2,751
U.S. small-cap | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	2,319	2,751
U.S. small-cap | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
U.S. small-cap | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
U.S. mid-cap
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	1,397	1,182
U.S. mid-cap | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	1,397	1,182
U.S. mid-cap | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
U.S. mid-cap | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
U.S. large-cap
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
U.S. large-cap | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
U.S. large-cap | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
U.S. large-cap | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
Non-U.S.
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
Non-U.S. | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
Non-U.S. | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
Non-U.S. | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
U.S. government securities
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	50,610	43,829
U.S. government securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	35,751	38,436
U.S. government securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	14,859	5,393
U.S. government securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
Non-U.S. government securities
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	2,242	2,092
Non-U.S. government securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
Non-U.S. government securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	2,242	2,092
Non-U.S. government securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
U.S. governement asset and mortgage backed securities
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	7,667
U.S. governement asset and mortgage backed securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
U.S. governement asset and mortgage backed securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	7,667
U.S. governement asset and mortgage backed securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
Corporate notes and bonds
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	108,023	68,762
Corporate notes and bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
Corporate notes and bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	108,023	68,762
Corporate notes and bonds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
State and local government securities
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	2,653	3,480
State and local government securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
State and local government securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	2,653	3,480
State and local government securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
Other investments
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	5,223
Other investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
Other investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	5,223
Other investments | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
Other fixed income
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	53,418	82,765
Short-term investments
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	$ 0	$ 7,003

Employee Benefit Plans (Summary

Employee Benefit Plans (Summary of Estimated Future Benefit Payments) (Details) $ in Thousands	Dec. 31, 2019USD ($)
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
2020	$ 18,016
2021	16,603
2022	15,257
2023	14,240
2024	13,640
Next 5 years	60,068
Total	137,824
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
2020	12,043
2021	12,273
2022	12,071
2023	11,974
2024	11,836
Next 5 years	58,640
Total	$ 118,837

Earnings Per Common Share (Deta

Earnings Per Common Share (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Basic weighted average shares outstanding (in shares)	16,218	19,663	23,725
Effect of dilutive securities (in shares)	1,080	966	515
Diluted weighted average shares outstanding (in shares)	17,298	20,629	24,240

Leases (Components of Lease Exp

Leases (Components of Lease Expense) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Leases [Abstract]
Operating lease cost	$ 3,921
Operating cash flows from operating leases	$ 3,842
Weighted average remaining lease term in years	5 years 11 months 1 day
Weighted average discount rate	5.50%

Leases (Schedule of Lease Minim

Leases (Schedule of Lease Minimum Payments) (Details) $ in Thousands	Dec. 31, 2019USD ($)
Leases [Abstract]
2020	$ 3,616
2021	3,367
2022	3,292
2023	3,261
2024	3,152
Thereafter	8,001
Total	24,689
Less imputed interest	(4,888)
Total operating lease liability	19,801
Accrued expenses and other current liabilities	2,514
Other noncurrent liabilities	17,287
Total operating lease liability	$ 19,801

Leases (Narrative) (Details)

Leases (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Leases [Abstract]
Operating Lease, Right-of-Use Asset	$ 19.2
Operating lease expense	12	$ 12.4	$ 19.2
Royalty expense	149.5	$ 166.1	$ 167.4
Surety bonds outstanding	$ 29.5

Risk Concentrations (Narrative)

Risk Concentrations (Narrative) (Details) $ in Thousands, T in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2019USD ($)T	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Concentration Risk [Line Items]
Trade accounts receivable	$ 168,125				$ 200,904				$ 168,125	$ 200,904
Tons of coal sold | T									90.3
Percentage of tons sold under long term contract									56.00%
Long term contracts percentage of company revenue									50.00%
Long-term contracts, life term, minimum									1 year
Long-term contracts, life term, maximum									4 years
Revenues	549,480	$ 619,467	$ 570,222	$ 555,183	650,963	$ 633,180	$ 592,349	$ 575,295	$ 2,294,352	2,451,787	$ 2,324,623
Europe
Concentration Risk [Line Items]
Revenues									537,117	559,165	388,926
Asia
Concentration Risk [Line Items]
Revenues									322,029	452,711	264,503
Central and South America
Concentration Risk [Line Items]
Revenues									82,476	79,085	30,982
Africa
Concentration Risk [Line Items]
Revenues									18,698	17,567	14,901
Brokered Sales
Concentration Risk [Line Items]
Revenues									0	2,372	$ 3,150
Electric utilities
Concentration Risk [Line Items]
Receivables	69,100				73,900				$ 69,100	$ 73,900
Percentage of total trade accounts receivable									41.00%	37.00%
Domestic and foreign steel producers
Concentration Risk [Line Items]
Trade accounts receivable	$ 98,600				$ 126,500				$ 98,600	$ 126,500
Trade receivables, percentage	59.00%				63.00%				59.00%	63.00%

Risk Concentrations (Schedule o

Risk Concentrations (Schedule of Foreign Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Concentration Risk [Line Items]
Revenues	$ 549,480	$ 619,467	$ 570,222	$ 555,183	$ 650,963	$ 633,180	$ 592,349	$ 575,295	$ 2,294,352	$ 2,451,787	$ 2,324,623
Europe
Concentration Risk [Line Items]
Revenues									537,117	559,165	388,926
Asia
Concentration Risk [Line Items]
Revenues									322,029	452,711	264,503
Central and South America
Concentration Risk [Line Items]
Revenues									82,476	79,085	30,982
Africa
Concentration Risk [Line Items]
Revenues									18,698	17,567	14,901
Brokered Sales
Concentration Risk [Line Items]
Revenues									0	2,372	3,150
Foreign Countries
Concentration Risk [Line Items]
Revenues									$ 960,320	$ 1,110,900	$ 702,462

Revenue Recognition (Schedule o

Revenue Recognition (Schedule of Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenues	$ 549,480	$ 619,467	$ 570,222	$ 555,183	$ 650,963	$ 633,180	$ 592,349	$ 575,295	$ 2,294,352	$ 2,451,787	$ 2,324,623
North America revenues
Disaggregation of Revenue [Line Items]
Revenues									1,334,032	1,340,887	1,622,161
Seaborne revenues
Disaggregation of Revenue [Line Items]
Revenues									960,320	1,110,900	702,462
Operating segments | PRB
Disaggregation of Revenue [Line Items]
Revenues									915,750	973,248	1,024,197
Operating segments | PRB | North America revenues
Disaggregation of Revenue [Line Items]
Revenues									915,750	971,337	1,024,197
Operating segments | PRB | Seaborne revenues
Disaggregation of Revenue [Line Items]
Revenues									0	1,911	0
Operating segments | MET
Disaggregation of Revenue [Line Items]
Revenues									990,550	1,036,621	887,839
Operating segments | MET | North America revenues
Disaggregation of Revenue [Line Items]
Revenues									217,381	160,969	312,874
Operating segments | MET | Seaborne revenues
Disaggregation of Revenue [Line Items]
Revenues									773,169	875,652	574,965
Operating segments | Other Thermal
Disaggregation of Revenue [Line Items]
Revenues									377,202	428,884	396,504
Operating segments | Other Thermal | North America revenues
Disaggregation of Revenue [Line Items]
Revenues									190,051	195,547	269,007
Operating segments | Other Thermal | Seaborne revenues
Disaggregation of Revenue [Line Items]
Revenues									187,151	233,337	127,497
Corporate, Other and Eliminations
Disaggregation of Revenue [Line Items]
Revenues									(10,850)	(13,034)	(16,083)
Corporate, Other and Eliminations | North America revenues
Disaggregation of Revenue [Line Items]
Revenues									(10,850)	(13,034)	(16,083)
Corporate, Other and Eliminations | Seaborne revenues
Disaggregation of Revenue [Line Items]
Revenues									$ 0	$ 0	$ 0

Revenue Recognition (Narrative)

Revenue Recognition (Narrative) (Details) - Coal T in Millions	Dec. 31, 2019T
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation (in tons)	67.4
Remaining performance obligations, fixed price contracts (in tons)	61.6
Remaining performance obligation, variable price contracts (in tons)	5.8
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation (in tons)	69
Remaining performance obligations, fixed price contracts (in tons)	64.9
Remaining performance obligation, variable price contracts (in tons)	4.1

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Amount accrued	$ 0.2	$ 0.2
Future commitments	$ 170.5

Segment Information (Narrative)

Segment Information (Narrative) (Details)	12 Months Ended
	Dec. 31, 2019line_of_business
Segment Reporting [Abstract]
Distinct lines of business	2

Segment Information (Schedule o

Segment Information (Schedule of Operating Segment Results) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenues	$ 549,480	$ 619,467	$ 570,222	$ 555,183	$ 650,963	$ 633,180	$ 592,349	$ 575,295	$ 2,294,352	$ 2,451,787	$ 2,324,623
Adjusted EBITDAR									363,167	437,778	419,697
Depreciation, depletion and amortization									112,055	119,563	122,464
Accretion on asset retirement obligations									20,548	27,970	30,209
Total Assets	1,867,756				1,887,060				1,867,756	1,887,060	1,979,632
Capital expenditures									266,356	95,272	59,205
Operating segments | PRB
Segment Reporting Information [Line Items]
Revenues									915,750	973,248	1,024,197
Adjusted EBITDAR									110,528	126,525	158,882
Depreciation, depletion and amortization									20,810	33,120	36,349
Accretion on asset retirement obligations									12,542	19,541	20,160
Total Assets	256,460				278,314				256,460	278,314	390,665
Capital expenditures									29,420	12,140	6,212
Operating segments | MET
Segment Reporting Information [Line Items]
Revenues									990,550	1,036,621	887,839
Adjusted EBITDAR									305,363	349,524	243,616
Depreciation, depletion and amortization									74,211	69,560	70,896
Accretion on asset retirement obligations									2,123	1,874	2,000
Total Assets	625,134				545,061				625,134	545,061	548,476
Capital expenditures									211,718	64,307	32,678
Operating segments | Other Thermal
Segment Reporting Information [Line Items]
Revenues									377,202	428,884	396,504
Adjusted EBITDAR									41,495	68,620	102,006
Depreciation, depletion and amortization									14,414	14,699	13,588
Accretion on asset retirement obligations									2,413	2,261	2,161
Total Assets	105,411				125,333				105,411	125,333	134,397
Capital expenditures									20,088	11,999	11,901
Corporate, Other and Eliminations
Segment Reporting Information [Line Items]
Revenues									(10,850)	(13,034)	(16,083)
Adjusted EBITDAR									(94,219)	(106,891)	(84,807)
Depreciation, depletion and amortization									2,620	2,184	1,631
Accretion on asset retirement obligations									3,470	4,294	5,888
Total Assets	$ 880,751				$ 938,352				880,751	938,352	906,094
Capital expenditures									$ 5,130	$ 6,826	$ 8,414

Segment Information (Reconcilia

Segment Information (Reconciliation of Segment Income from Operations to Consolidated Income Before Income Taxes) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Income before income taxes									$ 234,047	$ 260,101	$ 203,195
Interest expense, net									6,794	13,689	24,256
Depreciation, depletion and amortization									112,055	119,563	122,464
Accretion on asset retirement obligations									20,548	27,970	30,209
Amortization of sales contracts, net									(434)	11,107	53,985
Costs related to proposed joint venture with Peabody Energy									13,816	0	0
Preference Rights Lease Application settlement income									(39,000)	0	0
Net loss resulting from early retirement of debt and debt restructuring									0	485	2,547
Non-service related postretirement benefit costs									2,053	3,202	1,940
Reorganization items, net	$ 47	$ 0	$ 16	$ (87)	$ 60	$ 560	$ 740	$ 301	(24)	1,661	2,398
Adjusted EBITDA									363,167	437,778	419,697
Coal-Mac LLC
Segment Reporting Information [Line Items]
(Gain) loss on sale of disposal group									9,008	0	0
Lone Mountain Processing, Inc.
Segment Reporting Information [Line Items]
(Gain) loss on sale of disposal group									$ 4,304	$ 0	$ (21,297)

Quarterly Selected Financial _3

Quarterly Selected Financial Data (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 549,480	$ 619,467	$ 570,222	$ 555,183	$ 650,963	$ 633,180	$ 592,349	$ 575,295	$ 2,294,352	$ 2,451,787	$ 2,324,623
Gross profit	23,144	93,681	88,032	86,794	101,396	109,740	77,663	81,198
Income from operations	(6,960)	106,481	66,570	76,779	86,490	82,886	44,595	65,167	242,870	279,138	234,336
Reorganization items, net	(47)	0	(16)	87	(60)	(560)	(740)	(301)	24	(1,661)	(2,398)
Net income	$ (8,551)	$ 106,769	$ 62,840	$ 72,741	$ 86,094	$ 123,192	$ 43,306	$ 59,985	$ 233,799	$ 312,577	$ 238,450
Diluted earnings per common share (in dollars per share)	$ (0.57)	$ 6.34	$ 3.53	$ 3.91	$ 4.44	$ 6.10	$ 2.06	$ 2.74	$ 13.52	$ 15.15	$ 9.84

Valuation and Qualifying Acco_2

Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounts receivable and other receivables
Reserves deducted from asset accounts:
Balance at Beginning of Year	$ 0	$ 0	$ 0
Additions (Reductions) Charged to Costs and Expenses	0	0	0
Charged to Other Accounts	10,636	0	0
Deductions	0	0	0
Balance at End of Year	10,636	0	0
Current assets — supplies and inventory
Reserves deducted from asset accounts:
Balance at Beginning of Year	648	261	0
Additions (Reductions) Charged to Costs and Expenses	1,737	1,247	365
Charged to Other Accounts	(35)	0	(17)
Deductions	134	860	87
Balance at End of Year	2,216	648	261
Deferred income taxes
Reserves deducted from asset accounts:
Balance at Beginning of Year	530,612	610,571	1,021,553
Additions (Reductions) Charged to Costs and Expenses	(24,296)	(79,959)	(410,982)
Charged to Other Accounts	0	0
Deductions	0	0	0
Balance at End of Year	$ 506,316	$ 530,612	$ 610,571