Arch Resources (ARCH) 10-K 24 Feb 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Feb. 16, 2017	Jun. 30, 2016
Document and Entity Information [Abstract]
Entity Registrant Name	ARCH COAL INC
Entity Central Index Key	1,037,676
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		25,001,819
Entity Well known seasoned issuer	Yes
Entity Voluntary Filers	No
Entity Current reporting status	Yes
Entity Public Float			$ 6.4

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Predecessor [Member]
Revenues		$ 1,398,709	$ 2,573,260	$ 2,937,119
Costs, expenses and other operating
Cost of sales (exclusive of items shown separately below)		1,264,464	2,172,753	2,533,284
Depreciation, depletion and amortization		191,581	379,345	418,748
Accretion on asset retirement obligations		24,321	33,680	32,909
Amortization of sales contracts, net		(728)	(8,811)	(13,187)
Change in fair value of coal derivatives and coal trading activities, net		2,856	(1,583)	(3,686)
Asset impairment and mine closure costs		129,267	2,628,303	24,113
Losses from disposed operations resulting from Patriot Coal bankruptcy		0	116,343	0
Selling, general and administrative expenses		59,343	98,783	114,223
Other operating expense (income), net		(15,257)	19,510	(19,754)
Total operating expenses		1,655,847	5,438,323	3,086,650
Income (loss) from operations		(257,138)	(2,865,063)	(149,531)
Interest expense, net
Interest expense		(135,888)	(397,979)	(390,946)
Interest and investment income		2,653	4,430	7,758
Interest expense, net		(133,235)	(393,549)	(383,188)
Income (loss) before nonoperating expenses		(390,373)	(3,258,612)	(532,719)
Nonoperating expense
Net loss resulting from early retirement of debt and debt restructuring		(2,213)	(27,910)	0
Reorganization income (loss), net		1,630,041	0	0
Nonoperating Income (Expense)		1,627,828	(27,910)	0
Income (loss) before income taxes		1,237,455	(3,286,522)	(532,719)
Provision for (benefit from) income taxes		(4,626)	(373,380)	25,634
Net income (loss)		$ 1,242,081	$ (2,913,142)	$ (558,353)
Earnings per common share
Basic earnings per common share (in dollars per share)		$ 58.33	$ (136.86)	$ (26.31)
Diluted earnings per common share (in dollars per share)		$ 58.28	$ (136.86)	$ (26.31)
Weighted average shares outstanding
Basic weighted average shares outstanding		21,293	21,285	21,222
Diluted weighted average shares outstanding		21,313	21,285	21,222
Successor [Member]
Revenues	$ 575,688
Costs, expenses and other operating
Cost of sales (exclusive of items shown separately below)	470,644
Depreciation, depletion and amortization	32,604
Accretion on asset retirement obligations	7,634
Amortization of sales contracts, net	796
Change in fair value of coal derivatives and coal trading activities, net	396
Asset impairment and mine closure costs	0
Losses from disposed operations resulting from Patriot Coal bankruptcy	0
Selling, general and administrative expenses	22,836
Other operating expense (income), net	(5,340)
Total operating expenses	529,570
Income (loss) from operations	46,118
Interest expense, net
Interest expense	(11,241)
Interest and investment income	487
Interest expense, net	(10,754)
Income (loss) before nonoperating expenses	35,364
Nonoperating expense
Net loss resulting from early retirement of debt and debt restructuring	0
Reorganization income (loss), net	(759)
Nonoperating Income (Expense)	(759)
Income (loss) before income taxes	34,605
Provision for (benefit from) income taxes	1,156
Net income (loss)	$ 33,449
Earnings per common share
Basic earnings per common share (in dollars per share)	$ 1.34
Diluted earnings per common share (in dollars per share)	$ 1.31
Weighted average shares outstanding
Basic weighted average shares outstanding	25,002
Diluted weighted average shares outstanding	25,469

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Predecessor [Member]
Net income (loss)		$ 1,242,081	$ (2,913,142)	$ (558,353)
Derivative instruments
Comprehensive income (loss) before tax		(532)	(3,477)	3,102
Income tax benefit (provision)		80	1,252	(1,117)
Derivatives Qualifying as Hedges, Adjustment, Net of Tax		(452)	(2,225)	1,985
Pension, postretirement and other post-employment benefits
Comprehensive income (loss) before tax		(1,848)	(5,592)	(44,143)
Income tax benefit (provision)		483	2,011	15,891
Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax		(1,365)	(3,581)	(28,252)
Available-for-sale securities
Comprehensive income (loss) before tax		2,968	1,185	(12,788)
Income tax benefit (provision)		(1,042)	(435)	4,604
Available-for-sale Securities Adjustment, Net of Tax		1,926	750	(8,184)
Total other comprehensive income (loss)		109	(5,056)	(34,451)
Total comprehensive income (loss)		$ 1,242,190	$ (2,918,198)	$ (592,804)
Successor [Member]
Net income (loss)	$ 33,449
Derivative instruments
Comprehensive income (loss) before tax	0
Income tax benefit (provision)	0
Derivatives Qualifying as Hedges, Adjustment, Net of Tax	0
Pension, postretirement and other post-employment benefits
Comprehensive income (loss) before tax	24,067
Income tax benefit (provision)	0
Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	24,067
Available-for-sale securities
Comprehensive income (loss) before tax	387
Income tax benefit (provision)	0
Available-for-sale Securities Adjustment, Net of Tax	387
Total other comprehensive income (loss)	24,454
Total comprehensive income (loss)	$ 57,903

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets
Other current assets		$ 39,866
Current liabilities
Current maturities of debt		5,042,353
Predecessor [Member]
Current assets
Cash and cash equivalents		450,781
Short term investments		200,192
Restricted cash		97,542
Trade accounts receivable (net of allowance for doubtful accounts of $0.0 million and $7.8 million, respectively)		117,405
Other receivables		18,362
Inventories		196,720
Prepaid royalties		10,022
Deferred income taxes		0
Coal derivative assets		8,035
Other current assets		39,866
Total current assets		1,138,925
Property, plant and equipment
Coal lands and mineral rights		3,713,639
Plant and equipment		2,359,674
Deferred mine development		553,286
Property, plant and equipment, gross		6,626,599
Less accumulated depreciation, depletion and amortization		(3,007,570)
Property, plant and equipment, net		3,619,029
Other assets
Prepaid royalties		23,671
Equity investments		201,877
Other noncurrent assets		58,379
Total other assets		283,927
Total assets		5,041,881
Current liabilities
Accounts payable		128,131
Accrued expenses and other current liabilities		329,450
Current maturities of debt		5,042,353
Total current liabilities		5,499,934
Long-term debt		30,953
Asset retirement obligations		396,659
Accrued pension benefits		27,373
Accrued postretirement benefits other than pension		99,810
Accrued workers’ compensation		112,270
Other noncurrent liabilities		119,171
Total liabilities		6,286,170
Stockholders' equity (deficit)
Common stock		2,145
Paid-in capital		3,054,211
Treasury stock, at cost		(53,863)
Retained earnings (accumulated deficit)		(4,244,967)
Accumulated other comprehensive income (loss)		(1,815)
Total stockholders’ equity (deficit)		(1,244,289)
Total liabilities and stockholders’ equity (deficit)		$ 5,041,881
Successor [Member]
Current assets
Cash and cash equivalents	$ 305,372
Short term investments	88,072
Restricted cash	71,050
Trade accounts receivable (net of allowance for doubtful accounts of $0.0 million and $7.8 million, respectively)	184,483
Other receivables	19,877
Inventories	113,462
Prepaid royalties	2,281
Deferred income taxes	0
Coal derivative assets	262
Other current assets	93,763
Total current assets	878,622
Property, plant and equipment
Coal lands and mineral rights	387,591
Plant and equipment	418,182
Deferred mine development	280,323
Property, plant and equipment, gross	1,086,096
Less accumulated depreciation, depletion and amortization	(32,493)
Property, plant and equipment, net	1,053,603
Other assets
Prepaid royalties	0
Equity investments	96,074
Other noncurrent assets	108,298
Total other assets	204,372
Total assets	2,136,597
Current liabilities
Accounts payable	95,953
Accrued expenses and other current liabilities	205,240
Current maturities of debt	11,038
Total current liabilities	312,231
Long-term debt	351,841
Asset retirement obligations	337,227
Accrued pension benefits	38,884
Accrued postretirement benefits other than pension	101,445
Accrued workers’ compensation	184,568
Other noncurrent liabilities	63,824
Total liabilities	1,390,020
Stockholders' equity (deficit)
Common stock	250
Paid-in capital	688,424
Treasury stock, at cost	0
Retained earnings (accumulated deficit)	33,449
Accumulated other comprehensive income (loss)	24,454
Total stockholders’ equity (deficit)	746,577
Total liabilities and stockholders’ equity (deficit)	$ 2,136,597

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Successor [Member]
Allowance for doubtful accounts	$ 0
Common stock, par value (in dollars per share)	$ 0.01
Common stock, shares authorized	300,000,000
Common stock, shares issued	25,002,000
Predecessor [Member]
Allowance for doubtful accounts		$ 7.8
Common stock, par value (in dollars per share)		$ 0.01
Common stock, shares authorized		26,000,000
Common stock, shares issued		21,446,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Predecessor [Member]
Operating activties
Net income (loss)		$ 1,242,081	$ (2,913,142)	$ (558,353)
Adjustments to reconcile net income (loss) to cash provided by (used in) operating activities:
Depreciation, depletion and amortization		191,581	379,345	418,748
Accretion on asset retirement obligations		24,321	33,680	32,909
Amortization of sales contracts, net		(728)	(8,811)	(13,187)
Prepaid royalties expensed		4,791	8,109	9,698
Deferred income taxes		(419)	(367,210)	25,152
Employee stock-based compensation expense		2,096	5,760	9,847
Gains on disposals and divestitures		(6,628)	(2,270)	(27,512)
Asset impairment and noncash mine closure costs		119,194	2,613,345	16,868
Losses from disposed operations resulting from Patriot Coal bankruptcy		0	116,343	0
Amortization relating to financing activities		12,800	25,241	17,363
Net loss resulting from early retirement of debt and debt restructuring		2,213	27,910	0
Non-cash bankruptcy reorganization items		(1,775,910)	0	0
Changes in:
Receivables		(42,786)	98,212	(8,991)
Inventories		34,440	(6,534)	41,548
Coal derivative assets and liabilities		5,678	973	5,449
Accounts payable, accrued expenses and other current liabilities		15,316	(15,532)	41,680
Asset retirement obligations		(12,041)	(17,040)	(14,621)
Pension, postretirement and other postemployment benefits		(15,692)	4,800	(25,347)
Other		(28,525)	(27,546)	(4,833)
Cash provided by (used in) operating activities		(228,218)	(44,367)	(33,582)
Investing activities
Capital expenditures		(82,434)	(119,024)	(147,286)
Minimum royalty payments		(305)	(5,871)	(7,317)
Proceeds from disposals and divestitures		(2,921)	2,191	62,358
Purchases of short term investments		(98,750)	(246,735)	(211,929)
Proceeds from sales of short term investments		185,859	290,205	205,611
Proceeds from sale of investments in equity investments and securities		1,147	2,259	9,464
Investments in and advances to affiliates, net		(3,441)	(11,502)	(16,657)
Withdrawals (deposits) of restricted cash		15,979	(91,864)	(5,678)
Cash provided by (used in) investing activities		15,134	(180,341)	(111,434)
Financing activities
Payments to retire debt		0	0	(300)
Payments on term loan		0	(19,500)	(19,500)
Net receipts (payments) on other debt		(11,986)	(11,332)	(5,395)
Debt financing costs		(23,011)	0	(4,519)
Dividends paid		0	0	(2,123)
Expenses related to debt restructuring		(2,213)	(27,910)	0
Other		0	0	(15)
Cash provided by (used in) financing activities		(37,210)	(58,742)	(31,852)
Increase (decrease) in cash and cash equivalents		(250,294)	(283,450)	(176,868)
Cash and cash equivalents, beginning of period	$ 200,487	450,781	734,231	911,099
Cash and cash equivalents, end of period		200,487	450,781	734,231
SUPPLEMENTAL CASH FLOW INFORMATION
Cash paid during the period for interest		79,979	283,337	361,727
Cash refunded during the period for income taxes, net		49	$ 4,138	$ 4,896
Successor [Member]
Operating activties
Net income (loss)	33,449
Adjustments to reconcile net income (loss) to cash provided by (used in) operating activities:
Depreciation, depletion and amortization	32,604
Accretion on asset retirement obligations	7,634
Amortization of sales contracts, net	796
Prepaid royalties expensed	2,587
Deferred income taxes	3
Employee stock-based compensation expense	1,032
Gains on disposals and divestitures	(485)
Asset impairment and noncash mine closure costs	0
Losses from disposed operations resulting from Patriot Coal bankruptcy	0
Amortization relating to financing activities	467
Net loss resulting from early retirement of debt and debt restructuring	0
Non-cash bankruptcy reorganization items	0
Changes in:
Receivables	(22,196)
Inventories	24,870
Coal derivative assets and liabilities	1,662
Accounts payable, accrued expenses and other current liabilities	34,129
Asset retirement obligations	(4,535)
Pension, postretirement and other postemployment benefits	(5,625)
Other	(22,200)
Cash provided by (used in) operating activities	84,192
Investing activities
Capital expenditures	(15,214)
Minimum royalty payments	(63)
Proceeds from disposals and divestitures	572
Purchases of short term investments	0
Proceeds from sales of short term investments	23,000
Proceeds from sale of investments in equity investments and securities	0
Investments in and advances to affiliates, net	(823)
Withdrawals (deposits) of restricted cash	10,512
Cash provided by (used in) investing activities	17,984
Financing activities
Payments to retire debt	0
Payments on term loan	(816)
Net receipts (payments) on other debt	3,374
Debt financing costs	0
Dividends paid	0
Expenses related to debt restructuring	0
Other	151
Cash provided by (used in) financing activities	2,709
Increase (decrease) in cash and cash equivalents	104,885
Cash and cash equivalents, beginning of period	200,487
Cash and cash equivalents, end of period	305,372	$ 200,487
SUPPLEMENTAL CASH FLOW INFORMATION
Cash paid during the period for interest	39,620
Cash refunded during the period for income taxes, net	$ 287

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock [Member]	Paid-in Capital [Member]	Treasury Stock, at Cost [Member]	Retained Earnings (Accumulated Deficit) [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance (Predecessor [Member]) at Dec. 31, 2013	$ 2,253,249	$ 2,141	$ 3,038,613	$ (53,848)	$ (771,349)	$ 37,692
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss) | Predecessor [Member]	(592,804)				(558,353)	(34,451)
Employee stock-based compensation expense | Predecessor [Member]	9,847		9,847
Dividends on common shares ($0.01 per share) | Predecessor [Member]	(2,123)				(2,123)
Treasury shares purchased | Predecessor [Member]	(15)			(15)
Ending Balance (Predecessor [Member]) at Dec. 31, 2014	1,668,154	2,141	3,048,460	(53,863)	(1,331,825)	3,241
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss) | Predecessor [Member]	(2,918,198)				(2,913,142)	(5,056)
Issuance of 64 shares of common stock under the stock incentive plan-restricted stock and restricted stock units, net of forfeitures | Predecessor [Member]	(5)	4	(9)
Employee stock-based compensation expense | Predecessor [Member]	5,760		5,760
Ending Balance (Predecessor [Member]) at Dec. 31, 2015	(1,244,289)	2,145	3,054,211	(53,863)	(4,244,967)	(1,815)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss) | Predecessor [Member]	1,242,190				1,242,081	109
Employee stock-based compensation expense | Predecessor [Member]	2,099		2,099
Elimination of predecessor equity | Predecessor [Member]	0	(2,145)	(3,056,310)	53,863	3,002,886	1,706
Ending Balance (Predecessor [Member]) at Oct. 01, 2016	0	0	0	0	0	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of successor equity | Successor [Member]	687,483	250	687,233
Warrants exercised | Successor [Member]	159		159
Total comprehensive income (loss) | Successor [Member]	57,903				33,449	24,454
Employee stock-based compensation expense | Successor [Member]	1,032		1,032
Ending Balance (Successor [Member]) at Dec. 31, 2016	$ 746,577	$ 250	$ 688,424	$ 0	$ 33,449	$ 24,454

Consolidated Statements of Sto8

Consolidated Statements of Stockholders' Equity (Deficit) (Parenthetical) - Predecessor [Member] - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Restricted stock shares issued, net	64
Dividends declared per common share (in dollars per share)		$ 0.01

Basis of Presentation

Basis of Presentation	12 Months Ended
	Dec. 31, 2016
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 refer to both the Predecessor and Successor Company. 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, Kentucky, Virginia, Illinois, Wyoming and Colorado. All subsidiaries are wholly-owned. Intercompany transactions and accounts have been eliminated in consolidation. Chapter 11 Filing and 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 Financial Accounting Standards Board (“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 Statement of Operations. In addition, the pre-petition obligations that may be impacted by the bankruptcy reorganization process were classified on the balance sheet as liabilities subject to compromise. 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”). On the Plan Effective Date, the Company applied fresh start accounting which requires the Company to allocate its reorganization value to the fair value of assets and liabilities in conformity with the guidance for the acquisition method of accounting for business combinations. In addition to fresh start accounting, the Company’s consolidated financial statements reflect all impacts of the transactions contemplated by the Plan. Under the provisions of fresh start accounting, a new entity has been created for financial reporting purposes. The Company selected an accounting convenience date of October 1, 2016 for purposes of applying fresh start accounting as the activity between the convenience date and the Effective Date does not result in a material difference in the results. References to “Successor” in the financial statements and accompanying footnotes are in reference to reporting dates on or after October 2, 2016; references to “Predecessor” in the financial statements and accompanying footnotes are in reference to reporting dates through October 1, 2016 which includes the impact of the Plan provisions and the application of fresh start accounting. As such, the Company’s financial statements for the Successor will not be comparable in many respects to its financial statements for periods prior to the adoption of fresh start accounting and prior to the accounting for the effects of the Plan. For further information on fresh start accounting, please see Note 3 to the Consolidated Financial Statements, “ Emergence from Bankruptcy and Fresh Start Accounting .”

Accounting Policies

Accounting Policies	12 Months Ended
	Dec. 31, 2016
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. Restricted cash Restricted cash represents cash collateral supporting letters of credit issued under the Company’s accounts receivable securitization program. 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 expense (income), net ” in the consolidated statements of operations. Information about investment activity is provided in Note 9 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. See Note 10 to the Consolidated Financial Statements, “ Sales Contracts ” for further information related to the Company’s sales contracts. 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 fair valued 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 did not capitalize any interest costs during the periods October 2 through December 31, 2016 , January 1 through October 1, 2016 or for the year ended December 31, 2015 , 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 7 to 18 years. The useful lives of buildings and leasehold improvements generally range from 1 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 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. The net book value of the Company’s coal interests was $0.4 billion and $2.4 billion at December 31, 2016 and 2015 , 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 statement of operations 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. See additional discussion in Note 5 to the Consolidated Financial Statements, “ Impairment Charges and Mine Closure 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 was $5.2 million at December 31, 2016 , with $1.9 million classified as current. As these amounts relate to a credit facility with no outstanding borrowings, these current amounts are classified within “Other current assets” and the noncurrent amounts are classified within “Other noncurrent assets.” The unamortized balance of deferred financing costs at December 31, 2015 was $66.3 million with $65.6 million classified as current. As these debt issuance costs primarily related to a recognized liability, the current amounts are recorded in “Current maturities of debt” and the noncurrent amounts are recorded in “Long-term debt” in the accompanying consolidated balance sheets. 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 Expense (Income), net Other operating expense (income), net in the accompanying consolidated statements of operations 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; liquidated damage charges related to unused terminal and port capacity; royalties earned from properties leased to third parties; income from equity investments (Note 9 ); 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 ). 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. Additionally, the Company may hold certain coal derivative instruments for trading purposes. Derivative financial instruments are recognized in 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 a forecasted purchase or sale. 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 employee. The Company also currently provides certain postretirement medical and life insurance coverage for eligible employees. The cost of providing these benefits are determined on an actuarial basis and accrued over the employee’s 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. See further discussion in Note 18 , “ Stock-Based Compensation and Other Incentive Plans .” Recently Adopted Accounting Guidance In April 2015, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2015-03 (“ASU 2015-03”), Simplifying the Presentation of Debt Issuance Costs. ASU 2015-03 required debt issuance costs related to a recognized liability to be presented in the balance sheet as a direct reduction from the carrying amount of that liability, consistent with debt discounts. The Company adopted ASU 2015-03 in the first quarter of 2016 as mandated by the standard. The following reflects the retrospective application: December 31, 2015 (in thousands) Other current assets, prior to revision $ 104,723 Revision of debt issuance costs (64,857 ) Other current assets, as revised $ 39,866 Current maturities of debt, prior to revision $ 5,107,210 Revision of debt issuance costs (64,857 ) Current maturities of debt, as revised $ 5,042,353 Effective December 31, 2016, the Company adopted ASU No. 2014-15 (“ASU 2014-15”), Disclosures of Uncertainties about an Entity’s Ability to Continue as a Going Concern. ASU 2014-15 requires management to evaluate for each annual and interim reporting period whether conditions or events give rise to substantial doubt that an entity has the ability to continue as a going concern within one year following issuance of the financial statements and requires specific disclosures regarding the conditions or events leading to substantial doubt. The adoption of ASU 2014-15 did not have any impact on the Company’s financial position or results of operations. Effective December 31, 2016, the Company adopted the Accounting Standards Update No. 2015-17 (“ASU 2015-17”), Balance Sheet Classification of Deferred Taxes which requires that all deferred tax assets and liabilities, along with any related valuation allowance be classified as noncurrent on the balance sheet. The standard has been applied on a retrospective basis. The adoption of ASU 2015-17 did not have any impact on the Company’s financial position or results of operations. Investments at fair value include investments in funds, including certain money market funds, that are measured at net asset value (“NAV”). The Company uses NAV to measure the fair value of its fund investments when (i) the fund investment does not have a readily determinable fair value and (ii) the NAV of the investment fund is calculated in a manner consistent with the measurement principles of investment company accounting, including measurement of the underlying investments at fair value. The Company adopted ASU No. 2015-07 in January 2016, and, as required, disclosures in the paragraphs and tables below are limited to only those investments in funds that are measured at NAV. In accordance with ASU No. 2015-07, previously reported amounts have been conformed to the current presentation. Recent Accounting Guidance Issued Not Yet Effective In May 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers.” ASU 2014-09 is a comprehensive revenue recognition standard that will supersede nearly all existing revenue recognition guidance under current U.S. GAAP and replace it with a principle based approach for determining revenue recognition. ASU 2014-09 will require that companies recognize revenue based on the value of transferred goods or services as they occur in the contract. The ASU also will require additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. ASU 2014-09 is effective for interim and annual periods beginning after December 15, 2017. Early adoption is permitted only in annual reporting periods beginning after December 15, 2016, including interim periods therein. Entities will be able to transition to the standard either retrospectively or as a cumulative-effect adjustment as of the date of adoption. The Company’s primary source of revenue is from the sale of coal through both short-term and long-term contracts with utilities, industrial customers and steel producers whereby revenue is currently recognized when risk of loss has passed to the customer. Upon adoption of this new standard, the Company believes that the timing of revenue recognition related to our coal sales will remain consistent with our current practice. The Company is currently evaluating other revenue streams to determine the potential impact related to the adoption of the standard, as well as potential disclosures required by the standard. The Company will be adopting the standard under the modified retrospective approach. In February 2016, the FASB issued ASU No. 2016-02, “Leases” which, for operating leases, requires a lessee to recognize a right-of-use asset and a lease liability, initially measured at the present value of the lease payments, in its balance sheet. 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. The ASU is effective for public companies for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years; early adoption is permitted. The Company has both operating and capital leases. We expect the adoption of this standard to result in the recognition of right-of-use assets and lease liabilities not currently recorded on the Company’s financial statements. The Company is currently in the process of accumulating all contractual lease arrangements in order to determine the impact on its financial statements. In October 2016, the FASB issued ASU No. 2016-18, “Statement of Cash Flows-Restricted Cash.” The amendment requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. Therefore, amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning period and end of period total amounts shown on the statement of cash flows. ASU 2016-18 is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years; early adoption is permitted.

Emergence from Bankruptcy and F

Emergence from Bankruptcy and Fresh Start Accounting	12 Months Ended
	Dec. 31, 2016
Reorganizations [Abstract]
Emergence from Bankruptcy and Fresh Start Accounting	Emergence from Bankruptcy and Fresh Start Accounting 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 Statement of Operations. In addition, the pre-petition obligations that may be impacted by the bankruptcy reorganization process were classified on the balance sheet as liabilities subject to compromise. 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”). On the Plan Effective Date, the Company applied fresh start accounting which requires the Company to allocate its reorganization value to the fair value of assets and liabilities in conformity with the guidance for the acquisition method of accounting for business combinations. In addition to fresh start accounting, the Company’s consolidated financial statements reflect all impacts of the transactions contemplated by the Plan. Under the provisions of fresh start accounting, a new entity has been created for financial reporting purposes. The Company selected an accounting convenience date of October 1, 2016 for purposes of applying fresh start accounting as the activity between the convenience date and the Effective Date does not result in a material difference in the results. References to “Successor” in the financial statements and accompanying footnotes are in reference to reporting dates on or after October 2, 2016; references to “Predecessor” in the financial statements and accompanying footnotes are in reference to reporting dates through October 1, 2016 which includes the impact of the Plan provisions and the application of fresh start accounting. As such, the Company’s financial statements for the Successor will not be comparable in many respects to its financial statements for periods prior to the adoption of fresh start accounting and prior to the accounting for the effects of the Plan. The following is a summary of certain provisions of the Plan, as confirmed by the Bankruptcy Court pursuant to the Confirmation Order, and is not intended to be a complete description of the Plan. Treatment of Claims The Plan contemplates that: • Holders of allowed administrative expense claims, priority claims (other than administrative expense claims and priority tax claims) and secured claims (other than claims arising under priority claims, the prepetition first lien credit facility and prepetition second lien notes) will be paid in full. • Holders of allowed claims arising under the Debtors’ prepetition first lien credit facility (“First Lien Credit Facility”) will receive their pro rata distribution of (i) total cash payments equal to the greater of (A) $144.8 million less the amount of the adequate protection payments and (B) $30 million ; (ii) $326.5 million in principal amount of New First Lien Debt Facility; and (iii) 94% of the common stock of Reorganized Arch Coal (the “New Common Stock”), subject to dilution on account of (a) any Class A Common Stock (as defined below) issued upon exercise of the warrants (the “New Warrants”) issued pursuant to the Plan to purchase up to 12% of the fully diluted Class A Common Stock as of the Effective Date and exercisable at any time for a period of 7 years from the Effective Date at a strike price calculated based on a total equity capitalization of $1.425 billion ( $57 per share) and (b) the issuance of New Common Stock in an amount of up to 10% of the New Common Stock, on a fully diluted basis, pursuant to a management incentive plan (the “Management Incentive Plan”). • Holders of allowed claims on account of prepetition second lien or unsecured notes (the “Prepetition Notes”) will receive their pro rata distribution of (i) $22.636 million in cash, (ii) at such holder’s election, either (A) such holder’s pro rata share of the New Warrants or (B) such holder’s pro rata share of $25 million in cash and (iii) 6% of the New Common Stock (subject to dilution on account of any exercise of the New Warrants and pursuant to the Management Incentive Plan). • Holders of allowed general unsecured claims against Debtors (other than claims on account of the First Lien Credit Facility or Prepetition Notes) will receive their pro rata distribution of $7.364 million cash, less fees and expenses incurred by any professionals retained by a claims oversight committee up to $200,000 . • The Reorganized Debtors will waive and release any claims or causes of action that they have, had, or may have that are based on sections 502(d), 544, 545, 547, 548, 549, 550, 551, 553(b) and 724(a) of the Bankruptcy Code and analogous non-bankruptcy law for all purposes against (i) prepetition trade creditors and (ii) officers, directors, employees or representatives of the Debtors or the Reorganized Debtors and all agents and representatives of all of the foregoing. However, the Reorganized Debtors will retain the right to assert any said claims as defenses or counterclaims in any cause of action brought by any creditor. New First Lien Debt Facility For information related to the New First Lien Debt Facility, see Note 13 , “ Debt and Financing Arrangements .” Securitization Facility For information related to the Securitization Facility, see Note 13 , “ Debt and Financing Arrangements .” Warrant Agreement 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). Termination of Material Definitive Agreements On the Effective Date, by operation of the Plan, all outstanding obligations under the following notes issued by Arch Coal and guaranteed by certain subsidiary guarantors, (collectively, the “Cancelled Notes”) were cancelled and the indentures governing such obligations were cancelled except as necessary to (a) enforce the rights, claims and interests of the applicable trustee vis-a-vis any parties other than the Debtors, (b) allow each trustee to receive distributions under the Plan and to distribute them to the holders of the Cancelled Notes in accordance with the terms of the applicable indenture, (c) preserve any rights of the applicable trustee to compensation, reimbursement and indemnification under each of the applicable indentures solely as against any money or property distributable to holders of Cancelled Notes, (iv) permit each of the trustees to enforce any obligation owed to them under the Plan and (v) permit each of the trustees to appear in the Chapter 11 cases or in any proceeding in the Bankruptcy Court or any other court: • 7.000% Senior Notes due 2019, issued pursuant to an indenture dated as of June 14, 2011, by and among Arch Coal, as issuer, UMB Bank National Association, as trustee, and the guarantors named therein, as amended, supplemented or revised thereafter; • 7.250% Senior Notes due 2020, issued pursuant to an indenture dated as of August 9, 2010, by and among Arch Coal, as issuer, U.S. Bank National Association, as trustee, and the guarantors named therein, as amended, supplemented or revised thereafter; • 7.250% Senior Notes due 2021, issued pursuant to an indenture dated as of June 14, 2011, by and among Arch Coal, as issuer, UMB Bank National Association, as trustee, and the guarantors named therein, as amended, supplemented or revised thereafter; • 9.875% Senior Notes due 2019, issued pursuant to an indenture dated as of November 21, 2012, by and among Arch Coal, as issuer, UMB Bank National Association, as trustee, and the guarantors named therein, as amended, supplemented or revised thereafter; and • 8.000% Second Lien notes due 2019, issued pursuant to an indenture dated as of December 17, 2013, by and among Arch Coal, as issuer, Wilmington Savings Fund Society, as trustee and collateral agent as successor to UMB Bank National Association, and the guarantors named therein, as amended, supplemented or revised thereafter. On the Effective Date, by operation of the Plan, all outstanding obligations under the following credit agreement (the “Prepetition Credit Agreement”) entered into by Arch Coal and guaranteed by certain of Arch Coal’s subsidiaries and the related collateral, guaranty and other definitive agreements relating to the Prepetition Credit Agreement were cancelled and the Prepetition Credit Agreement was cancelled except as necessary to (i) enforce the rights, claims and interests of the Prepetition Agent (as defined below) and any predecessor thereof vis-a-vis the Lenders and any parties other than the Debtors, (ii) to allow the Prepetition Agent to receive distributions under the Plan and to distribute them to the lenders under the Prepetition Credit Agreement and (iii) preserve any rights of the Prepetition Agent and any predecessor thereof as against any money or property distributable to holders of claims arising out of the Prepetition Credit Agreement or any related transaction documents, including any priority in respect of payment and the right to exercise any charging lien: • Amended and Restated Credit Agreement, dated as of June 14, 2011 (as amended by the First Amendment, dated as of May 16, 2012, the Second Amendment, dated as of November 20, 2012, the Third Amendment, dated as of November 21, 2012 and the Fourth Amendment, dated as of December 17, 2013), among Arch Coal, Inc., as borrower, the lenders from time to time party thereto, Wilmington Trust, National Association, in its capacities as term loan facility administrative agent (as successor to Bank of America, N.A. in such capacity) and collateral agent (as successor to PNC Bank, National Association in such capacity) (in such capacities, the “Prepetition Agent”) On the Effective Date, all outstanding obligations under the following credit agreement (the “DIP Credit Agreement”) other than contingent and/or unliquidated obligations were paid in cash in full, all commitments under the DIP Credit Agreement and the related transaction documents referred to therein as the “Loan Documents” were terminated, all liens on property of the Debtors arising out of or related to the DIP Facility terminated and the Loan Documents were cancelled except with respect to (a) contingent and and/or unliquidated obligations under the Loan Documents which survive the Effective Date and continue to be governed by the Loan Documents and (b) the relationships among the DIP Agent (as defined below) and the lenders under the DIP Credit Agreement, as applicable, including but not limited to, those provisions relating to the rights of the DIP Agent and the lenders to expense reimbursement, indemnification and other similar amounts, certain reinstatement obligations set forth in the DIP Credit Agreement and any provisions that may survive termination or maturity of the credit facility governed by the DIP Credit Agreement in accordance with the terms thereof: • Superpriority Secured Debtor-In-Possession Credit Agreement, dated as of January 21, 2016 (as amended by the Waiver and Consent and Amendment No. 1, dated as of March 4, 2016, Amendment No. 2, dated as of March 28, 2016, Amendment No. 3, dated as of April 26, 2016, Amendment No. 4, dated as of June 10, 2016, Amendment No. 5, dated as of June 23, 2016, Amendment No. 6, dated as of July 20, 2016, and Amendment No. 7, dated as of September 28, 2016) among Arch Coal, Inc., as borrower, certain subsidiaries of Arch Coal, Inc., as guarantors, the lenders from time to time party there and Wilmington Trust, National Association, in its capacity as administrative agent and as collateral agent (in such capacities, the “DIP Agent”). Equity Securities Under the Plan, 24,589,834 shares of Class A Common Stock and 410,166 shares of Class B Common Stock, par value $.01 per share, (“Class B Common Stock” and together with Class A Common Stock, “Common Stock”) were distributed to the secured lenders and to certain holders of general unsecured claims under the Plan on the Effective Date. In addition, on the Effective Date, Arch Coal issued Warrants to purchase up to an aggregate of 1,914,856 shares of Class A Common Stock. Arch Coal relied, based on the confirmation order it received from the Bankruptcy Court, on Section 1145(a)(1) of the U.S. Bankruptcy Code to exempt from the registration requirements of the Securities Act of 1933, as amended (i) the offer and sale of Common Stock to the secured lenders and to the general unsecured creditors, (ii) the offer and sale of the Warrants to the holders of claims arising under the Cancelled Notes and (iii) the offer and sale of the Class A Common Stock issuable upon exercise of the Warrants. Section 1145(a)(1) of the Bankruptcy Code exempts the offer and sale of securities under a plan of reorganization from registration under Section 5 of the Securities Act and state laws if three principal requirements are satisfied: • the securities must be offered and sold under a plan of reorganization and must be securities of the debtor, of an affiliate participating in a joint plan of reorganization with the debtor or of a successor to the debtor under the plan of reorganization; • the recipients of the securities must hold claims against or interests in the debtor; and • the securities must be issued in exchange, or principally in exchange, for the recipient’s claim against or interest in the debtor. Reorganization Value Fresh start accounting provides, among other things, for a determination of the value to be assigned to the equity of the emerging company as of a date selected for financial reporting purposes. In conjunction with the bankruptcy proceedings, a third party financial advisor provided an enterprise value of the Company of approximately $650 million to $950 million . The final equity value of $687.5 million was based upon the approximate high end of the enterprise value established by the third party valuation plus excess cash of $64 million less the fair value of debt related to the New First Lien Debt Facility of $326.5 million . The high end of the enterprise value assumed a minimum cash balance at emergence of $250 million . The enterprise value of the Company was estimated using various valuation methods including: (i) comparable public company analysis, (ii) discounted cash flow analysis (“DCF”) and (iii) sum-of-the-parts analysis. The comparable public company analysis is based on the enterprise value of selected publicly traded companies that have operating and financial characteristics comparable in certain respects to the Company, for example, operational requirements and risk and profitability characteristics. Selected companies are comprised of coal mining companies with primary operations in the United States. Under this methodology, certain financial multiples and ratios that measure financial performance and value are calculated for each selected company and then applied to the Company’s financials to imply an enterprise value for the Company. The DCF analysis is a forward-looking enterprise valuation methodology that estimates the value of an assets or business by calculating the present value of expected future cash flows by that asset or business. The basis of the DCF analysis was the Company’s prepared projections which included a variety of estimates and assumptions, such as pricing and demand for coal. The Company’s pricing was based on its view of the market taking into account third party forward pricing curves adjusted for the quality of products sold by the Company. While the Company considers such estimates and assumptions reasonable, they are inherently subject to significant business, economic and competitive uncertainties, many of which are beyond the Company’s control and, therefore, may not be realized. Changes in these estimates and assumptions may have a significant effect on the determination of the Company’s enterprise value. The assumptions used in the calculations for the DCF analysis included projected revenue, cost and cash flows for the years ending December 31, 2016 through each respective mine life and represented the Company’s best estimates at the time the analysis was prepared. The DCF analysis was completed using discount rates at a range of estimated weighted average costs of capital ranging from 13.25% to 15.25% . The DCF analysis involves complex considerations and judgments concerning appropriate discount rates. Due to the unobservable inputs to the valuation, the fair value would be considered Level 3 in the fair value hierarchy. The sum-of-the-parts analysis is a more detailed market multiples approach the values each part of a company’s business separately based upon the enterprise values of selected publicly traded companies that have operating and financial characteristics comparable in certain respects to each part of the reorganized Company. Under this methodology, certain financial multiples and ratios that measure financial performance and value are calculated for each selected comparable company and then applied to the relevant segment of the Company’s financials to imply an enterprise value for the Company. Accounting Impact of Emergence Upon emergence in accordance with ASC 852, the Company applied fresh start accounting to its consolidated financial statements as of October 1, 2016 because (i) the reorganization value of the assets of the emerging entity immediately before the date of confirmation was less than the total of all postpetition liabilities and allowed claims and (ii) the holders of the existing voting shares immediately before confirmation received less than 50 percent of the voting shares of the emerging entity. Upon adoption of fresh start accounting, the Company became a new entity for financial reporting purposes reflecting the Successor capital structure. As such, a new accounting basis in the identifiable assets and liabilities assumed was established with no retained earnings or accumulated other comprehensive income (loss) (“OCI”). The following balance sheet illustrates the impacts of the implementation of the Plan and the application of fresh start accounting, which results in the opening balance sheet of the Successor company. As of October 1, 2016 (In thousands) Predecessor (a) Effect of Plan (b) Fresh Start Adjustments (c) Successor Assets Current assets Cash and cash equivalents $ 400,205 $ (199,718 ) (d) $ — $ 200,487 Short term investments 111,451 — — 111,451 Restricted cash 81,563 — — 81,563 Trade accounts receivable 165,522 — — 165,522 Other receivables 17,227 — 779 (j) 18,006 Inventories 159,410 — (21,078 ) (k) 138,332 Prepaid royalties 4,805 — — 4,805 Deferred income taxes — — — — Coal derivative assets 2,180 — — 2,180 Other current assets 36,960 6,367 53,851 (l) 97,178 Total current assets 979,323 (193,351 ) 33,552 819,524 Property, plant and equipment, net 3,434,941 — (2,363,829 ) (m) 1,071,112 Other assets Prepaid royalties 20,997 — (20,997 ) (n) — Equity investments 164,232 — (61,606 ) (o) 102,626 Other noncurrent assets 58,569 34,495 (e) 37,503 (p) 130,567 Total other assets 243,798 34,495 (45,100 ) 233,193 Total assets $ 4,658,062 $ (158,856 ) $ (2,375,377 ) $ 2,123,829 Liabilities and Stockholders’ Equity (Deficit) Liabilities not subject to compromise Accounts payable $ 74,595 $ — $ (250 ) (q) $ 74,345 Accrued expenses and other current liabilities 225,739 (36,331 ) (f) 26,644 (r) 216,052 Current maturities of debt 3,397 3,265 (g) — 6,662 Total current liabilities 303,731 (33,066 ) 26,394 297,059 Long-term debt 30,037 323,235 (g) — 353,272 Asset retirement obligations 394,699 — (60,570 ) (s) 334,129 Accrued pension benefits 23,716 — 24,565 (t) 48,281 Accrued other postretirement benefits 87,123 — 24,836 (t) 111,959 Accrued workers’ compensation 119,828 — 74,520 (u) 194,348 Deferred income taxes — — — — Other noncurrent liabilities 96,410 — 888 (v) 97,298 Total liabilities not subject to compromise 1,055,544 290,169 90,633 1,436,346 Liabilities subject to compromise 5,278,612 (5,278,612 ) (h) — — Total liabilities 6,334,156 (4,988,443 ) 90,633 1,436,346 Stockholders’ equity (deficit) Common stock, predecessor 2,145 (2,145 ) (i) — — Common stock, successor — 250 (b) — 250 Paid-in capital, predecessor 3,056,307 (3,056,307 ) (i) — — Paid-in capital, successor — 687,233 (b) — 687,233 Treasury stock, at cost (53,863 ) 53,863 (i) — — Accumulated earnings (deficit) (4,678,977 ) 7,146,693 (i) (2,467,716 ) — Accumulated other comprehensive income (loss) (1,706 ) — 1,706 — Total stockholders’ equity (deficit) (1,676,094 ) 4,829,587 (2,466,010 ) 687,483 Total liabilities and stockholders’ equity (deficit) $ 4,658,062 $ (158,856 ) $ (2,375,377 ) $ 2,123,829 (a) Represents the Predecessor consolidated balance sheet as of October 1, 2016. (b) Represents amounts recorded for the implementation of the Plan on the Effective Date. This includes the settlement of liabilities subject to compromise through a combination of cash payments, the issuance of new common stock and warrants and the issuance of new debt. The following is the calculation of the total pre-tax gain on the settlement of the liabilities subject to compromise: In thousands Liabilities subject to compromise $ 5,278,612 Less amounts issued to settle claims: Common stock (at par) Successor (250 ) Warrants Successor (14,822 ) Paid-in capital Successor (672,411 ) Issuance of Term Loan Successor (326,500 ) Cash payment to settle claims and professional fees (122,525 ) Total pre-tax gain on plan effects $ 4,142,104 (c) Represents the fresh start accounting adjustments required to record the assets and liabilities of the Company at fair value. (d) The following table reflects the use of cash at emergence: In thousands Payment to secured lenders $ 43,496 Payments to unsecured creditors 42,399 Final adequate protection payment 36,331 Collateral requirements 31,665 Professional fees 31,630 Other 14,197 Total cash outflow at emergence $ 199,718 (e) Represents amounts paid for required collateral deposits. (f) Represents the final adequate protection payments made to the secured lenders. (g) Represents the fair value of the $326.5 million new term loan of which $3.3 million is shown within current maturities of debt. (h) Liabilities subject to compromise include unsecured or under-secured liabilities incurred prior to the Chapter 11 filing; and consists of the following: Previously Reported Balance Sheet Line In thousands Debt $ 5,026,806 Accrued expenses and other current liabilities 136,295 Accounts payable 106,297 Other noncurrent liabilities 9,214 Total liabilities subject to compromise $ 5,278,612 (i) Reflects the impacts of the reorganization adjustments: In thousands Total pre-tax gain on settlement of claims $ 4,142,104 Cancellation of predecessor common stock 2,145 Cancellation of predecessor paid-in capital 3,056,307 Cancellation of predecessor treasury stock (53,863 ) Net impact on accumulated earnings (deficit) $ 7,146,693 (j) Represents adjustments to record other receivables at fair value which includes an $0.8 million short-term receivable related to insurance coverage for self-insured workers’ compensation obligations. (k) Represents the following fair value adjustments: a $7.3 million increase related to coal inventory which was fair valued at estimated selling prices less the sum of selling costs, shipping costs and a reasonable profit allowance for the selling effort offset by a $28.4 million reduction in critical spare parts inventory. During fresh start accounting, the Company changed its accounting policy with respect to critical spare parts with long lead times; previously these items were valued within inventory, but prospectively, these items will be capitalized within property, plant and equipment when purchased and depreciated over the life of the related equipment. (l) Represents the short-term portion of above market coal sales contracts of $71.1 million offset by $11.3 million in reductions related to prepaid balances. The fair value of sales contracts was estimated using a discounted cash flow model and will be amortized into earnings as the coal is shipped throughout the term of the associated contracts. (m) Represents a $2.4 billion reduction in property, plant and equipment to estimated fair value as discussed below: Predecessor Fresh Start Adjustments Successor (in thousands) Net Coal Properties $ 2,358,779 $ (1,971,314 ) $ 387,465 Net Plant & Equipment 812,888 (405,259 ) 407,629 Net Deferred Charges 263,274 12,744 276,018 $ 3,434,941 $ (2,363,829 ) $ 1,071,112 The fair value of coal properties was established at $387.5 million utilizing a discounted cash flow model and the market approach. The market approach was used to provide a starting value of the coal mineral reserves without consideration for economic obsolescence. The DCF model was based on assumptions market participants would use in the pricing of these assets as well as projections of revenues and expenditures that would be incurred to mine or maintain these coal reserves through the life of mine. The basis of the DCF analysis was the Company’s prepared projections which included a variety of estimates and assumptions, such as pricing and demand for coal. The Company’s pricing was based on its view of the market taking into account third party forward pricing curves adjusted for the quality of products sold by the Company. The fair value of plant and equipment was set at $407.6 million utilizing both market and cost approaches. The market approach was used to estimate the value of assets where detailed information for the asset was available and an active market was identified with a sufficient number of sales of comparable property that could be independently verified through reliable sources. The cost approach was utilized where there were limitations in the secondary equipment market to derive values from. The first step in the cost approach is the estimation of the cost required to replace the asset via construction or purchasing a new asset with similar utility adjusting for depreciation due to physical deterioration, functional obsolescence due to technology changes and economic obsolescence due to external factors such as regulatory changes. Useful lives were assigned to all assets based on remaining future economic benefit of each asset. The fair value of deferred charges represents the corresponding asset related to the asset retirement obligation discussed in item (q) below. (n) Represents a fair value adjustment to a long-term prepaid royalty balance that the Company has concluded should not be assigned value based on market conditions and after considering economic obsolescence. (o) Represents a fair value adjustment to the Company’s equity investments in Knight Hawk Holdings, LLC, a coal producer in the Illinois Basin; and Dominion Terminal Associates which operates a ground storage-to-vessel coal trans-loading facility in Newport News, Virginia. Equity investments were fair valued in a manner similar to the Company’s wholly-owned subsidiaries using a discounted cash flow model and comparable company approach. The discount rate selected was 14% and due to the unobservable nature of the inputs, the fair values are considered Level 3 in the fair value hierarchy. (p) Represents the long-term portion of above market coal sales contracts of $26.0 million and $18.6 million related to a long-term insurance receivable related to insurance coverage for self-insured workers’ compensation obligations partially offset by $13.2 million in reductions related to prepaid balances. The fair value of sales contracts was estimated using a discounted cash flow model and will be amortized into earnings as the coal is shipped throughout the term of the associated contracts. (q) Represents a fair value adjustment to miscellaneous accounts payable. (r) Represents fair value adjustments for the following: a $27.8 million increase related to the short-term portion of below market sales contracts offset by fair va

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Abstract]
Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) The following items are included in accumulated other comprehensive income (loss): Pension, Postretirement Accumulated and Other Post- Other Derivative Employment Available-for- Comprehensive Instruments Benefits Sale Securities Income (Loss) (In thousands) Predecessor Company January 1, 2015 $ 2,550 $ 2,860 $ (2,169 ) $ 3,241 Unrealized gains (losses) 3,903 (8,723 ) (3,333 ) (8,153 ) Amounts reclassified from accumulated other comprehensive income (loss) (6,128 ) 5,142 4,083 3,097 December 31, 2015 325 (721 ) (1,419 ) (1,815 ) Unrealized gains (losses) (138 ) — 701 563 Amounts reclassified from accumulated other comprehensive income (loss) (316 ) (1,363 ) 1,225 (454 ) Fresh start accounting adjustment 129 2,084 (507 ) 1,706 October 1, 2016 $ — $ — $ — $ — Successor Company Unrealized gains — 24,067 387 24,454 Amounts reclassified from accumulated other comprehensive income (loss) — — — — December 31, 2016 $ — $ 24,067 $ 387 $ 24,454 The unrealized gain in the successor period is the result of changes in the discount rates used to calculate our pension, postretirement health and occupational disease obligations. The following amounts were reclassified out of accumulated other comprehensive income (loss) during the respective periods: Details about accumulated other comprehensive income components Successor Predecessor Line Item in the Consolidated Statement of Operations October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 (in thousands) (in thousands) Derivative instruments $ — $ 397 $ 9,575 Revenues — (81 ) (3,447 ) Provision for (benefit from) income taxes $ — $ 316 $ 6,128 Net of tax Pension, postretirement and other post-employment benefits Amortization of prior service credits 1 $ — $ 7,854 $ 8,335 Amortization of net actuarial gains (losses) 1 — (6,010 ) (16,369 ) — 1,844 (8,034 ) Total before tax — (481 ) 2,892 Provision for (benefit from) income taxes $ — $ 1,363 $ (5,142 ) Net of tax Available-for-sale securities 2 $ — $ (2,263 ) $ (6,391 ) Interest and investment income — 1,038 2,308 Provision for (benefit from) income taxes $ — $ (1,225 ) $ (4,083 ) 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.

Impairment Charges and Mine Clo

Impairment Charges and Mine Closure Costs	12 Months Ended
	Dec. 31, 2016
Impairment Charges and Mine Closure Costs [Abstract]
Impairment Charges and Mine Closure Costs	Impairment Charges and Mine Closure Costs The following table summarizes the amounts reflected on the line “ Asset impairment and mine closure costs ” in the consolidated statements of operations: Successor Predecessor Description October 2 Through December 31, 2016 January 1 Through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 (In thousands) Coal lands and mineral rights $ — $ 74,144 $ 2,210,488 $ — Plant and equipment — — 199,107 1,512 Deferred development — — 159,474 — Prepaid royalties — 3,406 41,990 15,356 Equity investments — 40,920 21,325 — Inventories — — 66 — Other — 10,797 (4,147 ) 7,245 Total $ — $ 129,267 $ 2,628,303 $ 24,113 January 1 Through October 1, 2016 Impairment Charges During the period January 1 through October 1, 2016, the Company recorded the following to “Asset impairment and mine closure costs” in the Consolidated Statements of Operations: $74.1 million recorded in the first quarter related to the impairment of coal reserves and surface land in Kentucky that are being leased to a mining company that idled its mining operations; $3.4 million recorded in the first quarter related to the impairment on the portion of an advance royalty balance on a reserve base mined at the Company’s Mountain Laurel operation that will not be recouped; $2.9 million recorded in the first quarter related to an other-than-temporary-impairment charge on an available-for-sale security; a $38.0 million impairment recorded in the second quarter related to the Company’s equity investment in a brownfield bulk commodity terminal on the Columbia River in Longview, Washington as the Company relinquished its ownership rights in exchange for future throughput rights; $7.2 million of severance expense related to headcount reductions during the first half of the year; a $3.6 million curtailment charge related to the Company’s pension, postretirement health and black lung actuarial liabilities due to headcount reductions in the first half of the year. 2015 Impairment Charges In 2015, as a result of the continued deterioration in thermal and metallurgical coal markets and projections for a muted pricing recovery, certain of the Company’s mine complexes have incurred and are expected to continue to incur operating losses. The Company determined that the further weakening of the pricing environment in the last half of the year and the projected operating losses represented indicators of impairment with respect to certain of its long-lived assets or assets groups. Using current pricing expectations which reflected marketplace participant assumptions, life of mine cash flows were used to determine if the undiscounted cash flows exceeded the current asset values for certain operating complexes in the Company’s Appalachia segment. For multiple operating complexes, the undiscounted cash flows did not exceed the carrying value of the long-lived assets. Discounted cash flows were utilized to reduce the carrying value of those assets to fair value. The discount rate used reflected the then current financial difficulties present in the commodities sector in general and coal mining specifically; the perceived risk of financing coal mining in light of industry defaults; and the lack of an active market for buying or selling coal mining assets. Additionally, the Company determined that the then current market conditions represented an indicator of impairment for certain undeveloped coal properties that were acquired in times of significantly higher coal prices. The then current prices and the significant capital outlay that would have been required to develop these reserves indicated that the carrying value was not recoverable. As a result the Company recorded a $2.6 billion asset impairment charge in the last two quarters of 2015 of which $2.1 billion was recorded during the third quarter and the remaining $0.5 billion was recorded in the fourth quarter. Of the total charge. $2.2 billion was recorded to the Company’s Appalachia segment, with the remaining $0.4 billion recorded to the Company’s Other operating segment. There is no fair value remaining related to the impaired assets. During the second quarter of 2015, the Company recorded $19.1 million to “Asset impairment and mine closure costs” in the Consolidated Statements of Operations. An impairment charge of $12.2 million related to the portion of an advance royalty balance on a reserve base mined at the Company’s Mountain Laurel, Spruce and Briar Branch operations that was determined would not be recouped based on estimates of sales volume and pricing through the March 2017 recoupment period. Additionally, the Company recorded a $5.6 million impairment charge related to the closure of a higher-cost mining complex serving the metallurgical coal markets. 2014 Impairment Charges During the Company’s annual budgeting process for 2015 (performed in the fall of 2014), a review of forecasted revenues indicated that the remaining balance of advance royalty payments made on a reserve base supplying the Company’s Mountain Laurel, Spruce Mine and Briar Branch operations would not be recoupable against future royalties payments. Under the lease, any unrecouped advance payment balance at March 31, 2017 will be forfeited by the Company. Based on estimates of sales volumes and pricing through the end of the recoupment period, an impairment charge was recorded during the fourth quarter of 2014 for $15.4 million of the remaining $48.0 million balance that was determined would not be recouped. In response to weak metallurgical coal markets the Company idled a higher-cost mining complex in the third quarter of 2014 in order to concentrate on metallurgical coal production from its lowest-cost and highest-margin operations. Closure charges of $5.1 million were recognized during the third quarter of 2014 relating to the idling.

Losses from disposed operations

Losses from disposed operations resulting from Patriot Coal Bankruptcy	12 Months Ended
	Dec. 31, 2016
Discontinued Operations and Disposal Groups [Abstract]
Losses from disposed operations resulting from Patriot Coal Bankruptcy	Losses from disposed operations resulting from Patriot Coal bankruptcy On December 31, 2005, Arch entered into a purchase and sale agreement with Magnum to sell certain operations. On July 23, 2008, Patriot acquired Magnum. On May 12, 2015, Patriot and certain of its wholly owned subsidiaries (“Debtors”), including Magnum, filed voluntary petitions for reorganization under Chapter 11 of the U.S. Code in the U.S. Bankruptcy Court for the Eastern District of Virginia. Subsequently, on October 28, 2015, Patriot’s Plan of Reorganization was approved, including an authorization to reject their collective bargaining agreements and modify certain union-related retiree benefits. As a result of the Plan of Reorganization, the Company became statutorily responsible for retiree medical benefits pursuant to Section 9711 of the Coal Industry Retiree Health Benefit Act of 1992 for certain retirees of Magnum who retired prior to October 1, 1994. In addition, the Company has provided surety bonds to Patriot related to permits that were sold to an affiliate of Virginia Conservation Legacy Fund, Inc. (“VCLF”). Should VCLF not perform required reclamation, the Company would incur losses under the bonds and related indemnity agreements. The Company recognized $116.3 million in losses in 2015 related to the previously disposed operations as a result of the Patriot Coal bankruptcy. On November 22, 2016, Arch entered into a”Collateral Use Agreement” which caused the replacement, substitution and discharge of reclamation surety bonds related to the former Magnum properties placed by Arch in exchange for a collateral release of $20 million held by the bonding company to VCLF.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2016
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories consist of the following: Successor Predecessor December 31, 2016 December 31, 2015 (In thousands) Coal $ 37,268 $ 85,043 Repair parts and supplies 76,194 111,677 $ 113,462 $ 196,720 The repair parts and supplies are stated net of an allowance for slow-moving and obsolete inventories of $0.0 million at December 31, 2016 and $6.0 million at December 31, 2015 .

Investments in Available-for-Sa

Investments in Available-for-Sale Securities	12 Months Ended
	Dec. 31, 2016
Available-for-sale Securities [Abstract]
Investments in Available-for-Sale Securities	Investments in Available-for-Sale Securities The Company has invested primarily in highly liquid investment-grade corporate bonds. These investments are held in the custody of a major financial institution. These securities, along with the Company’s investments in marketable equity 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: Successor December 31, 2016 Balance Sheet Gross Gross Classification Unrealized Unrealized Fair Short-Term Other Cost Basis Gains Losses Value Investments Assets (In thousands) Available-for-sale: Corporate notes and bonds $ 88,161 $ — $ (89 ) $ 88,072 $ 88,072 $ — Equity securities 1,749 388 — 2,137 — 2,137 Total Investments $ 89,910 $ 388 $ (89 ) $ 90,209 $ 88,072 $ 2,137 Predecessor December 31, 2015 Balance Sheet Gross Gross Classification Unrealized Unrealized Fair Short-Term Other Cost Basis Gains Losses Value Investments Assets (In thousands) Available-for-sale: U.S. government and agency securities $ 10,007 $ — $ (12 ) $ 9,995 $ 9,995 $ — Corporate notes and bonds 190,496 — (299 ) 190,197 190,197 — Equity securities 3,938 668 (2,888 ) 1,718 — 1,718 Total Investments $ 204,441 $ 668 $ (3,199 ) $ 201,910 $ 200,192 $ 1,718 The aggregate fair value of investments with unrealized losses that had been owned for less than a year was $47.6 million and $184.6 million at December 31, 2016 and 2015 , respectively. The aggregate fair value of investments with unrealized losses that have been owned for over a year was $40.4 million and $15.8 million at December 31, 2016 and 2015 , respectively. The debt securities outstanding at December 31, 2016 have maturity dates ranging from the first quarter of 2017 through the fourth quarter of 2017 . 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, 2016
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investments and Membership Interests in Joint Ventures	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 Millennium Tongue River Other Total Predecessor Company January 1, 2014 $ 152,806 $ 14,137 $ 35,894 $ 18,419 $ 200 $ 221,456 Advances to (distributions from) affiliates, net (12,603 ) 3,774 6,742 2,541 3,600 4,054 Equity in comprehensive income (loss) 18,274 (4,173 ) (2,413 ) (220 ) (1,136 ) 10,332 December 31, 2014 158,477 13,738 40,223 20,740 2,664 235,842 Advances to (distributions from) affiliates, net (29,862 ) 3,207 7,052 913 330 (18,360 ) Equity in comprehensive income (loss) 22,977 (3,706 ) (9,686 ) (328 ) (1,278 ) 7,979 Impairment of equity investment — — — (21,325 ) (21,325 ) Sale of equity investment — — — — (2,259 ) (2,259 ) December 31, 2015 151,592 13,239 37,589 — (543 ) 201,877 Advances to (distributions from) affiliates, net (8,374 ) 1,474 1,966 — — (4,934 ) Equity in comprehensive income (loss) 9,033 (2,095 ) (1,530 ) — (94 ) 5,314 Impairment of equity investment — — (38,025 ) — — (38,025 ) Fresh start accounting adjustment (58,251 ) (4,018 ) — — 662 (61,607 ) October 1, 2016 $ 94,000 $ 8,600 $ — $ — $ 25 $ 102,625 Successor Company Advances to (distributions from) affiliates, net (9,076 ) 822 — — — (8,254 ) Equity in comprehensive income (loss) 2,569 (841 ) — — (25 ) 1,703 December 31, 2016 $ 87,493 $ 8,581 $ — $ — $ — $ 96,074 The Company holds a 49% equity interest in Knight Hawk Holdings, LLC (“Knight Hawk”), a coal producer in the Illinois Basin. The Company holds a general partnership interest of 21.875% in Dominion Terminal Associates (“DTA”), which is accounted for under the equity method. 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. The Company previously held a 38% ownership interest in Millennium Bulk Terminals-Longview, LLC (“Millennium”), the owner of a brownfield bulk commodity terminal on the Columbia River near Longview, Washington. Millennium continues to work on obtaining the required approvals and necessary permits to complete dredging and other upgrades to ship coal, alumina and cementitious material from the terminal. During the second quarter of 2016, the Company recorded an impairment charge of $38.0 million representing the entire value of its equity investment as the Company relinquished its ownership rights in exchange for future throughput rights through the facility when completed. The Company holds a 35% membership interest in the Tongue River Holding Company, LLC (“Tongue River”) joint venture. Tongue River will develop and construct a railway line near Miles City, Montana and the Company’s Otter Creek reserves. The Company had the right, upon the receipt of permits and approval for construction or under other prescribed circumstances, to require the other investors to purchase all of the Company’s units in the venture at an amount equal to the capital contributions made by the Company at that time, less any distributions received. During the third quarter of 2015, the Company recorded an impairment charge of $21.3 million representing the entire value of the Company’s investment in the project; the impairment charge is included on the line “Asset impairment and mine closure costs.” The Company is not required to make any future contingent payments related to development financing for any of its equity investees.

Sales Contracts

Sales Contracts	12 Months Ended
	Dec. 31, 2016
Acquired Sales Contracts [Abstract]
Sales Contracts	Sales Contracts The sales contracts reflected in the consolidated balance sheets are as follows: Successor Predecessor December 31, 2016 December 31, 2015 Assets Liabilities Net Total Assets Liabilities Net Total (In thousands) (In thousands) Original fair value $ 97,196 $ 31,742 $ 131,299 $ 166,697 Accumulated amortization (25,625 ) (24,829 ) (130,839 ) (151,354 ) Total $ 71,571 $ 6,913 $ 64,658 $ 460 $ 15,343 $ (14,883 ) Balance Sheet classification: Other current $ 59,702 $ 5,114 $ 460 $ 3,852 Other noncurrent $ 11,869 $ 1,799 $ — $ 11,491 The Company anticipates amortization of sales contracts, based upon expected shipments in the next five years, to be expense of approximately $54.3 million in 2017 , $10.7 million in 2018 , $1.1 million in 2019 , and income of $0.6 million in 2020 and $0.1 million in 2021 .

Derivatives

Derivatives	12 Months Ended
	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	Derivatives 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 45 to 50 million gallons of diesel fuel for use in its operations during 2017 . To protect the Company’s cash flows from increases in the price of diesel fuel for its operations, the Company may use forward physical diesel purchase contracts and purchase out-of-the-money heating oil call options to protect against substantial increases in pricing. At December 31, 2016 , the Company had heating oil call options for approximately 30.7 million gallons at an average strike price of $1.72 . 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, 2016 , the Company held derivatives for risk management purposes that are expected to settle in the following years: (Tons in thousands) 2017 2018 Total Coal sales 540 — 540 Coal purchases 480 — 480 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 gains of $0.2 million in the trading portfolio are expected to be realized in 2017 . 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: Successor Predecessor December 31, 2016 December 31, 2015 Fair Value of Derivatives Asset Liability Asset Liability (In thousands) Derivative Derivative Derivative Derivative Derivatives Designated as Hedging Instruments Coal $ — $ (15 ) $ 4 $ (20 ) Derivatives Not Designated as Hedging Instruments Heating oil -- diesel purchases 4,646 — 1,017 — Coal held for trading purposes, exchange traded swaps and futures 68,948 (68,740 ) 110,653 (104,814 ) Coal -- risk management 475 (580 ) 3,912 (1,947 ) Natural gas 86 (13 ) 494 (247 ) Total 74,155 (69,333 ) 116,076 (107,008 ) Total derivatives 74,155 (69,348 ) 116,080 (107,028 ) Effect of counterparty netting (69,247 ) 69,247 (107,028 ) 107,028 Net derivatives as classified in the balance sheets $ 4,908 $ (101 ) $ 4,807 $ 9,052 $ — $ 9,052 Successor Predecessor December 31, 2016 December 31, 2015 Net derivatives as reflected on the balance sheets Heating oil Other current assets $ 4,646 $ 1,017 Coal Coal derivative assets 262 8,035 Accrued expenses and other current liabilities (101 ) — $ 4,807 $ 9,052 The Company had a current asset for the right to reclaim cash collateral of $2.8 million and $1.7 million at December 31, 2016 and 2015 , respectively. These amounts are not included with the derivatives presented in the table above and are included in “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) Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 Coal sales (1) $ — $ (672 ) $ 12,816 10,842 Coal purchases (2) — 536 (6,718 ) (5,097 ) $ — $ (136 ) $ 6,098 $ 5,745 Gains (Losses) Reclassified from Other Comprehensive Income into Income Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 Coal sales $ — $ 1,634 $ 18,635 $ 5,336 Coal purchases — (1,237 ) (9,060 ) (2,693 ) $ — $ 397 $ 9,575 $ 2,643 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 Successor period from October 2 through December 31, 2016 , the Predecessor period from January 1 through October 1, 2016 , and for the Predecessor years ended December 31, 2015 , and 2014 . Derivatives Not Designated as Hedging Instruments (in thousands) For the noted periods, Gain (Loss) Recognized Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 Coal — unrealized (3) $ (408 ) $ (1,662 ) $ (3,883 ) $ 430 Coal — realized (4) $ 116 $ (476 ) $ 3,236 $ 5,956 Heating oil — diesel purchases (4) $ 827 $ 826 $ (8,294 ) $ (7,848 ) Heating oil — fuel surcharges (4) $ — $ — $ — $ (405 ) Natural gas $ (91 ) $ (463 ) $ 878 $ — Foreign currency $ (9 ) $ (451 ) $ (887 ) $ — Location in statement of operations: (1) — Revenues (2) — Cost of sales (3) — Change in fair value of coal derivatives and coal trading activities, net (4) — Other operating income, net The Company recognized net unrealized and realized losses of an immaterial amount for the period October 2 through December 31, 2016 and $0.9 million for the period January 1 through October 1, 2016 ; and net unrealized and realized gains of $5.7 million , and $3.2 million during the years ended December 31, 2015 and 2014 , respectively, related to its trading portfolio, which are included in the caption “Change in fair value of coal derivatives and coal trading activities, net” in the accompanying consolidated statements of operations, and are not included in the previous tables reflecting the effects of derivatives on measures of financial performance. Based on fair values at December 31, 2016 , 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 immaterial.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Dec. 31, 2016
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: Successor Predecessor December 31, 2016 December 31, 2015 (In thousands) Payroll and employee benefits $ 58,468 $ 58,423 Taxes other than income taxes 92,733 104,755 Interest 8,032 119,785 Sales contracts 5,114 3,852 Workers’ compensation 15,184 16,875 Asset retirement obligations 19,515 13,795 Other 6,194 11,965 $ 205,240 $ 329,450

Debt and Financing Arrangements

Debt and Financing Arrangements	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Debt and Financing Arrangements	Debt and Financing Arrangements Successor Predecessor December 31, 2016 December 31, 2015 (In thousands) Term loan due 2021 ($325.7 million face value) $ 325,684 $ — Term loan due 2018 ($1.9 billion and $1.93 billion face value, respectively) — 1,875,429 7.00% senior notes due 2019 at par — 1,000,000 8.00% senior secured notes due 2019 at par — 350,000 9.875% senior notes ($375.0 million face value) due 2019 — 365,600 7.25% senior notes due 2020 at par — 500,000 7.25% senior notes due 2021 at par — 1,000,000 Other 37,195 47,134 Debt issuance costs — (64,857 ) 362,879 5,073,306 Less current maturities of debt 11,038 5,042,353 Long-term debt $ 351,841 $ 30,953 Successor Company Debt New First Lien Debt Facility Borrowings under the New First Lien Debt Facility bear interest at a per annum rate equal to, at the option of Arch Coal, either (i) a London interbank offered rate plus an applicable margin of 9% , subject to a 1% LIBOR floor (the “LIBOR Rate”), or (ii) a base rate plus an applicable margin of 8% . Interest payments will be payable in cash, unless Arch Coal’s liquidity (as defined therein) after giving effect to the applicable interest payment would not exceed $300 million , in which case interest may be payable in kind (any such interest that is paid in kind, the “PIK Interest”). The term loans provided under the New First Lien Debt Facility (the “Term Loans”) are subject to quarterly principal amortization payments in an amount equal $816,250 . To the extent any interest is paid as PIK Interest on any interest payment date, the amount of the Term Loans in respect of which such PIK Interest is payable will be deemed to have accrued additional interest over the preceding interest period at 1.00% , which additional interest will be capitalized and added to the principal amount of outstanding Term Loans. The New First Lien Debt Facility is guaranteed by all existing and future wholly owned domestic subsidiaries of Arch Coal (collectively, the “Subsidiary Guarantors” and, together with Arch Coal, the “Exit Loan Parties”), subject to customary exceptions, and is secured by first priority security interests on substantially all assets of the Exit 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. Arch Coal 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 New First Lien 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 First Lien Debt Facility) and (ii) non-ordinary course asset sales or dispositions, subject to customary thresholds, exceptions and reinvestment rights. The New First Lien Debt Facility contains customary affirmative covenants and representations. The New First Lien Debt Facility also contains customary negative covenants, which, among other things, and subject to certain exceptions, include restrictions on (i) indebtedness, (ii) liens and guaranties, (iii) liquidations, mergers, consolidations, 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 indebtedness, (x) restrictions in agreements on dividends, intercompany loans and granting liens on the collateral, (xi) loans and investments, (xii) changes in organizational documents, (xiii) transactions with respect to bonding subsidiaries and (xiv) hedging transactions. The New First Lien Debt Facility does not contain any financial maintenance covenant. The New First Lien Debt Facility contains customary events of default, subject to customary thresholds and exceptions, including, among other things, (i) non-payment of principal and non-payment 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 $35 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 $35 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 $35 million , (ix) ERISA events, (x) a change of control or (xi) bankruptcy or insolvency proceedings relating to Arch Coal or any material subsidiary of Arch Coal. The New First Lien Debt Facility will mature on the date that is five years after the Effective Date. Securitization Facility On the Effective Date, Arch Coal extended and amended its existing $200 million trade accounts receivable securitization facility provided to Arch Receivable Company, LLC, a non-Debtor special-purpose entity that is a wholly owned subsidiary of Arch Coal (“Arch Receivable”) (the “Extended Securitization Facility”), which continues to support the issuance of letters of credit and reinstates Arch Receivable’s ability to request cash advances, as existed prior to the filing of the voluntary petitions for relief under the Bankruptcy Code. Pursuant to the Extended Securitization Facility, the Debtors 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 Effective Date, (ii) if the Liquidity (defined in the Extended Securitization Facility and consistent with the definition in the New First Lien Debt Facility) is less than $175 million for a period of 60 consecutive days, the date that is the 364th 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 and certain of the Reorganized Debtors (as defined above) 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 Debtors from the sale of coal and all proceeds thereof. As of December 31, 2016, letters of credit totaling $154.4 million were outstanding under the Extended Securitization Facility and the borrowing base was $83.4 million . As a result, cash collateral of $71.0 million has been placed in the Extended Securitization Facility at December 31, 2016 and there is no availability for borrowings. Predecessor Company Debt The following debt instruments were fully discharged by the Bankruptcy Court: • 7.00% Senior Notes due 2019; • 7.25% Senior Notes due 2020; • 7.25% Senior Notes due 2021; • 9.875% Senior Notes due 2019; • 8.00% Second Lien Notes due 2019; • Term loan due 2018; For additional information see Note 3 , “ Emergence from Bankruptcy and Fresh Start Accounting .” Debt Maturities The contractual maturities of debt as of December 31, 2016 are as follows: Year (In thousands) 2017 $ 11,038 2018 10,324 2019 11,479 2020 11,761 2021 317,987 Thereafter 290 $ 362,879 Financing Costs The Company paid financing costs of $23.0 million during the period January 1 through October 1, 2016 ; and zero and $4.5 million during the years ended December 31, 2015 and 2014 , respectively, in conjunction with its financing activities. The Company incurred $2.2 million of legal fees and financial advisory fees associated with debt restructuring activities in during the period January 1 through October 1, 2016 . Additionally, the Company incurred $24.2 million of legal fees and financial advisory fees associated with debt restructuring activities during 2015. During the year ended December 31, 2015 , the Company wrote off $3.7 million of deferred financing costs related to the termination of the revolver facility. All amounts have been reflected in the line, “ Net loss resulting from early retirement and refinancing of debt ” in the Consolidated Statement of Operations.

Taxes

Taxes	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Taxes	Taxes Under the Plan, the Company’s pre-petition equity, bank related debt and certain other obligations were cancelled and extinguished. Absent an exception, a debtor recognizes cancellation of debt income (CODI) upon discharge of its outstanding indebtedness for an amount of consideration that is less than its adjusted issue price. In accordance with Internal Revenue Code (IRC) Section 108, the Company excluded the amount of discharged indebtedness from taxable income since the IRC provides that a debtor in a bankruptcy case may exclude CODI from income but must reduce certain tax attributes by the amount of CODI realized as a result of the consummation of a plan of reorganization. The amount of CODI realized by a taxpayer is the adjusted issue price of any indebtedness discharged less than the sum of (i) the amount of cash paid, (ii) the issue price of any new indebtedness issued, and (iii) the fair market value the fair market value of any other consideration, including equity, issued. CODI from the discharge of indebtedness was $3,353 million . As a result of the CODI and in accordance with IRC rules, the Company reduced its gross federal net operating loss (NOL) carryovers $3,015 million , its alternative minimum tax (AMT) credits $92 million , its capital loss carryforwards $59.2 million and the tax basis in certain assets $3.2 million . The Company was able to retain $931.1 million of gross federal NOLs, $22.8 million of AMT credit and $5.9 million of capital loss carryforwards following the bankruptcy. Due to changes in ownership that occurred in connection with the Company’s emergence from bankruptcy, 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 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 significant 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. The Company is subject to U.S. federal income tax as well as income tax in multiple state jurisdictions. The tax years 2002 through 2016 remain open to examination for U.S. federal income tax matters and 2004 through 2016 remain open to examination for various state income tax matters. Significant components of the provision for (benefit from) income taxes are as follows: Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 (In thousands) Current: Federal $ — $ — $ — $ — State (252 ) 7 3 25 Total current (252 ) 7 3 25 Deferred: Federal 1,352 (4,720 ) (329,393 ) 18,535 State 56 87 (43,990 ) 7,074 Total deferred 1,408 (4,633 ) (373,383 ) 25,609 $ 1,156 $ (4,626 ) $ (373,380 ) $ 25,634 A reconciliation of the statutory federal income tax provision (benefit) at the statutory rate to the actual provision for (benefit from) income taxes follows: Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 (In thousands) Income tax provision (benefit) at statutory rate $ 12,112 $ 433,109 $ (1,150,283 ) $ (186,452 ) Percentage depletion allowance (4,292 ) (3,681 ) (19,035 ) (12,692 ) State taxes, net of effect of federal taxes 633 (46,122 ) (76,445 ) (3,903 ) Reversal of cancellation of indebtedness income — (1,493,162 ) — — Worthless stock deduction — (80,077 ) — — Change in valuation allowance (7,655 ) 1,185,326 865,146 226,929 Other, net 358 (19 ) 7,237 1,752 $ 1,156 $ (4,626 ) $ (373,380 ) $ 25,634 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: Successor Predecessor December 31, 2016 December 31, 2015 (In thousands) Deferred tax assets: Net operating loss carryforwards $ 376,293 $ 1,086,332 Alternative minimum tax credit carryforwards 22,798 120,994 Investment in tax partnerships & corporations 604,914 — Reclamation and mine closure — 121,276 Goodwill 5,135 38,671 Workers’ compensation — 42,835 Share based compensation — 22,612 Sales contracts — 17,466 Retiree benefit plans 4,013 16,996 Advance royalties — 18,751 Losses from disposed operations resulting from Patriot Coal bankruptcy — 39,287 Other, primarily accrued liabilities 30,103 45,303 Gross deferred tax assets 1,043,256 1,570,523 Valuation allowance (1,021,553 ) (1,135,399 ) Total deferred tax assets 21,703 435,124 Deferred tax liabilities: Plant and equipment 7,332 389,169 Deferred development — 41,047 Sales contracts 12,658 — Other 1,600 4,706 Total deferred tax liabilities 21,590 434,922 Net deferred (asset) liability (113 ) (202 ) The Company has gross federal net operating loss carryforwards for regular income tax purposes of $931.1 million at December 31, 2016 that will expire between 2022 and 2036 . The Company has an alternative minimum tax credit carryforward of $22.8 million at December 31, 2016 , which has no expiration date and can be used to offset future regular tax in excess of the alternative minimum tax. The future annual usage of NOLs and AMT credit will be limited under IRC section 382. As part of our efforts to create operational efficiency leading up to and through the bankruptcy process, we have consolidated our mining operations and land management into a partnership structure to match our legal form with the Company’s streamlined operations during 2016. As such, deferred taxes related to those operations are now reported based upon the book and tax outside basis difference in the partnership interests as provided in ASC 740-30-25-7, which results in a different basis of presentation that was used in 2015 under our prior legal structure. As recent cumulative losses constitute significant negative evidence with regards to future taxable income, the Company has relied solely on the expected reversal of taxable temporary differences to support the future realization of its deferred tax assets. The Company performs a detailed scheduling process of its net taxable temporary differences. At December 31, 2014, all deductible temporary differences were expected to be realized as there were sufficient deferred tax liabilities within the same jurisdiction and of the same character that are available to offset them. Valuation allowances were established for federal and state net operating losses and tax credits that were not offset by the reversal of other net taxable temporary differences before the expiration of the attribute. At December 31, 2015, additional losses were realized relating primarily to financial conditions and asset impairment charges. As a result, the expected reversal of taxable temporary differences were not sufficient to support the future realization of the deferred tax assets and an additional $865.1 million valuation allowance was recorded. Net deferred tax assets of $1,135 million were completely offset by a valuation allowance. At December 31, 2016, additional tax losses were realized primarily as a result of the non-recognition of CODI under section 108 of the IRC by the Predecessor entity. As a result, the expected reversal of taxable temporary differences were not sufficient to support the future realization of the deferred tax assets and an additional $1,185 million valuation allowance was recorded to the provision. Offsetting this increase was a net reduction in the valuation allowance of $1,289 million which did not impact the provision. This reduction was primarily the result of a decrease in NOLs and AMT credits due to the IRC section 108 offset rules. Net deferred tax assets of $1,022 million are completely offset by a valuation allowance. A reconciliation of the beginning and ending amounts of gross unrecognized tax benefits follows: (In thousands) Balance at January 1, 2014 $ 31,789 Additions based on tax positions related to the current year 2,920 Balance at December 31, 2014 34,709 Additions based on tax positions related to the current year 4,168 Balance at December 31, 2015 38,877 Additions for tax positions of prior years 2,979 Additions for tax positions related to the current year 2,709 Reductions as a result of bankruptcy (37,110 ) Balance at December 31, 2016 $ 7,455 If recognized, the entire amount of the gross unrecognized tax benefits at December 31, 2016 would affect the effective tax rate. As a result of the bankruptcy, federal and state governments are precluded from assessing additional tax in audits of tax periods ending prior to bankruptcy. As a result, the Company has released $37.1 million of gross unrecognized tax benefits for years 2015 and prior. These gross unrecognized tax benefits are fully offset by a corresponding release in valuation allowance. The Company recognizes interest and penalties related to unrecognized tax benefits in income tax expense. The Company had accrued interest and penalties of $0.5 million and $1.7 million at December 31, 2016 and 2015 , respectively. In the next 12 months, no gross unrecognized tax benefits are expected to be reduced due to the expiration of the statute of limitations.

Asset Retirement Obligations

Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2016
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, and reclaiming refuse areas and slurry ponds. The following table describes the changes to the Company’s asset retirement obligation liability: Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 (In thousands) Balance at beginning of period (including current portion) $ 354,326 $ 410,454 $ 418,118 Accretion expense 7,634 24,321 33,680 Obligations of divested operations — (14,702 ) (334 ) Adjustments to the liability from changes in estimates — 3,003 (28,570 ) Liabilities settled (5,218 ) (11,087 ) (12,440 ) Fresh start accounting adjustment — (57,663 ) — Balance at period end $ 356,742 $ 354,326 $ 410,454 Current portion included in accrued expenses (19,515 ) (17,290 ) (13,795 ) Noncurrent liability $ 337,227 $ 337,036 $ 396,659 As of December 31, 2016 , the Company had $528.3 million in surety bonds outstanding and $21.3 million in letters of credit to secure reclamation bonding obligations. Additionally, the Company has posted $33.4 million in cash as collateral related to reclamation surety bonds; this amount is recorded within “Noncurrent assets” on the Consolidated Balance Sheet.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2016
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 and coal commodity contracts 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, 2016 and 2015 . 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: Successor Fair Value at December 31, 2016 Total Level 1 Level 2 Level 3 (In thousands) Assets: Investments in marketable securities $ 90,209 $ 2,137 $ 88,072 $ — Derivatives 4,908 262 — 4,646 Total assets $ 95,117 $ 2,399 $ 88,072 $ 4,646 Liabilities: Derivatives $ 101 $ (8 ) $ — $ 109 Predecessor Fair Value at December 31, 2015 Total Level 1 Level 2 Level 3 (In thousands) Assets: Investments in marketable securities $ 201,910 $ 11,713 $ 190,197 $ — Derivatives 9,052 5,597 1,023 2,432 Total assets $ 210,962 $ 17,310 $ 191,220 $ 2,432 Liabilities: Derivatives $ — $ — $ — $ — 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. Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 (In thousands) (In thousands) Balance, beginning of period $ 3,842 $ 2,432 $ 3,040 Realized and unrealized losses recognized in earnings, net 926 (1,686 ) (8,602 ) Included in other comprehensive income — — (1,341 ) Purchases 1,225 5,021 13,541 Issuances (34 ) (488 ) (4,046 ) Settlements (1,422 ) (1,437 ) (160 ) Ending balance $ 4,537 $ 3,842 $ 2,432 Net unrealized gains of $0.4 million were recognized during the period October 2 through December 31, 2016 related to level 3 financial instruments held on December 31, 2016 . Cash and Cash Equivalents At December 31, 2016 and 2015 , the carrying amounts of cash and cash equivalents approximate their fair value. Fair Value of Long-Term Debt At December 31, 2016 and 2015 , the fair value of the Company’s debt, including amounts classified as current, was $362.9 million and $937.1 million , respectively. Fair values are based upon observed prices in an active market, when available, or from valuation models using market information, which fall into Level 2 in the fair value hierarchy.

Capital Stock

Capital Stock	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Capital Stock	Capital Stock Successor Company Equity Securities Under the Plan, 24,589,834 shares of Class A Common Stock and 410,166 shares of Class B Common Stock, par value $.01 per share, were distributed to the secured lenders and to certain holders of general unsecured claims under the Plan on the Effective Date. The Class A Common Stock and Class B Common stock are identical in all respects except that Class B Common Stock shall not be listed by the Company on any national securities exchange registered under Section 6 of the Securities Exchange Act of 1934, as amended. In addition, on the Effective Date, Arch Coal issued Warrants to purchase up to an aggregate of 1,914,856 shares of Class A Common Stock. Arch Coal relied, based on the confirmation order it received from the Bankruptcy Court, on Section 1145(a)(1) of the U.S. Bankruptcy Code to exempt from the registration requirements of the Securities Act of 1933, as amended (i) the offer and sale of Common Stock to the secured lenders and to the general unsecured creditors, (ii) the offer and sale of the Warrants to the holders of claims arising under the Cancelled Notes and (iii) the offer and sale of the Class A Common Stock issuable upon exercise of the Warrants. Section 1145(a)(1) of the Bankruptcy Code exempts the offer and sale of securities under a plan of reorganization from registration under Section 5 of the Securities Act and state laws if three principal requirements are satisfied: • the securities must be offered and sold under a plan of reorganization and must be securities of the debtor, of an affiliate participating in a joint plan of reorganization with the debtor or of a successor to the debtor under the plan of reorganization; • the recipients of the securities must hold claims against or interests in the debtor; and • the securities must be issued in exchange, or principally in exchange, for the recipient’s claim against or interest in the debtor. See Note 3 , “ Emergence from Bankruptcy and Fresh Start Accounting ” for additional information. Outstanding Warrants As of December 31, 2016, holders of warrants had exercised 2,871 of the warrants. 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. Predecessor Company Reverse Stock Split On August 4, 2015, the Company effected a 1-for-10 reverse stock split of our common stock. Each stockholder’s percentage ownership and proportional voting power remain unchanged as a result of the reverse stock split. All applicable share data, per share amounts and related information in the Consolidated Financial Statements and notes thereto have been adjusted retroactively to give effect to the 1-for-10 reverse stock split.

Stock-Based Compensation and Ot

Stock-Based Compensation and Other Incentive Plans	12 Months Ended
	Dec. 31, 2016
Share-based Compensation [Abstract]
Stock-Based Compensation And Other Incentive Plans	Stock-Based Compensation and Other Incentive Plans Successor Company 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 2.6 million at December 31, 2016 . 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. Three restricted stock unit awards were granted in the Successor period: two time based awards vesting over one and three years: and one performance based award vesting 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 award’s grant date fair value was determined using a Monte Carlo simulation. A volatility of 58% was selected 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: Common Shares Weighted Average Grant-Date Fair Value (Shares in thousands) Outstanding at October 2, 2016 — — Granted 384 $ 72.00 Forfeited — — Canceled — — Unvested outstanding at December 31, 2016 384 $ 72.00 The Company recognized expense related to restricted stock units for the period October 2, 2016 through December 31, 2016 of $1.0 million . 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 $1.6 million for the period October 2 through December 31, 2016 , $7.2 million for the period January 1 through October 1, 2016 , and $7.9 million and $10.1 million for the years ended December 31, 2015 and 2014 , respectively. The expense is included primarily in “Selling, general and administrative expenses” in the accompanying consolidated statements of operations. As part of the plan of reorganization, the Company’s Executive Officers agreed to a $6.0 million reduction in scheduled compensation payouts in 2017. The long term incentive compensation liability was reduced $3.7 million as a fresh start accounting adjustment and is reflected in the Successor period ending December 31, 2016 balance. Amounts accrued and unpaid for all grants under the plan totaled $13.9 million and $17.8 million as of December 31, 2016 and 2015 , respectively. Predecessor Company On the Effective Date, all shares of our old common stock, including any vested and unvested stock options, restricted stock and restricted stock units were canceled. Common Stock Stock options are granted at a strike price equal to the closing market price of the Company’s common stock on the date of grant and are generally subject to vesting provisions of a least one year from the date of grant. Compensation expense related to stock options for the period January 1, 2016 through October 1, 2016, and for the years ended 2015 and 2014 were $0.2 million , $1.4 million and $3.2 million , respectively. The majority of the cost relating to the stock-based compensation plans is included in “Selling, general and administrative expenses” in the accompanying consolidated statements of operations. Restricted stock units 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 three years. Compensation expense is based on the fair value on the grant date and is recorded ratably over the vesting period. Compensation expense related to restricted stock and restricted stock units for the period January 1, 2016 through October 1, 2016, and for the years ended 2015 and 2014 were $1.9 million , $5.9 million and $5.6 million , respectively. The majority of the cost relating to the stock-based compensation plans is included in “Selling, general and administrative expenses” in the accompanying consolidated statements of operations.

Workers' Compensation Expense

Workers' Compensation Expense	12 Months Ended
	Dec. 31, 2016
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 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 1.74% . 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: Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 (In thousands) Self-insured occupational disease benefits: Service cost $ 1,583 $ 3,465 $ 4,282 $ 1,734 Interest cost 1,126 3,184 3,944 2,914 Net amortization — 4,325 6,973 (216 ) Total occupational disease $ 2,709 $ 10,974 $ 15,199 $ 4,432 Traumatic injury claims and assessments 3,162 6,628 16,781 19,924 Total workers’ compensation expense $ 5,871 $ 17,602 $ 31,980 $ 24,356 The table below reconciles changes in the occupational disease liability for the respective period. Successor Predecessor (In thousands) October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Beginning of period $ 119,710 $ 90,836 $ 72,749 Service cost 1,583 3,465 4,282 Interest cost 1,126 3,184 3,944 Curtailments — 4,156 Actuarial (gain) loss (9,675 ) — 14,284 Benefit and administrative payments (1,585 ) (3,728 ) (4,423 ) Fresh start accounting adjustment — 21,797 — $ 111,159 $ 119,710 $ 90,836 The following table provides the assumptions used to determine the projected occupational disease obligation: Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 (Percentages) Occupational Disease Benefit Discount rate 4.31 3.80 4.76 Cost escalation rate N/A N/A N/A Summarized below is information about the amounts recognized in the accompanying consolidated balance sheets for workers’ compensation benefits: Successor Predecessor Year Ended December 31, 2016 Year Ended December 31, 2015 (In thousands) Occupational disease costs $ 111,159 $ 90,836 Traumatic and other workers’ compensation claims 88,593 38,309 Total obligations 199,752 129,145 Less amount included in accrued expenses 15,184 16,875 Noncurrent obligations $ 184,568 $ 112,270 As of December 31, 2016 , the Company had $146.2 million in surety bonds and letters of credit outstanding to secure workers’ compensation obligations. The Company’s recorded liabilities include $19.4 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 $0.8 million and $18.6 million .

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2016
Pension and Other Postretirement Benefit Expense [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 salaried employee postretirement benefit plans are contributory, with retiree contributions adjusted annually, 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. The idling of the Cumberland River mining operations in Appalachia in the third quarter of 2014 reduced the estimated years of future service for the CRCC Scotia Employee Association Pension Plan. 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. These two events triggered curtailment accounting, resulting in an immediate recognition of any unamortized gain or loss and the reduction in the projected benefit obligation which were recorded in the third and fourth quarter of 2014, respectively. 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 Successor Predecessor Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 (In thousands) CHANGE IN BENEFIT OBLIGATIONS Benefit obligations at beginning of period $ 341,427 $ 301,292 $ 353,736 $ 120,311 $ 103,460 $ 36,098 Service cost — — 9 180 393 866 Interest cost 2,768 9,338 14,604 978 3,223 1,904 Re-entry of former Magnum employees — — — — — 85,843 Settlements (135 ) — — — — — Curtailments — 454 — — 714 — Benefits paid (11,009 ) (8,699 ) (61,955 ) (1,962 ) (8,273 ) (3,646 ) Other-primarily actuarial gain (19,422 ) — (5,102 ) (7,640 ) — (17,605 ) Fresh start accounting adjustments — 39,042 — — 20,794 Benefit obligations at end of period $ 313,629 $ 341,427 $ 301,292 $ 111,867 $ 120,311 $ 103,460 CHANGE IN PLAN ASSETS Value of plan assets at beginning of period $ 292,726 $ 273,499 $ 336,709 $ — $ — $ — Actual return on plan assets (7,899 ) 27,811 (1,679 ) — — Employer contributions 407 115 424 1,962 8,273 3,646 Benefits paid (11,009 ) (8,699 ) (61,955 ) (1,962 ) (8,273 ) (3,646 ) Value of plan assets at end of period $ 274,225 $ 292,726 $ 273,499 $ — $ — $ — Accrued benefit cost $ (39,404 ) $ (48,701 ) $ (27,793 ) $ (111,867 ) $ (120,311 ) $ (103,460 ) ITEMS NOT YET RECOGNIZED AS A COMPONENT OF NET PERIODIC BENEFIT COST Prior service credit (cost) $ — $ — $ — $ — $ — $ 26,944 Accumulated gain (loss) 6,751 — (16,769 ) 7,640 — 11,313 $ 6,751 $ — $ (16,769 ) $ 7,640 $ — $ 38,257 BALANCE SHEET AMOUNTS Current liability $ (520 ) $ (420 ) $ (420 ) $ (10,422 ) $ (8,352 ) $ (3,650 ) Noncurrent liability (38,884 ) (48,281 ) $ (27,373 ) (101,445 ) (111,959 ) (99,810 ) $ (39,404 ) $ (48,701 ) $ (27,793 ) $ (111,867 ) $ (120,311 ) $ (103,460 ) Pension Benefits The accumulated benefit obligation for all pension plans was $313.6 million and $301.3 million at December 31, 2016 and 2015 , respectively. Due to the Company adopting the corridor method of amortizing actuarial gains (losses) during fresh start accounting, it is anticipated there will be no amortization recorded into net periodic benefit cost during 2017. Other Postretirement Benefits Due to the Company adopting the corridor method of amortizing actuarial gains (losses) during fresh start accounting, it is anticipated there will be no amortization recorded into net periodic benefit cost during 2017. Components of Net Periodic Benefit Cost . The following table details the components of pension and postretirement benefit costs (credits): Pension Benefits Other Postretirement Benefits Successor Predecessor Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 (In thousands) Service cost $ — $ — $ 9 $ 21,478 $ 180 $ 393 $ 866 $ 1,649 Interest cost 2,768 9,338 14,604 17,070 978 3,223 1,904 1,841 Curtailments — 454 — (25,368 ) — (970 ) — — Settlements (135 ) — 2,656 646 — — — — Expected return on plan assets (4,770 ) (13,623 ) (20,367 ) (23,756 ) — — — — Amortization of prior service credits — — — (257 ) — (7,854 ) (8,335 ) (10,003 ) Amortization of other actuarial losses (gains) — 3,973 8,850 3,128 — (849 ) (2,109 ) (761 ) Net benefit cost (credit) $ (2,137 ) $ 142 $ 5,752 $ (7,059 ) $ 1,158 $ (6,057 ) $ (7,674 ) $ (7,274 ) 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 weighted average assumptions used to determine the actuarial present value of projected benefit obligations for the respective periods. Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 (Percentages) Pension Benefits Discount rate 3.95 3.39 4.59 Rate of compensation increase N/A N/A N/A Other Postretirement Benefits Discount rate 3.93 3.37 4.57 Rate of compensation increase N/A N/A N/A The following table provides the weighted average assumptions used to determine net periodic benefit cost for the respective periods. Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 (Percentages) Pension Benefits Discount rate 3.39/3.95 4.59/3.80 4.15/4.61/4.41/4.60 5.08/4.23/4.14 Rate of compensation increase N/A N/A N/A N/A Expected return on plan assets 6.85 6.85 7.00 7.75 Other Postretirement Benefits Discount rate 3.37 4.57/3.80 3.91 4.58 Rate of compensation increase N/A N/A N/A N/A Expected return on plan assets N/A N/A N/A N/A The discount rates used in 2016, 2015 and 2014 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 2017 is 6.7% 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, 2016 by $11.1 million and the net periodic postretirement benefit cost for the year ended December 31, 2016 by $0.1 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 55% equity and 45% 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, 2016 and 2015 , 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 2016 2015 2016 2015 2016 2015 2016 2015 (In thousands) Equity Securities: (A) U.S. small-cap $ 13,520 $ 11,640 $ 13,520 $ 11,640 $ — $ — $ — $ — U.S. mid-cap 29,687 28,524 9,422 10,979 20,265 17,545 — — U.S. large-cap 70,226 67,244 34,107 33,249 36,119 33,995 — — Non-U.S. 18,937 18,785 — — 18,937 18,785 — — Fixed income securities: — U.S. government securities (B) 26,519 18,844 19,973 18,183 6,546 661 — — Non-U.S. government securities (C) 1,567 766 — — 1,567 766 — — U.S. government asset and mortgage backed securities (D) 1,074 1,056 — — 1,074 1,056 — — Corporate fixed income (E) 58,191 39,939 — — 58,191 39,939 — — State and local government securities (F) 6,406 5,725 — — 6,406 5,725 — — Other investments (I) 26,151 19,869 — — 6,910 1,234 19,241 18,635 Total $ 252,278 $ 212,392 $ 77,022 $ 74,051 $ 156,015 $ 119,706 $ 19,241 $ 18,635 Other fixed income (G) 35,519 Short-term investments (H) 8,598 Other liabilities (J) (22,170 ) $ 274,225 (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) Other fixed income investments are actively managed fixed income vehicles that are valued at the net asset value per share multiplied by the number of shares held as of the measurement date. (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 contributions of $0.4 million to the pension plans in 2017 , which is impacted by the Moving Ahead for Progress in the 21st Century Act (MAP-21). MAP-21 does not reduce the Company’s obligations under the plan, but redistributes the timing of required payments by providing near term funding relief for sponsors under the Pension Protection Act. The following represents expected future benefit payments from the plan, which reflect expected future service, as appropriate: Other Pension Postretirement Benefits Benefits (In thousands) 2017 $ 19,403 $ 12,300 2018 21,117 12,716 2019 20,763 13,033 2020 21,209 13,408 2021 21,917 13,763 Next 5 years 102,619 64,920 $ 207,028 $ 130,140 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 $3.5 million for the period October 2 through December 31, 2016 , $13.8 million for the period January 1 through October 1, 2016 and $20.5 million and $22.9 million for the years ended December 31, 2015 and 2014 , respectively.

Earnings (Loss) Per Common Shar

Earnings (Loss) Per Common Share	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Earnings (Loss) Per Common Share	Earnings (Loss) 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 shares 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: Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 (In Thousands) Weighted average shares outstanding: Basic weighted average shares outstanding 25,002 21,293 21,285 21,222 Effect of dilutive securities 467 20 — — Diluted weighted average shares outstanding 25,469 21,313 21,285 21,222

Leases

Leases	12 Months Ended
	Dec. 31, 2016
Leases [Abstract]
Leases	Leases The Company leases equipment, land and various other properties under non-cancelable long-term leases, expiring at various dates. Certain leases contain options that would allow the Company to extend the lease or purchase the leased asset at the end of the base lease term. In addition, the Company enters into various non-cancelable royalty lease agreements under which future minimum payments are due. Minimum payments due in future years under these agreements in effect at December 31, 2016 are as follows: Operating Leases Royalties (In thousands) 2017 $ 14,653 $ 3,994 2018 14,485 6,021 2019 5,321 6,105 2020 2,260 7,147 2021 1,985 7,809 Thereafter 10,317 46,499 $ 49,021 $ 77,575 Obligations for the future minimum payments under capital leases for equipment totaling $0.0 million and $40.0. million at December 31, 2016 and 2015, respectively, are included in other long term debt obligations in Note 13 , “ Debt and Financing Arrangements ”. Rental expense, including amounts related to these operating leases and other shorter-term arrangements, amounted to $5.0 million for the period October 2 through December 31, 2016 , $19.4 million for the period January 1 through October 1, 2016 , $28.4 million in 2015 and $42.1 million in 2014. 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 $45.3 million for the period October 2 through December 31, 2016 , $116.4 million for the period January 1 through October 1, 2016 , $227.7 million in 2015 and $242.5 million in 2014. As of December 31, 2016 , certain of the Company’s lease obligations were secured by outstanding surety bonds totaling $32.6 million .

Risk Concentrations

Risk Concentrations	12 Months Ended
	Dec. 31, 2016
Risks Concentrations [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 steam coal principally to domestic and foreign electric utilities and its metallurgical coal to domestic and foreign steel producers. As of December 31, 2016 and 2015 , accounts receivable from electric utilities of $96.0 million and $83.8 million , respectively, represented 52% and 72% of total trade receivables at each date. As of December 31, 2016 and 2015 , accounts receivable from sales of metallurgical-quality coal of $88.0 million and $32.8 million , respectively, represented 48% and 28% 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 are as follows: Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 (In thousands) (In thousands) Europe $ 61,408 $ 113,888 $ 170,314 $ 277,565 Asia 55,634 68,536 96,523 156,057 North America 43,831 56,594 40,315 78,445 Central and South America 13,224 41,861 55,323 20,496 Brokered Sales — — 32,848 79,354 Total $ 174,097 $ 280,879 $ 395,323 $ 611,917 The Company is committed under long-term contracts to supply steam 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 93.9 million tons of coal in 2016 . Approximately 76% of this tonnage (representing approximately 62% 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 five years. Third-party sources of coal The Company uses independent contractors to mine coal at certain mining complexes. The Company also purchases coal from third parties that it sells to customers. Factors beyond the Company’s control could affect the availability of coal produced for or purchased by the Company. Disruptions in the quantities of coal produced for or 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 The Company depends upon barge, rail, truck and belt transportation systems to deliver coal to its customers. Disruption of these transportation services due to weather-related problems, mechanical difficulties, strikes, lockouts, bottlenecks, and other events could temporarily impair the Company’s ability to supply coal to its customers In the past, disruptions in rail service have resulted in missed shipments and production interruptions.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
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, 2016 and 2015 , the Company had accrued $2.2 million and $2.8 million , respectively, for all legal matters, including $2.2 million and $2.8 million , respectively, 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 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 $48.0 million in 2017 , and is immaterial thereafter. The Company recognized expense relating to transportation capacity agreements of $1.6 million during the period January 1 through October 1, 2016 ; and $52.9 million and $36.5 million during the years ended December 31, 2015 and 2014 , respectively.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Segment Information	Segment Information The Company’s reportable business segments are based on two distinct lines of business, metallurgical and thermal, 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 EBITDAR, per-ton cash operating costs (defined as including all mining costs except depreciation, depletion, amortization, accretion on asset retirements obligations, and pass-through transportation expenses), and on other non-financial measures, such as safety and environmental performance. Adjusted EBITDAR is not a measure of financial performance in accordance with generally accepted accounting principles, and items excluded from Adjusted EBITDAR are significant in understanding and assessing our financial condition. Therefore, Adjusted EBITDAR 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 used Adjusted EBITDAR to measure the operating performance of its segments and allocate resources to the segments. Furthermore, analogous measures are used by industry analysts to evaluate the Company’s operating performance. Investors should be aware that the Company’s presentation of Adjusted EBITDAR may not be comparable to similarly titled measures used by other companies. Upon emergence from bankruptcy, the Company updated its reportable segments to reflect the manner in which its Chief Operating Decision Maker (CODM) views the reorganized Company’s business for purposes of reviewing performance and allocating resources. The Company now reports is 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, Kentucky, and Virginia, and the Other Thermal segment containing the Company’s supplementary thermal operations in Colorado, Illinois, and the Coal Mac thermal operation in West Virginia. Periods presented in this note have been recast for comparability. Operating segment results for the Successor period October 2 through December 31, 2016 and the Predecessor periods January 1 through October 1, 2016 and the years ended December 31, 2015 and 2014 are presented below. The Company measures its segments based on “adjusted earnings before interest, taxes, depreciation, depletion, amortization, accretion on asset retirements obligations, and reorganization items, net (Adjusted EBITDAR).” Adjusted EBITDAR does not reflect mine closure or impairment costs, since those are not reflected in the operating income reviewed by management. See Note 5 , “ Impairment Charges and Mine Closure Costs ” for discussion of these costs. 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. The asset amounts below represent an allocation of assets consistent with the basis used for the Company’s incentive compensation plans. The amounts in Corporate, Other and Eliminations represent primarily corporate assets (cash, receivables, investments, plant, property and equipment) as well as unassigned coal reserves, above-market sales contracts and other unassigned assets. (In thousands) PRB MET Other Thermal Corporate, Other and Eliminations Consolidated Successor Period October 2 through December 31, 2016 Revenues $ 275,703 $ 200,377 $ 97,382 $ 2,226 $575,688 Adjusted EBITDAR 55,765 30,819 31,159 (23,246 ) 94,497 Depreciation, depletion and amortization 9,949 18,287 3,911 457 32,604 Accretion on asset retirement obligation 5,049 528 540 1,517 7,634 Total assets 446,775 576,793 129,602 983,427 2,136,597 Capital expenditures 934 13,329 684 267 15,214 Predecessor Period January 1 through October 1, 2016 Revenues $ 726,747 $ 437,069 $ 213,052 $ 21,841 $1,398,709 Adjusted EBITDAR 113,185 11,851 31,448 (69,181 ) 87,303 Depreciation, depletion and amortization 100,151 55,311 32,310 3,809 191,581 Accretion on asset retirement obligation 16,940 1,765 1,988 3,628 24,321 Total assets 456,711 619,154 131,173 916,791 2,123,829 Capital expenditures 612 17,296 3,895 60,631 82,434 Predecessor Year Ended December 31, 2015 Revenues $ 1,448,440 $ 637,941 $ 428,809 $ 58,070 $ 2,573,260 Adjusted EBITDAR 281,039 70,450 42,734 (110,426 ) 283,797 Depreciation, depletion and amortization 176,257 133,463 47,786 21,839 379,345 Accretion on asset retirement obligation 22,156 2,267 2,658 6,599 33,680 Total assets 1,648,916 772,439 366,610 2,253,916 5,041,881 Capital expenditures 21,228 24,787 11,277 61,732 119,024 Predecessor Year Ended December 31, 2014 Revenues $ 1,490,377 $ 743,973 $ 535,783 $ 166,986 $ 2,937,119 Adjusted EBITDAR 218,731 112,719 78,238 (96,636 ) 313,052 Depreciation, depletion and amortization 168,522 163,644 52,991 33,591 418,748 Accretion on asset retirement obligation 20,748 2,089 2,412 7,660 32,909 Total assets 1,762,326 2,339,739 406,296 3,838,001 8,346,362 Capital expenditures 21,399 46,771 14,843 64,273 147,286 A reconciliation of segment Adjusted EBITDAR to consolidated income (loss) from continuing operations before income taxes follows: Successor Predecessor (In thousands) October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 Adjusted EBITDAR $ 94,497 $ 87,303 $ 283,797 $ 313,052 Depreciation, depletion and amortization (32,604 ) (191,581 ) (379,345 ) (418,748 ) Accretion on asset retirement obligations (7,634 ) (24,321 ) (33,680 ) (32,909 ) Amortization of sales contracts, net (796 ) 728 8,811 13,187 Asset impairment and mine closure costs — (129,267 ) (2,628,303 ) (24,113 ) Losses from disposed operations resulting from Patriot Coal bankruptcy — — (116,343 ) — Interest expense, net (10,754 ) (133,235 ) (393,549 ) (383,188 ) Net loss resulting from early retirement of debt and debt restructuring — (2,213 ) (27,910 ) — Reorganization items, net (759 ) 1,630,041 — — Fresh start coal inventory fair value adjustment (7,345 ) — — — Income (loss) before income taxes $ 34,605 $ 1,237,455 $ (3,286,522 ) $ (532,719 )

Quarterly Selected Financial Da

Quarterly Selected Financial Data (unaudited)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Quarterly Selected Financial Data (unaudited)	Quarterly Selected Financial Data (unaudited) Predecessor Successor Year Ended December 31, 2016 March 31 June 30 September 30 October 1 October 2 through December 31, 2016 (a) (b) (a) (b) (b) (b) (In thousands, except per share data) Revenues $ 428,106 $ 420,298 $ 550,305 — 575,688 Gross profit (loss) $ (53,325 ) $ (56,469 ) $ 31,042 — 64,458 Asset impairment and mine closure costs $ 85,520 $ 43,701 $ 46 — — Income (loss) from operations $ (158,412 ) $ (110,521 ) $ 11,795 $ — $ 46,118 Reorganization items, net $ (3,875 ) $ (21,271 ) $ (20,904 ) $ 1,676,091 $ (759 ) Net income (loss) $ (206,702 ) $ (175,887 ) $ (51,421 ) $ 1,676,091 $ 33,449 Diluted earnings (loss) per common share $ (9.71 ) $ (8.26 ) $ (2.41 ) $ 78.66 $ 1.31 Predecessor Year Ended December 31, 2015 March 31 June 30 September 30 December 31 (a) (a) (a) (In thousands, except per share data) Revenues $ 677,005 $ 644,462 $ 688,544 $ 563,249 Gross profit (loss) $ 14,256 $ (16,507 ) $ 47,275 $ (44,964 ) Asset impairment and mine closure costs $ — $ 19,146 $ 2,120,292 $ 488,865 Loss from operations $ (19,712 ) $ (69,546 ) $ (2,236,772 ) $ (539,033 ) Net loss $ (113,195 ) $ (168,103 ) $ (1,999,476 ) $ (632,368 ) Diluted loss per common share $ (5.32 ) $ (7.93 ) $ (93.91 ) $ (29.70 ) (a) Challenging coal markets resulted in impairment charges relating to mining and other operations, investments in equity method subsidiaries and prepaid mining royalties in 2016 and 2015. See further discussion in Note 5 , “ Impairment Charges and Mine Closure Costs “ and Note 9 , “ Equity Method Investments and Membership Interests in Joint Ventures .” (b) The Company filed for bankruptcy on January 11, 2016 and subsequently emerged on October 5, 2016. See further discussion in Note 3 , “ Emergence from Bankruptcy and Fresh Start Accounting .”

Valuation and Qualifying Accoun

Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2016
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) Successor October 2 through December 31, 2016 Reserves deducted from asset accounts: Accounts receivable and other receivables $ — $ — $ — $ — $ — Current assets — supplies and inventory — — — — — Deferred income taxes 1,033,982 (7,655 ) — — 1,026,327 Predecessor January 1 through October 1, 2016 Reserves deducted from asset accounts: Accounts receivable and other receivables $ 7,842 $ — $ — $ 7,842 $ — Current assets — supplies and inventory 5,991 844 (5,060 ) (c) 1,775 — Deferred income taxes 1,135,399 (101,417 ) — 1,033,982 Year ended December 31, 2015 Reserves deducted from asset accounts: Accounts receivable and other receivables $ 159 $ 7,683 $ — $ — $ 7,842 Current assets — supplies and inventory 6,625 431 — 1,065 5,991 Deferred income taxes 270,251 865,148 — — 1,135,399 Year ended December 31, 2014 Reserves deducted from asset accounts: Accounts receivable and other receivables $ 775 $ — $ — $ 616 $ 159 Current assets — supplies and inventory 8,446 580 (76 ) (b) 2,325 $ 6,625 Deferred income taxes 43,322 226,929 — — $ 270,251 (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, 2016
Accounting Policies [Abstract]
Consolidation Policy	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 refer to both the Predecessor and Successor Company. 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, Kentucky, Virginia, Illinois, Wyoming and Colorado. All subsidiaries are wholly-owned. Intercompany transactions and accounts have been eliminated in consolidation.
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 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.
Restricted cash	Restricted cash Restricted cash represents cash collateral supporting letters of credit issued under the Company’s accounts receivable securitization program.
Accounts Receivable	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	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 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 expense (income), net ” in the consolidated statements of operations. Information about investment activity is provided in Note 9 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. See Note 10 to the Consolidated Financial Statements, “ Sales Contracts ” for further information related to the Company’s sales contracts.
Exploration Costs	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	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	Property, Plant and Equipment Plant and Equipment Plant and equipment were fair valued 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 did not capitalize any interest costs during the periods October 2 through December 31, 2016 , January 1 through October 1, 2016 or for the year ended December 31, 2015 , 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 7 to 18 years. The useful lives of buildings and leasehold improvements generally range from 1 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 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. The net book value of the Company’s coal interests was $0.4 billion and $2.4 billion at December 31, 2016 and 2015 , 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 statement of operations 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. See additional discussion in Note 5 to the Consolidated Financial Statements, “ Impairment Charges and Mine Closure Costs .”
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.
Revenue Recognition	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 Expense (Income), net	Other Operating Expense (Income), net Other operating expense (income), net in the accompanying consolidated statements of operations 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; liquidated damage charges related to unused terminal and port capacity; royalties earned from properties leased to third parties; income from equity investments (Note 9 ); 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 ).
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. 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.
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. Additionally, the Company may hold certain coal derivative instruments for trading purposes. Derivative financial instruments are recognized in 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 a forecasted purchase or sale. 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.
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. 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.
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 employee. The Company also currently provides certain postretirement medical and life insurance coverage for eligible employees. The cost of providing these benefits are determined on an actuarial basis and accrued over the employee’s 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.
Stock-Based Compensation	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.
Recently Adopted Accounting Guidance and Recent Accounting Guidance Issued Not Yet Effective	Recently Adopted Accounting Guidance In April 2015, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2015-03 (“ASU 2015-03”), Simplifying the Presentation of Debt Issuance Costs. ASU 2015-03 required debt issuance costs related to a recognized liability to be presented in the balance sheet as a direct reduction from the carrying amount of that liability, consistent with debt discounts. The Company adopted ASU 2015-03 in the first quarter of 2016 as mandated by the standard. The following reflects the retrospective application: December 31, 2015 (in thousands) Other current assets, prior to revision $ 104,723 Revision of debt issuance costs (64,857 ) Other current assets, as revised $ 39,866 Current maturities of debt, prior to revision $ 5,107,210 Revision of debt issuance costs (64,857 ) Current maturities of debt, as revised $ 5,042,353 Effective December 31, 2016, the Company adopted ASU No. 2014-15 (“ASU 2014-15”), Disclosures of Uncertainties about an Entity’s Ability to Continue as a Going Concern. ASU 2014-15 requires management to evaluate for each annual and interim reporting period whether conditions or events give rise to substantial doubt that an entity has the ability to continue as a going concern within one year following issuance of the financial statements and requires specific disclosures regarding the conditions or events leading to substantial doubt. The adoption of ASU 2014-15 did not have any impact on the Company’s financial position or results of operations. Effective December 31, 2016, the Company adopted the Accounting Standards Update No. 2015-17 (“ASU 2015-17”), Balance Sheet Classification of Deferred Taxes which requires that all deferred tax assets and liabilities, along with any related valuation allowance be classified as noncurrent on the balance sheet. The standard has been applied on a retrospective basis. The adoption of ASU 2015-17 did not have any impact on the Company’s financial position or results of operations. Investments at fair value include investments in funds, including certain money market funds, that are measured at net asset value (“NAV”). The Company uses NAV to measure the fair value of its fund investments when (i) the fund investment does not have a readily determinable fair value and (ii) the NAV of the investment fund is calculated in a manner consistent with the measurement principles of investment company accounting, including measurement of the underlying investments at fair value. The Company adopted ASU No. 2015-07 in January 2016, and, as required, disclosures in the paragraphs and tables below are limited to only those investments in funds that are measured at NAV. In accordance with ASU No. 2015-07, previously reported amounts have been conformed to the current presentation. Recent Accounting Guidance Issued Not Yet Effective In May 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers.” ASU 2014-09 is a comprehensive revenue recognition standard that will supersede nearly all existing revenue recognition guidance under current U.S. GAAP and replace it with a principle based approach for determining revenue recognition. ASU 2014-09 will require that companies recognize revenue based on the value of transferred goods or services as they occur in the contract. The ASU also will require additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. ASU 2014-09 is effective for interim and annual periods beginning after December 15, 2017. Early adoption is permitted only in annual reporting periods beginning after December 15, 2016, including interim periods therein. Entities will be able to transition to the standard either retrospectively or as a cumulative-effect adjustment as of the date of adoption. The Company’s primary source of revenue is from the sale of coal through both short-term and long-term contracts with utilities, industrial customers and steel producers whereby revenue is currently recognized when risk of loss has passed to the customer. Upon adoption of this new standard, the Company believes that the timing of revenue recognition related to our coal sales will remain consistent with our current practice. The Company is currently evaluating other revenue streams to determine the potential impact related to the adoption of the standard, as well as potential disclosures required by the standard. The Company will be adopting the standard under the modified retrospective approach. In February 2016, the FASB issued ASU No. 2016-02, “Leases” which, for operating leases, requires a lessee to recognize a right-of-use asset and a lease liability, initially measured at the present value of the lease payments, in its balance sheet. 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. The ASU is effective for public companies for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years; early adoption is permitted. The Company has both operating and capital leases. We expect the adoption of this standard to result in the recognition of right-of-use assets and lease liabilities not currently recorded on the Company’s financial statements. The Company is currently in the process of accumulating all contractual lease arrangements in order to determine the impact on its financial statements. In October 2016, the FASB issued ASU No. 2016-18, “Statement of Cash Flows-Restricted Cash.” The amendment requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. Therefore, amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning period and end of period total amounts shown on the statement of cash flows. ASU 2016-18 is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years; early adoption is permitted.

Accounting Policies (Tables)

Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Schedule of Changes in Accounting Principles	The Company adopted ASU 2015-03 in the first quarter of 2016 as mandated by the standard. The following reflects the retrospective application: December 31, 2015 (in thousands) Other current assets, prior to revision $ 104,723 Revision of debt issuance costs (64,857 ) Other current assets, as revised $ 39,866 Current maturities of debt, prior to revision $ 5,107,210 Revision of debt issuance costs (64,857 ) Current maturities of debt, as revised $ 5,042,353

Emergence from Bankruptcy and38

Emergence from Bankruptcy and Fresh Start Accounting (Tables)	12 Months Ended
	Dec. 31, 2016
Fresh-Start Adjustment [Line Items]
Schedule of Reorganization Items, Net	The Company’s reorganization items, net for the respective periods are as follows: Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 (In thousands) Gain on settlement of claims (per above) $ — $ 4,142,104 $ — $ — Fresh start adjustments, net (per above) — (2,466,010 ) — — Professional fees (759 ) (46,053 ) — — $ (759 ) $ 1,630,041 $ — $ —
Reorganization and Fresh Start Adjustments [Member]
Fresh-Start Adjustment [Line Items]
Fresh-Start Condensed Balance Sheet	The following balance sheet illustrates the impacts of the implementation of the Plan and the application of fresh start accounting, which results in the opening balance sheet of the Successor company. As of October 1, 2016 (In thousands) Predecessor (a) Effect of Plan (b) Fresh Start Adjustments (c) Successor Assets Current assets Cash and cash equivalents $ 400,205 $ (199,718 ) (d) $ — $ 200,487 Short term investments 111,451 — — 111,451 Restricted cash 81,563 — — 81,563 Trade accounts receivable 165,522 — — 165,522 Other receivables 17,227 — 779 (j) 18,006 Inventories 159,410 — (21,078 ) (k) 138,332 Prepaid royalties 4,805 — — 4,805 Deferred income taxes — — — — Coal derivative assets 2,180 — — 2,180 Other current assets 36,960 6,367 53,851 (l) 97,178 Total current assets 979,323 (193,351 ) 33,552 819,524 Property, plant and equipment, net 3,434,941 — (2,363,829 ) (m) 1,071,112 Other assets Prepaid royalties 20,997 — (20,997 ) (n) — Equity investments 164,232 — (61,606 ) (o) 102,626 Other noncurrent assets 58,569 34,495 (e) 37,503 (p) 130,567 Total other assets 243,798 34,495 (45,100 ) 233,193 Total assets $ 4,658,062 $ (158,856 ) $ (2,375,377 ) $ 2,123,829 Liabilities and Stockholders’ Equity (Deficit) Liabilities not subject to compromise Accounts payable $ 74,595 $ — $ (250 ) (q) $ 74,345 Accrued expenses and other current liabilities 225,739 (36,331 ) (f) 26,644 (r) 216,052 Current maturities of debt 3,397 3,265 (g) — 6,662 Total current liabilities 303,731 (33,066 ) 26,394 297,059 Long-term debt 30,037 323,235 (g) — 353,272 Asset retirement obligations 394,699 — (60,570 ) (s) 334,129 Accrued pension benefits 23,716 — 24,565 (t) 48,281 Accrued other postretirement benefits 87,123 — 24,836 (t) 111,959 Accrued workers’ compensation 119,828 — 74,520 (u) 194,348 Deferred income taxes — — — — Other noncurrent liabilities 96,410 — 888 (v) 97,298 Total liabilities not subject to compromise 1,055,544 290,169 90,633 1,436,346 Liabilities subject to compromise 5,278,612 (5,278,612 ) (h) — — Total liabilities 6,334,156 (4,988,443 ) 90,633 1,436,346 Stockholders’ equity (deficit) Common stock, predecessor 2,145 (2,145 ) (i) — — Common stock, successor — 250 (b) — 250 Paid-in capital, predecessor 3,056,307 (3,056,307 ) (i) — — Paid-in capital, successor — 687,233 (b) — 687,233 Treasury stock, at cost (53,863 ) 53,863 (i) — — Accumulated earnings (deficit) (4,678,977 ) 7,146,693 (i) (2,467,716 ) — Accumulated other comprehensive income (loss) (1,706 ) — 1,706 — Total stockholders’ equity (deficit) (1,676,094 ) 4,829,587 (2,466,010 ) 687,483 Total liabilities and stockholders’ equity (deficit) $ 4,658,062 $ (158,856 ) $ (2,375,377 ) $ 2,123,829 (a) Represents the Predecessor consolidated balance sheet as of October 1, 2016. (b) Represents amounts recorded for the implementation of the Plan on the Effective Date. This includes the settlement of liabilities subject to compromise through a combination of cash payments, the issuance of new common stock and warrants and the issuance of new debt. The following is the calculation of the total pre-tax gain on the settlement of the liabilities subject to compromise: In thousands Liabilities subject to compromise $ 5,278,612 Less amounts issued to settle claims: Common stock (at par) Successor (250 ) Warrants Successor (14,822 ) Paid-in capital Successor (672,411 ) Issuance of Term Loan Successor (326,500 ) Cash payment to settle claims and professional fees (122,525 ) Total pre-tax gain on plan effects $ 4,142,104 (c) Represents the fresh start accounting adjustments required to record the assets and liabilities of the Company at fair value. (d) The following table reflects the use of cash at emergence: In thousands Payment to secured lenders $ 43,496 Payments to unsecured creditors 42,399 Final adequate protection payment 36,331 Collateral requirements 31,665 Professional fees 31,630 Other 14,197 Total cash outflow at emergence $ 199,718 (e) Represents amounts paid for required collateral deposits. (f) Represents the final adequate protection payments made to the secured lenders. (g) Represents the fair value of the $326.5 million new term loan of which $3.3 million is shown within current maturities of debt. (h) Liabilities subject to compromise include unsecured or under-secured liabilities incurred prior to the Chapter 11 filing; and consists of the following: Previously Reported Balance Sheet Line In thousands Debt $ 5,026,806 Accrued expenses and other current liabilities 136,295 Accounts payable 106,297 Other noncurrent liabilities 9,214 Total liabilities subject to compromise $ 5,278,612 (i) Reflects the impacts of the reorganization adjustments: In thousands Total pre-tax gain on settlement of claims $ 4,142,104 Cancellation of predecessor common stock 2,145 Cancellation of predecessor paid-in capital 3,056,307 Cancellation of predecessor treasury stock (53,863 ) Net impact on accumulated earnings (deficit) $ 7,146,693 (j) Represents adjustments to record other receivables at fair value which includes an $0.8 million short-term receivable related to insurance coverage for self-insured workers’ compensation obligations. (k) Represents the following fair value adjustments: a $7.3 million increase related to coal inventory which was fair valued at estimated selling prices less the sum of selling costs, shipping costs and a reasonable profit allowance for the selling effort offset by a $28.4 million reduction in critical spare parts inventory. During fresh start accounting, the Company changed its accounting policy with respect to critical spare parts with long lead times; previously these items were valued within inventory, but prospectively, these items will be capitalized within property, plant and equipment when purchased and depreciated over the life of the related equipment. (l) Represents the short-term portion of above market coal sales contracts of $71.1 million offset by $11.3 million in reductions related to prepaid balances. The fair value of sales contracts was estimated using a discounted cash flow model and will be amortized into earnings as the coal is shipped throughout the term of the associated contracts. (m) Represents a $2.4 billion reduction in property, plant and equipment to estimated fair value as discussed below: Predecessor Fresh Start Adjustments Successor (in thousands) Net Coal Properties $ 2,358,779 $ (1,971,314 ) $ 387,465 Net Plant & Equipment 812,888 (405,259 ) 407,629 Net Deferred Charges 263,274 12,744 276,018 $ 3,434,941 $ (2,363,829 ) $ 1,071,112 The fair value of coal properties was established at $387.5 million utilizing a discounted cash flow model and the market approach. The market approach was used to provide a starting value of the coal mineral reserves without consideration for economic obsolescence. The DCF model was based on assumptions market participants would use in the pricing of these assets as well as projections of revenues and expenditures that would be incurred to mine or maintain these coal reserves through the life of mine. The basis of the DCF analysis was the Company’s prepared projections which included a variety of estimates and assumptions, such as pricing and demand for coal. The Company’s pricing was based on its view of the market taking into account third party forward pricing curves adjusted for the quality of products sold by the Company. The fair value of plant and equipment was set at $407.6 million utilizing both market and cost approaches. The market approach was used to estimate the value of assets where detailed information for the asset was available and an active market was identified with a sufficient number of sales of comparable property that could be independently verified through reliable sources. The cost approach was utilized where there were limitations in the secondary equipment market to derive values from. The first step in the cost approach is the estimation of the cost required to replace the asset via construction or purchasing a new asset with similar utility adjusting for depreciation due to physical deterioration, functional obsolescence due to technology changes and economic obsolescence due to external factors such as regulatory changes. Useful lives were assigned to all assets based on remaining future economic benefit of each asset. The fair value of deferred charges represents the corresponding asset related to the asset retirement obligation discussed in item (q) below. (n) Represents a fair value adjustment to a long-term prepaid royalty balance that the Company has concluded should not be assigned value based on market conditions and after considering economic obsolescence. (o) Represents a fair value adjustment to the Company’s equity investments in Knight Hawk Holdings, LLC, a coal producer in the Illinois Basin; and Dominion Terminal Associates which operates a ground storage-to-vessel coal trans-loading facility in Newport News, Virginia. Equity investments were fair valued in a manner similar to the Company’s wholly-owned subsidiaries using a discounted cash flow model and comparable company approach. The discount rate selected was 14% and due to the unobservable nature of the inputs, the fair values are considered Level 3 in the fair value hierarchy. (p) Represents the long-term portion of above market coal sales contracts of $26.0 million and $18.6 million related to a long-term insurance receivable related to insurance coverage for self-insured workers’ compensation obligations partially offset by $13.2 million in reductions related to prepaid balances. The fair value of sales contracts was estimated using a discounted cash flow model and will be amortized into earnings as the coal is shipped throughout the term of the associated contracts. (q) Represents a fair value adjustment to miscellaneous accounts payable. (r) Represents fair value adjustments for the following: a $27.8 million increase related to the short-term portion of below market sales contracts offset by fair value adjustments to establish the current portion of pension, postretirement and workers’ compensation liabilities. The fair value of sales contracts was estimated using a discounted cash flow model and will be amortized into earnings as the coal is shipped throughout the term of the associated contracts. (s) Represents the fair value adjustment related to the Company’s asset retirement obligations which was calculated using discounted cash flow models based on current mine plans using the guidance provided within Accounting Standard Codification 410-20, “Asset Retirement Obligations.” The discount rates ranged from 7.06% to 9.08% . (t) Pension and postretirement benefits were fair valued based on plan assets and employee benefit obligations at October 1, 2016. The benefit obligations were computed using the applicable October 1, 2016 discount rates. In conjunction with fresh start accounting, the Company updated its mortality rate table assumptions and corridor assumption. (u) Represents fair value adjustments for workers’ compensation benefits, including occupational disease benefits, that were actuarially determined using the guidance provided within Accounting Standard Codification 712, “Non-retirement Post-employment Benefits.” Upon emergence, the Company’s accounting policy is to actuarially calculate this liability. Prior to emergence, the Company had accounted for its liability based on outstanding reserves calculated per third party administrators. (v) Represents the following fair value adjustments: $3.9 million increase related to the long-term portion of below market sales contracts partially offset by $3.1 million reduction in miscellaneous noncurrent liabilities. The fair value of sales contracts was estimated using a discounted cash flow model and will be amortized into earnings as the coal is shipped throughout the term of the associated contracts.

Accumulated Other Comprehensi39

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following items are included in accumulated other comprehensive income (loss): Pension, Postretirement Accumulated and Other Post- Other Derivative Employment Available-for- Comprehensive Instruments Benefits Sale Securities Income (Loss) (In thousands) Predecessor Company January 1, 2015 $ 2,550 $ 2,860 $ (2,169 ) $ 3,241 Unrealized gains (losses) 3,903 (8,723 ) (3,333 ) (8,153 ) Amounts reclassified from accumulated other comprehensive income (loss) (6,128 ) 5,142 4,083 3,097 December 31, 2015 325 (721 ) (1,419 ) (1,815 ) Unrealized gains (losses) (138 ) — 701 563 Amounts reclassified from accumulated other comprehensive income (loss) (316 ) (1,363 ) 1,225 (454 ) Fresh start accounting adjustment 129 2,084 (507 ) 1,706 October 1, 2016 $ — $ — $ — $ — Successor Company Unrealized gains — 24,067 387 24,454 Amounts reclassified from accumulated other comprehensive income (loss) — — — — December 31, 2016 $ — $ 24,067 $ 387 $ 24,454
Schedule of comprehensive income reclassifications	The following amounts were reclassified out of accumulated other comprehensive income (loss) during the respective periods: Details about accumulated other comprehensive income components Successor Predecessor Line Item in the Consolidated Statement of Operations October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 (in thousands) (in thousands) Derivative instruments $ — $ 397 $ 9,575 Revenues — (81 ) (3,447 ) Provision for (benefit from) income taxes $ — $ 316 $ 6,128 Net of tax Pension, postretirement and other post-employment benefits Amortization of prior service credits 1 $ — $ 7,854 $ 8,335 Amortization of net actuarial gains (losses) 1 — (6,010 ) (16,369 ) — 1,844 (8,034 ) Total before tax — (481 ) 2,892 Provision for (benefit from) income taxes $ — $ 1,363 $ (5,142 ) Net of tax Available-for-sale securities 2 $ — $ (2,263 ) $ (6,391 ) Interest and investment income — 1,038 2,308 Provision for (benefit from) income taxes $ — $ (1,225 ) $ (4,083 ) 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.

Impairment Charges and Mine C40

Impairment Charges and Mine Closure Costs (Tables)	12 Months Ended
	Dec. 31, 2016
Impairment Charges and Mine Closure Costs [Abstract]
Restructuring and Related Costs	The following table summarizes the amounts reflected on the line “ Asset impairment and mine closure costs ” in the consolidated statements of operations: Successor Predecessor Description October 2 Through December 31, 2016 January 1 Through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 (In thousands) Coal lands and mineral rights $ — $ 74,144 $ 2,210,488 $ — Plant and equipment — — 199,107 1,512 Deferred development — — 159,474 — Prepaid royalties — 3,406 41,990 15,356 Equity investments — 40,920 21,325 — Inventories — — 66 — Other — 10,797 (4,147 ) 7,245 Total $ — $ 129,267 $ 2,628,303 $ 24,113

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2016
Inventory Disclosure [Abstract]
Inventories	Inventories consist of the following: Successor Predecessor December 31, 2016 December 31, 2015 (In thousands) Coal $ 37,268 $ 85,043 Repair parts and supplies 76,194 111,677 $ 113,462 $ 196,720

Investments in Available-for-42

Investments in Available-for-Sale Securities (Tables)	12 Months Ended
	Dec. 31, 2016
Available-for-sale Securities [Abstract]
Available-for-sale Securities	The Company’s investments in available-for-sale marketable securities are as follows: Successor December 31, 2016 Balance Sheet Gross Gross Classification Unrealized Unrealized Fair Short-Term Other Cost Basis Gains Losses Value Investments Assets (In thousands) Available-for-sale: Corporate notes and bonds $ 88,161 $ — $ (89 ) $ 88,072 $ 88,072 $ — Equity securities 1,749 388 — 2,137 — 2,137 Total Investments $ 89,910 $ 388 $ (89 ) $ 90,209 $ 88,072 $ 2,137 Predecessor December 31, 2015 Balance Sheet Gross Gross Classification Unrealized Unrealized Fair Short-Term Other Cost Basis Gains Losses Value Investments Assets (In thousands) Available-for-sale: U.S. government and agency securities $ 10,007 $ — $ (12 ) $ 9,995 $ 9,995 $ — Corporate notes and bonds 190,496 — (299 ) 190,197 190,197 — Equity securities 3,938 668 (2,888 ) 1,718 — 1,718 Total Investments $ 204,441 $ 668 $ (3,199 ) $ 201,910 $ 200,192 $ 1,718

Equity Method Investments and43

Equity Method Investments and Membership Interests in Joint Ventures (Tables)	12 Months Ended
	Dec. 31, 2016
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 Millennium Tongue River Other Total Predecessor Company January 1, 2014 $ 152,806 $ 14,137 $ 35,894 $ 18,419 $ 200 $ 221,456 Advances to (distributions from) affiliates, net (12,603 ) 3,774 6,742 2,541 3,600 4,054 Equity in comprehensive income (loss) 18,274 (4,173 ) (2,413 ) (220 ) (1,136 ) 10,332 December 31, 2014 158,477 13,738 40,223 20,740 2,664 235,842 Advances to (distributions from) affiliates, net (29,862 ) 3,207 7,052 913 330 (18,360 ) Equity in comprehensive income (loss) 22,977 (3,706 ) (9,686 ) (328 ) (1,278 ) 7,979 Impairment of equity investment — — — (21,325 ) (21,325 ) Sale of equity investment — — — — (2,259 ) (2,259 ) December 31, 2015 151,592 13,239 37,589 — (543 ) 201,877 Advances to (distributions from) affiliates, net (8,374 ) 1,474 1,966 — — (4,934 ) Equity in comprehensive income (loss) 9,033 (2,095 ) (1,530 ) — (94 ) 5,314 Impairment of equity investment — — (38,025 ) — — (38,025 ) Fresh start accounting adjustment (58,251 ) (4,018 ) — — 662 (61,607 ) October 1, 2016 $ 94,000 $ 8,600 $ — $ — $ 25 $ 102,625 Successor Company Advances to (distributions from) affiliates, net (9,076 ) 822 — — — (8,254 ) Equity in comprehensive income (loss) 2,569 (841 ) — — (25 ) 1,703 December 31, 2016 $ 87,493 $ 8,581 $ — $ — $ — $ 96,074

Sales Contracts (Tables)

Sales Contracts (Tables)	12 Months Ended
	Dec. 31, 2016
Acquired Sales Contracts [Abstract]
Schedule of Sales Contracts	The sales contracts reflected in the consolidated balance sheets are as follows: Successor Predecessor December 31, 2016 December 31, 2015 Assets Liabilities Net Total Assets Liabilities Net Total (In thousands) (In thousands) Original fair value $ 97,196 $ 31,742 $ 131,299 $ 166,697 Accumulated amortization (25,625 ) (24,829 ) (130,839 ) (151,354 ) Total $ 71,571 $ 6,913 $ 64,658 $ 460 $ 15,343 $ (14,883 ) Balance Sheet classification: Other current $ 59,702 $ 5,114 $ 460 $ 3,852 Other noncurrent $ 11,869 $ 1,799 $ — $ 11,491

Derivatives (Tables)

Derivatives (Tables)	12 Months Ended
	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Price Risk Derivatives	At December 31, 2016 , the Company held derivatives for risk management purposes that are expected to settle in the following years: (Tons in thousands) 2017 2018 Total Coal sales 540 — 540 Coal purchases 480 — 480
Disclosure Of Fair Value Of Derivatives	The fair value and location of derivatives reflected in the accompanying consolidated balance sheets are as follows: Successor Predecessor December 31, 2016 December 31, 2015 Fair Value of Derivatives Asset Liability Asset Liability (In thousands) Derivative Derivative Derivative Derivative Derivatives Designated as Hedging Instruments Coal $ — $ (15 ) $ 4 $ (20 ) Derivatives Not Designated as Hedging Instruments Heating oil -- diesel purchases 4,646 — 1,017 — Coal held for trading purposes, exchange traded swaps and futures 68,948 (68,740 ) 110,653 (104,814 ) Coal -- risk management 475 (580 ) 3,912 (1,947 ) Natural gas 86 (13 ) 494 (247 ) Total 74,155 (69,333 ) 116,076 (107,008 ) Total derivatives 74,155 (69,348 ) 116,080 (107,028 ) Effect of counterparty netting (69,247 ) 69,247 (107,028 ) 107,028 Net derivatives as classified in the balance sheets $ 4,908 $ (101 ) $ 4,807 $ 9,052 $ — $ 9,052 Successor Predecessor December 31, 2016 December 31, 2015 Net derivatives as reflected on the balance sheets Heating oil Other current assets $ 4,646 $ 1,017 Coal Coal derivative assets 262 8,035 Accrued expenses and other current liabilities (101 ) — $ 4,807 $ 9,052
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) Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 Coal sales (1) $ — $ (672 ) $ 12,816 10,842 Coal purchases (2) — 536 (6,718 ) (5,097 ) $ — $ (136 ) $ 6,098 $ 5,745 Gains (Losses) Reclassified from Other Comprehensive Income into Income Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 Coal sales $ — $ 1,634 $ 18,635 $ 5,336 Coal purchases — (1,237 ) (9,060 ) (2,693 ) $ — $ 397 $ 9,575 $ 2,643 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 Successor period from October 2 through December 31, 2016 , the Predecessor period from January 1 through October 1, 2016 , and for the Predecessor years ended December 31, 2015 , and 2014 . Derivatives Not Designated as Hedging Instruments (in thousands) For the noted periods, Gain (Loss) Recognized Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 Coal — unrealized (3) $ (408 ) $ (1,662 ) $ (3,883 ) $ 430 Coal — realized (4) $ 116 $ (476 ) $ 3,236 $ 5,956 Heating oil — diesel purchases (4) $ 827 $ 826 $ (8,294 ) $ (7,848 ) Heating oil — fuel surcharges (4) $ — $ — $ — $ (405 ) Natural gas $ (91 ) $ (463 ) $ 878 $ — Foreign currency $ (9 ) $ (451 ) $ (887 ) $ — Location in statement of operations: (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 Cu46

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2016
Accrued Expenses and Other Current Liabilities [Abstract]
Schedule of Accrued Liabilities	Accrued expenses and other current liabilities consist of the following: Successor Predecessor December 31, 2016 December 31, 2015 (In thousands) Payroll and employee benefits $ 58,468 $ 58,423 Taxes other than income taxes 92,733 104,755 Interest 8,032 119,785 Sales contracts 5,114 3,852 Workers’ compensation 15,184 16,875 Asset retirement obligations 19,515 13,795 Other 6,194 11,965 $ 205,240 $ 329,450

Debt and Financing Arrangemen47

Debt and Financing Arrangements (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Debt	Successor Predecessor December 31, 2016 December 31, 2015 (In thousands) Term loan due 2021 ($325.7 million face value) $ 325,684 $ — Term loan due 2018 ($1.9 billion and $1.93 billion face value, respectively) — 1,875,429 7.00% senior notes due 2019 at par — 1,000,000 8.00% senior secured notes due 2019 at par — 350,000 9.875% senior notes ($375.0 million face value) due 2019 — 365,600 7.25% senior notes due 2020 at par — 500,000 7.25% senior notes due 2021 at par — 1,000,000 Other 37,195 47,134 Debt issuance costs — (64,857 ) 362,879 5,073,306 Less current maturities of debt 11,038 5,042,353 Long-term debt $ 351,841 $ 30,953
Schedule of Maturities of Long-term Debt	Year (In thousands) 2017 $ 11,038 2018 10,324 2019 11,479 2020 11,761 2021 317,987 Thereafter 290 $ 362,879

Taxes (Tables)

Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
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: Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 (In thousands) Current: Federal $ — $ — $ — $ — State (252 ) 7 3 25 Total current (252 ) 7 3 25 Deferred: Federal 1,352 (4,720 ) (329,393 ) 18,535 State 56 87 (43,990 ) 7,074 Total deferred 1,408 (4,633 ) (373,383 ) 25,609 $ 1,156 $ (4,626 ) $ (373,380 ) $ 25,634
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: Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 (In thousands) Income tax provision (benefit) at statutory rate $ 12,112 $ 433,109 $ (1,150,283 ) $ (186,452 ) Percentage depletion allowance (4,292 ) (3,681 ) (19,035 ) (12,692 ) State taxes, net of effect of federal taxes 633 (46,122 ) (76,445 ) (3,903 ) Reversal of cancellation of indebtedness income — (1,493,162 ) — — Worthless stock deduction — (80,077 ) — — Change in valuation allowance (7,655 ) 1,185,326 865,146 226,929 Other, net 358 (19 ) 7,237 1,752 $ 1,156 $ (4,626 ) $ (373,380 ) $ 25,634
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: Successor Predecessor December 31, 2016 December 31, 2015 (In thousands) Deferred tax assets: Net operating loss carryforwards $ 376,293 $ 1,086,332 Alternative minimum tax credit carryforwards 22,798 120,994 Investment in tax partnerships & corporations 604,914 — Reclamation and mine closure — 121,276 Goodwill 5,135 38,671 Workers’ compensation — 42,835 Share based compensation — 22,612 Sales contracts — 17,466 Retiree benefit plans 4,013 16,996 Advance royalties — 18,751 Losses from disposed operations resulting from Patriot Coal bankruptcy — 39,287 Other, primarily accrued liabilities 30,103 45,303 Gross deferred tax assets 1,043,256 1,570,523 Valuation allowance (1,021,553 ) (1,135,399 ) Total deferred tax assets 21,703 435,124 Deferred tax liabilities: Plant and equipment 7,332 389,169 Deferred development — 41,047 Sales contracts 12,658 — Other 1,600 4,706 Total deferred tax liabilities 21,590 434,922 Net deferred (asset) liability (113 ) (202 )
Summary of Income Tax Contingencies	A reconciliation of the beginning and ending amounts of gross unrecognized tax benefits follows: (In thousands) Balance at January 1, 2014 $ 31,789 Additions based on tax positions related to the current year 2,920 Balance at December 31, 2014 34,709 Additions based on tax positions related to the current year 4,168 Balance at December 31, 2015 38,877 Additions for tax positions of prior years 2,979 Additions for tax positions related to the current year 2,709 Reductions as a result of bankruptcy (37,110 ) Balance at December 31, 2016 $ 7,455

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2016
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: Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 (In thousands) Balance at beginning of period (including current portion) $ 354,326 $ 410,454 $ 418,118 Accretion expense 7,634 24,321 33,680 Obligations of divested operations — (14,702 ) (334 ) Adjustments to the liability from changes in estimates — 3,003 (28,570 ) Liabilities settled (5,218 ) (11,087 ) (12,440 ) Fresh start accounting adjustment — (57,663 ) — Balance at period end $ 356,742 $ 354,326 $ 410,454 Current portion included in accrued expenses (19,515 ) (17,290 ) (13,795 ) Noncurrent liability $ 337,227 $ 337,036 $ 396,659

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2016
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: Successor Fair Value at December 31, 2016 Total Level 1 Level 2 Level 3 (In thousands) Assets: Investments in marketable securities $ 90,209 $ 2,137 $ 88,072 $ — Derivatives 4,908 262 — 4,646 Total assets $ 95,117 $ 2,399 $ 88,072 $ 4,646 Liabilities: Derivatives $ 101 $ (8 ) $ — $ 109 Predecessor Fair Value at December 31, 2015 Total Level 1 Level 2 Level 3 (In thousands) Assets: Investments in marketable securities $ 201,910 $ 11,713 $ 190,197 $ — Derivatives 9,052 5,597 1,023 2,432 Total assets $ 210,962 $ 17,310 $ 191,220 $ 2,432 Liabilities: Derivatives $ — $ — $ — $ —
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. Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 (In thousands) (In thousands) Balance, beginning of period $ 3,842 $ 2,432 $ 3,040 Realized and unrealized losses recognized in earnings, net 926 (1,686 ) (8,602 ) Included in other comprehensive income — — (1,341 ) Purchases 1,225 5,021 13,541 Issuances (34 ) (488 ) (4,046 ) Settlements (1,422 ) (1,437 ) (160 ) Ending balance $ 4,537 $ 3,842 $ 2,432

Stock-Based Compensation and 51

Stock-Based Compensation and Other Incentive Plans (Tables)	12 Months Ended
	Dec. 31, 2016
Share-based Compensation [Abstract]
Schedule of Restricted Stock Units Activity	Information regarding the restricted stock units activity and weighted average grant-date fair value follows: Common Shares Weighted Average Grant-Date Fair Value (Shares in thousands) Outstanding at October 2, 2016 — — Granted 384 $ 72.00 Forfeited — — Canceled — — Unvested outstanding at December 31, 2016 384 $ 72.00

Workers' Compensation Expense (

Workers' Compensation Expense (Tables)	12 Months Ended
	Dec. 31, 2016
Compensation Related Costs [Abstract]
Workers' compensation expense	Workers’ compensation expense consists of the following components: Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 (In thousands) Self-insured occupational disease benefits: Service cost $ 1,583 $ 3,465 $ 4,282 $ 1,734 Interest cost 1,126 3,184 3,944 2,914 Net amortization — 4,325 6,973 (216 ) Total occupational disease $ 2,709 $ 10,974 $ 15,199 $ 4,432 Traumatic injury claims and assessments 3,162 6,628 16,781 19,924 Total workers’ compensation expense $ 5,871 $ 17,602 $ 31,980 $ 24,356
Schedule of Changes in Occupational Disease Obligations	The table below reconciles changes in the occupational disease liability for the respective period. Successor Predecessor (In thousands) October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Beginning of period $ 119,710 $ 90,836 $ 72,749 Service cost 1,583 3,465 4,282 Interest cost 1,126 3,184 3,944 Curtailments — 4,156 Actuarial (gain) loss (9,675 ) — 14,284 Benefit and administrative payments (1,585 ) (3,728 ) (4,423 ) Fresh start accounting adjustment — 21,797 — $ 111,159 $ 119,710 $ 90,836
Schedule of Occupational Disease Obligation Assumptions Used	The following table provides the assumptions used to determine the projected occupational disease obligation: Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 (Percentages) Occupational Disease Benefit Discount rate 4.31 3.80 4.76 Cost escalation rate N/A N/A N/A
Workers' compensation liabilities	Summarized below is information about the amounts recognized in the accompanying consolidated balance sheets for workers’ compensation benefits: Successor Predecessor Year Ended December 31, 2016 Year Ended December 31, 2015 (In thousands) Occupational disease costs $ 111,159 $ 90,836 Traumatic and other workers’ compensation claims 88,593 38,309 Total obligations 199,752 129,145 Less amount included in accrued expenses 15,184 16,875 Noncurrent obligations $ 184,568 $ 112,270

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2016
Pension and Other Postretirement Benefit Expense [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 Successor Predecessor Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 (In thousands) CHANGE IN BENEFIT OBLIGATIONS Benefit obligations at beginning of period $ 341,427 $ 301,292 $ 353,736 $ 120,311 $ 103,460 $ 36,098 Service cost — — 9 180 393 866 Interest cost 2,768 9,338 14,604 978 3,223 1,904 Re-entry of former Magnum employees — — — — — 85,843 Settlements (135 ) — — — — — Curtailments — 454 — — 714 — Benefits paid (11,009 ) (8,699 ) (61,955 ) (1,962 ) (8,273 ) (3,646 ) Other-primarily actuarial gain (19,422 ) — (5,102 ) (7,640 ) — (17,605 ) Fresh start accounting adjustments — 39,042 — — 20,794 Benefit obligations at end of period $ 313,629 $ 341,427 $ 301,292 $ 111,867 $ 120,311 $ 103,460 CHANGE IN PLAN ASSETS Value of plan assets at beginning of period $ 292,726 $ 273,499 $ 336,709 $ — $ — $ — Actual return on plan assets (7,899 ) 27,811 (1,679 ) — — Employer contributions 407 115 424 1,962 8,273 3,646 Benefits paid (11,009 ) (8,699 ) (61,955 ) (1,962 ) (8,273 ) (3,646 ) Value of plan assets at end of period $ 274,225 $ 292,726 $ 273,499 $ — $ — $ — Accrued benefit cost $ (39,404 ) $ (48,701 ) $ (27,793 ) $ (111,867 ) $ (120,311 ) $ (103,460 ) ITEMS NOT YET RECOGNIZED AS A COMPONENT OF NET PERIODIC BENEFIT COST Prior service credit (cost) $ — $ — $ — $ — $ — $ 26,944 Accumulated gain (loss) 6,751 — (16,769 ) 7,640 — 11,313 $ 6,751 $ — $ (16,769 ) $ 7,640 $ — $ 38,257 BALANCE SHEET AMOUNTS Current liability $ (520 ) $ (420 ) $ (420 ) $ (10,422 ) $ (8,352 ) $ (3,650 ) Noncurrent liability (38,884 ) (48,281 ) $ (27,373 ) (101,445 ) (111,959 ) (99,810 ) $ (39,404 ) $ (48,701 ) $ (27,793 ) $ (111,867 ) $ (120,311 ) $ (103,460 )
Other Postretirement Benefit Costs	The following table details the components of pension and postretirement benefit costs (credits): Pension Benefits Other Postretirement Benefits Successor Predecessor Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 (In thousands) Service cost $ — $ — $ 9 $ 21,478 $ 180 $ 393 $ 866 $ 1,649 Interest cost 2,768 9,338 14,604 17,070 978 3,223 1,904 1,841 Curtailments — 454 — (25,368 ) — (970 ) — — Settlements (135 ) — 2,656 646 — — — — Expected return on plan assets (4,770 ) (13,623 ) (20,367 ) (23,756 ) — — — — Amortization of prior service credits — — — (257 ) — (7,854 ) (8,335 ) (10,003 ) Amortization of other actuarial losses (gains) — 3,973 8,850 3,128 — (849 ) (2,109 ) (761 ) Net benefit cost (credit) $ (2,137 ) $ 142 $ 5,752 $ (7,059 ) $ 1,158 $ (6,057 ) $ (7,674 ) $ (7,274 )
Schedule of Assumptions Used	The following table provides the weighted average assumptions used to determine the actuarial present value of projected benefit obligations for the respective periods. Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 (Percentages) Pension Benefits Discount rate 3.95 3.39 4.59 Rate of compensation increase N/A N/A N/A Other Postretirement Benefits Discount rate 3.93 3.37 4.57 Rate of compensation increase N/A N/A N/A The following table provides the weighted average assumptions used to determine net periodic benefit cost for the respective periods. Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 (Percentages) Pension Benefits Discount rate 3.39/3.95 4.59/3.80 4.15/4.61/4.41/4.60 5.08/4.23/4.14 Rate of compensation increase N/A N/A N/A N/A Expected return on plan assets 6.85 6.85 7.00 7.75 Other Postretirement Benefits Discount rate 3.37 4.57/3.80 3.91 4.58 Rate of compensation increase N/A N/A N/A N/A Expected return on plan assets N/A N/A N/A N/A
Schedule of Allocation of Plan Assets	The Company’s pension plan assets at December 31, 2016 and 2015 , 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 2016 2015 2016 2015 2016 2015 2016 2015 (In thousands) Equity Securities: (A) U.S. small-cap $ 13,520 $ 11,640 $ 13,520 $ 11,640 $ — $ — $ — $ — U.S. mid-cap 29,687 28,524 9,422 10,979 20,265 17,545 — — U.S. large-cap 70,226 67,244 34,107 33,249 36,119 33,995 — — Non-U.S. 18,937 18,785 — — 18,937 18,785 — — Fixed income securities: — U.S. government securities (B) 26,519 18,844 19,973 18,183 6,546 661 — — Non-U.S. government securities (C) 1,567 766 — — 1,567 766 — — U.S. government asset and mortgage backed securities (D) 1,074 1,056 — — 1,074 1,056 — — Corporate fixed income (E) 58,191 39,939 — — 58,191 39,939 — — State and local government securities (F) 6,406 5,725 — — 6,406 5,725 — — Other investments (I) 26,151 19,869 — — 6,910 1,234 19,241 18,635 Total $ 252,278 $ 212,392 $ 77,022 $ 74,051 $ 156,015 $ 119,706 $ 19,241 $ 18,635 Other fixed income (G) 35,519 Short-term investments (H) 8,598 Other liabilities (J) (22,170 ) $ 274,225 (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) Other fixed income investments are actively managed fixed income vehicles that are valued at the net asset value per share multiplied by the number of shares held as of the measurement date. (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, which reflect expected future service, as appropriate: Other Pension Postretirement Benefits Benefits (In thousands) 2017 $ 19,403 $ 12,300 2018 21,117 12,716 2019 20,763 13,033 2020 21,209 13,408 2021 21,917 13,763 Next 5 years 102,619 64,920 $ 207,028 $ 130,140

Earnings (Loss) Per Common Sh54

Earnings (Loss) Per Common Share (Tables)	12 Months Ended
	Dec. 31, 2016
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: Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 (In Thousands) Weighted average shares outstanding: Basic weighted average shares outstanding 25,002 21,293 21,285 21,222 Effect of dilutive securities 467 20 — — Diluted weighted average shares outstanding 25,469 21,313 21,285 21,222

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2016
Leases [Abstract]
Operating Leases of Lessee Disclosure	Minimum payments due in future years under these agreements in effect at December 31, 2016 are as follows: Operating Leases Royalties (In thousands) 2017 $ 14,653 $ 3,994 2018 14,485 6,021 2019 5,321 6,105 2020 2,260 7,147 2021 1,985 7,809 Thereafter 10,317 46,499 $ 49,021 $ 77,575

Risk Concentrations (Tables)

Risk Concentrations (Tables)	12 Months Ended
	Dec. 31, 2016
Risks Concentrations [Abstract]
Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas	The Company’s foreign revenues by geographical location are as follows: Successor Predecessor October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 (In thousands) (In thousands) Europe $ 61,408 $ 113,888 $ 170,314 $ 277,565 Asia 55,634 68,536 96,523 156,057 North America 43,831 56,594 40,315 78,445 Central and South America 13,224 41,861 55,323 20,496 Brokered Sales — — 32,848 79,354 Total $ 174,097 $ 280,879 $ 395,323 $ 611,917

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Schedule Of Operating Segment Results	The asset amounts below represent an allocation of assets consistent with the basis used for the Company’s incentive compensation plans. The amounts in Corporate, Other and Eliminations represent primarily corporate assets (cash, receivables, investments, plant, property and equipment) as well as unassigned coal reserves, above-market sales contracts and other unassigned assets. (In thousands) PRB MET Other Thermal Corporate, Other and Eliminations Consolidated Successor Period October 2 through December 31, 2016 Revenues $ 275,703 $ 200,377 $ 97,382 $ 2,226 $575,688 Adjusted EBITDAR 55,765 30,819 31,159 (23,246 ) 94,497 Depreciation, depletion and amortization 9,949 18,287 3,911 457 32,604 Accretion on asset retirement obligation 5,049 528 540 1,517 7,634 Total assets 446,775 576,793 129,602 983,427 2,136,597 Capital expenditures 934 13,329 684 267 15,214 Predecessor Period January 1 through October 1, 2016 Revenues $ 726,747 $ 437,069 $ 213,052 $ 21,841 $1,398,709 Adjusted EBITDAR 113,185 11,851 31,448 (69,181 ) 87,303 Depreciation, depletion and amortization 100,151 55,311 32,310 3,809 191,581 Accretion on asset retirement obligation 16,940 1,765 1,988 3,628 24,321 Total assets 456,711 619,154 131,173 916,791 2,123,829 Capital expenditures 612 17,296 3,895 60,631 82,434 Predecessor Year Ended December 31, 2015 Revenues $ 1,448,440 $ 637,941 $ 428,809 $ 58,070 $ 2,573,260 Adjusted EBITDAR 281,039 70,450 42,734 (110,426 ) 283,797 Depreciation, depletion and amortization 176,257 133,463 47,786 21,839 379,345 Accretion on asset retirement obligation 22,156 2,267 2,658 6,599 33,680 Total assets 1,648,916 772,439 366,610 2,253,916 5,041,881 Capital expenditures 21,228 24,787 11,277 61,732 119,024 Predecessor Year Ended December 31, 2014 Revenues $ 1,490,377 $ 743,973 $ 535,783 $ 166,986 $ 2,937,119 Adjusted EBITDAR 218,731 112,719 78,238 (96,636 ) 313,052 Depreciation, depletion and amortization 168,522 163,644 52,991 33,591 418,748 Accretion on asset retirement obligation 20,748 2,089 2,412 7,660 32,909 Total assets 1,762,326 2,339,739 406,296 3,838,001 8,346,362 Capital expenditures 21,399 46,771 14,843 64,273 147,286
Reconciliation Statement Of Segment Income From Operations To Consolidated Income Before Income Taxes	A reconciliation of segment Adjusted EBITDAR to consolidated income (loss) from continuing operations before income taxes follows: Successor Predecessor (In thousands) October 2 through December 31, 2016 January 1 through October 1, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014 Adjusted EBITDAR $ 94,497 $ 87,303 $ 283,797 $ 313,052 Depreciation, depletion and amortization (32,604 ) (191,581 ) (379,345 ) (418,748 ) Accretion on asset retirement obligations (7,634 ) (24,321 ) (33,680 ) (32,909 ) Amortization of sales contracts, net (796 ) 728 8,811 13,187 Asset impairment and mine closure costs — (129,267 ) (2,628,303 ) (24,113 ) Losses from disposed operations resulting from Patriot Coal bankruptcy — — (116,343 ) — Interest expense, net (10,754 ) (133,235 ) (393,549 ) (383,188 ) Net loss resulting from early retirement of debt and debt restructuring — (2,213 ) (27,910 ) — Reorganization items, net (759 ) 1,630,041 — — Fresh start coal inventory fair value adjustment (7,345 ) — — — Income (loss) before income taxes $ 34,605 $ 1,237,455 $ (3,286,522 ) $ (532,719 )

Quarterly Selected Financial 58

Quarterly Selected Financial Data (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	Predecessor Successor Year Ended December 31, 2016 March 31 June 30 September 30 October 1 October 2 through December 31, 2016 (a) (b) (a) (b) (b) (b) (In thousands, except per share data) Revenues $ 428,106 $ 420,298 $ 550,305 — 575,688 Gross profit (loss) $ (53,325 ) $ (56,469 ) $ 31,042 — 64,458 Asset impairment and mine closure costs $ 85,520 $ 43,701 $ 46 — — Income (loss) from operations $ (158,412 ) $ (110,521 ) $ 11,795 $ — $ 46,118 Reorganization items, net $ (3,875 ) $ (21,271 ) $ (20,904 ) $ 1,676,091 $ (759 ) Net income (loss) $ (206,702 ) $ (175,887 ) $ (51,421 ) $ 1,676,091 $ 33,449 Diluted earnings (loss) per common share $ (9.71 ) $ (8.26 ) $ (2.41 ) $ 78.66 $ 1.31 Predecessor Year Ended December 31, 2015 March 31 June 30 September 30 December 31 (a) (a) (a) (In thousands, except per share data) Revenues $ 677,005 $ 644,462 $ 688,544 $ 563,249 Gross profit (loss) $ 14,256 $ (16,507 ) $ 47,275 $ (44,964 ) Asset impairment and mine closure costs $ — $ 19,146 $ 2,120,292 $ 488,865 Loss from operations $ (19,712 ) $ (69,546 ) $ (2,236,772 ) $ (539,033 ) Net loss $ (113,195 ) $ (168,103 ) $ (1,999,476 ) $ (632,368 ) Diluted loss per common share $ (5.32 ) $ (7.93 ) $ (93.91 ) $ (29.70 ) (a) Challenging coal markets resulted in impairment charges relating to mining and other operations, investments in equity method subsidiaries and prepaid mining royalties in 2016 and 2015. See further discussion in Note 5 , “ Impairment Charges and Mine Closure Costs “ and Note 9 , “ Equity Method Investments and Membership Interests in Joint Ventures .” (b) The Company filed for bankruptcy on January 11, 2016 and subsequently emerged on October 5, 2016. See further discussion in Note 3 , “ Emergence from Bankruptcy and Fresh Start Accounting .”

Accounting Policies (Narrative)

Accounting Policies (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Statutory Accounting Practices
Mineral rights	$ 400,000	$ 2,400,000
Deferred finance costs, net	5,182	66,300
Deferred finance costs, current	$ 1,900	$ 65,600
Exploration and Production Equipment [Member] | Minimum [Member]
Statutory Accounting Practices
Estimated useful life	7 years
Exploration and Production Equipment [Member] | Maximum [Member]
Statutory Accounting Practices
Estimated useful life	18 years
Building and Building Improvements [Member] | Minimum [Member]
Statutory Accounting Practices
Estimated useful life	1 year
Building and Building Improvements [Member] | Maximum [Member]
Statutory Accounting Practices
Estimated useful life	18 years
Mining Properties and Mineral Rights [Member] | Minimum [Member]
Statutory Accounting Practices
Term of contract	10 years
Mining Properties and Mineral Rights [Member] | Maximum [Member]
Statutory Accounting Practices
Term of contract	50 years

Accounting Policies (Accounting

Accounting Policies (Accounting Principle Adopted) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other current assets		$ 39,866
Revision of debt issuance costs	$ (5,182)	(66,300)
Current maturities of debt		5,042,353
Scenario, Previously Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other current assets		104,723
Current maturities of debt		5,107,210
Accounting Standards Update 03-2015 [Member] | Other Current Assets [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revision of debt issuance costs		(64,857)
Accounting Standards Update 03-2015 [Member] | Long-term Debt, Current [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revision of debt issuance costs		$ (64,857)

(Treatment of Claims and New Fi

(Treatment of Claims and New First Lien Debt Facility) (Details)	Oct. 05, 2016USD ($)$ / shares
Fresh-Start Adjustment [Line Items]
Holders of allowed claims pro-rata amount of cash to settle claims	$ 144,800,000
Holders of allowed claims amount of cash to settle claims	$ 30,000,000
Holders of allowed claims percentage of common stock outstanding upon reorganization	94.00%
Holders of allowed claims warrant exercise period	7 years
Holders of allowed claims total equity value of common stock	$ 1,425,000,000
Exercise price of warrants (in usd per share) | $ / shares	$ 57
Holders of allowed claims percentage of common stock outstanding pursuant to incentive plan upon reorganization	10.00%
Unsecured note holders pro rata amount of cash to settle claims	$ 22,636,000
Unsecured note holders pro rata amount of cash in lieu of warrants	$ 25,000,000
Unsecured note holders percentage of common stock outstanding upon reorganization	6.00%
Other general holders pro rata amount of cash to settle claims	$ 7,364,000
Other general holders professional expenses retained by claims committee	200,000
New First Lien Debt Facility [Member] | Senior Notes [Member]
Fresh-Start Adjustment [Line Items]
Amount of debt instrument	$ 326,500,000
Class A Common Stock [Member]
Fresh-Start Adjustment [Line Items]
Holders of allowed claims percentage of common stock outstanding upon reorganization	12.00%

(Securitization Facility and Wa

(Securitization Facility and Warrant Agreement) (Details) - USD ($)	Oct. 05, 2016	Oct. 02, 2016
Fresh-Start Adjustment [Line Items]
Number of securities called by each warrant (in shares)	1
Exercise price of warrants (in usd per share)	$ 57
Percentage of listed common stock	90.00%
Number of shares of common stock underlying warrant multiplier	$ 0
Class A Common Stock [Member]
Fresh-Start Adjustment [Line Items]
Aggregate number of securities called by warrants (in shares)	1,914,856	1,914,856
Common stock, par value (in usd per share)	$ 0.01

(Termination of Material Defini

(Termination of Material Definitive Agreements, Sale of Equity Securities and Reorganization Value) (Details) - USD ($)	Oct. 05, 2016	Dec. 31, 2016	Oct. 02, 2016	Oct. 01, 2016	Jan. 11, 2016
Fresh-Start Adjustment [Line Items]
Reorganization value			$ 687,500,000
Excess cash			64,000,000
Minimum cash balance assumption			$ 250,000,000
Minimum [Member]
Fresh-Start Adjustment [Line Items]
Reorganization value				$ 650,000,000
Maximum [Member]
Fresh-Start Adjustment [Line Items]
Reorganization value				$ 950,000,000
Discounted Cash Flow Valuation Technique [Member] | Minimum [Member]
Fresh-Start Adjustment [Line Items]
Discount rate (percent)	13.25%
Discounted Cash Flow Valuation Technique [Member] | Maximum [Member]
Fresh-Start Adjustment [Line Items]
Discount rate (percent)	15.25%
7.00% Senior Notes Due 2019 [Member]
Fresh-Start Adjustment [Line Items]
Senior notes interest rate (percent)		7.00%			7.00%
7.25% Senior Notes Due 2020 [Member]
Fresh-Start Adjustment [Line Items]
Senior notes interest rate (percent)		7.25%			7.25%
7.25% Senior Notes Due 2021 [Member]
Fresh-Start Adjustment [Line Items]
Senior notes interest rate (percent)		7.25%			7.25%
9.875% Senior Notes Due 2019 [Member]
Fresh-Start Adjustment [Line Items]
Senior notes interest rate (percent)		9.875%			9.875%
Amount of debt instrument		$ 375,000,000
8.00% Senior Secured Notes due 2019 [Member]
Fresh-Start Adjustment [Line Items]
Senior notes interest rate (percent)		8.00%			8.00%
Class A Common Stock [Member]
Fresh-Start Adjustment [Line Items]
Common stock, shares issued (in shares)			24,589,834
Common stock, par value (in usd per share)	$ 0.01
Aggregate number of securities called by warrants (in shares)	1,914,856		1,914,856
Class B Common Stock [Member]
Fresh-Start Adjustment [Line Items]
Common stock, shares issued (in shares)			410,166
Common stock, par value (in usd per share)			$ 0.01
New First Lien Debt Facility [Member] | Senior Notes [Member]
Fresh-Start Adjustment [Line Items]
Amount of debt instrument	$ 326,500,000

Emergence from Bankruptcy and64

Emergence from Bankruptcy and Fresh Start Accounting (Accounting Impact of Emergence) (Details) $ in Thousands	Oct. 01, 2016USD ($)
Reorganizations [Abstract]
Percentage of voting shares received upon emergence of new entity (percent)	50.00%
Assets
Fresh-Start Adjustment, Increase (Decrease), Property and Equipment, Net	$ (2,363,829)
Fresh Start Adjustments [Member]
Assets
Fresh-Start Adjustment, Increase (Decrease), Receivables, Net	779
Fresh-Start Adjustment, Increase (Decrease), Inventories	(21,078)
Fresh-Start Adjustment, Increase (Decrease), Prepaid and Other Current Assets	53,851
Fresh-Start Adjustment, Increase (Decrease), Current Assets	33,552
Fresh-Start Adjustment, Increase (Decrease), Property and Equipment, Net	(2,363,829)
Fresh-Start Adjustment, Increase (Decrease), Prepaid Royalties	(20,997)
Fresh-Start Adjustment, Increase (Decrease), Equity Investments	(61,606)
Fresh-Start Adjustment, Increase (Decrease), Other Assets, Noncurrent	37,503
Fresh-Start Adjustment, Increase (Decrease), Other Assets	(45,100)
Fresh-Start Adjustment, Increase (Decrease), Assets	(2,375,377)
Liabilities not subject to compromise
Fresh-Start Adjustment, Increase (Decrease), Accounts Payable	(250)
Fresh-Start Adjustment, Increase (Decrease), Accrued Liabilities and Other Current Liabilities	26,644
Fresh-Start Adjustment, Increase (Decrease), Current Liabilities	26,394
Fresh-Start Adjustment, Increase (Decrease), Asset Retirement Obligations	(60,570)
Fresh-Start Adjustment, Increase (Decrease), Pension Obligations	24,565
Fresh-Start Adjustment, Increase (Decrease), Other Postretirement Obligations	24,836
Fresh-Start Adjustment, Increase (Decrease), Accrued Workers' Compensation	74,520
Fresh-Start Adjustment, Increase (Decrease), Noncurrent Other Obligations	888
Fresh-Start Adjustment, Increase (Decrease), Other Noncurrent Obligations	90,633
Fresh-Start Adjustment, Increase (Decrease), Liabilities	90,633
Stockholders’ equity (deficit)
Fresh-Start Adjustment, Increase (Decrease), Retained Earnings (Deficit)	(2,467,716)
Fresh-Start Adjustment, Increase (Decrease), Accumulated Other Comprehensive Income (Loss)	1,706
Fresh-Start Adjustment, Increase (Decrease), Stockholders' Equity	(2,466,010)
Fresh-Start Adjustment, Increase (Decrease), Liabilities and Stockholders' Equity	(2,375,377)
Effect of Plan [Member]
Assets
Fresh-Start Adjustment, Increase (Decrease), Cash and Cash Equivalents	(199,718)
Fresh-Start Adjustment, Increase (Decrease), Prepaid and Other Current Assets	6,367
Fresh-Start Adjustment, Increase (Decrease), Current Assets	(193,351)
Fresh-Start Adjustment, Increase (Decrease), Other Assets, Noncurrent	34,495
Fresh-Start Adjustment, Increase (Decrease), Other Assets	34,495
Fresh-Start Adjustment, Increase (Decrease), Assets	(158,856)
Liabilities not subject to compromise
Fresh-Start Adjustment, Increase (Decrease), Accrued Liabilities and Other Current Liabilities	(36,331)
Fresh-Start Adjustment, Increase (Decrease), Current Maturities of Long-term Debt	3,265
Fresh-Start Adjustment, Increase (Decrease), Current Liabilities	(33,066)
Fresh-Start Adjustment, Increase (Decrease), Long-term Debt	323,235
Fresh-Start Adjustment, Increase (Decrease), Other Noncurrent Obligations	290,169
Fresh-Start Adjustment, Increase (Decrease), Liabilities Subject to Compromise	(5,278,612)
Fresh-Start Adjustment, Increase (Decrease), Liabilities	(4,988,443)
Stockholders’ equity (deficit)
Fresh-Start Adjustment, Increase (Decrease), Preferred and Common Stock Held in Treasury	53,863
Fresh-Start Adjustment, Increase (Decrease), Retained Earnings (Deficit)	7,146,693
Fresh-Start Adjustment, Increase (Decrease), Stockholders' Equity	4,829,587
Fresh-Start Adjustment, Increase (Decrease), Liabilities and Stockholders' Equity	(158,856)
Predecessor [Member]
Preconfirmation
Preconfirmation, Cash and cash equivalents	400,205
Preconfirmation, Short term investments	111,451
Preconfirmation, Restricted cash	81,563
Preconfirmation, Trade accounts receivable	165,522
Preconfirmation, Other Receivables	17,227
Preconfirmation, Inventories	159,410
Preconfirmation, Prepaid Royalties, Current	4,805
Preconfirmation, Deferred Income Tax Assets, Current	0
Preconfirmation, Coal Derivative Assets	2,180
Preconfirmation, Prepaid and Other Current Assets	36,960
Preconfirmation, Current Assets	979,323
Preconfirmation, Property and Equipment, Net	3,434,941
Preconfirmation, Prepaid Royalties, Noncurrent	20,997
Preconfirmation, Investments	164,232
Preconfirmation, Other Assets, Noncurrent	58,569
Preconfirmation, Other Assets	243,798
Preconfirmation, Assets	4,658,062
Preconfirmation, Accounts Payable	74,595
Precomfirmation, Accrued expenses and other current liabilities	225,739
Preconfirmation, Current Maturities of Long-term Debt	3,397
Preconfirmation, Current Liabilities	303,731
Preconfirmation, Long-term Debt	30,037
Preconfirmation, Asset Retirement Obligations	394,699
Preconfirmation, Pension Obligations	23,716
Preconfirmation, Other Postretirement Obligations	87,123
Preconfirmation, Accrued Workers' Compensation	119,828
Preconfirmation, Noncurrent Other Obligations	96,410
Preconfirmation, Liabilities Not Subject to Compromise	1,055,544
Preconfirmation, Liabilities Subject to Compromise	5,278,612
Preconfirmation, Liabilities	6,334,156
Preconfirmation, Common Stock	2,145
Preconfirmation, Additional Paid-in Capital	3,056,307
Preconfirmation, Preferred and Common Stock Held in Treasury	(53,863)
Preconfirmation, Retained Earnings (Deficit)	(4,678,977)
Preconfirmation, Accumulated Other Comprehensive Income (Loss)	(1,706)
Preconfirmation, Stockholders' Equity	(1,676,094)
Preconfirmation, Liabilities and Stockholders' Equity	4,658,062
Stockholders’ equity (deficit)
Fresh-Start Adjustment, Increase (Decrease), Common Stock	(2,145)
Fresh-Start Adjustment, Increase (Decrease), Additional Paid-in Capital	(3,056,307)
Fresh-Start Adjustment, Increase (Decrease), Preferred and Common Stock Held in Treasury	53,863
Fresh-Start Adjustment, Increase (Decrease), Retained Earnings (Deficit)	7,146,693
Predecessor [Member] | Effect of Plan [Member]
Stockholders’ equity (deficit)
Fresh-Start Adjustment, Increase (Decrease), Common Stock	(2,145)
Fresh-Start Adjustment, Increase (Decrease), Additional Paid-in Capital	(3,056,307)
Successor [Member]
Postconfirmation
Postconfirmation, Cash and Cash Equivalents	200,487
Postconfirmation, Short-term Investments	111,451
Postconfirmation, Restricted Cash and Cash Equivalents, Current	81,563
Postconfirmation, Receivables, Net	165,522
Postconfirmation, Other Receivables	18,006
Postconfirmation, Inventories	138,332
Postconfirmation, Prepaid Royalties, Current	4,805
Postconfirmation, Deferred Income Tax Assets, Current	0
Postconfirmation, Coal Derivative Assets	2,180
Postconfirmation, Prepaid and Other Current Assets	97,178
Postconfirmation, Current Assets	819,524
Postconfirmation, Property and Equipment, Net	1,071,112
Postconfirmation, Prepaid Royalties, Noncurrent	0
Postconfirmation, Investments	102,626
Postconfirmation, Other Assets, Noncurrent	130,567
Postconfirmation, Other Assets	233,193
Postconfirmation, Assets	2,123,829
Postconfirmation, Accounts Payable	74,345
Postcomfirmation, Accrued expenses and other current liabilities	216,052
Postconfirmation, Current Maturities of Long-term Debt	6,662
Postconfirmation, Current Liabilities	297,059
Postconfirmation, Long-term Debt	353,272
Postconfirmation, Asset Retirement Obligations	334,129
Postconfirmation, Pension Obligations	48,281
Postconfirmation, Other Postretirement Obligations	111,959
Postconfirmation, Accrued Workers' Compensation	194,348
Postconfirmation, Noncurrent Other Obligations	97,298
Postconfirmation, Liabilities Not Subject to Compromise	1,436,346
Postconfirmation, Liabilities Subject to Compromise	0
Postconfirmation, Liabilities	1,436,346
Postconfirmation, Common Stock	250
Postconfirmation, Additional Paid-in Capital	687,233
Postconfirmation, Preferred and Common Stock Held in Treasury	0
Postconfirmation, Retained Earnings (Deficit)	0
Postconfirmation, Accumulated Other Comprehensive Income (Loss)	0
Postconfirmation, Stockholders' Equity	687,483
Postconfirmation, Liabilities and Stockholders' Equity	2,123,829
Successor [Member] | Effect of Plan [Member]
Stockholders’ equity (deficit)
Fresh-Start Adjustment, Increase (Decrease), Common Stock	250
Fresh-Start Adjustment, Increase (Decrease), Additional Paid-in Capital	$ 687,233

Emergence from Bankruptcy and65

Emergence from Bankruptcy and Fresh Start Accounting (Liabilities Subject to Compromise) (Details) $ in Thousands	Oct. 01, 2016USD ($)
Reorganizations [Abstract]
Liabilities subject to compromise	$ 5,278,612
Common stock (at par) Successor	(250)
Warrants Successor	(14,822)
Paid-in capital Successor	(672,411)
Issuance of Term Loan Successor	(326,500)
Cash payment to settle claims and professional fees	(122,525)
Total pre-tax gain on plan effects	$ 4,142,104

Emergence from Bankruptcy and66

Emergence from Bankruptcy and Fresh Start Accounting (Cash Used) (Details) $ in Thousands	Oct. 05, 2016USD ($)
Reorganizations [Abstract]
Payment to secured lenders	$ 43,496
Payments to unsecured creditors	42,399
Final adequate protection payment	36,331
Collateral requirements	31,665
Professional fees	31,630
Other	14,197
Total cash outflow at emergence	$ 199,718

Emergence from Bankruptcy and67

Emergence from Bankruptcy and Fresh Start Accounting (Reorganization Adjustments and Property, Plant and Equipment) (Details) - USD ($) $ in Thousands	Oct. 01, 2016	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Fresh-Start Adjustment [Line Items]
Fresh-Start Adjustment, Increase (Decrease), Property and Equipment, Net	$ (2,363,829)		$ (2,363,829)
Total pre-tax gain on plan effects	4,142,104
Coal Properties, Net [Member]
Fresh-Start Adjustment [Line Items]
Fresh-Start Adjustment, Increase (Decrease), Property and Equipment, Net	(1,971,314)		(1,971,314)
Plant and Equipment, Net [Member]
Fresh-Start Adjustment [Line Items]
Fresh-Start Adjustment, Increase (Decrease), Property and Equipment, Net	(405,259)		(405,259)
Deferred Charges, Net [Member]
Fresh-Start Adjustment [Line Items]
Fresh-Start Adjustment, Increase (Decrease), Property and Equipment, Net	12,744		12,744
Predecessor [Member]
Fresh-Start Adjustment [Line Items]
Property, plant and equipment, net	3,434,941		3,434,941	$ 3,619,029
Total pre-tax gain on plan effects	4,142,104		4,142,104	$ 0	$ 0
Cancellation of predecessor common stock	2,145		2,145
Cancellation of predecessor paid-in capital	3,056,307		3,056,307
Cancellation of predecessor treasury stock	(53,863)		(53,863)
Net impact on accumulated earnings (deficit)	7,146,693		7,146,693
Predecessor [Member] | Coal Properties, Net [Member]
Fresh-Start Adjustment [Line Items]
Property, plant and equipment, net	2,358,779		2,358,779
Predecessor [Member] | Plant and Equipment, Net [Member]
Fresh-Start Adjustment [Line Items]
Property, plant and equipment, net	812,888		812,888
Predecessor [Member] | Deferred Charges, Net [Member]
Fresh-Start Adjustment [Line Items]
Property, plant and equipment, net	263,274		263,274
Successor [Member]
Fresh-Start Adjustment [Line Items]
Property, plant and equipment, net	1,071,112	$ 1,053,603	1,071,112
Total pre-tax gain on plan effects		$ 0
Successor [Member] | Coal Properties, Net [Member]
Fresh-Start Adjustment [Line Items]
Property, plant and equipment, net	387,465		387,465
Successor [Member] | Plant and Equipment, Net [Member]
Fresh-Start Adjustment [Line Items]
Property, plant and equipment, net	407,629		407,629
Successor [Member] | Deferred Charges, Net [Member]
Fresh-Start Adjustment [Line Items]
Property, plant and equipment, net	$ 276,018		$ 276,018

Emergence from Bankruptcy and68

Emergence from Bankruptcy and Fresh Start Accounting (Unsecured or Under-Secured Liabilities Previously Reported) (Details) - USD ($) $ in Thousands	Oct. 01, 2016	Jan. 11, 2016
Fresh-Start Adjustment [Line Items]
Liabilities Subject to Compromise	$ 5,278,612
Scenario, Previously Reported [Member]
Fresh-Start Adjustment [Line Items]
Debt		$ 5,026,806
Accrued expenses and other current liabilities		136,295
Accounts payable		106,297
Other noncurrent liabilities		9,214
Liabilities Subject to Compromise		$ 5,278,612

Emergence from Bankruptcy and69

Emergence from Bankruptcy and Fresh Start Accounting (Additional Information to Liabilities Subject to Compromise) (Details) - USD ($) $ in Thousands	Oct. 05, 2016	Oct. 01, 2016	Dec. 31, 2016	Dec. 31, 2015
Fresh-Start Adjustment [Line Items]
Fair value of senior notes and other long-term debt, including amounts classified as current			$ 362,900	$ 937,100
Current maturities of debt				$ 5,042,353
Insurance receivable, current			800
Decrease in property plant and equipment, net		$ 2,363,829
Successor [Member]
Fresh-Start Adjustment [Line Items]
Current maturities of debt			11,038
Term Loan Due 2021 [Member]
Fresh-Start Adjustment [Line Items]
Term loan			325,684
Term Loan Due 2021 [Member] | Successor [Member]
Fresh-Start Adjustment [Line Items]
Fair value of senior notes and other long-term debt, including amounts classified as current		326,500
Term loan			$ 325,684
Current maturities of debt		$ 3,300
Minimum [Member] | Discounted Cash Flow Valuation Technique [Member]
Fresh-Start Adjustment [Line Items]
Discount rate (percent)	13.25%
Maximum [Member] | Discounted Cash Flow Valuation Technique [Member]
Fresh-Start Adjustment [Line Items]
Discount rate (percent)	15.25%
Asset Retirement Obligation Costs [Member] | Minimum [Member] | Discounted Cash Flow Valuation Technique [Member]
Fresh-Start Adjustment [Line Items]
Discount rate (percent)		7.06%
Asset Retirement Obligation Costs [Member] | Maximum [Member] | Discounted Cash Flow Valuation Technique [Member]
Fresh-Start Adjustment [Line Items]
Discount rate (percent)		9.08%
Plant and Equipment, Net [Member]
Fresh-Start Adjustment [Line Items]
Decrease in property plant and equipment, net		$ 405,259
Plant and Equipment, Net [Member] | Market Approach and Cost Approach Valuation Techniques [Member] | Successor [Member]
Fresh-Start Adjustment [Line Items]
Fair value of property, plant and equipment, net		407,600
Coal Properties, Net [Member]
Fresh-Start Adjustment [Line Items]
Decrease in property plant and equipment, net		1,971,314
Coal Properties, Net [Member] | Discounted Cash Flow and Market Approach Valuation Techniques [Member] | Successor [Member]
Fresh-Start Adjustment [Line Items]
Fair value of property, plant and equipment, net		387,500
Fresh Start Adjustments [Member]
Fresh-Start Adjustment [Line Items]
Increase (decrease) in inventories		(21,078)
Increase in current above market sales contracts		71,100
Decrease in prepaid expenses		11,300
Decrease in property plant and equipment, net		2,363,829
Increase in current below market sales contracts		27,800
Increase in noncurrent above market sales contract		26,000
Increase in noncurrent insurance receivables		18,600
Decrease in noncurrent prepaid balances		13,200
Increase in noncurrent below market sales contracts		3,900
Decrease in miscellaneous noncurrent liabilities		3,100
Fresh Start Adjustments [Member] | Coal Inventory [Member]
Fresh-Start Adjustment [Line Items]
Increase (decrease) in inventories		7,300
Fresh Start Adjustments [Member] | Critical Spare Parts [Member]
Fresh-Start Adjustment [Line Items]
Increase (decrease) in inventories		$ (28,400)
Equity Method Investments [Member] | Level 3 [Member] | Discounted Cash Flow Approach and Comparable Company Approach [Member]
Fresh-Start Adjustment [Line Items]
Discount rate (percent)		14.00%

Emergence from Bankruptcy and70

Emergence from Bankruptcy and Fresh Start Accounting (Reorganization Items, Net and Contractual Interest Expense During Bankruptcy) (Details) - USD ($) $ in Thousands	Oct. 01, 2016	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Fresh-Start Adjustment [Line Items]
Gain on settlement of claims	$ 4,142,104
Predecessor [Member]
Fresh-Start Adjustment [Line Items]
Gain on settlement of claims	4,142,104					$ 4,142,104	$ 0	$ 0
Fresh start adjustments						(2,466,010)	0	0
Professional fees						(46,053)	0	0
Reorganization Items	$ 1,676,091		$ (20,904)	$ (21,271)	$ (3,875)	1,630,041	$ 0	$ 0
Contractual interest expense						300,900
Interest Expense						$ 135,900
Successor [Member]
Fresh-Start Adjustment [Line Items]
Gain on settlement of claims		$ 0
Fresh start adjustments		0
Professional fees		(759)
Reorganization Items		$ (759)

Accumulated Other Comprehensi71

Accumulated Other Comprehensive Income (Loss) (Schedule of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2015
Predecessor [Member]
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Beginning balance		$ (1,815)
Unrealized gains (losses)		563	$ (8,153)
Amounts reclassified from accumulated other comprehensive income (loss)		(454)	3,097
Fresh start accounting adjustment		1,706
Ending balance			(1,815)
Predecessor [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Beginning balance	$ 0	(1,815)	3,241
Ending balance		0	(1,815)
Predecessor [Member] | Derivative Instruments [Member]
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Beginning balance	0	325	2,550
Unrealized gains (losses)		(138)	3,903
Amounts reclassified from accumulated other comprehensive income (loss)		(316)	(6,128)
Fresh start accounting adjustment		129
Ending balance		0	325
Predecessor [Member] | Pension, Postretirement and Other Post-Employment Benefits [Member]
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Beginning balance	0	(721)	2,860
Unrealized gains (losses)		0	(8,723)
Amounts reclassified from accumulated other comprehensive income (loss)		(1,363)	5,142
Fresh start accounting adjustment		2,084
Ending balance		0	(721)
Predecessor [Member] | Available-for-Sale Securities [Member]
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Beginning balance	0	(1,419)	(2,169)
Unrealized gains (losses)		701	(3,333)
Amounts reclassified from accumulated other comprehensive income (loss)		1,225	4,083
Fresh start accounting adjustment		(507)
Ending balance		$ 0	$ (1,419)
Successor [Member]
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Unrealized gains (losses)	24,454
Amounts reclassified from accumulated other comprehensive income (loss)	0
Ending balance	24,454
Successor [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Ending balance	24,454
Successor [Member] | Derivative Instruments [Member]
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Unrealized gains (losses)	0
Amounts reclassified from accumulated other comprehensive income (loss)	0
Ending balance	0
Successor [Member] | Pension, Postretirement and Other Post-Employment Benefits [Member]
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Unrealized gains (losses)	24,067
Amounts reclassified from accumulated other comprehensive income (loss)	0
Ending balance	24,067
Successor [Member] | Available-for-Sale Securities [Member]
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Unrealized gains (losses)	387
Amounts reclassified from accumulated other comprehensive income (loss)	0
Ending balance	$ 387

Accumulated Other Comprehensi72

Accumulated Other Comprehensive Income (Loss) (Schedule of Reclassifications) (Details) - USD ($) $ in Thousands	Oct. 01, 2016	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Successor [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Revenues		$ 575,688
Income (loss) before income taxes		34,605
Provision for (benefit from) income taxes		(1,156)
Net income (loss)		33,449
Successor [Member] | Reclassification out of accumulated other comprehensive income [Member] | Derivative Instruments [Member] | Commodity Contract [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Revenues		0
Provision for (benefit from) income taxes		0
Net income (loss)		0
Successor [Member] | Reclassification out of accumulated other comprehensive income [Member] | Pension, Postretirement and Other Post-Employment Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of prior service credits		0
Amortization of net actuarial gains (losses)		0
Income (loss) before income taxes		0
Provision for (benefit from) income taxes		0
Net income (loss)		0
Successor [Member] | Reclassification out of accumulated other comprehensive income [Member] | Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest and investment income		0
Provision for (benefit from) income taxes		0
Net income (loss)		$ 0
Predecessor [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Revenues			$ 550,305	$ 420,298	$ 428,106	$ 563,249	$ 688,544	$ 644,462	$ 677,005	$ 1,398,709	$ 2,573,260	$ 2,937,119
Income (loss) before income taxes										1,237,455	(3,286,522)	(532,719)
Provision for (benefit from) income taxes										4,626	373,380	(25,634)
Net income (loss)	$ 1,676,091		$ (51,421)	$ (175,887)	$ (206,702)	$ (632,368)	$ (1,999,476)	$ (168,103)	$ (113,195)	1,242,081	(2,913,142)	$ (558,353)
Predecessor [Member] | Reclassification out of accumulated other comprehensive income [Member] | Derivative Instruments [Member] | Commodity Contract [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Revenues										397	9,575
Provision for (benefit from) income taxes										(81)	(3,447)
Net income (loss)										316	6,128
Predecessor [Member] | Reclassification out of accumulated other comprehensive income [Member] | Pension, Postretirement and Other Post-Employment Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of prior service credits										7,854	8,335
Amortization of net actuarial gains (losses)										(6,010)	(16,369)
Income (loss) before income taxes										1,844	(8,034)
Provision for (benefit from) income taxes										(481)	2,892
Net income (loss)										1,363	(5,142)
Predecessor [Member] | Reclassification out of accumulated other comprehensive income [Member] | Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest and investment income										(2,263)	(6,391)
Provision for (benefit from) income taxes										1,038	2,308
Net income (loss)										$ (1,225)	$ (4,083)

Impairment Charges and Mine C73

Impairment Charges and Mine Closure Costs (Details) - USD ($) $ in Millions	3 Months Ended						6 Months Ended		12 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2016	Dec. 31, 2015	Dec. 31, 2015
Impaired Long-Lived Assets Held and Used [Line Items]
Other-than-temporary impairment loss on available-for-sale securities		$ 2.9
Severance costs							$ 7.2
Curtailments							$ 3.6
Asset impairment and mine closure costs			$ 488.9	$ 2,100	$ 19.1			$ 2,600
Impairment charge of higher-cost mining complex					5.6
Restructuring charges				$ 5.1
Royalty Agreements [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Prepaid royalties		3.4			$ 12.2
Impairment charge						$ 15.4			$ 48
APP [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment and mine closure costs									2,200
Other Segments [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment and mine closure costs									$ 400
Kentucky [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Net book value of idled facility		$ 74.1
Longview, Washington [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Other-than-temporary impairment loss on available-for-sale securities	$ 38

Impairment Charges and Mine C74

Impairment Charges and Mine Closure Costs (Summary Asset Impairments and Mine Closure Costs) (Details) - USD ($) $ in Thousands	3 Months Ended								6 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2015	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment and mine closure costs					$ 488,900	$ 2,100,000	$ 19,100		$ 2,600,000
Predecessor [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Coal lands and mineral rights										$ 74,144	$ 2,210,488	$ 0
Plant and equipment										0	199,107	1,512
Deferred development										0	159,474	0
Prepaid royalties										3,406	41,990	15,356
Equity investments										40,920	21,325	0
Inventories										0	66	0
Other										10,797	(4,147)	7,245
Asset impairment and mine closure costs		$ 46	$ 43,701	$ 85,520	$ 488,865	$ 2,120,292	$ 19,146	$ 0		$ 129,267	$ 2,628,303	$ 24,113
Successor [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Coal lands and mineral rights	$ 0
Plant and equipment	0
Deferred development	0
Prepaid royalties	0
Equity investments	0
Inventories	0
Other	0
Asset impairment and mine closure costs	$ 0

Losses from disposed operatio75

Losses from disposed operations resulting from Patriot Coal Bankruptcy (Details) - Magnum [Member] - USD ($) $ in Millions	Nov. 22, 2016	Dec. 31, 2015
Discontinued Operations, Held-for-sale or Disposed of by Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Losses related to previously disposed off operations		$ 116.3
Surety Bond [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Decease in collateral held by bonding company	$ 20

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Allowance for slow-moving and obsolete inventories	$ 0	$ 6,000
Successor [Member]
Property, Plant and Equipment [Line Items]
Coal	37,268
Repair parts and supplies	76,194
Inventories	$ 113,462
Predecessor [Member]
Property, Plant and Equipment [Line Items]
Coal		85,043
Repair parts and supplies		111,677
Inventories		$ 196,720

Investments in Available-for-77

Investments in Available-for-Sale Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Successor [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost Basis	$ 89,910
Gross Unrealized Gains	388
Gross Unrealized Losses	(89)
Fair Value	90,209
Total Investments	88,072
Successor [Member] | Short-term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Corporate notes and bonds	88,072
Total Investments	88,072
Successor [Member] | Other Assets [Member]
Schedule of Available-for-sale Securities [Line Items]
Equity Securities, Fair Value	2,137
Successor [Member] | Corporate Notes and Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Debt Securities, Amortized Cost Basis	88,161
Debt Securities, Gross Unrealized Gains	0
Debt Securities, Gross Unrealized Losses	(89)
Debt Securities, Fair Value	88,072
Successor [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Equity Securities, Amortized Cost Basis	1,749
Equity Securities, Gross Unrealized Gains	388
Equity Securities, Gross Unrealized Losses	0
Equity Securities, Fair Value	$ 2,137
Predecessor [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost Basis		$ 204,441
Gross Unrealized Gains		668
Gross Unrealized Losses		(3,199)
Fair Value		201,910
Total Investments		200,192
Predecessor [Member] | Short-term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
US government and agency securities		9,995
Corporate notes and bonds		190,197
Total Investments		200,192
Predecessor [Member] | Other Assets [Member]
Schedule of Available-for-sale Securities [Line Items]
Equity Securities, Fair Value		1,718
Predecessor [Member] | US Government and Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Debt Securities, Amortized Cost Basis		10,007
Debt Securities, Gross Unrealized Gains		0
Debt Securities, Gross Unrealized Losses		(12)
Debt Securities, Fair Value		9,995
Predecessor [Member] | Corporate Notes and Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Debt Securities, Amortized Cost Basis		190,496
Debt Securities, Gross Unrealized Gains		0
Debt Securities, Gross Unrealized Losses		(299)
Debt Securities, Fair Value		190,197
Predecessor [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Equity Securities, Amortized Cost Basis		3,938
Equity Securities, Gross Unrealized Gains		668
Equity Securities, Gross Unrealized Losses		(2,888)
Equity Securities, Fair Value		$ 1,718

Investments in Available-for-78

Investments in Available-for-Sale Securities (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Available-for-sale Securities [Abstract]
Continuous unrealized loss position for less than a year	$ 47.6	$ 184.6
Continuous unrealized loss position for over a year	$ 40.4	$ 15.8

Equity Method Investments and79

Equity Method Investments and Membership Interests in Joint Ventures (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2016	Sep. 30, 2015	Dec. 31, 2016	Dec. 31, 2015
Knight Hawk [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest (percent)			49.00%
DTA [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest (percent)				21.875%
Millennium [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest (percent)				38.00%
Impairment of equity investment	$ (38,000)
Tongue River [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest (percent)				35.00%
Impairment of equity investment		$ (21,300)

Equity Method Investments and80

Equity Method Investments and Membership Interests in Joint Ventures (Schedule of Equity Method Investments) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended	12 Months Ended
	Dec. 31, 2016	Jun. 30, 2016	Sep. 30, 2015	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Millennium [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Impairment of equity investment		$ (38,000)
Tongue River [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Impairment of equity investment			$ (21,300)
Predecessor [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Beginning Balance	$ 102,625			$ 201,877	$ 235,842	$ 221,456
Advances to (distributions from) affiliates, net				(4,934)	(18,360)	4,054
Equity in comprehensive income (loss)				5,314	7,979	10,332
Impairment of equity investment				(38,025)	(21,325)
Sale of equity investment					(2,259)
Fresh start accounting adjustment				(61,607)
Ending Balance				102,625	201,877	235,842
Predecessor [Member] | Knight Hawk [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Beginning Balance	94,000			151,592	158,477	152,806
Advances to (distributions from) affiliates, net				(8,374)	(29,862)	(12,603)
Equity in comprehensive income (loss)				9,033	22,977	18,274
Impairment of equity investment				0
Fresh start accounting adjustment				(58,251)
Ending Balance				94,000	151,592	158,477
Predecessor [Member] | DTA [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Beginning Balance	8,600			13,239	13,738	14,137
Advances to (distributions from) affiliates, net				1,474	3,207	3,774
Equity in comprehensive income (loss)				(2,095)	(3,706)	(4,173)
Fresh start accounting adjustment				(4,018)
Ending Balance				8,600	13,239	13,738
Predecessor [Member] | Millennium [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Beginning Balance	0			37,589	40,223	35,894
Advances to (distributions from) affiliates, net				1,966	7,052	6,742
Equity in comprehensive income (loss)				(1,530)	(9,686)	(2,413)
Impairment of equity investment				(38,025)
Fresh start accounting adjustment				0
Ending Balance				0	37,589	40,223
Predecessor [Member] | Tongue River [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Beginning Balance	0				20,740	18,419
Advances to (distributions from) affiliates, net				0	913	2,541
Equity in comprehensive income (loss)				0	(328)	(220)
Impairment of equity investment				0	(21,325)
Fresh start accounting adjustment				0
Ending Balance				0		20,740
Predecessor [Member] | Other [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Beginning Balance	25			(543)	2,664	200
Advances to (distributions from) affiliates, net				0	330	3,600
Equity in comprehensive income (loss)				(94)	(1,278)	(1,136)
Impairment of equity investment				0
Sale of equity investment					(2,259)
Fresh start accounting adjustment				662
Ending Balance				$ 25	$ (543)	$ 2,664
Successor [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Advances to (distributions from) affiliates, net	(8,254)
Equity in comprehensive income (loss)	1,703
Ending Balance	96,074
Successor [Member] | Knight Hawk [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Advances to (distributions from) affiliates, net	(9,076)
Equity in comprehensive income (loss)	2,569
Ending Balance	87,493
Successor [Member] | DTA [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Advances to (distributions from) affiliates, net	822
Equity in comprehensive income (loss)	(841)
Ending Balance	8,581
Successor [Member] | Millennium [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Ending Balance	0
Successor [Member] | Tongue River [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Ending Balance	0
Successor [Member] | Other [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Equity in comprehensive income (loss)	(25)
Ending Balance	$ 0

Sales Contracts (Narrative) (De

Sales Contracts (Narrative) (Details) $ in Millions	Dec. 31, 2016USD ($)
Acquired Sales Contracts [Abstract]
2,017	$ 54.3
2,018	10.7
2,019	1.1
2,020	0.6
2,021	$ 0.1

Sales Contracts (Schedule of Sa

Sales Contracts (Schedule of Sales Contracts) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Successor [Member]
Acquired Finite-Lived Intangible Assets And Liabilities By Major Class [Line Items]
Prepaid royalties	$ 0
Acquired fair value, Assets	97,196
Acquired fair value, Liabilities	31,742
Accumulated amortization, Asset	(25,625)
Accumulated amortization, Liabilities	(24,829)
Total, Assets	71,571
Total, Liabilities	6,913
Net total, Liabilities	64,658
Coal Supply Agreement, Liabilities	5,114
Successor [Member] | Other Current Assets [Member]
Acquired Finite-Lived Intangible Assets And Liabilities By Major Class [Line Items]
Coal supply agreement, Assets	59,702
Successor [Member] | Accrued Liabilities [Member]
Acquired Finite-Lived Intangible Assets And Liabilities By Major Class [Line Items]
Coal Supply Agreement, Liabilities	5,114
Successor [Member] | Other Assets [Member]
Acquired Finite-Lived Intangible Assets And Liabilities By Major Class [Line Items]
Coal supply agreement, Assets	11,869
Successor [Member] | Other Noncurrent Liabilities [Member]
Acquired Finite-Lived Intangible Assets And Liabilities By Major Class [Line Items]
Coal Supply Agreement, Liabilities	$ 1,799
Predecessor [Member]
Acquired Finite-Lived Intangible Assets And Liabilities By Major Class [Line Items]
Prepaid royalties		$ 3,406	$ 41,990	$ 15,356
Acquired fair value, Assets			131,299
Acquired fair value, Liabilities			166,697
Accumulated amortization, Asset			(130,839)
Accumulated amortization, Liabilities			(151,354)
Total, Assets			460
Total, Liabilities			15,343
Net total, Liabilities			(14,883)
Coal Supply Agreement, Liabilities			3,852
Predecessor [Member] | Other Current Assets [Member]
Acquired Finite-Lived Intangible Assets And Liabilities By Major Class [Line Items]
Coal supply agreement, Assets			460
Predecessor [Member] | Accrued Liabilities [Member]
Acquired Finite-Lived Intangible Assets And Liabilities By Major Class [Line Items]
Coal Supply Agreement, Liabilities			3,852
Predecessor [Member] | Other Assets [Member]
Acquired Finite-Lived Intangible Assets And Liabilities By Major Class [Line Items]
Coal supply agreement, Assets			0
Predecessor [Member] | Other Noncurrent Liabilities [Member]
Acquired Finite-Lived Intangible Assets And Liabilities By Major Class [Line Items]
Coal Supply Agreement, Liabilities			$ 11,491

Derivatives (Narrative) (Detail

Derivatives (Narrative) (Details) gal in Millions, $ in Millions	9 Months Ended	12 Months Ended
	Oct. 01, 2016USD ($)	Dec. 31, 2016USD ($)gal$ / option	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Derivative [Line Items]
Net unrealized and realized gains (losses) related to trading portfolio	$ (0.9)		$ 5.7	$ 3.2
Year One [Member]
Derivative [Line Items]
Value of trading portfolio realized		$ 0.2
Diesel Purchases [Member] | Heating Oil [Member]
Derivative [Line Items]
Quantities under derivative contracts | gal		30.7
Average strike price (in dollars per option) | $ / option		1.72
Diesel Purchases [Member] | Minimum [Member]
Derivative [Line Items]
Gallons of diesel fuel purchased annually | gal		45
Diesel Purchases [Member] | Maximum [Member]
Derivative [Line Items]
Gallons of diesel fuel purchased annually | gal		50
Other Current Liabilities [Member]
Derivative [Line Items]
Right to reclaim cash collateral, liability			$ 1.7
Other Current Assets [Member]
Derivative [Line Items]
Right to reclaim cash collateral, asset		$ 2.8

Derivatives (Schedule of Price

Derivatives (Schedule of Price Risk Derivatives) (Details) T in Thousands	Dec. 31, 2016T
Coal Sales [Member]
Derivative [Line Items]
Derivatives Held	540
Coal Purchases [Member]
Derivative [Line Items]
Derivatives Held	480
Year One [Member] | Coal Sales [Member]
Derivative [Line Items]
Derivatives Held	540
Year One [Member] | Coal Purchases [Member]
Derivative [Line Items]
Derivatives Held	480
Year Two [Member] | Coal Sales [Member]
Derivative [Line Items]
Derivatives Held	0
Year Two [Member] | Coal Purchases [Member]
Derivative [Line Items]
Derivatives Held	0

Derivatives (Disclosure of Fair

Derivatives (Disclosure of Fair Value of Derivatives) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Predecessor [Member]
Derivative [Line Items]
Derivative Assets		$ 116,080
Derivative Liabilities		(107,028)
Effect of counterparty netting in derivative assets		(107,028)
Effect of counterparty netting in derivative liabilities		107,028
Net derivative assets as classified in the balance sheet		9,052
Net derivative liabilities as classified in the balance sheet		0
Net derivatives as classified in the balance sheet		9,052
Predecessor [Member] | Designated as Hedging Instrument [Member] | Coal [Member]
Derivative [Line Items]
Derivative Assets		4
Derivative Liabilities		(20)
Predecessor [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative Assets		116,076
Derivative Liabilities		(107,008)
Predecessor [Member] | Not Designated as Hedging Instrument [Member] | Heating Oil-Diesel Purchases [Member]
Derivative [Line Items]
Derivative Assets		1,017
Predecessor [Member] | Not Designated as Hedging Instrument [Member] | Coal Held for Trading Purposes [Member]
Derivative [Line Items]
Derivative Assets		110,653
Derivative Liabilities		(104,814)
Predecessor [Member] | Not Designated as Hedging Instrument [Member] | Coal [Member]
Derivative [Line Items]
Derivative Assets		3,912
Derivative Liabilities		(1,947)
Predecessor [Member] | Not Designated as Hedging Instrument [Member] | Natural Gas [Member]
Derivative [Line Items]
Derivative Assets		494
Derivative Liabilities		$ (247)
Successor [Member]
Derivative [Line Items]
Derivative Assets	$ 74,155
Derivative Liabilities	(69,348)
Effect of counterparty netting in derivative assets	(69,247)
Effect of counterparty netting in derivative liabilities	69,247
Net derivative assets as classified in the balance sheet	4,908
Net derivative liabilities as classified in the balance sheet	(101)
Net derivatives as classified in the balance sheet	4,807
Successor [Member] | Designated as Hedging Instrument [Member] | Coal [Member]
Derivative [Line Items]
Derivative Assets	0
Derivative Liabilities	(15)
Successor [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative Assets	74,155
Derivative Liabilities	(69,333)
Successor [Member] | Not Designated as Hedging Instrument [Member] | Heating Oil-Diesel Purchases [Member]
Derivative [Line Items]
Derivative Assets	4,646
Successor [Member] | Not Designated as Hedging Instrument [Member] | Coal Held for Trading Purposes [Member]
Derivative [Line Items]
Derivative Assets	68,948
Derivative Liabilities	(68,740)
Successor [Member] | Not Designated as Hedging Instrument [Member] | Coal [Member]
Derivative [Line Items]
Derivative Assets	475
Derivative Liabilities	(580)
Successor [Member] | Not Designated as Hedging Instrument [Member] | Natural Gas [Member]
Derivative [Line Items]
Derivative Assets	86
Derivative Liabilities	$ (13)

Derivatives (Net Derivatives as

Derivatives (Net Derivatives as Reflected on the Balance Sheets) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Successor [Member]
Derivatives, Fair Value [Line Items]
Net derivatives as classified in the balance sheet	$ 4,807
Successor [Member] | Other Current Assets [Member] | Heating Oil [Member]
Derivatives, Fair Value [Line Items]
Net derivatives as classified in the balance sheet	4,646
Successor [Member] | Coal Derivative Assets [Member] | Coal [Member]
Derivatives, Fair Value [Line Items]
Net derivatives as classified in the balance sheet	262
Successor [Member] | Coal Derivative Liabilities [Member] | Coal [Member]
Derivatives, Fair Value [Line Items]
Net derivatives as classified in the balance sheet	$ (101)
Predecessor [Member]
Derivatives, Fair Value [Line Items]
Net derivatives as classified in the balance sheet		$ 9,052
Predecessor [Member] | Other Current Assets [Member] | Heating Oil [Member]
Derivatives, Fair Value [Line Items]
Net derivatives as classified in the balance sheet		1,017
Predecessor [Member] | Coal Derivative Assets [Member] | Coal [Member]
Derivatives, Fair Value [Line Items]
Net derivatives as classified in the balance sheet		8,035
Predecessor [Member] | Coal Derivative Liabilities [Member] | Coal [Member]
Derivatives, Fair Value [Line Items]
Net derivatives as classified in the balance sheet		$ 0

Derivatives (Effects of Derivat

Derivatives (Effects of Derivatives on Measures of Financial Performance) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI (Effective Portion)	$ 0	$ (136)	$ 6,098	$ 5,745
Gains (Losses) Reclassified from Accumulated OCI into Income (Effective Portion)	0	397	9,575	2,643
Successor [Member] | Coal [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives	(408)
Coal derivative settlements, non-hedging	116
Successor [Member] | Heating Oil-Diesel Purchases [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Realized Gains (Losses)	827
Successor [Member] | Heating Oil-Fuel Surchages [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Realized Gains (Losses)	0
Successor [Member] | Natural Gas [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Realized Gains (Losses)	(91)
Successor [Member] | Foreign Currency [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Realized Gains (Losses)	(9)
Predecessor [Member] | Coal [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Derivatives		(1,662)	(3,883)	430
Coal derivative settlements, non-hedging		(476)	3,236	5,956
Predecessor [Member] | Heating Oil-Diesel Purchases [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Realized Gains (Losses)		826	(8,294)	(7,848)
Predecessor [Member] | Heating Oil-Fuel Surchages [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Realized Gains (Losses)		0		(405)
Predecessor [Member] | Natural Gas [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Realized Gains (Losses)		(463)	878	0
Predecessor [Member] | Foreign Currency [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Realized Gains (Losses)		(451)	(887)	0
Long [Member] | Coal Contract [Member] | Designated as Hedging Instrument [Member] | Cost of Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI (Effective Portion)	0	536	(6,718)	(5,097)
Gains (Losses) Reclassified from Accumulated OCI into Income (Effective Portion)	0	(1,237)	(9,060)	(2,693)
Short [Member] | Coal Contract [Member] | Designated as Hedging Instrument [Member] | Sales Revenue, Net [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI (Effective Portion)	0	(672)	12,816	10,842
Gains (Losses) Reclassified from Accumulated OCI into Income (Effective Portion)	$ 0	$ 1,634	$ 18,635	$ 5,336

Accrued Expenses and Other Cu88

Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2015
Successor [Member]
Debt Instrument [Line Items]
Payroll and employee benefits	$ 58,468
Taxes other than income taxes	92,733
Interest	8,032
Sales contracts	5,114
Workers’ compensation	15,184
Asset retirement obligations	19,515
Other	6,194
Accrued Liabilities, Current	$ 205,240
Predecessor [Member]
Debt Instrument [Line Items]
Payroll and employee benefits			$ 58,423
Taxes other than income taxes			104,755
Interest			119,785
Sales contracts			3,852
Workers’ compensation			16,875
Asset retirement obligations		$ 17,290	13,795
Other			11,965
Accrued Liabilities, Current			$ 329,450

Debt and Financing Arrangemen89

Debt and Financing Arrangements (Debt Outstanding) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Oct. 01, 2016	Jan. 11, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Debt issuance costs	$ (5,182)			$ (66,300)
Current maturities of debt				5,042,353
Term Loan Due 2021 [Member]
Debt Instrument [Line Items]
Term loan	$ 325,684
7.00% Senior Notes Due 2019 [Member]
Debt Instrument [Line Items]
Senior notes interest rate (percent)	7.00%		7.00%
8.00% Senior Secured Notes due 2019 [Member]
Debt Instrument [Line Items]
Senior notes interest rate (percent)	8.00%		8.00%
9.875% Senior Notes Due 2019 [Member]
Debt Instrument [Line Items]
Senior notes interest rate (percent)	9.875%		9.875%
7.25% Senior Notes Due 2020 [Member]
Debt Instrument [Line Items]
Senior notes interest rate (percent)	7.25%		7.25%
7.25% Senior Notes Due 2021 [Member]
Debt Instrument [Line Items]
Senior notes interest rate (percent)	7.25%		7.25%
Successor [Member]
Debt Instrument [Line Items]
Other	$ 37,195
Debt issuance costs	0
Total	362,879
Current maturities of debt	11,038
Long-term debt	351,841
Successor [Member] | Term Loan Due 2021 [Member]
Debt Instrument [Line Items]
Term loan	325,684
Current maturities of debt		$ 3,300
Successor [Member] | 7.00% Senior Notes Due 2019 [Member]
Debt Instrument [Line Items]
Senior notes	0
Successor [Member] | 8.00% Senior Secured Notes due 2019 [Member]
Debt Instrument [Line Items]
Senior notes	0
Successor [Member] | 9.875% Senior Notes Due 2019 [Member]
Debt Instrument [Line Items]
Senior notes	0
Successor [Member] | 7.25% Senior Notes Due 2020 [Member]
Debt Instrument [Line Items]
Senior notes	0
Successor [Member] | 7.25% Senior Notes Due 2021 [Member]
Debt Instrument [Line Items]
Senior notes	0
Predecessor [Member]
Debt Instrument [Line Items]
Other				47,134
Debt issuance costs				(64,857)
Total				5,073,306
Current maturities of debt				5,042,353
Long-term debt				30,953
Predecessor [Member] | 7.00% Senior Notes Due 2019 [Member]
Debt Instrument [Line Items]
Senior notes interest rate (percent)		7.00%
Senior notes				1,000,000
Predecessor [Member] | 8.00% Senior Secured Notes due 2019 [Member]
Debt Instrument [Line Items]
Senior notes interest rate (percent)		8.00%
Senior notes				350,000
Predecessor [Member] | 9.875% Senior Notes Due 2019 [Member]
Debt Instrument [Line Items]
Senior notes interest rate (percent)		9.875%
Senior notes				365,600
Predecessor [Member] | 7.25% Senior Notes Due 2020 [Member]
Debt Instrument [Line Items]
Senior notes interest rate (percent)		7.25%
Senior notes				500,000
Predecessor [Member] | 7.25% Senior Notes Due 2021 [Member]
Debt Instrument [Line Items]
Senior notes interest rate (percent)		7.25%
Senior notes				1,000,000
Term Loan Due 2018 [Member] | Loans Payable [Member]
Debt Instrument [Line Items]
Term loan	1,886,125			1,930,000
Term Loan Due 2018 [Member] | Successor [Member] | Loans Payable [Member]
Debt Instrument [Line Items]
Term loan	$ 0
Term Loan Due 2018 [Member] | Predecessor [Member] | Loans Payable [Member]
Debt Instrument [Line Items]
Term loan				$ 1,875,429

Debt and Financing Arrangemen90

Debt and Financing Arrangements (Successor Company Debt) (Details) - USD ($)	Oct. 05, 2016	Dec. 31, 2016	Jan. 13, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Letters of credit outstanding				$ 21,300,000
Successor [Member]
Debt Instrument [Line Items]
Securitized accounts receivable			$ 200,000,000
Term of securitization agreement	3 years
Securitization agreement liquidity covenant amount	$ 175,000,000
Number of consecutive days under liquidity threshold	60 days
Successor [Member] | Senior Notes [Member] | New First Lien Debt Facility [Member]
Debt Instrument [Line Items]
Maximum amount of Debtors' liquidity	$ 300,000,000
Quarterly principal amortization payments	$ 816,250
Accrual of PIK interest (percent)	1.00%
Amount of voting equity interests of domestic subsidiaries guaranteed (percent)	100.00%
Amount of voting equity interests of foreign owned subsidiaries guaranteed (percent)	65.00%
Net cash proceeds of from debt issuances and other non-ordinary sales or dispositions (percent)	100.00%
Default to indebtedness	$ 35,000,000
Default to surety, reclamation or similar bond	50,000,000
Default to uninsured judgment	35,000,000
Uninsured losses or proceedings against	$ 35,000,000
Term of instrument	5 years
Successor [Member] | Senior Notes [Member] | New First Lien Debt Facility [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	9.00%
Successor [Member] | Senior Notes [Member] | New First Lien Debt Facility [Member] | LIBOR [Member] | Minimum [Member]
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	1.00%
Successor [Member] | Senior Notes [Member] | New First Lien Debt Facility [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	8.00%
Successor [Member] | Line of Credit [Member] | Extended Securitization Facility [Member]
Debt Instrument [Line Items]
Letters of credit outstanding		$ 154,000,000
Borrowing base		83,400,000
Cash collateral		71,000,000
Remaining availability		$ 0

Debt and Financing Arrangemen91

Debt and Financing Arrangements (Predecessor Company Debt) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Jan. 11, 2016
7.00% Senior Notes Due 2019 [Member]
Debt Instrument [Line Items]
Senior notes interest rate (percent)				7.00%	7.00%
7.25% Senior Notes Due 2020 [Member]
Debt Instrument [Line Items]
Senior notes interest rate (percent)				7.25%	7.25%
7.25% Senior Notes Due 2021 [Member]
Debt Instrument [Line Items]
Senior notes interest rate (percent)				7.25%	7.25%
9.875% Senior Notes Due 2019 [Member]
Debt Instrument [Line Items]
Senior notes interest rate (percent)				9.875%	9.875%
8.00% Senior Secured Notes due 2019 [Member]
Debt Instrument [Line Items]
Senior notes interest rate (percent)				8.00%	8.00%
Predecessor [Member]
Debt Instrument [Line Items]
2,017				$ 11,038
2,018				10,324
2,019				11,479
2,020				11,761
2,021				317,987
Thereafter				290
Total				$ 362,879
Debt financing costs	$ 23,011	$ 0	$ 4,519
Professional fees	$ 2,200	24,200
Predecessor [Member] | 7.00% Senior Notes Due 2019 [Member]
Debt Instrument [Line Items]
Senior notes interest rate (percent)	7.00%
Predecessor [Member] | 7.25% Senior Notes Due 2020 [Member]
Debt Instrument [Line Items]
Senior notes interest rate (percent)	7.25%
Predecessor [Member] | 7.25% Senior Notes Due 2021 [Member]
Debt Instrument [Line Items]
Senior notes interest rate (percent)	7.25%
Predecessor [Member] | 9.875% Senior Notes Due 2019 [Member]
Debt Instrument [Line Items]
Senior notes interest rate (percent)	9.875%
Predecessor [Member] | 8.00% Senior Secured Notes due 2019 [Member]
Debt Instrument [Line Items]
Senior notes interest rate (percent)	8.00%
Predecessor [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Write off of deferred debt issuance cost		$ 3,700

Taxes (Narrative) (Details)

Taxes (Narrative) (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Oct. 02, 2016	Oct. 01, 2016
Operating Loss Carryforwards [Line Items]
Cancellation of debt income				$ 3,353,000,000
Decrease in operating loss carryforwards					$ 3,015,000,000
Decrease in tax basis of assets					3,200,000
Operating loss carryforwards	$ 931,100,000	$ 931,100,000
Annual limitation on operating loss use	29,800,000	29,800,000
Increase (decrease) in valuation allowance	(1,289,000,000)		$ 865,100,000
Additional valuation allowance	1,185,000,000	1,185,000,000
Net operating loss carryforwards	1,022,000,000	1,022,000,000	1,135,000,000
Interest and penalties accrued related to unrecognized tax benefits	$ 500,000	500,000	$ 1,700,000
Reductions as a result of lapses in the statute of limitations		$ 37,110,000
Alternative Minimum Tax Credits [Member]
Operating Loss Carryforwards [Line Items]
Decrease in tax credit carryforwards					92,000,000
Tax credit carryforwards				22,800,000
Capital Loss Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Decrease in tax credit carryforwards					$ 59,200,000
Tax credit carryforwards				5,900,000
Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards				$ 931,100,000

Taxes (Schedule of Components o

Taxes (Schedule of Components of Income Tax) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Predecessor [Member]
Current:
Federal		$ 0	$ 0	$ 0
State		7	3	25
Total current		7	3	25
Deferred:
Federal		(4,720)	(329,393)	18,535
State		87	(43,990)	7,074
Total deferred		(4,633)	(373,383)	25,609
Provision for (benefit from) income taxes		$ (4,626)	$ (373,380)	$ 25,634
Successor [Member]
Current:
Federal	$ 0
State	(252)
Total current	(252)
Deferred:
Federal	1,352
State	56
Total deferred	1,408
Provision for (benefit from) income taxes	$ 1,156

Taxes (Schedule of Effective In

Taxes (Schedule of Effective Income Tax Rate Reconciliation) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Predecessor [Member]
Income Tax Examination [Line Items]
Income tax provision (benefit) at statutory rate		$ 433,109	$ (1,150,283)	$ (186,452)
Percentage depletion allowance		(3,681)	(19,035)	(12,692)
State taxes, net of effect of federal taxes		(46,122)	(76,445)	(3,903)
Reversal of cancellation of indebtedness income		(1,493,162)	0	0
Worthless stock deduction		(80,077)	0	0
Change in valuation allowance		1,185,326	865,146	226,929
Other, net		(19)	7,237	1,752
Provision for (benefit from) income taxes		$ (4,626)	$ (373,380)	$ 25,634
Successor [Member]
Income Tax Examination [Line Items]
Income tax provision (benefit) at statutory rate	$ 12,112
Percentage depletion allowance	(4,292)
State taxes, net of effect of federal taxes	633
Reversal of cancellation of indebtedness income	0
Worthless stock deduction	0
Change in valuation allowance	(7,655)
Other, net	358
Provision for (benefit from) income taxes	$ 1,156

Taxes (Schedule of Deferred Tax

Taxes (Schedule of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Income Tax Contingency [Line Items]
Net operating loss carryforwards	$ 1,022,000	$ 1,135,000
Predecessor [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards		1,086,332
Alternative minimum tax credit carryforwards		120,994
Investment in tax partnerships & corporations		0
Reclamation and mine closure		121,276
Goodwill		38,671
Workers’ compensation		42,835
Share based compensation		22,612
Sales contracts		17,466
Retiree benefit plans		16,996
Advance royalties		18,751
Losses from disposed operations resulting from Patriot Coal bankruptcy		39,287
Other, primarily accrued liabilities		45,303
Gross deferred tax assets		1,570,523
Valuation allowance		(1,135,399)
Total deferred tax assets		435,124
Plant and equipment		389,169
Deferred development		41,047
Sales contracts		0
Other		4,706
Total deferred tax liabilities		434,922
Net deferred (asset) liability		$ (202)
Successor [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards	376,293
Alternative minimum tax credit carryforwards	22,798
Investment in tax partnerships & corporations	604,914
Reclamation and mine closure	0
Goodwill	5,135
Workers’ compensation	0
Share based compensation	0
Sales contracts	0
Retiree benefit plans	4,013
Advance royalties	0
Losses from disposed operations resulting from Patriot Coal bankruptcy	0
Other, primarily accrued liabilities	30,103
Gross deferred tax assets	1,043,256
Valuation allowance	(1,021,553)
Total deferred tax assets	21,703
Plant and equipment	7,332
Deferred development	0
Sales contracts	12,658
Other	1,600
Total deferred tax liabilities	21,590
Net deferred (asset) liability	$ (113)

Taxes (Schedule of Gross Unreco

Taxes (Schedule of Gross Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning Balance	$ 38,877	$ 34,709	$ 31,789
Additions based on tax positions related to the current year	2,709	4,168	2,920
Additions for tax positions of prior years	2,979
Reductions as a result of lapses in the statute of limitations	(37,110)
Ending Balance	$ 7,455	$ 38,877	$ 34,709

Asset Retirement Obligations (N

Asset Retirement Obligations (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
asset retirement obligations [Line Items]
Letters of credit outstanding		$ 21.3
Cash collateral for surety bond	$ 33.4
Asset retirement obligations [Member]
asset retirement obligations [Line Items]
Surety bonds outstanding		$ 528.3

Asset Retirement Obligations (S

Asset Retirement Obligations (Schedule of Asset Retirement Obligations) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Successor [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning Balance	$ 354,326
Accretion expense	7,634
Obligations of divested operations	0
Adjustments to the liability from changes in estimates	0
Liabilities settled	(5,218)
Fresh start accounting adjustment	0
Ending Balance	356,742	$ 354,326
Current portion included in accrued expenses	(19,515)
Noncurrent liability	337,227
Predecessor [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning Balance	$ 354,326	410,454	$ 418,118
Accretion expense		24,321	33,680	$ 32,909
Obligations of divested operations		(14,702)	(334)
Adjustments to the liability from changes in estimates		3,003	(28,570)
Liabilities settled		(11,087)	(12,440)
Fresh start accounting adjustment		(57,663)	0
Ending Balance		354,326	410,454	$ 418,118
Current portion included in accrued expenses		(17,290)	(13,795)
Noncurrent liability		$ 337,036	$ 396,659

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of senior notes and other long-term debt, including amounts classified as current	$ 362.9	$ 937.1
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net unrealized gains related to level 3 financial instruments	$ 0.4

Fair Value Measurements (Summar

Fair Value Measurements (Summary of Financial Assets and Liabilities Accounted for at Fair Value) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Successor [Member]
Assets:
Investments in marketable securities	$ 90,209
Derivatives	4,908
Total assets	95,117
Liabilities:
Derivatives	101
Successor [Member] | Level 1 [Member]
Assets:
Investments in marketable securities	2,137
Derivatives	262
Total assets	2,399
Liabilities:
Derivatives	(8)
Successor [Member] | Level 2 [Member]
Assets:
Investments in marketable securities	88,072
Total assets	88,072
Liabilities:
Derivatives	0
Successor [Member] | Level 3 [Member]
Assets:
Derivatives	4,646
Total assets	4,646
Liabilities:
Derivatives	$ 109
Predecessor [Member]
Assets:
Investments in marketable securities		$ 201,910
Derivatives		9,052
Total assets		210,962
Liabilities:
Derivatives		0
Predecessor [Member] | Level 1 [Member]
Assets:
Investments in marketable securities		11,713
Derivatives		5,597
Total assets		17,310
Predecessor [Member] | Level 2 [Member]
Assets:
Investments in marketable securities		190,197
Derivatives		1,023
Total assets		191,220
Liabilities:
Derivatives		0
Predecessor [Member] | Level 3 [Member]
Assets:
Derivatives		2,432
Total assets		2,432
Liabilities:
Derivatives		$ 0

Fair Value Measurements (Sum101

Fair Value Measurements (Summary of Change in the Fair Values of Financial Instruments Categorized as Level 3) (Details) - Level 3 [Member] - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2015
Successor [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	$ 3,842
Realized and unrealized losses recognized in earnings, net	926
Included in other comprehensive income	0
Purchases	1,225
Issuances	(34)
Settlements	(1,422)
Ending balance	4,537	$ 3,842
Predecessor [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	$ 3,842	2,432	$ 3,040
Realized and unrealized losses recognized in earnings, net		(1,686)	(8,602)
Included in other comprehensive income		0	(1,341)
Purchases		5,021	13,541
Issuances		(488)	(4,046)
Settlements		(1,437)	(160)
Ending balance		$ 3,842	$ 2,432

(Narrative) (Details)

(Narrative) (Details)	Aug. 04, 2015	Dec. 31, 2016$ / sharesshares	Oct. 05, 2016$ / shares	Oct. 02, 2016$ / sharesshares	Dec. 31, 2015$ / sharesshares
Class of Stock [Line Items]
Warrants exercised		2,871
Successor [Member]
Class of Stock [Line Items]
Common stock, shares issued		25,002,000
Common stock, par value | $ / shares		$ 0.01
Predecessor [Member]
Class of Stock [Line Items]
Common stock, shares issued					21,446,000
Common stock, par value | $ / shares					$ 0.01
Reverse stock split conversion ratio	0.1
Class A Common Stock [Member]
Class of Stock [Line Items]
Common stock, shares issued				24,589,834
Common stock, par value | $ / shares			$ 0.01
Class A Common Stock [Member] | Successor [Member]
Class of Stock [Line Items]
Common stock, shares issued				24,589,834
Common stock, par value | $ / shares				$ 0.01
Warrants issued				1,914,856
Class B Common Stock [Member]
Class of Stock [Line Items]
Common stock, shares issued				410,166
Common stock, par value | $ / shares				$ 0.01
Class B Common Stock [Member] | Successor [Member]
Class of Stock [Line Items]
Common stock, shares issued				410,166
Common stock, par value | $ / shares				$ 0.01

Stock-Based Compensation and103

Stock-Based Compensation and Other Incentive Plans (Narrative) (Details) shares in Millions, $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016USD ($)awardshares	Oct. 01, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of award types granted in period | award	3
Fresh-start accounting adjustment to incentive compensation	$ 3.7
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 1	$ 1.9	$ 5.9	$ 5.6
Time Based Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of award types granted in period | award	2
Time Based Restricted Stock Units (RSUs) [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year
Time Based Restricted Stock Units (RSUs) [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Performance Based Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of award types granted in period | award	1
Vesting period	3 years
Volatility rate (percent)	58.00%
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense		0.2	$ 1.4	3.2
2016 Omnibus Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for incentive plan | shares	3
Number of shares available for grant | shares	2.6
Long Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Requisite service period			3 years
Compensation expense	$ 1.6	$ 7.2	$ 7.9	$ 10.1
Reduction in scheduled compensation payouts	6
Amounts unpaid under long term incentive plan	$ 13.9		$ 17.8

Stock-Based Compensation and104

Stock-Based Compensation and Other Incentive Plans (Restricted Stock Unit Activity) (Details) - Restricted Stock Units (RSUs) [Member] shares in Thousands	3 Months Ended
	Dec. 31, 2016$ / sharesshares
Restricted Stock Common Shares
Outstanding at beginning of period (in shares) | shares	0
Granted (in shares) | shares	384
Forfeited (in shares) | shares	0
Canceled (in shares) | shares	0
Outstanding at end of period (in shares) | shares	384
Weighted Average Grant Date Fair Value
Outstanding weighted average grant date fair value at beginning of period (in dollars per share) | $ / shares	$ 0
Granted (in dollars per share) | $ / shares	$ 72
Forfeited (in dollars per share) | $ / shares	0
Canceled (in dollars per share) | $ / shares	$ 0
Outstanding weighted average grant date fair value at end of period (in dollars per share) | $ / shares	$ 72

Workers' Compensation Expens105

Workers' Compensation Expense (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Reimbursable liabilities		$ 19.4
Insurance receivable, current		0.8
Insurance receivable, noncurrent		$ 18.6
Workers' Compensation [Member]
Defined Benefit Plan Disclosure [Line Items]
Surety bonds and letters of credit outstanding	$ 146.2

Workers' Compensation Expens106

Workers' Compensation Expense (Worker's Compensation Expense) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Successor [Member]
Accrued Workers' Compensation [Line Items]
Service cost	$ 1,583
Interest cost	1,126
Net amortization	0
Successor [Member] | Workers' Compensation [Member]
Accrued Workers' Compensation [Line Items]
Total workers’ compensation expense	5,871
Successor [Member] | Occupational Disease [Member]
Accrued Workers' Compensation [Line Items]
Service cost	1,583
Interest cost	1,126
Total occupational disease	2,709
Successor [Member] | Traumatic Injury Claims and Assessments [Member]
Accrued Workers' Compensation [Line Items]
Traumatic injury claims and assessments	$ 3,162
Predecessor [Member]
Accrued Workers' Compensation [Line Items]
Service cost		$ 3,465	$ 4,282	$ 1,734
Interest cost		3,184	3,944	2,914
Net amortization		4,325	6,973	(216)
Predecessor [Member] | Workers' Compensation [Member]
Accrued Workers' Compensation [Line Items]
Total workers’ compensation expense		17,602	31,980	24,356
Predecessor [Member] | Occupational Disease [Member]
Accrued Workers' Compensation [Line Items]
Service cost		3,465	4,282
Interest cost		3,184	3,944
Total occupational disease		10,974	15,199	4,432
Predecessor [Member] | Traumatic Injury Claims and Assessments [Member]
Accrued Workers' Compensation [Line Items]
Traumatic injury claims and assessments		$ 6,628	$ 16,781	$ 19,924

Workers' Compensation Expens107

Workers' Compensation Expense (Schedule of Amounts Recognized in Balance Sheet) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Oct. 02, 2016	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Accrued Workers' Compensation [Line Items]
Insurance receivable, current	$ 800
Successor [Member]
Accrued Workers' Compensation [Line Items]
Total obligations	199,752
Less amount included in accrued expenses	15,184
Noncurrent obligations	184,568
Predecessor [Member]
Accrued Workers' Compensation [Line Items]
Total obligations				$ 129,145
Less amount included in accrued expenses				16,875
Noncurrent obligations				112,270
Occupational Disease [Member] | Successor [Member]
Accrued Workers' Compensation [Line Items]
Occupational disease costs	111,159	$ 119,710
Occupational Disease [Member] | Predecessor [Member]
Accrued Workers' Compensation [Line Items]
Occupational disease costs			$ 119,710	90,836	$ 72,749
Workers' Compensation [Member] | Successor [Member]
Accrued Workers' Compensation [Line Items]
Occupational disease costs	$ 88,593
Workers' Compensation [Member] | Predecessor [Member]
Accrued Workers' Compensation [Line Items]
Occupational disease costs				$ 38,309

Workers' Compensation Expens108

Workers' Compensation Expense (Occupational Disease Costs Activity and Assumptions) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Jun. 30, 2016	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Self Insurance Reserve [Roll Forward]
Curtailments		$ 3,600
Successor [Member]
Self Insurance Reserve [Roll Forward]
Service cost	$ 1,583
Interest cost	1,126
Predecessor [Member]
Self Insurance Reserve [Roll Forward]
Service cost			$ 3,465	$ 4,282	$ 1,734
Interest cost			3,184	3,944	2,914
Occupational Disease [Member] | Successor [Member]
Self Insurance Reserve [Roll Forward]
Service cost	1,583
Interest cost	1,126
Curtailments	0
Actuarial (gain) loss	(9,675)
Benefit and administrative payments	(1,585)
Fresh start accounting adjustment	0
End of period	$ 111,159
Discount rate (percent)	4.31%
Occupational Disease [Member] | Predecessor [Member]
Self Insurance Reserve [Roll Forward]
Beginning of period	$ 119,710	$ 90,836	90,836	72,749
Service cost			3,465	4,282
Interest cost			3,184	3,944
Curtailments			4,156
Actuarial (gain) loss			0	14,284
Benefit and administrative payments			(3,728)	(4,423)
Fresh start accounting adjustment			21,797	0
End of period			$ 119,710	$ 90,836	$ 72,749
Discount rate (percent)			3.80%	4.76%

Employee Benefit Plans (Narrati

Employee Benefit Plans (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation of pension plans	$ 313.6		$ 313.6	$ 301.3
Health care cost trend rate assumed			6.70%
Ultimate trend rate			4.50%
Effect of one percentage point increase on postretirement benefit obligation			$ 11.1
Effect of one percentage point increase on postretirement benefit cost			$ 0.1
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations (percent)			55.00%
Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations (percent)			45.00%
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Contributions			$ 0.4
Other postretirement benefits payments	$ 3.5	$ 13.8		$ 20.5	$ 22.9

Employee Benefit Plans (Schedul

Employee Benefit Plans (Schedule of Defined Benefit Plans Disclosures) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Jun. 30, 2016	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Curtailments		$ 3,600
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Value of Plan Assets at beginning of year		212,392	$ 212,392
Value of Plan Assets at end of year	$ 274,225			$ 212,392
Pension Benefits [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Value of Plan Assets at end of year	252,278
Predecessor [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Service cost			3,465	4,282	$ 1,734
Interest cost			3,184	3,944	2,914
Predecessor [Member] | Pension Benefits [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligations at beginning of year	341,427	301,292	301,292	353,736
Service cost	0		0	9	21,478
Interest cost			9,338	14,604	17,070
Re-entry of former Magnum employees			0	0
Settlements			0	0
Curtailments			454
Benefits paid			(8,699)	(61,955)
Other-primarily actuarial gain			0	(5,102)
Benefit Obligations at end of year			341,427	301,292	353,736
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Value of Plan Assets at beginning of year	292,726	273,499	273,499	336,709
Actual return on plan assets			27,811	(1,679)
Employer contributions			115	424
Benefits paid			(8,699)	(61,955)
Value of Plan Assets at end of year			292,726	273,499	336,709
Accrued benefit cost			(48,701)	(27,793)
Prior service credit (cost)			0	0
Accumulated gain (loss)			0	(16,769)
Total not yet recognized as a component of net periodic benefit cost			0	(16,769)
Current liability			(420)	(420)
Noncurrent liability			(48,281)	(27,373)
Pension and Other Postretirement Defined Benefit Plans, Liabilities			(48,701)	(27,793)
Fresh start accounting adjustment			39,042	0
Predecessor [Member] | Other Postretirement Benefits [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligations at beginning of year	120,311	103,460	103,460	36,098
Service cost			393	866	1,649
Interest cost			3,223	1,904	1,841
Re-entry of former Magnum employees			0	85,843
Settlements			0	0
Curtailments			714	0
Benefits paid			(8,273)	(3,646)
Other-primarily actuarial gain			0	(17,605)
Benefit Obligations at end of year			120,311	103,460	36,098
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Value of Plan Assets at beginning of year	0	$ 0	0	0
Actual return on plan assets			0	0
Employer contributions			8,273	3,646
Benefits paid			(8,273)	(3,646)
Value of Plan Assets at end of year			0	0	$ 0
Accrued benefit cost			(120,311)	(103,460)
Prior service credit (cost)			0	26,944
Accumulated gain (loss)			0	11,313
Total not yet recognized as a component of net periodic benefit cost			0	38,257
Current liability			(8,352)	(3,650)
Noncurrent liability			(111,959)	(99,810)
Pension and Other Postretirement Defined Benefit Plans, Liabilities			(120,311)	$ (103,460)
Fresh start accounting adjustment			20,794
Successor [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Service cost	1,583
Interest cost	1,126
Successor [Member] | Pension Benefits [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligations at beginning of year	341,427
Service cost	0
Interest cost	2,768
Re-entry of former Magnum employees	0
Settlements	(135)
Curtailments	0
Benefits paid	(11,009)
Other-primarily actuarial gain	(19,422)
Benefit Obligations at end of year	313,629		341,427
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Value of Plan Assets at beginning of year	292,726
Actual return on plan assets	(7,899)
Employer contributions	407
Benefits paid	(11,009)
Value of Plan Assets at end of year	274,225		292,726
Accrued benefit cost	(39,404)
Prior service credit (cost)	0
Accumulated gain (loss)	6,751
Total not yet recognized as a component of net periodic benefit cost	6,751
Current liability	(520)
Noncurrent liability	(38,884)
Pension and Other Postretirement Defined Benefit Plans, Liabilities	(39,404)
Fresh start accounting adjustment	0
Successor [Member] | Other Postretirement Benefits [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligations at beginning of year	120,311
Service cost	180
Interest cost	978
Re-entry of former Magnum employees	0
Settlements	0
Curtailments	0
Benefits paid	(1,962)
Other-primarily actuarial gain	(7,640)
Benefit Obligations at end of year	111,867		120,311
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Value of Plan Assets at beginning of year	0
Employer contributions	1,962
Benefits paid	(1,962)
Value of Plan Assets at end of year	0		$ 0
Accrued benefit cost	(111,867)
Prior service credit (cost)	0
Accumulated gain (loss)	7,640
Total not yet recognized as a component of net periodic benefit cost	7,640
Current liability	(10,422)
Noncurrent liability	(101,445)
Pension and Other Postretirement Defined Benefit Plans, Liabilities	(111,867)
Fresh start accounting adjustment	$ 0

Employee Benefit Plans (Sche111

Employee Benefit Plans (Schedule of Net Benefit Costs) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Predecessor [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		$ 3,465	$ 4,282	$ 1,734
Interest cost		3,184	3,944	2,914
Predecessor [Member] | Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0	0	9	21,478
Interest cost		9,338	14,604	17,070
Curtailments		454	0	(25,368)
Settlements		0	2,656	646
Expected return on plan assets		(13,623)	(20,367)	(23,756)
Amortization of prior service credits		0	0	(257)
Amortization of other actuarial losses (gains)		3,973	8,850	3,128
Total net benefit		142	5,752	(7,059)
Predecessor [Member] | Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		393	866	1,649
Interest cost		3,223	1,904	1,841
Curtailments		(970)	0	0
Settlements		0	0	0
Expected return on plan assets		0	0	0
Amortization of prior service credits		(7,854)	(8,335)	(10,003)
Amortization of other actuarial losses (gains)		(849)	(2,109)	(761)
Total net benefit		$ (6,057)	$ (7,674)	$ (7,274)
Successor [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1,583
Interest cost	1,126
Successor [Member] | Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0
Interest cost	2,768
Curtailments	0
Settlements	(135)
Expected return on plan assets	(4,770)
Amortization of prior service credits	0
Amortization of other actuarial losses (gains)	0
Total net benefit	(2,137)
Successor [Member] | Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	180
Interest cost	978
Curtailments	0
Settlements	0
Expected return on plan assets	0
Amortization of prior service credits	0
Amortization of other actuarial losses (gains)	0
Total net benefit	$ 1,158

Employee Benefit Plans (Sche112

Employee Benefit Plans (Schedule of Assumptions Used to Calculate Benefit Obligations) (Details)	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2015
Predecessor [Member] | Pension Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate		339.00%	459.00%
Predecessor [Member] | Other Postretirement Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate		337.00%	457.00%
Successor [Member] | Pension Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate			395.00%
Successor [Member] | Other Postretirement Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	393.00%

Employee Benefit Plans (Sche113

Employee Benefit Plans (Schedule of Assumptions Used) (Details)	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2014	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Successor [Member] | Pension Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	3.95%		3.39%
Expected return on plan assets			685.00%
Successor [Member] | Other Postretirement Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate			337.00%
Predecessor [Member] | Pension Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate		4.60%		3.80%	4.41%	4.61%	4.14%	4.23%	4.59%	4.15%	5.08%
Expected return on plan assets												685.00%	700.00%	775.00%
Predecessor [Member] | Other Postretirement Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate				5.70%					3.80%				391.00%	458.00%

Employee Benefit Plans (Sche114

Employee Benefit Plans (Schedule of Allocation of Plan Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Other liabilities	$ (22,170)
Total fair value of plan assets	274,225	$ 212,392
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	77,022	74,051
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	156,015	119,706
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	19,241	18,635
U.S. Small-Cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	13,520	11,640
U.S. Small-Cap [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	13,520	11,640
U.S. Mid-Cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	29,687	28,524
U.S. Mid-Cap [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	9,422	10,979
U.S. Mid-Cap [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	20,265	17,545
U.S. Large-Cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	70,226	67,244
U.S. Large-Cap [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	34,107	33,249
U.S. Large-Cap [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	36,119	33,995
Non-U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	18,937	18,785
Non-U.S. [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	18,937	18,785
U.S. Government Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	26,519	18,844
U.S. Government Securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	19,973	18,183
U.S. Government Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	6,546	661
Non-U.S. Government Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	1,567	766
Non-U.S. Government Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	1,567	766
U.S. governement asset and mortgage backed securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	1,074	1,056
U.S. governement asset and mortgage backed securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	1,074	1,056
Corporate fixed income [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	58,191	39,939
Corporate fixed income [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	58,191	39,939
State and Local Government Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	6,406	5,725
State and Local Government Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	6,406	5,725
Other Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	26,151	19,869
Other Investments [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	6,910	1,234
Other Investments [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	19,241	$ 18,635
Other fixed income [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	35,519
Short-term Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	$ 8,598

Employee Benefit Plans (Summary

Employee Benefit Plans (Summary of Estimated Future Benefit Payments) (Details) $ in Thousands	Dec. 31, 2015USD ($)
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
2,017	$ 19,403
2,018	21,117
2,019	20,763
2,020	21,209
2,021	21,917
Thereafter	102,619
Total	207,028
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
2,017	12,300
2,018	12,716
2,019	13,033
2,020	13,408
2,021	13,763
Thereafter	64,920
Total	$ 130,140

Earnings (Loss) Per Common S116

Earnings (Loss) Per Common Share (Weighted Average Number of Shares) (Details) - USD ($) shares in Thousands, $ in Thousands	Oct. 01, 2016	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Predecessor [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income (loss)	$ 1,676,091		$ (51,421)	$ (175,887)	$ (206,702)	$ (632,368)	$ (1,999,476)	$ (168,103)	$ (113,195)	$ 1,242,081	$ (2,913,142)	$ (558,353)
Less: earnings allocated to participating securities										0	0	0
Net income (loss) attributable to common shareholders, after earnings allocated to participating securities										$ 1,242,081	$ (2,913,142)	$ (558,353)
Basic weighted average shares outstanding										21,293	21,285	21,222
Effect of dilutive securities										20	0	0
Diluted weighted average shares outstanding										21,313	21,285	21,222
Successor [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income (loss)		$ 33,449
Less: earnings allocated to participating securities		(217)
Net income (loss) attributable to common shareholders, after earnings allocated to participating securities		$ 33,232
Basic weighted average shares outstanding		25,002
Effect of dilutive securities		467
Diluted weighted average shares outstanding		25,469

Leases (Narrative) (Details)

Leases (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
lease payments [Line Items]
Capital Lease Obligations	$ 0		$ 40
Rental expense	5	$ 19.4	28.4	$ 42.1
Royalty expense	45.3	$ 116.4	$ 227.7	$ 242.5
lease [Member]
lease payments [Line Items]
Surety bonds outstanding	$ 32.6

Leases (Schedule of Lease Minim

Leases (Schedule of Lease Minimum Payments) (Details) $ in Thousands	Dec. 31, 2016USD ($)
Property Subject to Operating Lease [Member]
lease payments [Line Items]
2,017	$ 14,653
2,018	14,485
2,019	5,321
2,020	2,260
2,021	1,985
Thereafter	10,317
Total	49,021
Royalty [Member]
lease payments [Line Items]
2,017	3,994
2,018	6,021
2,019	6,105
2,020	7,147
2,021	7,809
Thereafter	46,499
Total	$ 77,575

Risk Concentrations (Narrative)

Risk Concentrations (Narrative) (Details) T in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)T	Dec. 31, 2015USD ($)
Concentration Risk [Line Items]
Tons of coal sold | T	93.9
Percentage of tons sold under long term contract	76.00%
Long term contracts percentage of company revenue	62.00%
Long-term contracts, life term, minimum	1 year
Long-term contracts, life term, maximum	5 years
Electric Utilities [Member]
Concentration Risk [Line Items]
Receivables	$ 96	$ 83.8
Percentage of total trade accounts receivable	52.00%	72.00%
Domestic And Foreign Steel Producers [Member]
Concentration Risk [Line Items]
Trade accounts receivable (net of allowance for doubtful accounts of $0.0 million and $7.8 million, respectively)	$ 88	$ 32.8
Trade receivables, percentage	48.00%	28.00%

Risk Concentrations (Schedule o

Risk Concentrations (Schedule of Foreign Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Successor [Member]
foreign revenue [Line Items]
Sales to customers in foreign countries	$ 174,097
Successor [Member] | Europe [Member]
foreign revenue [Line Items]
Sales to customers in foreign countries	61,408
Successor [Member] | Asia [Member]
foreign revenue [Line Items]
Sales to customers in foreign countries	55,634
Successor [Member] | North America [Member]
foreign revenue [Line Items]
Sales to customers in foreign countries	43,831
Successor [Member] | Central and South America [Member]
foreign revenue [Line Items]
Sales to customers in foreign countries	13,224
Successor [Member] | Brokered Sales [Member]
foreign revenue [Line Items]
Sales to customers in foreign countries	$ 0
Predecessor [Member]
foreign revenue [Line Items]
Sales to customers in foreign countries		$ 280,879	$ 395,323	$ 611,917
Predecessor [Member] | Europe [Member]
foreign revenue [Line Items]
Sales to customers in foreign countries		113,888	170,314	277,565
Predecessor [Member] | Asia [Member]
foreign revenue [Line Items]
Sales to customers in foreign countries		68,536	96,523	156,057
Predecessor [Member] | North America [Member]
foreign revenue [Line Items]
Sales to customers in foreign countries		56,594	40,315	78,445
Predecessor [Member] | Central and South America [Member]
foreign revenue [Line Items]
Sales to customers in foreign countries		41,861	55,323	20,496
Predecessor [Member] | Brokered Sales [Member]
foreign revenue [Line Items]
Sales to customers in foreign countries		$ 0	$ 32,848	$ 79,354

Commitments and Contingencies (

Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016
Loss Contingencies [Line Items]
Amount accrued		$ 2.8		$ 2.2
Amount accrued current portion		2.8		2.2
2,017				$ 48
Transportation capacity agreements	$ 1.6	$ 52.9	$ 36.5

Segment Information (Schedule o

Segment Information (Schedule of Operating Segment Results) (Details) - USD ($) $ in Thousands	3 Months Ended								9 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Successor [Member]
Segment Reporting Information [Line Items]
Revenues	$ 575,688
Adjusted EBITDAR	94,497
Depreciation, depletion and amortization	32,604
Accretion on asset retirement obligations	7,634
Total assets	2,136,597
Capital expenditures	15,214
Successor [Member] | Operating Segments [Member] | PRB [Member]
Segment Reporting Information [Line Items]
Revenues	275,703
Adjusted EBITDAR	55,765
Depreciation, depletion and amortization	9,949
Accretion on asset retirement obligations	5,049
Total assets	446,775
Capital expenditures	934
Successor [Member] | Operating Segments [Member] | APP [Member]
Segment Reporting Information [Line Items]
Revenues	200,377
Adjusted EBITDAR	30,819
Depreciation, depletion and amortization	18,287
Accretion on asset retirement obligations	528
Total assets	576,793
Capital expenditures	13,329
Successor [Member] | Operating Segments [Member] | Other Thermal [Member]
Segment Reporting Information [Line Items]
Revenues	97,382
Adjusted EBITDAR	31,159
Depreciation, depletion and amortization	3,911
Accretion on asset retirement obligations	540
Total assets	129,602
Capital expenditures	684
Successor [Member] | Corporate, Other and Elimination
Segment Reporting Information [Line Items]
Revenues	2,226
Adjusted EBITDAR	(23,246)
Depreciation, depletion and amortization	457
Accretion on asset retirement obligations	1,517
Total assets	983,427
Capital expenditures	$ 267
Predecessor [Member]
Segment Reporting Information [Line Items]
Revenues		$ 550,305	$ 420,298	$ 428,106	$ 563,249	$ 688,544	$ 644,462	$ 677,005	$ 1,398,709	$ 2,573,260	$ 2,937,119
Adjusted EBITDAR									87,303	283,797	313,052
Depreciation, depletion and amortization									191,581	379,345	418,748
Accretion on asset retirement obligations									24,321	33,680	32,909
Total assets					5,041,881				2,123,829	5,041,881	8,346,362
Capital expenditures									82,434	119,024	147,286
Predecessor [Member] | Operating Segments [Member] | PRB [Member]
Segment Reporting Information [Line Items]
Revenues									726,747	1,448,440	1,490,377
Adjusted EBITDAR									113,185	281,039	218,731
Depreciation, depletion and amortization									100,151	176,257	168,522
Accretion on asset retirement obligations									16,940	22,156	20,748
Total assets					1,648,916				456,711	1,648,916	1,762,326
Capital expenditures									612	21,228	21,399
Predecessor [Member] | Operating Segments [Member] | APP [Member]
Segment Reporting Information [Line Items]
Revenues									437,069	637,941	743,973
Adjusted EBITDAR									11,851	70,450	112,719
Depreciation, depletion and amortization									55,311	133,463	163,644
Accretion on asset retirement obligations									1,765	2,267	2,089
Total assets					772,439				619,154	772,439	2,339,739
Capital expenditures									17,296	24,787	46,771
Predecessor [Member] | Operating Segments [Member] | Other Thermal [Member]
Segment Reporting Information [Line Items]
Revenues									213,052	428,809	535,783
Adjusted EBITDAR									31,448	42,734	78,238
Depreciation, depletion and amortization									32,310	47,786	52,991
Accretion on asset retirement obligations									1,988	2,658	2,412
Total assets					366,610				131,173	366,610	406,296
Capital expenditures									3,895	11,277	14,843
Predecessor [Member] | Corporate, Other and Elimination
Segment Reporting Information [Line Items]
Revenues									21,841	58,070	166,986
Adjusted EBITDAR									(69,181)	(110,426)	(96,636)
Depreciation, depletion and amortization									3,809	21,839	33,591
Accretion on asset retirement obligations									3,628	6,599	7,660
Total assets					$ 2,253,916				916,791	2,253,916	3,838,001
Capital expenditures									$ 60,631	$ 61,732	$ 64,273

Segment Information (Reconcilia

Segment Information (Reconciliation of Segment Income from Operations to Consolidated Income Before Income Taxes) (Details) - USD ($) $ in Thousands	Oct. 01, 2016	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2015	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Asset impairment and mine closure costs						$ (488,900)	$ (2,100,000)	$ (19,100)		$ (2,600,000)
Predecessor [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDAR											$ 87,303	$ 283,797	$ 313,052
Depreciation, depletion and amortization											(191,581)	(379,345)	(418,748)
Accretion on asset retirement obligations											(24,321)	(33,680)	(32,909)
Amortization of sales contracts, net											728	8,811	13,187
Asset impairment and mine closure costs			$ (46)	$ (43,701)	$ (85,520)	$ (488,865)	$ (2,120,292)	$ (19,146)	$ 0		(129,267)	(2,628,303)	(24,113)
Losses from disposed operations resulting from Patriot Coal bankruptcy											0	(116,343)	0
Interest expense, net											(133,235)	(393,549)	(383,188)
Net loss resulting from early retirement of debt and debt restructuring											(2,213)	(27,910)	0
Reorganization items, net	$ 1,676,091		$ (20,904)	$ (21,271)	$ (3,875)						1,630,041	0	0
Fresh start coal inventory fair value adjustment											0	0	0
Income (loss) before income taxes											$ 1,237,455	$ (3,286,522)	$ (532,719)
Successor [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDAR		$ 94,497
Depreciation, depletion and amortization		(32,604)
Accretion on asset retirement obligations		(7,634)
Amortization of sales contracts, net		(796)
Asset impairment and mine closure costs		0
Losses from disposed operations resulting from Patriot Coal bankruptcy		0
Interest expense, net		(10,754)
Net loss resulting from early retirement of debt and debt restructuring		0
Reorganization items, net		(759)
Fresh start coal inventory fair value adjustment		(7,345)
Income (loss) before income taxes		$ 34,605

Quarterly Selected Financial124

Quarterly Selected Financial Data (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	Oct. 01, 2016	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2015	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Class of Stock [Line Items]
Asset impairment and mine closure costs						$ 488,900	$ 2,100,000	$ 19,100		$ 2,600,000
Predecessor [Member]
Class of Stock [Line Items]
Revenues			$ 550,305	$ 420,298	$ 428,106	563,249	688,544	644,462	$ 677,005		$ 1,398,709	$ 2,573,260	$ 2,937,119
Gross profit (loss)			31,042	(56,469)	(53,325)	(44,964)	47,275	(16,507)	14,256
Asset impairment and mine closure costs			46	43,701	85,520	488,865	2,120,292	19,146	0		129,267	2,628,303	24,113
Income (loss) from operations			11,795	(110,521)	(158,412)	(539,033)	(2,236,772)	(69,546)	(19,712)		(257,138)	(2,865,063)	(149,531)
Reorganization items, net	$ 1,676,091		(20,904)	(21,271)	(3,875)						1,630,041	0	0
Net income (loss)	$ 1,676,091		$ (51,421)	$ (175,887)	$ (206,702)	$ (632,368)	$ (1,999,476)	$ (168,103)	$ (113,195)		$ 1,242,081	$ (2,913,142)	$ (558,353)
Diluted earnings per common share (in dollars per share)	$ 78.66		$ (2.41)	$ (8.26)	$ (9.71)	$ (29.70)	$ (93.91)	$ (7.93)	$ (5.32)		$ 58.28	$ (136.86)	$ (26.31)
Successor [Member]
Class of Stock [Line Items]
Revenues		$ 575,688
Gross profit (loss)		64,458
Asset impairment and mine closure costs		0
Income (loss) from operations		46,118
Reorganization items, net		(759)
Net income (loss)		$ 33,449
Diluted earnings per common share (in dollars per share)		$ 1.31

Valuation and Qualifying Acc125

Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2015	Dec. 31, 2014
Successor [Member] | Other assets — other notes and accounts receivable
Reserves deducted from asset accounts:
Balance at Beginning of Year	$ 0
Additions (Reductions) Charged to Costs and Expenses	0
Charged to Other Accounts	0
Deductions	0
Balance at End of Year	0	$ 0
Successor [Member] | Current assets — supplies and inventory
Reserves deducted from asset accounts:
Balance at Beginning of Year	0
Additions (Reductions) Charged to Costs and Expenses	0
Charged to Other Accounts	0
Deductions	0
Balance at End of Year	0	0
Successor [Member] | Deferred income taxes
Reserves deducted from asset accounts:
Balance at Beginning of Year	1,033,982
Additions (Reductions) Charged to Costs and Expenses	(7,655)
Charged to Other Accounts	0
Deductions	0
Balance at End of Year	1,026,327	1,033,982
Predecessor [Member] | Other assets — other notes and accounts receivable
Reserves deducted from asset accounts:
Balance at Beginning of Year	0	7,842	$ 159	$ 775
Additions (Reductions) Charged to Costs and Expenses		0	7,683	0
Charged to Other Accounts		0	0	0
Deductions		7,842	0	616
Balance at End of Year		0	7,842	159
Predecessor [Member] | Current assets — supplies and inventory
Reserves deducted from asset accounts:
Balance at Beginning of Year	0	5,991	6,625	8,446
Additions (Reductions) Charged to Costs and Expenses		844	431	580
Charged to Other Accounts		(5,060)	0	(76)
Deductions		1,775	1,065	2,325
Balance at End of Year		0	5,991	6,625
Predecessor [Member] | Deferred income taxes
Reserves deducted from asset accounts:
Balance at Beginning of Year	$ 1,033,982	1,135,399	270,251	43,322
Additions (Reductions) Charged to Costs and Expenses		(101,417)	865,148	226,929
Charged to Other Accounts			0	0
Deductions		0	0	0
Balance at End of Year		$ 1,033,982	$ 1,135,399	$ 270,251