WESTMORELAND COAL (WLBAQ) 10-Q 10 May 16 2016 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2016	May. 06, 2016
Document Documentand Entity Information [Abstract]
Entity Registrant Name	WESTMORELAND COAL Co
Entity Central Index Key	106,455
Document Type	10-Q
Document Period End Date	Mar. 31, 2016
Amendment Flag	false
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		18,537,502

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 17,754	$ 22,936
Receivables:
Trade	150,068	134,141
Loan and lease receivables	5,968	6,157
Contractual third-party reclamation receivables	12,564	8,020
Other	19,021	11,598
Total receivables	187,621	159,916
Inventories	143,399	121,858
Other current assets	19,951	16,103
Total current assets	368,725	320,813
Property, plant and equipment:
Land and mineral rights	596,448	476,447
Plant and equipment	869,901	790,677
Gross property, plant and equipment	1,466,349	1,267,124
Less accumulated depreciation, depletion and amortization	586,968	554,008
Net property, plant and equipment	879,381	713,116
Loan and lease receivables	51,823	49,313
Advanced coal royalties	16,367	19,781
Reclamation deposits	77,807	77,364
Restricted investments	143,345	140,807
Contractual third-party reclamation receivables, less current portion	154,816	86,915
Investment in joint venture	29,014	27,374
Intangible assets, net of accumulated amortization of $2.9 million and $15.9 million at March 31, 2016 and December 31, 2015, respectively	28,574	29,190
Other assets	20,837	11,904
Total Assets	1,770,689	1,476,577
Current liabilities:
Current installments of long-term debt	77,375	38,852
Revolving lines of credit	0	1,970
Accounts payable and accrued expenses:
Trade and other accrued liabilities	136,844	109,850
Interest payable	11,749	15,527
Production taxes	54,215	46,895
Postretirement medical benefits	13,855	13,855
SERP	368	368
Deferred revenue	20,303	10,715
Asset retirement obligations	49,445	43,950
Other current liabilities	36,782	30,688
Total current liabilities	400,936	312,670
Long-term debt, less current installments	1,051,674	979,073
Workers' compensation, less current portion	5,034	5,068
Excess of black lung benefit obligation over trust assets	17,423	17,220
Postretirement medical benefits, less current portion	288,437	285,518
Pension and SERP obligations, less current portion	44,221	44,808
Deferred revenue, less current portion	21,986	24,613
Asset retirement obligations, less current portion	450,422	375,813
Intangible liabilities, net of accumulated amortization of $10.0 million and $9.8 million at March 31, 2016 and December 31, 2015, respectively	3,203	3,470
Other liabilities	37,434	30,208
Total liabilities	2,320,770	2,078,461
Shareholders' deficit:
Common stock of $0.01 par value; authorized 30,000,000 shares; issued and outstanding 18,402,961 shares at March 31, 2016 and 18,162,148 shares at December 31, 2015	184	182
Other paid-in capital	243,297	240,721
Accumulated other comprehensive loss	(151,897)	(171,300)
Accumulated deficit	(641,635)	(672,219)
Total Westmoreland Coal Company shareholders’ deficit	(550,051)	(602,616)
Noncontrolling interest	(30)	732
Total deficit	(550,081)	(601,884)
Total Liabilities and Shareholders' Deficit	$ 1,770,689	$ 1,476,577

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Intangible assets, accumulated amortization	$ 2.9	$ 15.9
Intangible liabilities, accumulated amortization	$ 10	$ 9.8
Common stock, par value (in USD per share)	$ 0.01	$ 2.50
Common stock, shares authorized	30,000,000	30,000,000
Common stock, shares issued	18,402,961	18,162,148
Common stock, shares outstanding	18,402,961	18,162,148

Consolidated Statements of Oper

Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Income Statement [Abstract]
Revenues	$ 354,721	$ 371,483
Costs, expenses and other:
Cost of sales	273,802	301,711
Depreciation, depletion and amortization	35,013	38,059
Selling and administrative	31,672	26,716
Heritage health benefit expenses	3,015	3,059
Loss on sale/disposal of assets	336	229
Restructuring charges	0	553
Derivative loss (gain)	2,600	(5,276)
Income from equity affiliates	(1,293)	(2,025)
Other operating loss (gain)	(1,962)	2
Total costs, expenses and other	343,183	363,028
Operating income	11,538	8,455
Other income (expense):
Interest expense	(29,669)	(24,735)
Interest income	1,791	2,140
Gain (loss) on foreign exchange	(1,387)	2,109
Other income (loss)	(122)	193
Total other income (expense)	(29,387)	(20,293)
Loss before income taxes	(17,849)	(11,838)
Income tax expense (benefit)	(47,935)	2,040
Net income (loss)	30,086	(13,878)
Less net loss attributable to noncontrolling interest	(498)	(2,146)
Net income (loss) applicable to common shareholders	$ 30,584	$ (11,732)
Net income (loss) per share applicable to common shareholders:
Basic and diluted (in dollars per share)	$ 1.67	$ (0.67)
Weighted average number of common shares outstanding:
Basic (shares)	18,262	17,621
Diluted (shares)	18,269	17,621

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 30,086	$ (13,878)
Other comprehensive income (loss):
Amortization of accumulated actuarial gains or losses, pension	818	1,110
Adjustments to accumulated actuarial losses and transition obligations, pension	172	203
Amortization of accumulated actuarial gains or losses, transition obligations, and prior service costs, postretirement medical benefit	200	327
Adjustments of accumulated actuarial losses and transition obligations, postretirement medical benefit	(688)	0
Tax effect of other comprehensive income gains	(57)	(575)
Change in foreign currency translation adjustment	19,239	(27,140)
Unrealized and realized gains and losses on available-for-sale securities	(281)	325
Other comprehensive income (loss)	19,403	(25,750)
Comprehensive loss attributable to the Parent company	$ 49,489	$ (39,628)

Consolidated Statements of Defi

Consolidated Statements of Deficit (Unaudited) $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)shares
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ (601,884)
WMLP distributions	(262)
Common stock issued as compensation	2,578
Net income (loss)	30,086
Other comprehensive income (loss)	19,401
Ending balance	(550,081)
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 182
Beginning balance, shares | shares	18,162,148
Common stock issued as compensation	$ 2
Common stock options exercised, shares | shares	240,813
Ending balance	$ 184
Ending balance, shares | shares	18,402,961
Other Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 240,721
Common stock issued as compensation	2,576
Ending balance	243,297
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(171,300)
Other comprehensive income (loss)	19,403
Ending balance	(151,897)
Accumulated Deficit
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(672,219)
Net income (loss)	30,584
Ending balance	(641,635)
Noncontrolling Interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	732
WMLP distributions	(262)
Common stock issued as compensation	0
Net income (loss)	(498)
Other comprehensive income (loss)	(2)
Ending balance	$ (30)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities:
Net income (loss)	$ 30,086	$ (13,878)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion and amortization	35,013	38,059
Accretion of asset retirement obligation and receivable	7,007	7,031
Share-based compensation	2,578	1,522
Non-cash interest expense	2,269	1,327
Amortization of deferred financing costs	3,214	2,532
Loss (gain) on derivative instruments	2,600	(5,276)
Loss (gain) on foreign exchange	1,387	(2,109)
Income from equity affiliates	(1,293)	(2,025)
Deferred income tax expense (benefit)	(47,973)	2,766
Other	299	(499)
Changes in operating assets and liabilities:
Receivables	(10,052)	(15,899)
Inventories	(6,956)	(4,957)
Accounts payable and accrued expenses	2,098	12,336
Deferred revenue	3,389	605
Asset retirement obligation	(7,977)	(4,838)
Other assets and liabilities	2,552	(15,057)
Net cash provided by operating activities	18,241	1,640
Cash flows from investing activities:
Additions to property, plant and equipment	(5,548)	(13,027)
Change in restricted investments	(3,172)	2,106
Cash payments in escrow for future acquisitions	0	34,000
Cash payments related to acquisitions and other	(126,865)	(35,887)
Cash acquired related to acquisition, net	0	2,783
Proceeds from sale of restricted investments	1,626	1,123
Payments related to loan and lease receivables	1,620	2,591
Payments related to loan and lease receivables	(312)	(1,044)
Other	1,530	(3,295)
Net cash used in investing activities	(131,121)	(10,650)
Cash flows from financing activities:
Borrowings from long-term debt, net of debt discount	121,225	79,359
Repayments of long-term debt	(9,018)	(17,160)
Borrowings on revolving lines of credit	77,500	32,675
Repayments of revolving lines of credit	(79,500)	(42,251)
Debt issuance costs and other refinancing costs	(2,927)	(2,806)
Other	(262)	98
Net cash provided by financing activities	107,018	49,915
Effect of exchange rate changes on cash	680	(1,770)
Net increase (decrease) in cash and cash equivalents	(5,182)	39,135
Cash and cash equivalents, beginning of period	22,936	14,258
Cash and cash equivalents, end of period	17,754	53,393
Non-cash transactions:
Accrued purchases of property and equipment	2,279	8,107
Capital leases and other financing sources	$ 0	$ 12,700

BASIS OF PRESENTATION

BASIS OF PRESENTATION	3 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
BASIS OF PRESENTATION	e accompanying unaudited consolidated financial statements include accounts of Westmoreland Coal Company, or the Company, or Parent, and its subsidiaries and controlled entities including those of Westmoreland Resource Partners LP (“WMLP”). All intercompany transactions and accounts have been eliminated in consolidation. The consolidated financial statements of the Company have been prepared in accordance with United States generally accepted accounting principles and require the use of management’s estimates. The financial information contained in this Quarterly Report on Form 10-Q is unaudited, but reflects all adjustments, which are, in the opinion of management, necessary for a fair presentation of the financial information for the periods shown. Such adjustments are of a normal recurring nature. Certain prior amounts have been reclassified to conform to current period presentation. The results of operations for the three months ended March 31, 2016 are not necessarily indicative of results to be expected for the year ending December 31, 2016 . These unaudited quarterly consolidated financial statements should be read in conjunction with the consolidated financial statements and notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015 (“ 2015 Form 10-K”). The accounting principles followed by the Company are set forth in the Notes to the Company’s consolidated financial statements in its 2015 Form 10-K. Recently Adopted Accounting Pronouncements In April 2015, the FASB issued ASU 2015-03, Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs , which requires that debt issuance costs related to a recognized liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The Company adopted this standard on January 1, 2016 and retrospectively applied the guidance to prior periods. Recently Issued Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2014-09, Revenue from Contracts with Customers , issued as a new Topic, Accounting Standards Codification (ASC) Topic 606. The new revenue recognition standard provides a five-step analysis of transactions to determine when and how revenue is recognized. The core principle of the guidance is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2015-14, issued in August 2015, deferred the effective date of ASU 2014-09 to fiscal years beginning after December 15, 2017. The Company can either adopt these standards retrospectively or as a cumulative-effect adjustment as of the date of adoption. The Company is currently evaluating the effect that adopting this new accounting guidance will have on its consolidated results of operations, cash flows and financial position. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) (“ASU 2016-02”). The amendments in ASU 2016-02 require companies that lease assets to recognize on their balance sheets the assets and liabilities for the rights and obligations generated by contracts longer than one year. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018 with early adoption permitted. The guidance is required to be applied by the modified retrospective transition approach. The Company is currently evaluating the effect that adopting this new accounting guidance will have on its consolidated results of operations, cash flows and financial position.

ACQUISITION

ACQUISITION	3 Months Ended
	Mar. 31, 2016
Business Combinations [Abstract]
ACQUISITION	2. ACQUISITION Acquisition of San Juan On January 31, 2016, Westmoreland San Juan, LLC (“WSJ”), a variable interest entity of the Company, acquired San Juan Coal Company (“SJCC”), which operates the San Juan mine in Farmington, New Mexico, and San Juan Transportation Company (together with SJCC, the “San Juan Entities” and such transaction, the “San Juan Acquisition”) for a total cash purchase price of approximately $126.9 million , subject to post-closing adjustments. The San Juan mine is the exclusive supplier of coal to the adjacent San Juan Generating Station (“SJGS”) under a coal supply agreement through 2022. The San Juan operations are included in the Company’s Coal - U.S. segment. See Note 3 - Variable Interest Entity for additional information. WSJ financed the San Juan Acquisition with a $125.0 million loan from NM Capital Utility Corporation, an affiliate of Public Service Company of New Mexico (one of the owners of SJGS), and with available cash on hand. See Note 6 - Debt and Lines of Credit for additional information. The San Juan Acquisition has been accounted for under the acquisition method of accounting that requires the total purchase consideration to be allocated to the assets acquired and liabilities assumed based on estimates of fair value. The allocation of the purchase price is preliminary pending the completion of various analyses and the finalization of estimates. During the measurement period (which is not to exceed one year from the acquisition date), additional assets or liabilities may be recognized if new information is obtained about facts and circumstances that existed as of the acquisition date that, if known, would have resulted in the recognition of those assets or liabilities as of that date. The preliminary allocation may be adjusted after obtaining additional information regarding, among other things, asset valuations, liabilities assumed and revisions of previous estimates, and these adjustments may be significant. Certain estimates in the San Juan purchase price allocation are classified as Level 3 fair value estimates. A preliminary allocation of the purchase consideration follows (in millions): Provisional as of March 31, 2016 Purchase price: Cash paid $ 126.9 Preliminary allocation of purchase price: Assets: Inventories - coal and supplies $ 8.8 Other Receivables 9.5 Contractual third-party reclamation receivable 4.6 Total current assets 22.9 Land and mineral rights 108.8 Plant and equipment 73.5 Contractual third-party reclamation receivable 66.8 Other assets 10.5 Total assets 282.5 Liabilities: Trade payables and other accrued liabilities 13.5 Production taxes 2.0 Other liabilities 9.4 Asset retirement obligations 4.6 Total current liabilities 29.5 Asset retirement obligations, less current portion 66.8 Postretirement medical 1.9 Deferred income taxes 48.0 Other liabilities 9.4 Total liabilities 155.6 Net fair value $ 126.9 Unaudited Pro Forma Information The following unaudited pro forma information has been prepared for illustrative purposes only and assumes the San Juan Acquisition occurred on January 1, 2015. The unaudited pro forma results have been prepared based on estimates and assumptions, which the Company believes are reasonable, however, they are not necessarily indicative of the consolidated results of operations had the acquisitions occurred on the dates indicated above, or of future results of operations. (In thousands, except per share data) Three Months Ended March 31, Three Months Ended March 31, 2016 2015 Total Revenues As reported $ 354,721 $ 371,483 Pro forma (unaudited) $ 380,996 $ 451,782 Operating Income As reported $ 11,538 $ 8,455 Pro forma (unaudited) $ 12,633 $ 18,148 Net income (loss) applicable to common shareholders As reported $ 30,584 $ (11,732 ) Pro forma (unaudited) $ 31,009 $ (5,587 ) Net income (loss) per share applicable to common shareholders (basic and diluted) As reported $ 1.67 $ (0.67 ) Pro forma (unaudited) $ 1.70 $ (0.32 )

VARIABLE INTEREST ENTITY

VARIABLE INTEREST ENTITY	3 Months Ended
	Mar. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
VARIABLE INTEREST ENTITY	3. VARIABLE INTEREST ENTITY As of March 31, 2016 , we consolidated our 100% owned WSJ subsidiary which is a variable interest entity (“VIE”). WSJ is a VIE due to another party potentially having the right to receive WSJ’s expected residual returns. The Company is the primary beneficiary because it has the power to direct the activities that most significantly impact WSJ’s economic performance. See Note 2 - Acquisition and Note 6 - Debt and Lines of Credit for additional information. The following table presents amounts included in our Consolidated Balance Sheet that are for the use of or are the obligation of our consolidated VIE. March 31, 2016 Balance Sheet Classification (In thousands) Assets (liabilities): Cash and cash equivalents $ 4,349 Cash and cash equivalents Receivables 26,866 Receivables Inventories and other current assets 14,482 Other current assets Land and mineral rights 108,641 Land and mineral rights Property, plant and equipment, net 69,743 Property, plant and equipment, net Contractual third-party reclamation receivables 71,336 Contractual third-party reclamation receivables Other noncurrent assets 8,875 Other noncurrent assets Debt (114,464 ) Current installments of long-term debt and Long-term debt, less current installments Trade accounts payable (22,530 ) Accounts payable Other current liabilities (25,361 ) Other current liabilities Asset retirement obligations (71,495 ) Asset retirement obligations and Asset retirement obligations, less current portion Deferred income taxes (47,977 ) Deferred income taxes Other liabilities $ (9,361 ) Other noncurrent liabilities

INVENTORIES

INVENTORIES	3 Months Ended
	Mar. 31, 2016
Inventory Disclosure [Abstract]
INVENTORIES	4. INVENTORIES Inventories consisted of the following: March 31, 2016 December 31, 2015 (In thousands) Coal stockpiles $ 51,960 $ 38,636 Coal fuel inventories 7,619 7,194 Materials and supplies 86,741 78,784 Reserve for obsolete inventory (2,921 ) (2,756 ) Total $ 143,399 $ 121,858

RESTRICTED INVESTMENTS

RESTRICTED INVESTMENTS	3 Months Ended
	Mar. 31, 2016
Disclosure Restricted Investments and Bond Collateral [Abstract]
RESTRICTED INVESTMENTS	5. RESTRICTED INVESTMENTS The Company invests certain bond collateral, reclamation deposits, and other restricted investments in a limited selection of fixed-income investment options and receives the investment returns on these investments. These investments are not available to meet the Company’s general cash needs. These accounts include available-for-sale securities. Available-for-sale securities are reported at fair value with unrealized gains and losses excluded from earnings and reported in Accumulated other comprehensive loss . The Company’s carrying value and estimated fair value of its restricted investments and bond collateral at March 31, 2016 were as follows: Restricted Investments and Bond Collateral Reclamation Deposits Total Restricted Investments (In thousands) Cash and cash equivalents $ 85,948 $ 29,554 $ 115,502 Time deposits 2,455 — 2,455 Available-for-sale 54,942 48,253 103,195 $ 143,345 $ 77,807 $ 221,152 The Company’s carrying value and estimated fair value of its restricted investments and bond collateral at December 31, 2015 were as follows: Restricted Investments and Bond Collateral Reclamation Deposits Total Restricted Investments (In thousands) Cash and cash equivalents $ 102,539 $ 45,819 $ 148,358 Time deposits 2,455 — 2,455 Available-for-sale 35,813 31,545 67,358 $ 140,807 $ 77,364 $ 218,171 Available-for-Sale Restricted Investments The cost basis, gross unrealized holding gains and losses, and fair value of available-for-sale securities at March 31, 2016 were as follows (in thousands): Restricted Investments and Bond Collateral Reclamation Deposits Total Restricted Investments (In thousands) Cost basis $ 55,868 $ 48,945 $ 104,813 Gross unrealized holding gains 245 382 627 Gross unrealized holding losses (1,171 ) (1,074 ) (2,245 ) Fair value $ 54,942 $ 48,253 $ 103,195 The cost basis, gross unrealized holding gains and losses, and fair value of available-for-sale securities at December 31, 2015 were as follows: Restricted Investments and Bond Collateral Reclamation Deposits Total Restricted Investments (In thousands) Cost basis $ 36,715 $ 31,977 $ 68,692 Gross unrealized holding gains 167 521 688 Gross unrealized holding losses (1,069 ) (953 ) (2,022 ) Fair value $ 35,813 $ 31,545 $ 67,358

DEBT AND LINES OF CREDIT

DEBT AND LINES OF CREDIT	3 Months Ended
	Mar. 31, 2016
Debt Disclosure [Abstract]
DEBT AND LINES OF CREDIT	6. DEBT AND LINES OF CREDIT The Company and its subsidiaries are subject to the following debt arrangements: Total Debt Outstanding March 31, 2016 December 31, 2015 (In thousands) 8.75% Notes $ 350,000 $ 350,000 WCC Term Loan Facility 326,349 327,172 San Juan Loan 125,000 — WMLP Term Loan Facility 301,215 299,248 Capital lease obligations 65,439 71,168 Revolving Credit Facility — 1,970 Other 6,647 7,251 Total debt 1,174,650 1,056,809 Less debt discount and debt issuance costs (45,601 ) (36,914 ) Less current installments (77,375 ) (40,822 ) Total debt outstanding, less current installments $ 1,051,674 $ 979,073 The following table presents aggregate contractual debt maturities of all debt: March 31, (In thousands) 2016 $ 61,292 2017 70,626 2018 315,889 2019 17,096 2020 338,584 Thereafter 371,163 Total debt $ 1,174,650 8.75% Notes The $350 million in principal amount of 8.75% senior secured notes due 2022 (“8.75% Notes”) were issued by the Parent and are guaranteed by Westmoreland Energy LLC, Westmoreland Mining LLC and Westmoreland Resources, Inc. and their respective subsidiaries (other than Absaloka Coal, LLC, Westmoreland Risk Management, Inc. and certain other immaterial subsidiaries). The 8.75% Notes are not guaranteed by Westmoreland Canada LLC or any of its subsidiaries, Westmoreland San Juan, LLC or any of its subsidiaries, nor are they guaranteed by Westmoreland Resources GP, LLC or WMLP, referred to as the “Non-guarantors.” WCC Term Loan Facility The WCC Term Loan Facility, due in 2020 (the “WCC Term Loan Facility”), is a primary obligation of the Parent and is guaranteed by Westmoreland Energy LLC, Westmoreland Mining LLC, Westmoreland Resources, Inc. and certain other direct and indirect subsidiaries of the Company (other than Absaloka Coal, LLC, Westmoreland Risk Management, Inc., certain other immaterial subsidiaries, and the Non-guarantors). San Juan Loan The San Juan Loan, due February 2, 2021, (the “San Juan Loan”) is a senior secured term loan and is a primary obligation of Westmoreland San Juan, LLC. The San Juan Loan is guaranteed by SJCC, and is secured by substantially all of SJCC’s assets. The San Juan Loan is expected to bear interest at a (i) 7.25% rate (the “Margin Rate”) plus (ii) (A) the London Interbank Offered Rate for a three month period plus (B) a statutory reserve rate, which such Margin Rate increases incrementally during each year of the San Juan Loan term. The San Juan Loan has no prepayment penalties. The agreements governing the San Juan Loan include representations and warranties and covenants regarding the ownership and operation of SJCC and the properties acquired in the San Juan Acquisition and standard special purpose bankruptcy remote entity covenants designed to preserve the separateness from Westmoreland of each of (i) WSJ, (ii) its direct parent company, Westmoreland San Juan Holdings, Inc., and (iii) SJCC (collectively, the “Westmoreland San Juan Entities”). Obligations under the San Juan Loan are recourse only to the Westmoreland San Juan Entities and their assets and neither Westmoreland nor its subsidiaries (other than the Westmoreland San Juan Entities) is an obligor under the San Juan Loan in any respect. The agreement governing the San Juan Loan requires that all revenues of the San Juan Entities, aside from payments on certain leases, are deposited into a cash management collection account swept monthly for operating expenses, capital expenditures, and Loan payment and prepayment. The assets and credit of SJCC are not available to satisfy the debts and other obligations of any of the Company other than the Westmoreland San Juan Entities. WMLP Term Loan Facility The WMLP Term Loan Facility (the “WMLP Term Loan Facility”), due in 2018, is a primary obligation of Oxford Mining Company, LLC, a wholly owned subsidiary of WMLP, is guaranteed by WMLP and its subsidiaries, and is secured by substantially all of WMLP's and its subsidiaries' assets. WMLP Revolving Credit Facility On October 23, 2015, WMLP and its subsidiaries entered into a loan and security agreement with the lenders party thereto and The PrivateBank and Trust Company, as administrative agent, which permits borrowings up to the aggregate principal amount of $15.0 million and letters of credit in an aggregate outstanding amount of up to $10.0 million , which reduces availability under the WMLP revolving credit facility on a dollar-for-dollar basis. At March 31, 2016 , availability under the WMLP revolving credit facility was $15.0 million . Capital Lease Obligations During the three months ended March 31, 2016 , the Company did not enter into any new capital leases. Revolving Credit Facility Under the Company’s revolving credit facility with the lenders party thereto and The PrivateBank and Trust Company, as administrative agent (the “Revolving Credit Facility”), the Company has a total aggregate borrowing capacity of $75.0 million between June 15th and August 15th of each year, with an aggregate borrowing capacity of $50.0 million outside of these periods. As of March 31, 2016 , the Company had no borrowings under the Revolving Credit Facility and had outstanding letters of credit against its aggregate borrowing capacity in the amount of $13.7 million . Deferred Financing Costs Due to the adoption of ASU 2015-03, Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs , debt issuance costs related to the Company’s debt liabilities are now reported in the balance sheet as a direct deduction from the face amount of the notes. The adoption of this standard resulted in the reclassification of $25.8 million of unamortized debt issuance costs from the non-current asset, Other assets, to a reduction of Long-term debt, less current portion on the consolidated balance sheet as of December 31, 2015.

POSTRETIREMENT MEDICAL BENEFITS

POSTRETIREMENT MEDICAL BENEFITS AND PENSION	3 Months Ended
	Mar. 31, 2016
Compensation and Retirement Disclosure [Abstract]
POSTRETIREMENT MEDICAL BENEFITS AND PENSION	7. POSTRETIREMENT MEDICAL BENEFITS AND PENSION Postretirement Medical Benefits The Company provides postretirement medical benefits to retired employees and their dependents as mandated by the Coal Industry Retiree Health Benefit Act of 1992 and pursuant to collective bargaining agreements. The Company also provides these benefits to qualified full-time employees pursuant to collective bargaining agreements. The components of net periodic postretirement medical benefit cost are as follows: Three Months Ended March 31, 2016 2015 (In thousands) Components of net periodic benefit cost: Service cost $ 935 $ 1,054 Interest cost 3,111 2,907 Amortization of deferred items 200 327 Total net periodic benefit cost $ 4,246 $ 4,288 The following table shows the net periodic postretirement medical benefit costs that relate to current and former mining operations: Three Months Ended March 31, 2016 2015 (In thousands) Former mining operations $ 2,135 $ 2,034 Current operations 2,111 2,254 Total net periodic benefit cost $ 4,246 $ 4,288 The costs for the former mining operations are included in Heritage health benefit expenses and costs for current operations are included in Cost of sales and Selling and administrative expenses. Pension The Company provides pension benefits to qualified full-time employees pursuant to collective bargaining agreements. The Company incurred net periodic benefit costs of providing these pension benefits as follows: Three Months Ended March 31, 2016 2015 (In thousands) Components of net periodic benefit cost: Service cost $ 608 $ 506 Interest cost 2,287 1,985 Expected return on plan assets (3,231 ) (2,639 ) Amortization of deferred items 1,039 1,110 Total net periodic pension cost $ 703 $ 962 These costs are included in Cost of sales and Selling and administrative expenses. The Company made $0.2 million of contributions to its pension plans in the three months ended March 31, 2016 . The Company expects to make $0.2 million of contributions to its pension plans during the remainder of 2016 .

DERIVATIVE INSTRUMENTS

DERIVATIVE INSTRUMENTS	3 Months Ended
	Mar. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVE INSTRUMENTS	The fair value of outstanding derivative instruments not designated as hedging instruments on the accompanying unaudited Consolidated Balance Sheets was as follows (in thousands): Derivative Instruments Balance Sheet Location March 31, 2016 December 31, 2015 Contracts to purchase power Other current liabilities $ 15,934 $ 13,679 Contracts to purchase power Other liabilities 23,834 23,656 The effect of derivative instruments not designated as hedging instruments on the accompanying unaudited Consolidated Statements of Operations was as follows (in thousands): Three Months Ended March 31, Derivative Instruments Statement of Operations Location 2016 2015 Contracts to purchase power Derivative gain (loss) $ (2,600 ) $ 5,276

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	3 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	9. FAIR VALUE MEASUREMENTS Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. See Note 5 - Restricted Investments and Note 8 - Derivative Instruments for additional disclosures related to fair value measurements. The fair value hierarchy prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy, as defined below, gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. • Level 1, defined as observable inputs such as quoted prices in active markets for identical assets. • Level 2, 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. • Level 3, defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions. The table below sets forth, by level, the Company’s financial assets and liabilities that are accounted for at fair value at March 31, 2016 : Fair Quoted Prices in Active Markets for Identical Assets or Liabilities Significant Other Observable Inputs Value Level 1 Level 2 (In thousands) Assets: Available-for-sale investments included in Restricted investments $ 54,942 $ 54,942 $ — Available-for-sale investments included in Reclamation deposits 48,253 48,253 — Total assets $ 103,195 $ 103,195 $ — Liabilities: Contracts to purchase power included in Other current liabilities and Other liabilities $ (39,767 ) $ — $ (39,767 ) Warrants issued by WMLP included in Other liabilities (557 ) (557 ) — Total liabilities $ (40,324 ) $ (557 ) $ (39,767 ) Long-term debt fair value estimates are based on observed prices for securities with an active trading market when available (Level 2) and otherwise using discount rate estimates based on interest rates (Level 3). As of March 31, 2016 , the Company had no long-term debt with Level 3 fair values. The estimated fair values of the Company’s debt with fixed and variable interest rates are as follows: Fixed Interest Rate Variable Interest Rate Carrying Value Fair Value Carrying Value Fair Value (In thousands) (In thousands) March 31, 2016 $ 346,114 $ 204,750 $ 737,997 $ 440,250 December 31, 2015 $ 345,984 $ 213,500 $ 619,341 $ 388,380

INCOME TAXES

INCOME TAXES	3 Months Ended
	Mar. 31, 2016
Income Tax Disclosure [Abstract]
INCOME TAXES	10. INCOME TAX For interim income tax reporting the Company estimates its annual effective tax rate and applies this effective tax rate to its year to date pre-tax (loss) income. For the three months ended March 31, 2015 , the effective tax rate differed from the statutory rate primarily as a result of the U.S. and Canadian valuation allowances and the impact of the statutory rate change in Alberta, Canada. For the three months ended March 31, 2016 , the effective tax rate differed from the statutory rate primarily due to the U.S. and Canadian valuation allowances, and for the recognition of changes in the Company’s net deferred tax assets due to the acquisition of SJCC. As part of the San Juan acquisition, the Company acquired $48.0 million in deferred tax liabilities. Changes in the acquiring company’s deferred tax assets or liabilities subsequent to a business combination are required to be recorded currently in income during the quarter in which the transaction occurs. Accordingly, the $48.0 million decrease in the Company’s net deferred tax assets resulted in the release of a corresponding $48.0 million valuation allowance and recognition of a tax benefit in the three months ended March 31, 2016 .

SHAREHOLDERS' DEFICIT AND ACCUM

SHAREHOLDERS' DEFICIT AND ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	3 Months Ended
	Mar. 31, 2016
Equity [Abstract]
SHAREHOLDERS' DEFICIT AND ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	11. STOCKHOLDERS’ DEFICIT AND ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) Changes in Accumulated Other Comprehensive Income (Loss) The following table reflects the changes in accumulated other comprehensive income (loss) by component: Pension Postretirement Unrealized gains and losses on available-for-sale Foreign currency translation adjustment Tax effect of other comprehensive income gains Accumulated other comprehensive income (loss) (In thousands) Balance at December 31, 2015 $ (34,558 ) $ (31,086 ) $ (1,325 ) $ (69,901 ) $ (34,430 ) $ (171,300 ) Other comprehensive income (loss) before reclassifications 172 (688 ) (281 ) 19,239 (57 ) 18,385 Amounts reclassified from accumulated other comprehensive income (loss) 818 200 — — — 1,018 Balance at March 31, 2016 $ (33,568 ) $ (31,574 ) $ (1,606 ) $ (50,662 ) $ (34,487 ) $ (151,897 ) The following table reflects the reclassifications out of accumulated other comprehensive loss for the three months ended March 31, 2016 (in thousands): Details about accumulated other comprehensive loss components Amount reclassified from accumulated other comprehensive loss Affected line item in the statement where net income (loss) is presented Three Months Ended March 31, 2016 Available-for sale securities Realized gains and losses on available-for sale securities $ — Other income (loss) Amortization of defined benefit pension items Prior service costs $ 2 Cost of sales and Selling and administrative Actuarial losses 816 Cost of sales and Selling and administrative Total $ 818 Amortization of postretirement medical items Prior service costs $ (159 ) Cost of sales and Selling and administrative Actuarial losses 359 Cost of sales and Selling and administrative Total $ 200

SHARE-BASED COMPENSATION

SHARE-BASED COMPENSATION	3 Months Ended
	Mar. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
SHARE-BASED COMPENSATION	12. SHARE-BASED COMPENSATION The Company grants employees and non-employee directors restricted stock units. The Company recognized compensation expense from share-based arrangements shown in the following table: Three Months Ended March 31, 2016 2015 (In thousands) Recognition of fair value of restricted stock units, stock options and SARs over vesting period; and issuance of stock $ 1,112 $ 663 Contributions of stock to the Company’s 401(k) plan 1,466 859 Total share-based compensation expense $ 2,578 $ 1,522 Restricted Stock Units No restricted stock units were granted, vested, or forfeited during the three months ended March 31, 2016 . Unamortized compensation expense is expected to be recognized over the next three years. A summary of outstanding restricted stock units as of March 31, 2016 is as follows: Units Weighted Average Grant-Date Fair Value Unamortized Compensation Expense (In thousands) Non-vested at March 31, 2016 354,311 $ 28.44 $ 5,516 Stock Options No stock options granted, vested, or forfeited during the three months ended March 31, 2016 . A summary of stock options outstanding as of March 31, 2016 is as follows: Stock Options Weighted Average Exercise Price Weighted Average Remaining Contractual Life (In years) Aggregate Intrinsic Value (In thousands) Unamortized Compensation Expense (In thousands) Outstanding at March 31, 2016 109,306 $ 22.16 1.9 — — SARs There were no SARs granted during the three months ended March 31, 2016 . A summary of SARs activity for the three months ended March 31, 2016 is as follows: SARs Weighted Average Exercise Price Weighted Average Remaining Contractual Life (In years) Aggregate Intrinsic Value (In thousands) Unamortized Compensation Expense (In thousands) Outstanding at December 31, 2015 16,943 $ 25.44 Expired (3,733 ) $ 23.99 Outstanding and exercisable at March 31, 2016 13,210 $ 25.85 0.2 $ — $ —

EARNINGS PER SHARE

EARNINGS PER SHARE	3 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
EARNINGS PER SHARE	13. EARNINGS PER SHARE Basic earnings (loss) per share has been computed by dividing the net income (loss) applicable to common shareholders by the weighted average number of shares of common stock outstanding during each period. Net income (loss) applicable to common shareholders includes the adjustment for net income or loss attributable to noncontrolling interest. Diluted earnings (loss) per share is computed by including the dilutive effect of common stock that would be issued assuming conversion or exercise of outstanding stock options, stock appreciation rights and restricted stock units. No such items were included in the computations of diluted loss per share in the three months ended March 31, 2015 because the Company incurred a net loss applicable to common shareholders in that period and the effect of inclusion would have been anti-dilutive. Three Months Ended March 31, 2016 2015 (In thousands) Income (loss) for basic earning per share calculation: Net income (loss) allocated to common shareholders $ 30,584 $ (11,732 ) Weighted average shares outstanding: Basic weighted average shares outstanding 18,262 17,621 Effect of restricted stock units 7 — Diluted weighted average shares outstanding 18,269 17,621 The table below shows the number of shares that were excluded from the calculation of diluted income (loss) per share because their inclusion would be anti-dilutive to the calculation: Three Months Ended March 31, 2016 2015 (In thousands) Restricted stock units, stock options and SARs 470 524

SEGMENT INFORMATION

SEGMENT INFORMATION	3 Months Ended
	Mar. 31, 2016
Segment Reporting [Abstract]
SEGMENT INFORMATION	14. SEGMENT INFORMATION Segment information is based on a management approach, which requires segmentation based upon the Company’s internal organization, reporting of revenue, and operating income. The Company’s operations are classified into six reporting segments: Coal - U.S., Coal - Canada, Coal - WMLP, Power, Heritage, and Corporate. On August 1, 2015, the Company contributed 100% of the outstanding equity interests in Westmoreland Kemmerer, LLC (“Kemmerer”) to WMLP (the “Kemmerer Drop”), and, accordingly, to enable comparability, all segment disclosures have been adjusted to remove financial information for Kemmerer from the Coal - U.S. segment and present it in the Coal - WMLP segment for each of the three months ended March 31, 2016 and 2015 . Summarized financial information by segment is as follows: Coal - U.S. (1) Coal - Canada Coal - WMLP (2) Power (3) Heritage Corporate (2) Consolidated (In thousands) Three Months Ended March 31, 2016 Revenues $ 155,179 $ 93,434 $ 92,481 $ 21,995 $ — $ (8,368 ) $ 354,721 Restructuring charges — — — — — — — Depreciation, depletion, and amortization 14,138 5,639 15,265 — — (29 ) 35,013 Operating income (loss) 11,280 12,409 809 (5,801 ) (3,481 ) (3,678 ) 11,538 Total assets 945,328 523,876 411,656 41,717 16,379 (168,267 ) 1,770,689 Capital expenditures 2,655 1,349 1,544 — — — 5,548 Three Months Ended March 31, 2015 Revenues $ 154,869 $ 103,242 $ 109,090 $ 20,647 $ — $ (16,365 ) $ 371,483 Restructuring charges — — 553 — — — 553 Depreciation, depletion, and amortization 9,379 11,265 14,889 2,484 — 42 38,059 Operating income (loss) 7,118 9,865 (369 ) 413 (3,349 ) (5,223 ) 8,455 Total assets 576,344 583,536 453,620 172,310 16,005 13,237 1,815,052 Capital expenditures 7,157 4,049 4,812 579 — (3,570 ) 13,027 ____________________ (1) The San Juan Acquisition was completed on January 31, 2016. For the three months ended March 31, 2016 , revenues for the San Juan Entities were $26.6 million and operating losses were $3.1 million . (2) The Coal - WMLP segment recorded revenues of $7.9 million and $16.4 million for intersegment revenues to the Coal - U.S. segment for the three months ended March 31, 2016 and March 31, 2015 , respectively. Eliminations for intersegment revenues and cost of sales are presented within the Corporate segment. (3) Total assets as of March 31, 2016 reflect a $133.1 million asset impairment in the Power segment that was recorded during the fourth quarter of 2015. No such impairment had been recorded as of March 31, 2015.

CONTINGENCIES

CONTINGENCIES	3 Months Ended
	Mar. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
CONTINGENCIES	15. CONTINGENCIES The Company is a party to routine claims and lawsuits with respect to various matters. The Company provides for costs related to contingencies when a loss is probable and the amount is reasonably estimable. After conferring with counsel, it is the opinion of management that the ultimate resolution of pending claims will not have a material adverse effect on the consolidated financial condition, results of operations, or liquidity of the Company.

BASIS OF PRESENTATION Basis of

BASIS OF PRESENTATION Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
Consolidation Policy	The consolidated financial statements of the Company have been prepared in accordance with United States generally accepted accounting principles and require the use of management’s estimates. The financial information contained in this Quarterly Report on Form 10-Q is unaudited, but reflects all adjustments, which are, in the opinion of management, necessary for a fair presentation of the financial information for the periods shown. Such adjustments are of a normal recurring nature. Certain prior amounts have been reclassified to conform to current period presentation. The results of operations for the three months ended March 31, 2016 are not necessarily indicative of results to be expected for the year ending December 31, 2016 . These unaudited quarterly consolidated financial statements should be read in conjunction with the consolidated financial statements and notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015 (“ 2015 Form 10-K”). The accounting principles followed by the Company are set forth in the Notes to the Company’s consolidated financial statements in its 2015 Form 10-K.
Recently Issued Accounting Pronouncements	Recently Adopted Accounting Pronouncements In April 2015, the FASB issued ASU 2015-03, Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs , which requires that debt issuance costs related to a recognized liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The Company adopted this standard on January 1, 2016 and retrospectively applied the guidance to prior periods. Recently Issued Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2014-09, Revenue from Contracts with Customers , issued as a new Topic, Accounting Standards Codification (ASC) Topic 606. The new revenue recognition standard provides a five-step analysis of transactions to determine when and how revenue is recognized. The core principle of the guidance is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2015-14, issued in August 2015, deferred the effective date of ASU 2014-09 to fiscal years beginning after December 15, 2017. The Company can either adopt these standards retrospectively or as a cumulative-effect adjustment as of the date of adoption. The Company is currently evaluating the effect that adopting this new accounting guidance will have on its consolidated results of operations, cash flows and financial position. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) (“ASU 2016-02”). The amendments in ASU 2016-02 require companies that lease assets to recognize on their balance sheets the assets and liabilities for the rights and obligations generated by contracts longer than one year. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018 with early adoption permitted. The guidance is required to be applied by the modified retrospective transition approach. The Company is currently evaluating the effect that adopting this new accounting guidance will have on its consolidated results of operations, cash flows and financial position.

ACQUISITION (Tables)

ACQUISITION (Tables)	3 Months Ended
	Mar. 31, 2016
Business Acquisition [Line Items]
Summary of pro forma information	The following unaudited pro forma information has been prepared for illustrative purposes only and assumes the San Juan Acquisition occurred on January 1, 2015. The unaudited pro forma results have been prepared based on estimates and assumptions, which the Company believes are reasonable, however, they are not necessarily indicative of the consolidated results of operations had the acquisitions occurred on the dates indicated above, or of future results of operations. (In thousands, except per share data) Three Months Ended March 31, Three Months Ended March 31, 2016 2015 Total Revenues As reported $ 354,721 $ 371,483 Pro forma (unaudited) $ 380,996 $ 451,782 Operating Income As reported $ 11,538 $ 8,455 Pro forma (unaudited) $ 12,633 $ 18,148 Net income (loss) applicable to common shareholders As reported $ 30,584 $ (11,732 ) Pro forma (unaudited) $ 31,009 $ (5,587 ) Net income (loss) per share applicable to common shareholders (basic and diluted) As reported $ 1.67 $ (0.67 ) Pro forma (unaudited) $ 1.70 $ (0.32 )
San Juan Coal Company
Business Acquisition [Line Items]
Summary of purchase consideration and allocation of purchase consideration	A preliminary allocation of the purchase consideration follows (in millions): Provisional as of March 31, 2016 Purchase price: Cash paid $ 126.9 Preliminary allocation of purchase price: Assets: Inventories - coal and supplies $ 8.8 Other Receivables 9.5 Contractual third-party reclamation receivable 4.6 Total current assets 22.9 Land and mineral rights 108.8 Plant and equipment 73.5 Contractual third-party reclamation receivable 66.8 Other assets 10.5 Total assets 282.5 Liabilities: Trade payables and other accrued liabilities 13.5 Production taxes 2.0 Other liabilities 9.4 Asset retirement obligations 4.6 Total current liabilities 29.5 Asset retirement obligations, less current portion 66.8 Postretirement medical 1.9 Deferred income taxes 48.0 Other liabilities 9.4 Total liabilities 155.6 Net fair value $ 126.9

VARIABLE INTEREST ENTITY (Table

VARIABLE INTEREST ENTITY (Tables)	3 Months Ended
	Mar. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Variable Interest Entities	The following table presents amounts included in our Consolidated Balance Sheet that are for the use of or are the obligation of our consolidated VIE. March 31, 2016 Balance Sheet Classification (In thousands) Assets (liabilities): Cash and cash equivalents $ 4,349 Cash and cash equivalents Receivables 26,866 Receivables Inventories and other current assets 14,482 Other current assets Land and mineral rights 108,641 Land and mineral rights Property, plant and equipment, net 69,743 Property, plant and equipment, net Contractual third-party reclamation receivables 71,336 Contractual third-party reclamation receivables Other noncurrent assets 8,875 Other noncurrent assets Debt (114,464 ) Current installments of long-term debt and Long-term debt, less current installments Trade accounts payable (22,530 ) Accounts payable Other current liabilities (25,361 ) Other current liabilities Asset retirement obligations (71,495 ) Asset retirement obligations and Asset retirement obligations, less current portion Deferred income taxes (47,977 ) Deferred income taxes Other liabilities $ (9,361 ) Other noncurrent liabilities

INVENTORIES (Tables)

INVENTORIES (Tables)	3 Months Ended
	Mar. 31, 2016
Inventory Disclosure [Abstract]
Inventories	Inventories consisted of the following: March 31, 2016 December 31, 2015 (In thousands) Coal stockpiles $ 51,960 $ 38,636 Coal fuel inventories 7,619 7,194 Materials and supplies 86,741 78,784 Reserve for obsolete inventory (2,921 ) (2,756 ) Total $ 143,399 $ 121,858

RESTRICTED INVESTMENTS (Tables)

RESTRICTED INVESTMENTS (Tables)	3 Months Ended
	Mar. 31, 2016
Disclosure Restricted Investments and Bond Collateral [Abstract]
Carrying value and estimated fair value of restricted investments and bond collateral	The Company’s carrying value and estimated fair value of its restricted investments and bond collateral at March 31, 2016 were as follows: Restricted Investments and Bond Collateral Reclamation Deposits Total Restricted Investments (In thousands) Cash and cash equivalents $ 85,948 $ 29,554 $ 115,502 Time deposits 2,455 — 2,455 Available-for-sale 54,942 48,253 103,195 $ 143,345 $ 77,807 $ 221,152 The Company’s carrying value and estimated fair value of its restricted investments and bond collateral at December 31, 2015 were as follows: Restricted Investments and Bond Collateral Reclamation Deposits Total Restricted Investments (In thousands) Cash and cash equivalents $ 102,539 $ 45,819 $ 148,358 Time deposits 2,455 — 2,455 Available-for-sale 35,813 31,545 67,358 $ 140,807 $ 77,364 $ 218,171
Amortized cost, gross unrealized holding gains and losses and fair value of available-for-sale securities	The cost basis, gross unrealized holding gains and losses, and fair value of available-for-sale securities at March 31, 2016 were as follows (in thousands): Restricted Investments and Bond Collateral Reclamation Deposits Total Restricted Investments (In thousands) Cost basis $ 55,868 $ 48,945 $ 104,813 Gross unrealized holding gains 245 382 627 Gross unrealized holding losses (1,171 ) (1,074 ) (2,245 ) Fair value $ 54,942 $ 48,253 $ 103,195 The cost basis, gross unrealized holding gains and losses, and fair value of available-for-sale securities at December 31, 2015 were as follows: Restricted Investments and Bond Collateral Reclamation Deposits Total Restricted Investments (In thousands) Cost basis $ 36,715 $ 31,977 $ 68,692 Gross unrealized holding gains 167 521 688 Gross unrealized holding losses (1,069 ) (953 ) (2,022 ) Fair value $ 35,813 $ 31,545 $ 67,358

LINES OF CREDIT AND DEBT (Table

LINES OF CREDIT AND DEBT (Tables)	3 Months Ended
	Mar. 31, 2016
Debt Disclosure [Abstract]
Outstanding lines of credit and long-term debt	The Company and its subsidiaries are subject to the following debt arrangements: Total Debt Outstanding March 31, 2016 December 31, 2015 (In thousands) 8.75% Notes $ 350,000 $ 350,000 WCC Term Loan Facility 326,349 327,172 San Juan Loan 125,000 — WMLP Term Loan Facility 301,215 299,248 Capital lease obligations 65,439 71,168 Revolving Credit Facility — 1,970 Other 6,647 7,251 Total debt 1,174,650 1,056,809 Less debt discount and debt issuance costs (45,601 ) (36,914 ) Less current installments (77,375 ) (40,822 ) Total debt outstanding, less current installments $ 1,051,674 $ 979,073
Contractual maturities of all long-term debt	The following table presents aggregate contractual debt maturities of all debt: March 31, (In thousands) 2016 $ 61,292 2017 70,626 2018 315,889 2019 17,096 2020 338,584 Thereafter 371,163 Total debt $ 1,174,650

POSTRETIREMENT MEDICAL BENEFI29

POSTRETIREMENT MEDICAL BENEFITS AND PENSION (Tables)	3 Months Ended
	Mar. 31, 2016
Postretirement Medical Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Components of net periodic benefit cost	The components of net periodic postretirement medical benefit cost are as follows: Three Months Ended March 31, 2016 2015 (In thousands) Components of net periodic benefit cost: Service cost $ 935 $ 1,054 Interest cost 3,111 2,907 Amortization of deferred items 200 327 Total net periodic benefit cost $ 4,246 $ 4,288 The following table shows the net periodic postretirement medical benefit costs that relate to current and former mining operations: Three Months Ended March 31, 2016 2015 (In thousands) Former mining operations $ 2,135 $ 2,034 Current operations 2,111 2,254 Total net periodic benefit cost $ 4,246 $ 4,288
Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Components of net periodic benefit cost	The Company incurred net periodic benefit costs of providing these pension benefits as follows: Three Months Ended March 31, 2016 2015 (In thousands) Components of net periodic benefit cost: Service cost $ 608 $ 506 Interest cost 2,287 1,985 Expected return on plan assets (3,231 ) (2,639 ) Amortization of deferred items 1,039 1,110 Total net periodic pension cost $ 703 $ 962

DERIVATIVE INSTRUMENTS (Tables)

DERIVATIVE INSTRUMENTS (Tables)	3 Months Ended
	Mar. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Other Derivatives Not Designated as Hedging Instruments, Statements of Financial Performance and Financial Position, Location	The fair value of outstanding derivative instruments not designated as hedging instruments on the accompanying unaudited Consolidated Balance Sheets was as follows (in thousands): Derivative Instruments Balance Sheet Location March 31, 2016 December 31, 2015 Contracts to purchase power Other current liabilities $ 15,934 $ 13,679 Contracts to purchase power Other liabilities 23,834 23,656 The effect of derivative instruments not designated as hedging instruments on the accompanying unaudited Consolidated Statements of Operations was as follows (in thousands): Three Months Ended March 31, Derivative Instruments Statement of Operations Location 2016 2015 Contracts to purchase power Derivative gain (loss) $ (2,600 ) $ 5,276

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	3 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Summary of financial assets at fair value	The table below sets forth, by level, the Company’s financial assets and liabilities that are accounted for at fair value at March 31, 2016 : Fair Quoted Prices in Active Markets for Identical Assets or Liabilities Significant Other Observable Inputs Value Level 1 Level 2 (In thousands) Assets: Available-for-sale investments included in Restricted investments $ 54,942 $ 54,942 $ — Available-for-sale investments included in Reclamation deposits 48,253 48,253 — Total assets $ 103,195 $ 103,195 $ — Liabilities: Contracts to purchase power included in Other current liabilities and Other liabilities $ (39,767 ) $ — $ (39,767 ) Warrants issued by WMLP included in Other liabilities (557 ) (557 ) — Total liabilities $ (40,324 ) $ (557 ) $ (39,767 )
Estimated fair values of Company's debt	The estimated fair values of the Company’s debt with fixed and variable interest rates are as follows: Fixed Interest Rate Variable Interest Rate Carrying Value Fair Value Carrying Value Fair Value (In thousands) (In thousands) March 31, 2016 $ 346,114 $ 204,750 $ 737,997 $ 440,250 December 31, 2015 $ 345,984 $ 213,500 $ 619,341 $ 388,380

SHAREHOLDERS' DEFICIT AND ACC32

SHAREHOLDERS' DEFICIT AND ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Tables)	3 Months Ended
	Mar. 31, 2016
Equity [Abstract]
Changes in Accumulated Other Comprehensive Income by component	The following table reflects the changes in accumulated other comprehensive income (loss) by component: Pension Postretirement Unrealized gains and losses on available-for-sale Foreign currency translation adjustment Tax effect of other comprehensive income gains Accumulated other comprehensive income (loss) (In thousands) Balance at December 31, 2015 $ (34,558 ) $ (31,086 ) $ (1,325 ) $ (69,901 ) $ (34,430 ) $ (171,300 ) Other comprehensive income (loss) before reclassifications 172 (688 ) (281 ) 19,239 (57 ) 18,385 Amounts reclassified from accumulated other comprehensive income (loss) 818 200 — — — 1,018 Balance at March 31, 2016 $ (33,568 ) $ (31,574 ) $ (1,606 ) $ (50,662 ) $ (34,487 ) $ (151,897 )
Reclassifications out of Accumulated Other Comprehensive Income for the period	The following table reflects the reclassifications out of accumulated other comprehensive loss for the three months ended March 31, 2016 (in thousands): Details about accumulated other comprehensive loss components Amount reclassified from accumulated other comprehensive loss Affected line item in the statement where net income (loss) is presented Three Months Ended March 31, 2016 Available-for sale securities Realized gains and losses on available-for sale securities $ — Other income (loss) Amortization of defined benefit pension items Prior service costs $ 2 Cost of sales and Selling and administrative Actuarial losses 816 Cost of sales and Selling and administrative Total $ 818 Amortization of postretirement medical items Prior service costs $ (159 ) Cost of sales and Selling and administrative Actuarial losses 359 Cost of sales and Selling and administrative Total $ 200

SHARE-BASED COMPENSATION (Table

SHARE-BASED COMPENSATION (Tables)	3 Months Ended
	Mar. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Compensation cost arising from share-based arrangements	The Company recognized compensation expense from share-based arrangements shown in the following table: Three Months Ended March 31, 2016 2015 (In thousands) Recognition of fair value of restricted stock units, stock options and SARs over vesting period; and issuance of stock $ 1,112 $ 663 Contributions of stock to the Company’s 401(k) plan 1,466 859 Total share-based compensation expense $ 2,578 $ 1,522
Summary of Restricted Stock Unit activity	A summary of outstanding restricted stock units as of March 31, 2016 is as follows: Units Weighted Average Grant-Date Fair Value Unamortized Compensation Expense (In thousands) Non-vested at March 31, 2016 354,311 $ 28.44 $ 5,516
Summary of Stock Option Activity	A summary of stock options outstanding as of March 31, 2016 is as follows: Stock Options Weighted Average Exercise Price Weighted Average Remaining Contractual Life (In years) Aggregate Intrinsic Value (In thousands) Unamortized Compensation Expense (In thousands) Outstanding at March 31, 2016 109,306 $ 22.16 1.9 — —
Summary of Stock Appreciation Rights	A summary of SARs activity for the three months ended March 31, 2016 is as follows: SARs Weighted Average Exercise Price Weighted Average Remaining Contractual Life (In years) Aggregate Intrinsic Value (In thousands) Unamortized Compensation Expense (In thousands) Outstanding at December 31, 2015 16,943 $ 25.44 Expired (3,733 ) $ 23.99 Outstanding and exercisable at March 31, 2016 13,210 $ 25.85 0.2 $ — $ —

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	3 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	Three Months Ended March 31, 2016 2015 (In thousands) Income (loss) for basic earning per share calculation: Net income (loss) allocated to common shareholders $ 30,584 $ (11,732 ) Weighted average shares outstanding: Basic weighted average shares outstanding 18,262 17,621 Effect of restricted stock units 7 — Diluted weighted average shares outstanding 18,269 17,621
Antidilutive Securities Excluded from Computation of Earnings Per Share	The table below shows the number of shares that were excluded from the calculation of diluted income (loss) per share because their inclusion would be anti-dilutive to the calculation: Three Months Ended March 31, 2016 2015 (In thousands) Restricted stock units, stock options and SARs 470 524

SEGMENT INFORMATION (Tables)

SEGMENT INFORMATION (Tables)	3 Months Ended
	Mar. 31, 2016
Segment Reporting [Abstract]
Summarized financial information by segment	Summarized financial information by segment is as follows: Coal - U.S. (1) Coal - Canada Coal - WMLP (2) Power (3) Heritage Corporate (2) Consolidated (In thousands) Three Months Ended March 31, 2016 Revenues $ 155,179 $ 93,434 $ 92,481 $ 21,995 $ — $ (8,368 ) $ 354,721 Restructuring charges — — — — — — — Depreciation, depletion, and amortization 14,138 5,639 15,265 — — (29 ) 35,013 Operating income (loss) 11,280 12,409 809 (5,801 ) (3,481 ) (3,678 ) 11,538 Total assets 945,328 523,876 411,656 41,717 16,379 (168,267 ) 1,770,689 Capital expenditures 2,655 1,349 1,544 — — — 5,548 Three Months Ended March 31, 2015 Revenues $ 154,869 $ 103,242 $ 109,090 $ 20,647 $ — $ (16,365 ) $ 371,483 Restructuring charges — — 553 — — — 553 Depreciation, depletion, and amortization 9,379 11,265 14,889 2,484 — 42 38,059 Operating income (loss) 7,118 9,865 (369 ) 413 (3,349 ) (5,223 ) 8,455 Total assets 576,344 583,536 453,620 172,310 16,005 13,237 1,815,052 Capital expenditures 7,157 4,049 4,812 579 — (3,570 ) 13,027 ____________________ (1) The San Juan Acquisition was completed on January 31, 2016. For the three months ended March 31, 2016 , revenues for the San Juan Entities were $26.6 million and operating losses were $3.1 million . (2) The Coal - WMLP segment recorded revenues of $7.9 million and $16.4 million for intersegment revenues to the Coal - U.S. segment for the three months ended March 31, 2016 and March 31, 2015 , respectively. Eliminations for intersegment revenues and cost of sales are presented within the Corporate segment. (3) Total assets as of March 31, 2016 reflect a $133.1 million asset impairment in the Power segment that was recorded during the fourth quarter of 2015. No such impairment had been recorded as of March 31, 2015.

ACQUISITION - Narrative (Detail

ACQUISITION - Narrative (Details) - USD ($) $ in Thousands	Jan. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Acquisition loan		$ 1,174,650	$ 1,056,809
San Juan Coal Company
Business Acquisition [Line Items]
Cash paid	$ 126,900
Loan from NM Capital Utility Corporation | Term Notes
Business Acquisition [Line Items]
Acquisition loan	$ 125,000	$ 125,000	$ 0

ACQUISITION - Summary of purcha

ACQUISITION - Summary of purchase consideration and allocation of purchase consideration (Details) - San Juan Coal Company $ in Millions	Jan. 31, 2016USD ($)
Purchase Price:
Cash paid	$ 126.9
Assets:
Inventories - coal and supplies	8.8
Other current assets	9.5
Contractual third-party reclamation receivable	4.6
Total current assets	22.9
Land and mineral rights	108.8
Plant and equipment	73.5
Contractual third-party reclamation receivable	66.8
Other assets	10.5
Total Assets	282.5
Liabilities:
Trade payables and other accrued liabilities	13.5
Production taxes	2
Other current liabilities	9.4
Asset retirement obligations	4.6
Total current liabilities	29.5
Asset retirement obligations, less current portion	66.8
Postretirement medical	1.9
Other liabilities	9.4
Deferred tax liabilities	48
Total Liabilities	155.6
Net fair value	$ 126.9

ACQUISITION - Summary of Pro Fo

ACQUISITION - Summary of Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Total Revenues
As reported	$ 354,721	$ 371,483
Pro forma (unaudited)	380,996	451,782
Operating Income
As reported	11,538	8,455
Pro forma (unaudited)	12,633	18,148
Net income (loss) applicable to common shareholders
As reported	30,584	(11,732)
Pro forma (unaudited)	$ 31,009	$ (5,587)
Net income (loss) per share applicable to common shareholders (basic and diluted)
As reported, (in dollars per share)	$ 1.67	$ (0.67)
Pro forma (unaudited) (in dollars per share)	$ 1.70	$ (0.32)

VARIABLE INTEREST ENTITY (Detai

VARIABLE INTEREST ENTITY (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Variable Interest Entity [Line Items]
Ownership percentage in Constitution (percent)	100.00%
Cash and cash equivalents	$ 17,754	$ 22,936	$ 53,393	$ 14,258
Receivables	187,621	159,916
Other current assets	19,951	16,103
Land and mineral rights	596,448	476,447
Property, plant and equipment, net	879,381	713,116
Contractual third-party reclamation receivables, less current portion	154,816	86,915
Other noncurrent assets	20,837	11,904
Debt	(77,375)	(38,852)
Asset Retirements Obligations	(450,422)	(375,813)
Other liabilities	(21,986)	$ (24,613)
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Cash and cash equivalents	4,349
Receivables	26,866
Other current assets	14,482
Land and mineral rights	108,641
Property, plant and equipment, net	69,743
Contractual third-party reclamation receivables, less current portion	71,336
Other noncurrent assets	8,875
Debt	(114,464)
Trade accounts payable	(22,530)
Other current liabilities	(25,361)
Asset Retirements Obligations	(71,495)
Deferred income taxes	(47,977)
Other liabilities	$ (9,361)

INVENTORIES (Detail)

INVENTORIES (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Coal stockpiles	$ 51,960	$ 38,636
Coal fuel inventories	7,619	7,194
Materials and supplies	86,741	78,784
Reserve for obsolete inventory	(2,921)	(2,756)
Total	$ 143,399	$ 121,858

RESTRICTED INVESTMENTS - Carryi

RESTRICTED INVESTMENTS - Carrying Value and Estimated Fair Value of Restricted Investments and Bond Collateral (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Investment [Line Items]
Restricted investments and bond collateral	$ 143,345	$ 140,807
Restricted Investments and Bond Collateral
Investment [Line Items]
Cash and cash equivalents	85,948	102,539
Time deposits	2,455	2,455
Available-for-sale	54,942	35,813
Restricted investments and bond collateral	143,345	140,807
Reclamation Deposits
Investment [Line Items]
Cash and cash equivalents	29,554	45,819
Time deposits	0	0
Available-for-sale		31,545
Available-for-sale investments included in Reclamation deposits	48,253
Restricted investments and bond collateral	77,807	77,364
Restricted Investments
Investment [Line Items]
Cash and cash equivalents	115,502	148,358
Time deposits	2,455	2,455
Available-for-sale	103,195	67,358
Restricted investments and bond collateral	$ 221,152	$ 218,171

RESTRICTED INVESTMENTS - Amorti

RESTRICTED INVESTMENTS - Amortized Cost, Gross Unrealized Holding Gains and Losses and Fair Value of Held-to-Maturity Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Restricted Investments and Bond Collateral
Schedule of Available-for-sale Securities [Line Items]
Cost basis	$ 55,868	$ 36,715
Gross unrealized holding gains	245	167
Gross unrealized holding losses	(1,171)	(1,069)
Fair value	54,942	35,813
Reclamation Deposits
Schedule of Available-for-sale Securities [Line Items]
Cost basis	48,945	31,977
Gross unrealized holding gains	382	521
Gross unrealized holding losses	(1,074)	(953)
Fair value	48,253	31,545
Restricted Investments
Schedule of Available-for-sale Securities [Line Items]
Cost basis	104,813	68,692
Gross unrealized holding gains	627	688
Gross unrealized holding losses	(2,245)	(2,022)
Fair value	$ 103,195	$ 67,358

DEBT AND LINES OF CREDIT - Outs

DEBT AND LINES OF CREDIT - Outstanding Lines of Credit and Debt (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Jan. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Total debt	$ 1,174,650		$ 1,056,809
Less debt discount and debt issuance costs	(45,601)		(36,914)
Less current installments	77,375		40,822
Total debt outstanding, less current installments	1,051,674		979,073
Capital lease obligations
Debt Instrument [Line Items]
Total debt	65,439		71,168
Other
Debt Instrument [Line Items]
Total debt	6,647		7,251
Senior secured notes due 2022 | Senior Notes
Debt Instrument [Line Items]
Total debt	$ 350,000		350,000
Stated interest rate (percent)	8.75%
Term loan facility due 2020 | Term Notes
Debt Instrument [Line Items]
Total debt	$ 326,349		327,172
San Juan Loan | Term Notes
Debt Instrument [Line Items]
Total debt	$ 125,000	$ 125,000	0
Stated interest rate (percent)	7.25%
WMLP term loan facility due 2018 | Term Notes
Debt Instrument [Line Items]
Total debt	$ 301,215		299,248
Revolving line of credit | Revolving line of credit
Debt Instrument [Line Items]
Total debt	$ 0		$ 1,970

DEBT AND LINES OF CREDIT - Cont

DEBT AND LINES OF CREDIT - Contractual Maturities of Long Term Debt (Details) $ in Thousands	Mar. 31, 2016USD ($)
Debt Disclosure [Abstract]
2,016	$ 61,292
2,017	70,626
2,018	315,889
2,019	17,096
2,020	338,584
Thereafter	371,163
Total	$ 1,174,650

DEBT AND LINES OF CREDIT - Addi

DEBT AND LINES OF CREDIT - Additional Information (Detail) - USD ($)	Mar. 31, 2016	Dec. 31, 2015	Oct. 23, 2015	Sep. 30, 2015
Debt Instrument [Line Items]
Revolving lines of credit	$ 0	$ 1,970,000
Revolving line of credit
Debt Instrument [Line Items]
Maximum borrowing capacity	50,000,000
Revolving lines of credit				$ 0
Outstanding letters of credit	13,700,000
Senior secured notes due 2022 | Senior Notes
Debt Instrument [Line Items]
Senior secured notes	$ 350,000,000
Stated interest rate (percent)	8.75%
San Juan Loan | Term Notes
Debt Instrument [Line Items]
Stated interest rate (percent)	7.25%
Seasonal Increase to Borrowing Capacity | Revolving line of credit
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 75,000,000
Long-term Debt, Less Current Portion | Adjustments for New Accounting Pronouncement
Debt Instrument [Line Items]
Unamortized debt issuance costs		$ 25,800,000
WMLP and subsidiaries | Revolving line of credit
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 15,000,000
Remaining borrowing capacity	$ 15,000,000
WMLP and subsidiaries | Letter of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 10,000,000

POSTRETIREMENT MEDICAL BENEFI46

POSTRETIREMENT MEDICAL BENEFITS AND PENSION - Postretirement Medicial Benefit Obligations Balance Sheet Disclosures (Details) - Postretirement Medical Benefits - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Components of net periodic benefit cost:
Service cost	$ 935	$ 1,054
Interest cost	3,111	2,907
Amortization of deferred items	200	327
Total net periodic benefit cost	$ 4,246	$ 4,288

POSTRETIREMENT MEDICAL BENEFI47

POSTRETIREMENT MEDICAL BENEFITS AND PENSION - Postretirement Medical Benefit Obligations Income Statement Disclosures (Details) - Postretirement Medical Benefits - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Net periodic postretirement medical benefit costs relating to current and former mining operations:
Total net periodic benefit cost	$ 4,246	$ 4,288
Former Mining Operations
Net periodic postretirement medical benefit costs relating to current and former mining operations:
Total net periodic benefit cost	2,135	2,034
Current Operations
Net periodic postretirement medical benefit costs relating to current and former mining operations:
Total net periodic benefit cost	$ 2,111	$ 2,254

POSTRETIREMENT MEDICAL BENEFI48

POSTRETIREMENT MEDICAL BENEFITS AND PENSION - Pension Benefit Disclosures (Details) - Pension - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 608	$ 506
Interest cost	2,287	1,985
Expected return on plan assets	(3,231)	(2,639)
Amortization of deferred items	1,039	1,110
Total net periodic benefit cost	703	$ 962
Employer contributions during the period	200
Expected employer contributions to pension plans during the remainder of the year	$ 200

DERIVATIVE INSTRUMENTS (Details

DERIVATIVE INSTRUMENTS (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2016USD ($)	Mar. 31, 2015USD ($)	Sep. 30, 2015$ / MWh	Dec. 31, 2015USD ($)
Derivative [Line Items]
Gain (loss) on derivative, net	$ (2,600)	$ 5,276
Not Designated as Hedging Instrument | Power Contract | Derivative loss
Derivative [Line Items]
Gain (loss) on derivative, net	(2,600)	$ 5,276
Not Designated as Hedging Instrument | Power Contract | Other current liabilities
Derivative [Line Items]
Derivative Liability	15,934			$ 13,679
Not Designated as Hedging Instrument | Power Contract | Other liabilities
Derivative [Line Items]
Derivative Liability	$ 23,834			$ 23,656
Minimum | Power Contract
Derivative [Line Items]
Contracted power price notional amount | $ / MWh			41.05
Maximum | Power Contract
Derivative [Line Items]
Contracted power price notional amount | $ / MWh			55.2
Weighted Average | Power Contract
Derivative [Line Items]
Contracted power price notional amount | $ / MWh			43.51

FAIR VALUE MEASUREMENTS Summary

FAIR VALUE MEASUREMENTS Summary of Financial Assets at Fair Value (Details) - Fair Value, Measurements, Recurring $ in Thousands	Mar. 31, 2016USD ($)
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments included in Restricted investments and bond collateral	$ 54,942
Available-for-sale investments included in Reclamation deposits	48,253
Available-for-sale investments	103,195
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments included in Restricted investments and bond collateral	0
Available-for-sale investments included in Reclamation deposits	0
Available-for-sale investments	0
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments included in Restricted investments and bond collateral	54,942
Available-for-sale investments included in Reclamation deposits	48,253
Available-for-sale investments	103,195
Other Current Liabilities and Other Liabilities [Member] | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability	(557)
Other Current Liabilities and Other Liabilities [Member] | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability	(39,767)
Other Current Liabilities and Other Liabilities [Member] | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability	(40,324)
Other Current Liabilities and Other Liabilities [Member] | Power Contract | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability	0
Other Current Liabilities and Other Liabilities [Member] | Power Contract | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability	(39,767)
Other Current Liabilities and Other Liabilities [Member] | Power Contract | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability	(39,767)
Other liabilities | Warrant | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability	(557)
Other liabilities | Warrant | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability	0
Other liabilities | Warrant | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability	$ (557)

FAIR VALUE MEASUREMENTS (Detail

FAIR VALUE MEASUREMENTS (Details) - Significant unobservable inputs, Level 3 - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt at fixed interest rate	$ 346,114	$ 345,984
Debt at variable interest rate	737,997	619,341
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt at fixed interest rate	204,750	213,500
Debt at variable interest rate	$ 440,250	$ 388,380

INCOME TAXES Income Tax Disclos

INCOME TAXES Income Tax Disclosure (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Jan. 31, 2016
Business Acquisition [Line Items]
Decrease to deferred tax assets	$ (48)
Release of valuation allowance	$ (48)
San Juan Coal Company
Business Acquisition [Line Items]
Deferred tax liabilities		$ 48

SHAREHOLDERS' DEFICIT AND ACC53

SHAREHOLDERS' DEFICIT AND ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Changes in Accumulated Other Comprehensive Income by component (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	$ (171,300)
Other comprehensive income before reclassifications	18,385
Amounts reclassified from accumulated other comprehensive income (loss)	1,018
Balance at end of period	(151,897)
Defined benefit plans adjustment | Pension
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(34,558)
Other comprehensive income before reclassifications	172
Amounts reclassified from accumulated other comprehensive income (loss)	818
Balance at end of period	(33,568)
Defined benefit plans adjustment | Postretirement Medical Benefits
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(31,086)
Other comprehensive income before reclassifications	(688)
Amounts reclassified from accumulated other comprehensive income (loss)	200
Balance at end of period	(31,574)
Available for sale securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(1,325)
Other comprehensive income before reclassifications	(281)
Amounts reclassified from accumulated other comprehensive income (loss)	0
Balance at end of period	(1,606)
Foreign currency translation adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(69,901)
Other comprehensive income before reclassifications	19,239
Balance at end of period	(50,662)
Tax effect of other comprehensive income gains
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(34,430)
Other comprehensive income before reclassifications	(57)
Balance at end of period	$ (34,487)

SHAREHOLDERS' DEFICIT AND ACC54

SHAREHOLDERS' DEFICIT AND ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Reclassifications out of Accumulated Other Comprehensive Income (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)
Defined benefit plans adjustment | Pension
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Prior service costs	$ 2
Actuarial losses	816
Amortization of defined benefit pension and postretirement medical benefits	818
Defined benefit plans adjustment | Postretirement Medical Benefits
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Prior service costs	(159)
Actuarial losses	359
Amortization of defined benefit pension and postretirement medical benefits	200
Other income (loss) | Unrealized Gains and Losses on Available-for-sale Securities, Net
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Realized gains and losses on available-for sale securities	$ 0

SHARE-BASED COMPENSATION - Comp

SHARE-BASED COMPENSATION - Compensation Expense from Share-Based Arrangements (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Recognition of fair value of restricted stock units, stock options, and SARs over vesting period; and issuance of common stock	$ 1,112	$ 663
Contributions of stock to the Company's 401(k) plan	1,466	859
Total share-based compensation expense	$ 2,578	$ 1,522

SHARE-BASED COMPENSATION - Summ

SHARE-BASED COMPENSATION - Summary of Restricted Stock Unit Activity (Detail) - Restricted Stock Units (RSUs) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period for recognition of unamortized compensation expense	3 years
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Granted (units)	0
Vested (units)	0
Forfeited (units)	0
Balance end of period (units)	354,311
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Weighted Average Grant Date Fair Value, end of period (in USD per share) | $ / shares	$ 28.44
Unamortized Compensation Expense | $	$ 5,516

SHARE-BASED COMPENSATION - Su57

SHARE-BASED COMPENSATION - Summary of Stock Options and SARs (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)$ / sharesshares
Stock Appreciation Rights (SARs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance, beginning of period, shares	16,943
Granted, shares	0
Expired, shares	(3,733)
Balance, end of period, shares	13,210
Balance, beginning of period, weighted average exercise price | $ / shares	$ 25.44
Expired, weighted average exercise price | $ / shares	23.99
Balance, end of period, weighted average exercise price | $ / shares	$ 25.85
Outstanding - Weighted Average Remaining Contractual Life (In years)	2 months 12 days
Exercisable - Weighted Average Remaining Contractual Life (In years)	2 months 12 days
Aggregate Intrinsic Value | $	$ 0
Unamortized Compensation Expense | $	$ 0
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares	0
Vested, shares	0
Forfeited, shares	0
Balance, end of period, shares	109,306
Balance, end of period, weighted average exercise price | $ / shares	$ 22.16
Outstanding - Weighted Average Remaining Contractual Life (In years)	1 year 10 months 24 days
Aggregate Intrinsic Value | $	$ 0
Unamortized Compensation Expense | $	$ 0

EARNINGS PER SHARE - Antidiluti

EARNINGS PER SHARE - Antidilutive securities excluded from the computation of earnings per share (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Restricted stock units, stock options and SARs
Class of Stock [Line Items]
Shares excluded from diluted shares calculation	470	524

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Earnings Per Share [Abstract]
Net income (loss) allocated to common shareholders	$ 30,584	$ (11,732)
Basic weighted average shares outstanding (shares)	18,262	17,621
Effect of restricted stock units (shares)	7	0
Diluted weighted average shares outstanding (shares)	18,269	17,621

SEGMENT INFORMATION - Summarize

SEGMENT INFORMATION - Summarized Financial Information by Segment (Detail) $ in Thousands		Aug. 01, 2015	Mar. 31, 2016USD ($)segments		Mar. 31, 2015USD ($)	Dec. 31, 2015USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments | segments			6
Revenues			$ 354,721		$ 371,483
Restructuring charges			0		553
Depreciation, depletion and amortization			35,013		38,059
Operating income (loss)			11,538		8,455
Total assets			1,770,689		1,815,052	$ 1,476,577
Capital expenditures			5,548		13,027
Coal - U.S. Segment
Segment Reporting Information [Line Items]
Revenues	[1]		155,179		154,869
Restructuring charges	[1]		0		0
Depreciation, depletion and amortization	[1]		14,138		9,379
Operating income (loss)	[1]		11,280		7,118
Total assets	[1]		945,328		576,344
Capital expenditures	[1]		2,655		7,157
Coal - Canada Segment
Segment Reporting Information [Line Items]
Revenues			93,434		103,242
Restructuring charges			0		0
Depreciation, depletion and amortization			5,639		11,265
Operating income (loss)			12,409		9,865
Total assets			523,876		583,536
Capital expenditures			1,349		4,049
Coal - WMLP Segment
Segment Reporting Information [Line Items]
Revenues	[2]		92,481		109,090
Restructuring charges	[2]		0		553
Depreciation, depletion and amortization	[2]		15,265		14,889
Operating income (loss)	[2]		809		(369)
Total assets	[2]		411,656		453,620
Capital expenditures	[2]		1,544		4,812
Power Segment
Segment Reporting Information [Line Items]
Revenues			21,995		20,647
Restructuring charges			0		0
Depreciation, depletion and amortization			0		2,484
Operating income (loss)			(5,801)		413
Total assets			41,717	[2]	172,310
Capital expenditures			0		579
Asset impairment charges			133,100		0
Heritage Segment
Segment Reporting Information [Line Items]
Revenues			0		0
Restructuring charges			0		0
Depreciation, depletion and amortization			0		0
Operating income (loss)			(3,481)		(3,349)
Total assets			16,379		16,005
Capital expenditures			0		0
Corporate and Eliminations
Segment Reporting Information [Line Items]
Revenues	[3]		(8,368)		(16,365)
Restructuring charges	[3]		0		0
Depreciation, depletion and amortization	[3]		(29)		42
Operating income (loss)	[3]		(3,678)		(5,223)
Total assets	[3]		(168,267)		13,237
Capital expenditures	[3]		0		(3,570)
Buckingham Coal Company, LLC | Coal - U.S. Segment
Segment Reporting Information [Line Items]
Revenues			26,600
Operating income (loss)			3,100
Revenues to the Coal - U.S. segment | Coal - WMLP Segment
Segment Reporting Information [Line Items]
Revenues			$ 7,900		$ 16,400
Westmoreland Kemmerer, LLC
Segment Reporting Information [Line Items]
Ownership interest in LLC (percent)		100.00%
[1]	The San Juan Acquisition was completed on January 31, 2016. For the three months ended March 31, 2016, revenues for the San Juan Entities were $26.6 million and operating losses were $3.1 million.
[2]	Total assets as of March 31, 2016 reflect a $133.1 million asset impairment in the Power segment that was recorded during the fourth quarter of 2015. No such impairment had been recorded as of March 31, 2015.
[3]	The Coal - WMLP segment recorded revenues of $7.9 million and $16.4 million for intersegment revenues to the Coal - U.S. segment for the three months ended March 31, 2016 and March 31, 2015, respectively