WESTMORELAND COAL (WLBAQ) 10-Q 28 Apr 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	Apr. 23, 2015
Document Documentand Entity Information [Abstract]
Entity Registrant Name	WESTMORELAND COAL Co
Entity Central Index Key	106455
Document Type	10-Q
Document Period End Date	31-Mar-15
Amendment Flag	FALSE
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	-19
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		17,908,598

Consolidated_Balance_Sheets_Un

Consolidated Balance Sheets (Unaudited) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$53,393	$14,258
Receivables:
Trade	154,167	143,052
Loan and lease receivables	9,609	10,493
Contractual third-party reclamation receivables	14,457	12,462
Other	16,300	19,923
Total receivables	194,533	185,930
Inventories	133,819	133,855
Deferred income taxes	14,696	13,083
Other current assets	15,077	13,645
Total current assets	411,518	360,771
Property, plant and equipment:
Land and mineral rights	496,034	500,226
Plant and equipment	989,914	956,112
Gross property, plant and equipment	1,485,948	1,456,338
Less accumulated depreciation, depletion and amortization	562,413	528,676
Net property, plant and equipment	923,535	927,662
Loan and lease receivables	65,417	73,180
Advanced coal royalties	19,637	17,508
Reclamation deposits	76,715	77,907
Restricted investments and bond collateral	129,813	164,389
Contractual third-party reclamation receivables, less current portion	100,818	104,021
Investment in joint venture	32,395	33,409
Intangible assets, net of accumulated amortization of $15.8 million and $15.3 million at March 31, 2015 and December 31, 2014, respectively	30,784	31,315
Other assets	39,116	39,416
Total Assets	1,829,748	1,829,578
Current liabilities:
Current installments of long-term debt	42,554	43,136
Revolving lines of credit	0	9,576
Accounts payable and accrued expenses:
Trade and other accrued liabilities	141,479	149,514
Interest payable	9,180	2,699
Production taxes	52,174	45,747
Workers' compensation	1,018	671
Postretirement medical benefits	13,263	13,263
SERP	368	368
Deferred revenue	17,372	13,175
Asset retirement obligations	48,024	43,289
Other current liabilities	27,054	52,459
Total current liabilities	352,486	373,897
Long-term debt, less current installments	1,004,623	932,075
Workers' compensation, less current portion	6,223	6,315
Excess of black lung benefit obligation over trust assets	11,916	11,252
Postretirement medical benefits, less current portion	293,253	293,156
Pension and SERP obligations, less current portion	48,226	49,779
Deferred revenue, less current portion	32,914	35,255
Asset retirement obligations, less current portion	399,378	409,456
Intangible liabilities, net of accumulated amortization of $13.8 million and $13.5 million at March 31, 2015 and December 31, 2014, respectively	4,271	4,538
Deferred income taxes	37,444	34,852
Other liabilities	27,686	28,448
Total liabilities	2,218,420	2,179,023
Shareholders' deficit:
Preferred stock of $1.00 par value Authorized 5,000,000 shares; issued and outstanding nil shares at March 31, 2015 and 91,669 at December 31, 2014	0	92
Common stock of $2.50 par value Authorized 30,000,000 shares; Issued and outstanding 17,769,746 shares at March 31, 2015 and 17,102,777 shares at December 31, 2014	44,421	42,756
Other paid-in capital	184,475	185,644
Accumulated other comprehensive loss	-150,046	-124,296
Accumulated deficit	-480,637	-468,902
Total Westmoreland Coal Company shareholders’ deficit	-401,787	-364,706
Noncontrolling interest	13,115	15,261
Total deficit	-388,672	-349,445
Total Liabilities and Shareholders' Deficit	$1,829,748	$1,829,578

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, except Share data, unless otherwise specified
Statement of Financial Position [Abstract]
Intangible assets, accumulated amortization	$15.80	$15.30
Intangible liabilities, accumulated amortization	$13.80	$13.50
Preferred stock, par value (in USD per share)	$1	$1
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	91,669
Preferred stock, shares outstanding	0	91,669
Common stock, par value (in USD per share)	$2.50	$2.50
Common stock, shares authorized	30,000,000	30,000,000
Common stock, shares issued	17,769,746	17,102,777
Common stock, shares outstanding	17,769,746	17,102,777

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (Unaudited) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Income Statement [Abstract]
Revenues	$371,483	$180,202
Costs, expenses and other:
Cost of sales	301,711	138,630
Depreciation, depletion and amortization	38,059	16,059
Selling and administrative	26,716	13,331
Heritage health benefit expenses	3,059	3,544
Loss on sale/disposal of assets	229	38
Restructuring charges	553	397
Derivative gain	-5,276	0
Income from equity affiliates	-2,025	0
Other operating loss	2	150
Total costs, expenses and other	363,028	172,149
Operating income	8,455	8,053
Other income (expense):
Interest expense	-24,735	-20,798
Interest income	2,140	302
Gain (loss) on foreign exchange	2,109	-6,790
Other income	193	93
Total other income (expense)	-20,293	-27,193
Loss before income taxes	-11,838	-19,140
Income tax expense (benefit)	2,040	-110
Net loss	-13,878	-19,030
Less net loss attributable to noncontrolling interest	-2,146	0
Net loss attributable to the Parent company	-11,732	-19,030
Less preferred stock dividend requirements	0	261
Net loss applicable to common shareholders	($11,732)	($19,291)
Net loss per share applicable to common shareholders:
Basic and diluted (in dollars per share)	($0.67)	($1.30)
Weighted average number of common shares outstanding:
Basic and diluted (shares)	17,621	14,787

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Loss (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net loss	($13,878)	($19,030)
Other comprehensive income (loss):
Amortization of accumulated actuarial gains or losses, pension	1,110	359
Adjustments to accumulated actuarial losses and transition obligations, pension	203	0
Amortization of accumulated actuarial gains or losses, transition obligations, and prior service costs, postretirement medical benefit	327	5
Tax effect of other comprehensive income gains	-575	-138
Change in foreign currency translation adjustment	-27,140	0
Unrealized and realized gains and losses on available-for-sale securities	325	0
Other comprehensive income	-25,750	226
Comprehensive loss attributable to the Parent company	($39,628)	($18,804)

Consolidated_Statements_of_Sha

Consolidated Statements of Shareholders' Deficit (Unaudited) (USD $)	Total	Preferred Stock	Common Stock	Other Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit	Noncontrolling Interest
In Thousands, except Share data
Beginning balance at Dec. 31, 2014	($349,445)	$92	$42,756	$185,644	($124,296)	($468,902)	$15,261
Beginning balance, shares at Dec. 31, 2014		91,669	17,102,777
Preferred dividends declared	-3					-3
Common stock issued as compensation	1,522		75	1,447
Common stock options exercised, shares			29,801
Conversion of convertible notes and securities	-319	-92	1,511	-1,738
Conversion of convertible notes and securities (shares)		-91,669	604,557
Issuance of restricted stock	-799		79	-878
Issuance of restricted stock, shares			32,611
Net loss	-13,878					-11,732	-2,146
Other comprehensive loss	-25,750				-25,750
Ending balance at Mar. 31, 2015	($388,672)	$0	$44,421	$184,475	($150,046)	($480,637)	$13,115
Ending balance, shares at Mar. 31, 2015		0	17,769,746

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities:
Net loss	($13,878)	($19,030)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion and amortization	38,059	16,059
Accretion of asset retirement obligation and receivable	7,031	3,479
Non-cash tax benefits	-575	-138
Amortization of intangible assets and liabilities, net	-253	153
Share-based compensation	1,522	728
Loss on sale/disposal of assets	229	38
Non-cash interest expense	1,327	0
Amortization of deferred financing costs	2,532	271
Other	-29	0
Gain on sales of investment securities	-15	0
Gain on derivative	-5,276	0
Loss (gain) on foreign exchange	-2,109	6,790
Income from equity affiliates	-2,025	0
Distributions from equity affiliates	144	0
Changes in operating assets and liabilities:
Receivables	-15,899	5,202
Inventories	-4,957	4,525
Excess of black lung benefit obligation over trust assets	664	701
Deferred income tax	2,766	0
Accounts payable and accrued expenses	12,336	10,959
Deferred revenue	605	-1,302
Income tax payable	-481	28
Accrual for workers' compensation	-1,158	-69
Asset retirement obligation	-4,838	-1,352
Accrual for postretirement medical benefits	424	906
Pension and SERP obligations	1,211	-293
Other assets and liabilities	-15,717	1,993
Net cash provided by operating activities	1,640	29,648
Cash flows from investing activities:
Additions to property, plant and equipment	-13,027	-3,050
Change in restricted investments and bond collateral and reclamation deposits	538	-465,544
Cash released from escrow for acquisition	34,000	0
Cash payments related to acquisitions and other	-35,887	0
Cash acquired related to acquisitionss	2,783	0
Net proceeds from sales of assets	1,123	0
Proceeds from sale of restricted investments	1,568	0
Payments related to loan and lease receivables	-1,044	0
Receipts from loan and lease receivables	2,591	0
Receivable from customer for property and equipment purchases	0	-10
Other	-3,295	-60
Net cash used in investing activities	-10,650	-468,664
Cash flows from financing activities:
Change in book overdrafts	420	-315
Borrowings from long-term debt, net of debt discount	79,359	454,219
Repayments of long-term debt	-17,160	-6,239
Borrowings on revolving lines of credit	32,675	0
Repayments of revolving lines of credit	-42,251	0
Debt issuance costs and other refinancing costs	-2,806	-7,598
Preferred dividends paid	-3	-261
Proceeds from issuance of common shares	0	0
Exercise of stock options	0	0
Redemption of preferred stock	-319	0
Net cash provided by financing activities	49,915	439,806
Effect of foreign exchange rates on cash	-1,770	0
Net increase in cash and cash equivalents	39,135	790
Cash and cash equivalents, beginning of period	14,258	61,110
Cash and cash equivalents, end of period	53,393	61,900
Non-cash transactions:
Accrued purchases of property and equipment	8,107	983
Capital leases and other financing sources	$12,700	$12,936

BASIS_OF_PRESENTATION

BASIS OF PRESENTATION	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
BASIS OF PRESENTATION	BASIS OF PRESENTATION
	The accompanying unaudited consolidated financial statements include accounts of Westmoreland Coal Company, or the Company, or Parent, and its subsidiaries and controlled entities. The Company’s current principal activities are conducted within the United States and Canada. U.S. activities include the production and sale of coal from its mines in Montana, Wyoming, North Dakota, Texas, and Ohio and the ownership of the Roanoke Valley power plants, or ROVA, in North Carolina. Canadian activities include the production and sale of coal from six surface mines in Alberta and Saskatchewan, selling char to the barbecue briquette industry, and a 50% interest in a joint venture which produces activated carbon. The Company’s activities are primarily conducted through wholly owned subsidiaries. All intercompany transactions and accounts have been eliminated in consolidation.
	U.S. Coal Operations – The Company’s Kemmerer Mine is owned by its subsidiary Westmoreland Kemmerer, Inc., or Kemmerer. The Company’s Absaloka Mine is owned by its subsidiary Westmoreland Resources, Inc., or WRI. The Beulah, Jewett, Rosebud, and Savage Mines are owned through the Company’s subsidiary Westmoreland Mining LLC, or WML. The Company’s Buckingham Mine is owned by its subsidiary WCC Land Holding Company, Inc. See Note 2 for additional information on the Buckingham Mine.
	Canadian Operations – Prairie Mines & Royalty ULC, or PMRU, operates five surface coal mines in Alberta and Saskatchewan. PMRU owns and operates the Paintearth, Sheerness, Genesee, Poplar River and Estevan mines. PMRU directly owns a 50% joint venture interest in the Estevan Activated Carbon Joint Venture, at the Estevan mine, which produces activated carbon for the removal of mercury from flue gas. PMRU also sells char to the barbecue briquette industry. Coal Valley Resources Inc., or CVRI, operates the Coal Valley Mine which is a surface mine located in West Central Alberta where the majority of coal is exported overseas to Asian utility companies and commodity traders. CVRI operated the Obed Mountain surface mine, which ceased production in 2013 and is currently in reclamation.
	Master Limited Partnership – On December 31, 2014, the Company acquired Westmoreland Resources GP, LLC (formerly Oxford Resources GP, LLC) (the “GP”), the general partner of Westmoreland Resource Partners, LP (formerly Oxford Resource Partners, LP) (NYSE: WMLP, “WMLP”). Concurrent with the acquisition of the GP, Westmoreland contributed certain royalty-bearing coal reserves to WMLP in return for common units representing limited partner interests in WMLP, resulting in the Company owning approximately 79% of the outstanding equity interests in WMLP. WMLP is a low-cost producer of high value thermal coal in Northern Appalachia. WMLP markets its coal primarily to large electric utilities with coal-fire, base load scrubbed power plants under long-term coal sales contracts. See Note 2 for additional information.
	The consolidated financial statements of the Company have been prepared in accordance with United States generally accepted accounting principles and require use of management’s estimates. The financial information contained in this 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. The results of operations for the three months ended March 31, 2015 are not necessarily indicative of results to be expected for the year ending December 31, 2015.
	These 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, 2014 (the “2014 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 2014 Form 10-K. Most of the descriptions of the accounting principles and other footnote disclosures previously made have been omitted in this report so long as the interim information presented is not misleading or inconsistent.
	Debt Obligations
	As of March 31, 2015, the Company is subject to three major debt arrangements: (1) $350.0 million in aggregate principal amount of 8.75% senior secured notes at the parent level (the “8.75% Notes”); (2) a secured term loan facility at the parent level in the aggregate principal amount of $423.9 million (the “WCC Term Loan Facility”); and (3) a secured term loan facility at WMLP in the aggregate principal amount of $176.3 million (the “WMLP Term Loan Facility”).
	The 8.75% Notes are guaranteed by Westmoreland Energy LLC, Westmoreland Kemmerer, Inc., 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, nor are they guaranteed by Westmoreland Resources GP, LLC or Westmoreland Resource Partners, LP, referred to as the Non-guarantors. The WCC Term Loan Facility is guaranteed by Westmoreland Energy LLC, Westmoreland Kemmerer, Inc., 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., Westmoreland Canada, LLC, Westmoreland Resources GP, LLC, Westmoreland Resource Partners, LP and certain other immaterial subsidiaries).
	Borrowings under the WMLP Term Loan Facility are secured by substantially all of WMLP’s and its subsidiaries’ assets.
	Inventories
	Inventories, which include materials and supplies as well as raw coal, are stated at the lower of cost or market. Cost is determined using the average cost method. Coal inventory costs include labor, supplies, equipment, depreciation, depletion, amortization, operating overhead and other related costs.
	Derivatives
	The Company enters into financial derivatives to manage exposure to fluctuations in foreign currency exchange rates and power prices. The Company does not utilize derivative financial instruments for trading purposes or for speculative purposes.
	The Company’s derivative instruments are recorded at fair value with changes in fair value recognized in the Consolidated Statements of Operations at the end of each period in Gain (loss) on foreign exchange or Derivative gain.
	Foreign Exchange Transactions
	Amounts held and transactions denominated in foreign currencies other than the operating unit’s functional currency give rise to foreign exchange gains and losses which are included within Gain (loss) on foreign exchange.
	Equity-Method Investments
	The Company’s 50% interest in the Estevan Activated Carbon Joint Venture is accounted for under the equity method of accounting. Investments in unconsolidated affiliates that the Company has the ability to exercise significant influence over, but not control, are accounted for under the equity method of accounting. Under the equity method of accounting, the Company records its proportionate share of the entity’s net income or loss at each reporting period in Income from equity affiliates on the Consolidated Statements of Operations with a corresponding entry to increase or decrease the carrying value of the investment.
	Loan and Lease Receivables
	The Company periodically makes loans and finance leases at the Genesee mine in accordance with its operating agreement with its only customer for purposes of funding capital expenditures and working capital requirements. Finance lease and loan receivables are measured at the present value of the future lease payments at the inception of the arrangement. Lease payments received are comprised of a repayment of principal and finance income. Finance income is recognized based on the interest rate implicit in the finance lease. PMRU recognizes finance income over periods between 3 and 27 years, which reflect a constant periodic return on its net investment in the finance lease. Initial direct costs are included in the initial measurement of the finance lease receivables and reduce the amount of income recognized over the lease term.
	Income Taxes
	The Company’s effective tax rate in the three months ended March 31, 2015, was lower than the effective tax rate in the three months ended March 31, 2014, primarily due to the forecasted 2015 decrease in pre-tax loss and an increase in income tax expense related to the our acquisition of PMRU and CVRI (the “Canadian Acquisition”).
	For the three months ended March 31, 2015, the Company’s effective tax rate differs from the statutory rate primarily due to the U.S. valuation allowance and foreign operations. For the three months ended March 31, 2014, the Company’s effective tax rate differs from the statutory rate primarily due to the U.S. valuation allowance.
	Foreign Currency Translation
	The functional currency of the Company’s Canadian operations is the Canadian dollar. The Company’s Canadian operations’ assets and liabilities are translated at period end exchange rates, and revenues and costs are translated using average exchange rates for the period. Foreign currency translation adjustments are reported in Other comprehensive income.
	Noncontrolling Interest
	The Company owns 100% of the GP equity units and thereby has controlling interest of WMLP. The Company includes the accounts of the GP and provides for a noncontrolling interest in WMLP, which was approximately 21% at March 31, 2015.
	Recently Adopted 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. This ASU is effective beginning in fiscal 2017 and can be adopted by the Company either 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 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 new guidance should be applied on a retrospective basis, wherein the balance sheet of each individual period presented should be adjusted to reflect the period-specific effects of applying the new guidance. Upon transition, an entity is required to comply with the applicable disclosures for a change in an accounting principle. These disclosures include the nature of and reason for the change in accounting principle, the transition method, a description of the prior-period information that has been retrospectively adjusted, and the effect of the change on the financial statement line items (i.e., debt issuance cost asset and the debt liability). The new guidance is effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years, with early adoption permitted for financial statement that have not been previous issued. Management projects the impact to the financial statements resulting in balance sheet reclassification for which the Deferred financing costs, net account is recharacterized as a a contra-liability reducing the Long-term debt, less current installments balance for each of the respective periods upon adoption.

ACQUISITIONS

ACQUISITIONS	3 Months Ended
	Mar. 31, 2015
Business Combinations [Abstract]
ACQUISITION	ACQUISITIONS
	Acquisition of Buckingham Coal Company, LLC
	On January 1, 2015, Westmoreland completed the acquisition of Buckingham Coal Company, LLC, an Ohio-based coal supplier (“Buckingham”), pursuant to an agreement dated January 1, 2015 among WCC Land Holding Company, Inc., an affiliate of the Company, for an initial cash purchase price of $34.0 million, reduced by a working capital adjustment of $1.6 million (the “Buckingham Acquisition”). The Buckingham operations are included in the Company’s Coal - U.S. segment.
	The acquisition of Buckingham 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. These adjustments may be significant and will be accounted for retrospectively.
	A summary of the purchase consideration and a preliminary allocation of the purchase consideration follows (in millions):
		Provisional
		as of
		March 31,
		2015
	Purchase Price:
	Cash paid - Initial payment	$	34
	Cash received - Working capital adjustment	(1.6		)
	Net cash consideration	$	32.4
	Preliminary allocation of purchase price:
	Assets:
	Cash and cash equivalents	$	2.8
	Inventories - materials and supplies	2
	Inventories - coal	—
	Other current assets	0.1
	Total current assets	4.9
	Land and mineral rights	11
	Plant and equipment	24.7
	Total Assets	40.6
	Liabilities:
	Trade payables and other accrued liabilities	(4.4		)
	Asset retirement obligations	(1.0		)
	Total current liabilities	(5.4		)
	Asset retirement obligations, less current portion	(2.8		)
	Total Liabilities	(8.2		)
	Net fair value	$	32.4
	Acquisition of General Partner of Westmoreland Resource Partners, LP
	On December 31, 2014, the Company completed the acquisition of the GP (the “GP Acquisition”), and completed a contribution of certain royalty-bearing coal reserves to WMLP in return for WMLP common units (the “Contribution” and together with the GP Acquisition, the “WMLP Transactions”).
	Westmoreland paid $30.0 million in December 2014 and $3.5 million in January 2015 to acquire the GP; and received 4,512,500 common units of WMLP (on a post-split basis following a 12-to-1 reverse split of WMLP’s common and general partner units) as consideration for the Contribution.
	In connection with the closing, WMLP’s name was changed to Westmoreland Resource Partners, LP from Oxford Resource Partners, LP and the name of the GP was changed to Westmoreland Resources GP, LLC from Oxford Resources GP, LLC. The common units of WMLP trade on the NYSE under the symbol “WMLP”.
	The acquisition of the GP 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. These adjustments may be significant and will be accounted for retrospectively.
	A summary of the purchase consideration and a preliminary allocation of the purchase consideration follows (in millions):
	Purchase Price:
	Cash paid at closing	$	30
	Contingent consideration	3.5
	Fair value of outstanding WMLP units (1)	10.8
	Total purchase consideration	$	44.3
	Preliminary allocation of purchase price:
	Assets:
	Trade receivables and other	$	22.5
	Inventories - materials and supplies	7.4
	Inventories - coal	6.6
	Other current assets	1.3
	Total current assets	37.8
	Land and mineral rights	38.6
	Plant and equipment	134
	Advanced coal royalties	9.2
	Restricted investments and bond collateral	10.6
	Intangible assets	31
	Other assets	0.2
	Total Assets	261.4
	Liabilities:
	Trade payables and other accrued liabilities	(19.1		)
	Asset retirement obligations	(7.8		)
	Other current liabilities	(4.0		)
	Total current liabilities	(30.9		)
	Long-term debt, less current installments	(160.1		)
	Asset retirement obligations, less current portion	(23.9		)
Warrants	(2.0		)
Other liabilities	(0.2		)
Total Liabilities	(217.1		)
Net Assets	44.3
Non-controlling Interest	(10.8		)
Invested Equity	$	33.5
(1) Represents the market price of WMLP units outstanding using the December 31, 2014 closing price of $1.00.
No goodwill was recorded in the GP Acquisition and $31.0 million of intangible assets to be amortized over a fifteen-year period were identified in the GP Acquisition. The intangible asset identified in the GP Acquisition is a favorable terminal lease at a dock in Ohio which was fair valued based on more favorable market prices than contracted prices in lease agreements as measured during a business combination.
Canadian Acquisition
On April 28, 2014, Westmoreland Coal Company acquired PMRU and CVRI. These Canadian operations include six producing thermal coal mines in the Canadian provinces of Alberta and Saskatchewan, a char production facility, and a 50% interest in an activated carbon plant.
Unaudited Pro Forma Information
The following unaudited pro forma information has been prepared for illustrative purposes only and assumes the acquisitions occurred on January 1, 2013, in the case of the Canadian Acquisition and the WMLP Transactions, and on January 1, 2014, in the case of the Buckingham Acquisition. 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,
	2014
Total Revenues
As reported	$	180,202
Pro forma (unaudited)	$	465,791
Operating Income
As reported	$	8,053
Pro forma (unaudited)	$	36,176
Net income (loss) applicable to common shareholders
As reported	$	(19,291	)
Pro forma (unaudited)	$	1,382
Net income (loss) per share applicable to common shareholders
As reported	$	(1.30	)
Pro forma (unaudited)	$	0.09

INVENTORIES

INVENTORIES	3 Months Ended
	Mar. 31, 2015
Inventory Disclosure [Abstract]
INVENTORIES	INVENTORIES
	Inventories consisted of the following:
		March 31, 2015			December 31, 2014
		(In thousands)
	Coal stockpiles	$	42,266		$	41,795
	Coal fuel inventories	9,524			6,531
	Materials and supplies	84,713			88,584
	Reserve for obsolete inventory	(2,684		)	(3,055		)
	Total	$	133,819		$	133,855

RESTRICTED_INVESTMENTS_AND_BON

RESTRICTED INVESTMENTS AND BOND COLLATERAL	3 Months Ended
	Mar. 31, 2015
Disclosure Restricted Investments and Bond Collateral [Abstract]
RESTRICTED INVESTMENTS AND BOND COLLATERAL	RESTRICTED INVESTMENTS AND BOND COLLATERAL
	The Company’s restricted investments and bond collateral consist of the following:
		March 31, 2015			31-Dec-14
		(In thousands)
	Coal - U.S. Segment:
	Reclamation bond collateral:
	Kemmerer Mine	$	25,692		$	25,282
	Absaloka Mine	11,799			11,781
	Rosebud Mine	3,145			3,145
	Beulah Mine	1,270			1,270
	Buckingham acquisition escrow	—			34,000
	Coal - Canada Segment:
	PMRU	18,209			18,199
	CVRI	31,869			31,866
	Coal - WMLP Segment:
	WMLP	9,547			10,634
	Power Segment:
	Power contract collateral	12,600			12,600
	Corporate Segment:
	Postretirement medical benefit bonds	8,834			8,780
	Workers’ compensation bonds	6,848			6,832
	Total restricted investments and bond collateral	$	129,813		$	164,389
	For all of its restricted investments and bond collateral accounts, the Company can select from limited fixed-income investment options for the funds and receive the investment returns on these investments. Funds in the restricted investments and bond collateral accounts 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, 2015 were as follows:
		Carrying Value			Fair Value		Fair Value Hierarchy
		(In thousands)
	Cash and cash equivalents	$	92,771		$	92,771	Level 1
	Time deposits	2,451			2,451		Level 1
	Available-for-sale	34,591			34,591		Level 1
		$	129,813		$	129,813
	Available-for-Sale Restricted Investments and Bond Collateral
	The cost basis, gross unrealized holding gains and losses, and fair value of available-for-sale securities at March 31, 2015 were as follows (in thousands):
	Cost basis	$	34,212
	Gross unrealized holding gains	901
	Gross unrealized holding losses	(522		)
	Fair value	$	34,591
	Maturities of available-for-sale securities were as follows at March 31, 2015:
		Cost Basis			Fair Value
		(In thousands)
	Due within one year	$	391		$	378
	Due in five years or less	12,262			12,424
	Due after five years to ten years	12,953			12,993
	Due in more than ten years	8,606			8,796
		$	34,212		$	34,591

RESTRUCTURING_CHARGES

RESTRUCTURING CHARGES	3 Months Ended
	Mar. 31, 2015
Restructuring and Related Activities [Abstract]
RESTRUCTURING CHARGES	RESTRUCTURING CHARGES
	In 2013, the Company entered into an agreement with Virginia Electric Power Company, to restructure the remaining 5 years of the ROVA contract. The Company recorded restructuring charges for ROVA restructuring of nil and $0.4 million for the three months ended March 31, 2015 and March 31, 2014, respectively.
	The table below represents the restructuring provision activity related to the ROVA restructuring affecting our Power segment during the three months ended March 31, 2015 (in millions):
	Beginning Balance		Restructuring Charges		Restructuring Payments		Ending Balance
	$	0.4	$	—	$	0.4	$	—
	During 2014, the Company initiated strategic changes related to the Canadian Acquisition and the GP Acquisition. The restructuring actions were completed in 2014 for the Canadian Acquisition and are expected to be completed in 2015 for the GP Acquisition. The Company recorded restructuring charges for one-time employee termination benefits of $0.6 million and nil for the three months ended March 31, 2015 and 2014, respectively, and expects that accruals will be paid through 2016.
	The table below represents the restructuring provision activity related to the Canadian Acquisition and the GP Acquisition affecting our Coal - Canada, Coal - U.S. and Coal - WMLP segments during the three months ended March 31, 2015 (in millions):
	Beginning Balance		Restructuring Charges		Restructuring Payments		Ending Balance
	$	8.8	$	0.6	$	5.8	$	3.6

LINES_OF_CREDIT_AND_LONGTERM_D

LINES OF CREDIT AND LONG-TERM DEBT	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
LINES OF CREDIT AND LONG-TERM DEBT	LINES OF CREDIT AND DEBT
	The amounts outstanding under the Company’s debt consisted of the following as of the dates indicated:
		Total Debt Outstanding
		March 31, 2015			December 31, 2014
		(In thousands)
	8.75% Notes due 2022	$	350,000		$	350,000
	WCC Term Loan Facility due 2020	423,938			350,000
	WMLP Term Loan Facility due 2018	176,327			175,000
	Capital lease obligations	101,893			109,351
	Revolving line of credit	—			9,576
	Other	9,627			4,062
	Debt discount	(14,608		)	(13,202		)
	Total debt outstanding	1,047,177			984,787
	Less current installments	(42,554		)	(52,712		)
	Total debt outstanding, less current installments	$	1,004,623		$	932,075
	The following table presents aggregate contractual debt maturities of all debt:
		As of March 31, 2015
		(In thousands)
	2015	$	32,756
	2016	41,944
	2017	33,031
	2018	12,505
	2019	186,514
	Thereafter	755,035
	Total	1,061,785
	Less: debt discount	(14,608		)
	Total debt	$	1,047,177
	On January 22, 2015, the Company amended the WCC Term Loan Facility to increase the borrowings by $75.0 million, for an aggregate principal amount of $425.0 million as of that date. The amendments to the WCC Term Loan Facility were made in connection with the acquisition of Buckingham and for working capital. Net proceeds were $71.0 million after a 2.5% discount, 1.5% broker fee, a consent fee of 1.17%, and $0.1 million of additional debt issuance costs.
	Under the revolving line of credit (the “Revolving Credit Facility”) the maximum available borrowing amount is $50.0 million. As of March 31, 2015, the Company had no borrowings under the Revolving Credit Facility and had outstanding letters of credit in the amount of $22.8 million.
	During the three months ended March 31, 2015, the Company entered into $12.7 million of new capital leases.
	Additional information regarding the Company’s debt is outlined in Note 6 to the Consolidated Financial Statements in the Company’s 2014 Annual Report on Form 10-K.

POSTRETIREMENT_MEDICAL_BENEFIT

POSTRETIREMENT MEDICAL BENEFITS AND PENSION	3 Months Ended
	Mar. 31, 2015
Compensation and Retirement Disclosure [Abstract]
POSTRETIREMENT MEDICAL BENEFITS AND PENSION	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,
		2015			2014
		(In thousands)
	Components of net periodic benefit cost:
	Service cost	$	1,054		$	822
	Interest cost	2,907			3,203
	Amortization of deferred items	327			5
	Total net periodic benefit cost	$	4,288		$	4,030
	The following table shows the net periodic postretirement medical benefit costs that relate to current and former mining operations:
		Three Months Ended March 31,
		2015			2014
		(In thousands)
	Former mining operations	$	2,034		$	2,403
	Current operations	2,254			1,627
	Total net periodic benefit cost	$	4,288		$	4,030
	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,
		2015			2014
		(In thousands)
	Components of net periodic benefit cost:
	Service cost	$	506		$	500
	Interest cost	1,985			1,747
	Expected return on plan assets	(2,639		)	(2,154		)
	Amortization of deferred items	1,110			359
	Total net periodic pension cost	$	962		$	452
	These costs are included in Cost of sales and Selling and administrative expenses.
	The Company made no contributions to its pension plans in the three months ended March 31, 2015. The Company expects to make $1.2 million of contributions to its pension plans during the remainder of 2015.

HERITAGE_HEALTH_BENEFIT_EXPENS

HERITAGE HEALTH BENEFIT EXPENSES	3 Months Ended
	Mar. 31, 2015
Heritage Health Benefit Expenses [Abstract]
HERITAGE HEALTH BENEFIT EXPENSES	HERITAGE HEALTH BENEFIT EXPENSES
	The caption Heritage health benefit expenses used in the consolidated statements of operations refers to costs of benefits the Company provides to its former mining operation employees. The components of these expenses are as follows:
		Three Months Ended March 31,
		2015		2014
		(In thousands)
	Health care benefits	$	2,049	$	2,276
	Combined benefit fund payments	462		512
	Workers’ compensation benefits	110		136
	Black lung benefits	438		620
	Total	$	3,059	$	3,544

ASSET_RETIREMENT_OBLIGATIONS_C

ASSET RETIREMENT OBLIGATIONS, CONTRACTUAL THIRD-PARTY RECLAMATION RECEIVABLES, AND RECLAMATION DEPOSITS	3 Months Ended
	Mar. 31, 2015
Asset Retirement Obligation Disclosure [Abstract]
ASSET RETIREMENT OBLIGATIONS, CONTRACTUAL THIRD-PARTY RECLAMATION RECEIVABLES, AND RECLAMATION DEPOSITS	ASSET RETIREMENT OBLIGATIONS, CONTRACTUAL THIRD-PARTY RECLAMATION RECEIVABLE AND RECLAMATION DEPOSITS
	The asset retirement obligation, contractual third-party reclamation receivable, and reclamation deposits for each of the Company’s operating segments at March 31, 2015 are summarized below:
		Asset			Contractual			Reclamation
		Retirement			Third-Party			Deposits
		Obligation			Reclamation
					Receivable
		(In thousands)
	Coal - U.S.	$	295,569		$	109,126		$	76,715
	Coal - Canada	118,285			6,149			—
	Coal - WMLP	32,569			—			—
	Power	979			—			—
	Total	$	447,402		$	115,275		$	76,715
	Asset Retirement Obligations
	Changes in the Company’s asset retirement obligations were as follows:
		Three Months Ended March 31,
		2015			2014
		(In thousands)
	Asset retirement obligations, beginning of year (including current portion)	$	452,745		$	279,864
	Accretion	9,701			5,836
	Liabilities settled	(8,195		)	(4,437		)
	Changes due to amount and timing of reclamation	336			—
	Asset retirement obligations acquired	3,769			—
	Changes due to foreign currency translation	(10,954		)	—
	Asset retirement obligations, end of period	447,402			281,263
	Less current portion	(48,024		)	(22,227		)
	Asset retirement obligations, less current portion	$	399,378		$	259,036
	Contractual Third-Party Reclamation Receivables
	At March 31, 2015, the Company recognized an asset of $115.3 million as contractual third-party reclamation receivables, representing the present value of customer obligations to reimburse the Company for future reclamation expenditures.
	Reclamation Deposits
	The Company’s reclamation deposits will be used to fund final reclamation activities. The Company’s carrying value and estimated fair value of its reclamation deposits at March 31, 2015 were as follows:
		Carrying Value			Fair Value			Fair Value Hierarchy
		(In thousands)
	Cash and cash equivalents	$	43,228		$	43,228		Level 1
	Available-for-sale securities	33,487			33,487			Level 1
		$	76,715		$	76,715
	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.
	Available-for-Sale Reclamation Deposits
	The cost basis, gross unrealized holding gains and losses, and fair value of available-for-sale securities at March 31, 2015 were as follows (in thousands):
	Cost basis	$	33,118
	Gross unrealized holding gains	964
	Gross unrealized holding losses	(595		)
	Fair value	$	33,487
	Maturities of available-for-sale securities were as follows at March 31, 2015:
		Cost Basis			Fair Value
		(In thousands)
	Within one year	$	226		$	240
	Due in five years or less	17,820			18,030
	Due after five years to ten years	6,622			6,514
	Due in more than ten years	8,450			8,703
		$	33,118		$	33,487

DERIVATIVE_INSTRUMENTS

DERIVATIVE INSTRUMENTS	3 Months Ended
	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVE INSTRUMENTS	DERIVATIVE INSTRUMENTS
	Derivative Assets and Liabilities
	The Company evaluates all of its financial instruments to determine if such instruments are derivatives, derivatives that qualify for the normal purchase normal sale exception, or contain features that qualify as embedded derivatives. All derivative financial instruments, except for derivatives that qualify for the normal purchase normal sale exception, are recognized on the balance sheet at fair value. Changes in fair value are recognized in earnings if they are not eligible for hedge accounting or in other comprehensive income if they qualify for cash flow hedge accounting.
	In the first quarter of 2014, the Company entered into two foreign currency exchange forward contracts to purchase Canadian Dollars to manage a portion of its exposure to fluctuating rates of exchange on anticipated Canadian Dollar-denominated Canadian Acquisition cash flows. These two foreign currency contracts had a total notional amount of $348.3 million and were settled in April 2014.
	During 2014, the Company entered into contracts to purchase power at its ROVA facility to manage exposure to power price fluctuations. These contracts cover the period from April 2014 to March 2019 and contracted power prices range from $41.05 to $56.33 megawatts per hour, with a weighted average contract price of $43.39 over the remaining contract lives. The fair value of these power price derivatives are based on comparing contracted prices to projected future prices.
	The fair value of outstanding derivative instruments not designated as hedging instruments on the accompanying Consolidated Balance Sheets was as follows (in thousands):
	Derivative Instruments	Balance Sheet Location	March 31, 2015		31-Dec-14
	Contracts to purchase power	Other current liabilities	$	6,546	$	8,265
	Contracts to purchase power	Other liabilities	21,666		21,103
	The effect of derivative instruments not designated as hedging instruments on the accompanying Consolidated Statements of Operations was as follows (in thousands):
	Derivative Instruments	Statement of	Three Months Ended March 31, 2015		Three Months Ended March 31, 2014
		Operations Location
	Canadian dollar foreign exchange forward contracts	Gain (loss) on foreign exchange	$	—	$	(6,790	)
	Contracts to purchase power	Derivative gain	5,276		—

FAIR_VALUE_MEASUREMENTS

FAIR VALUE MEASUREMENTS	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	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 Notes 4, 9 and 10 for additional disclosures related to fair value measurements.
	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 that are accounted for at fair value at March 31, 2015:
		Level 1
		(In thousands)
	Assets:
	Available-for-sale investments included in Restricted investments and bond collateral	$	34,591
	Available-for-sale investments included in Reclamation deposits	33,487
	Total assets	$	68,078
	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, 2015, 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)
	31-Dec-14	$	345,498	$	348,250	$	341,300	$	344,750
	March 31, 2015	$	345,617	$	350,875	$	413,712	$	421,818
	The Company uses derivative financial instruments, primarily foreign exchange contracts and forward contracts to purchase power, to reduce its exposure to market risks from changes in foreign exchange rates and changes in prices for power, respectively. The foreign exchange contracts are measured at fair value using quoted forward foreign exchange prices from counterparties corroborated by market-based pricing (Level 2). The contracts to purchase power are measured at fair value using forward pricing curves for power from counterparties corroborated by market-based pricing (Level 2). Additional information related to the Company’s derivative financial instruments is disclosed in Notes 1 and 10 to the consolidated financial statements.
	The Company’s non-recurring fair value measurements include asset retirement obligations (refer to Note 9).
	The Company determines the estimated fair value of its asset retirement obligations by calculating the present value of estimated cash flows related to reclamation liabilities using Level 3 inputs. The significant inputs used to calculate such liabilities includes estimates of costs to be incurred, the Company’s credit adjusted discount rate, inflation rates and estimated dates of reclamation. The asset retirement liability is accreted to its present value each period and the capitalized asset retirement cost is depleted using the units-of-production method.
	The fair value of assets and liabilities acquired through business combinations is calculated using a discounted-cash flow approach using Level 3 inputs. Cash flow estimates require forecasts and assumptions for many years into the future for a variety of factors.

SHAREHOLDERS_DEFICIT_AND_ACCUM

SHAREHOLDERS' DEFICIT AND ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	3 Months Ended
	Mar. 31, 2015
Stockholders' Equity Note [Abstract]
SHAREHOLDERS' DEFICIT AND ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	SHAREHOLDERS’ DEFICIT AND ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)
	Preferred Stock
	The Company paid less than $0.1 million of preferred stock dividends for the three months ended March 31, 2015. During the three ended March 31, 2015, approximately 88,494 shares of preferred stock were converted into 604,557 shares of common stock and 3,175 shares of preferred stock were redeemed under a mandatory redemption for $0.3 million. At March 31, 2015, there were no outstanding preferred stock shares.
	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			Accumulated
						medical benefits			securities, net					other			other
														comprehensive			comprehensive
														income gains			income (loss)
		(In thousands)
	Balance at December 31, 2014	$	(36,065	)		$	(39,716	)	$	413	$	(17,880	)	$	(31,048	)	$	(124,296	)
	Other comprehensive income (loss) before reclassifications	203				—			311		(27,140		)	(575		)	(27,201		)
	Amounts reclassified from accumulated other comprehensive income (loss)	1,110				327			14		—			—			1,451
	Balance at March 31, 2015	$	(34,752	)		$	(39,389	)	$	738	$	(45,020	)	$	(31,623	)	$	(150,046	)
	The following table reflects the reclassifications out of accumulated other comprehensive loss for the three months ended March 31, 2015 are as follows (in thousands):
	Details about accumulated other comprehensive loss components		Amount reclassified from accumulated				Affected line item
			other comprehensive loss1				in the statement
							where net income
			Three Months Ended March 31, 2015				(loss) is presented
	Available-for sale securities
	Realized gains and losses on available-for sale securities		$	14			Other income (loss)
	Amortization of defined benefit pension items
	Prior service costs		$	2
	Actuarial losses		1,108				2
	Total		$	1,110
	Amortization of postretirement medical items
	Prior service costs		$	(159	)		3
	Actuarial losses		486				3
	Total		$	327
	____________________
	-1	Amounts in parentheses indicate debits to income/loss.
	-2	These accumulated other comprehensive loss components are included in the computation of net periodic pension cost. (See Note 7 - Pension for additional details)
	-3	These accumulated other comprehensive loss components are included in the computation of net periodic postretirement medical cost. (See Note 7 - Postretirement Medical Benefits for additional details)

SHAREBASED_COMPENSATION

SHARE-BASED COMPENSATION	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
SHARE-BASED COMPENSATION	SHARE-BASED COMPENSATION
	The Company grants employees and non-employee directors restricted stock units. Non-employee directors receive equity awards with a value of $90,000 after each annual meeting.
	The Company recognized compensation expense from share-based arrangements shown in the following table:
		Three Months Ended March 31,
		2015			2014
		(In thousands)
	Recognition of fair value of restricted stock units, stock options and SARs over vesting period; and issuance of stock	$	663		$	728
	Contributions of stock to the Company’s 401(k) plan	859			—
	Total share-based compensation expense	$	1,522		$	728
	Restricted Stock Units
	A summary of restricted stock award activity for the three months ended March 31, 2015 is as follows:
		Units		Weighted			Unamortized
				Average			Compensation
				Grant-Date			Expense
				Fair Value			(In thousands)
	Non-vested at December 31, 2014	409,362		$	13.87
	Vested	(9,639	)	9.49
	Forfeited	(3,610	)	30.76
	Non-vested at March 31, 2015	396,113		$	15.41		$	2,516		(1)
	____________________
	-1	Expected to be recognized over the next three years.
	In April 2015, 233,974 restricted stock units were granted, of which 117,003 units will vest ratably over a three-year period. The remaining 116,971 units are performance-based, which will vest and pay out at the end of a three-year period if performance goals are met.
	Stock Options
	A summary of stock option activity for the three months ended March 31, 2015 is as follows:
		Stock Options		Weighted			Weighted		Aggregate Intrinsic		Unamortized
				Average			Average		Value		Compensation
				Exercise Price			Remaining		(In thousands)		Expense
							Contractual				(In thousands)
							Life
							(In years)
	Outstanding at December 31, 2014	110,806		$	22.15
	Expired	—		—
	Outstanding and exercisable at March 31, 2015	110,806		$	22.15		2.9		$	510	$	—
	There were no stock options granted during the three months ended March 31, 2015.
	SARs
	A summary of SARs activity for the three months ended March 31, 2015 is as follows:
		SARs		Weighted			Weighted		Aggregate Intrinsic		Unamortized
				Average Exercise Price			Average		Value		Compensation
							Remaining		(In thousands)		Expense
							Contractual				(In thousands)
							Life
							(In years)
	Outstanding at December 31, 2014	16,943		$	25.44
	Expired	—		—
	Outstanding and exercisable at March 31, 2015	16,943		$	25.44		1.1		$	22	$	—
	There were no SARs granted during the three months ended March 31, 2015.

EARNINGS_PER_SHARE

EARNINGS PER SHARE	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
EARNINGS PER SHARE	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 convertible notes and securities, 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 and 2014 because the Company incurred a net loss applicable to common shareholders in these periods and the effect of inclusion would have been anti-dilutive.
	The table below shows the number of shares that were excluded from the calculation of diluted loss per share because their inclusion would be anti-dilutive to the calculation:
		Three Months Ended March 31,
		2015		2014
		(In thousands)
	Convertible securities	$	—	$	828
	Restricted stock units, stock options and SARs	524		779
	Total shares excluded from diluted shares calculation	$	524	$	1,607

BUSINESS_SEGMENT_INFORMATION

BUSINESS SEGMENT INFORMATION	3 Months Ended
	Mar. 31, 2015
Segment Reporting [Abstract]
BUSINESS SEGMENT INFORMATION	BUSINESS 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 and Eliminations. The Buckingham operations are included in the Company’s Coal - U.S. segment.
	Summarized financial information by segment is as follows:
		Coal -			Coal - Canada(2)			Coal - WMLP(3)			Power		Heritage			Corporate and Eliminations(4)			Consolidated
		U.S.(1)
		(In thousands)
	Three Months Ended March 31, 2015
	Revenues	$	196,392		$	103,242		$	67,567		$	20,647	$	—		$	(16,365	)	$	371,483
	Restructuring charges	—			—			553			—		—			—			553
	Depreciation, depletion, and amortization	14,088			11,265			10,180			2,484		—			42			38,059
	Operating income (loss)	11,266			9,865			(4,517		)	413		(3,349		)	(5,223		)	8,455
	Total assets	733,833			593,684			296,131			172,310		16,005			17,785			1,829,748
	Capital expenditures	10,399			4,049			1,570			579		—			(3,570		)	13,027
	Three Months Ended March 31, 2014
	Revenues	$	158,190		$	—		$	—		$	22,012	$	—		$	—		$	180,202
	Restructuring charges	—			—			—			397		—			—			397
	Depreciation, depletion, and amortization	13,459			—			—			2,524		—			76			16,059
	Operating income (loss)	13,447			—			—			1,744		(3,830		)	(3,308		)	8,053
	Total assets	697,916			—			—			167,998		15,622			525,611			1,407,147
	Capital expenditures	3,053			—			—			35		—			(38		)	3,050
	____________________
	-1	The Buckingham Acquisition was completed on January 1, 2015. For the three months ended March 31, 2015, revenues and operating income for Buckingham were $30.1 million and $1.0 million, respectively.
	-2	The Canadian operations were acquired on April 28, 2014, therefore, there is no activity for the three months ended March 31, 2014.
	-3	The operations reported under the segment Coal - WMLP were acquired on December 31, 2014, therefore, there is no activity for the three months ended March 31, 2014.
	-4	The Coal - WMLP segment recorded revenues of $16.4 million for intersegment revenues to the Coal - U.S. segment.
	A reconciliation of segment income from operations to loss before income taxes follows:
		Three Months Ended March 31,
		2015			2014
		(In thousands)
	Income from operations	$	8,455		$	8,053
	Interest expense	(24,735		)	(20,798		)
	Interest income	2,140			302
	Gain (loss) on foreign exchange	2,109			(6,790		)
	Other income	193			93
	Loss before income taxes	$	(11,838	)	$	(19,140	)

CONTINGENCIES

CONTINGENCIES	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
CONTINGENCIES	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, 2015
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 use of management’s estimates. The financial information contained in this 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. The results of operations for the three months ended March 31, 2015 are not necessarily indicative of results to be expected for the year ending December 31, 2015.
	These 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, 2014 (the “2014 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 2014 Form 10-K. Most of the descriptions of the accounting principles and other footnote disclosures previously made have been omitted in this report so long as the interim information presented is not misleading or inconsistent.
Debt	Debt Obligations
	As of March 31, 2015, the Company is subject to three major debt arrangements: (1) $350.0 million in aggregate principal amount of 8.75% senior secured notes at the parent level (the “8.75% Notes”); (2) a secured term loan facility at the parent level in the aggregate principal amount of $423.9 million (the “WCC Term Loan Facility”); and (3) a secured term loan facility at WMLP in the aggregate principal amount of $176.3 million (the “WMLP Term Loan Facility”).
	The 8.75% Notes are guaranteed by Westmoreland Energy LLC, Westmoreland Kemmerer, Inc., 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, nor are they guaranteed by Westmoreland Resources GP, LLC or Westmoreland Resource Partners, LP, referred to as the Non-guarantors. The WCC Term Loan Facility is guaranteed by Westmoreland Energy LLC, Westmoreland Kemmerer, Inc., 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., Westmoreland Canada, LLC, Westmoreland Resources GP, LLC, Westmoreland Resource Partners, LP and certain other immaterial subsidiaries).
	Borrowings under the WMLP Term Loan Facility are secured by substantially all of WMLP’s and its subsidiaries’ assets.
Inventories	Inventories
	Inventories, which include materials and supplies as well as raw coal, are stated at the lower of cost or market. Cost is determined using the average cost method. Coal inventory costs include labor, supplies, equipment, depreciation, depletion, amortization, operating overhead and other related costs.
Derivatives	Derivatives
	The Company enters into financial derivatives to manage exposure to fluctuations in foreign currency exchange rates and power prices. The Company does not utilize derivative financial instruments for trading purposes or for speculative purposes.
	The Company’s derivative instruments are recorded at fair value with changes in fair value recognized in the Consolidated Statements of Operations at the end of each period in Gain (loss) on foreign exchange or Derivative gain.
Foreign Currency Transactions	Foreign Exchange Transactions
	Amounts held and transactions denominated in foreign currencies other than the operating unit’s functional currency give rise to foreign exchange gains and losses which are included within Gain (loss) on foreign exchange.
	Foreign Currency Translation
	The functional currency of the Company’s Canadian operations is the Canadian dollar. The Company’s Canadian operations’ assets and liabilities are translated at period end exchange rates, and revenues and costs are translated using average exchange rates for the period. Foreign currency translation adjustments are reported in Other comprehensive income.
Equity Method Investments	Equity-Method Investments
	The Company’s 50% interest in the Estevan Activated Carbon Joint Venture is accounted for under the equity method of accounting. Investments in unconsolidated affiliates that the Company has the ability to exercise significant influence over, but not control, are accounted for under the equity method of accounting. Under the equity method of accounting, the Company records its proportionate share of the entity’s net income or loss at each reporting period in Income from equity affiliates on the Consolidated Statements of Operations with a corresponding entry to increase or decrease the carrying value of the investment.
Loan and Lease Receivables	Loan and Lease Receivables
	The Company periodically makes loans and finance leases at the Genesee mine in accordance with its operating agreement with its only customer for purposes of funding capital expenditures and working capital requirements. Finance lease and loan receivables are measured at the present value of the future lease payments at the inception of the arrangement. Lease payments received are comprised of a repayment of principal and finance income. Finance income is recognized based on the interest rate implicit in the finance lease. PMRU recognizes finance income over periods between 3 and 27 years, which reflect a constant periodic return on its net investment in the finance lease. Initial direct costs are included in the initial measurement of the finance lease receivables and reduce the amount of income recognized over the lease term.
Income Taxes	Income Taxes
	The Company’s effective tax rate in the three months ended March 31, 2015, was lower than the effective tax rate in the three months ended March 31, 2014, primarily due to the forecasted 2015 decrease in pre-tax loss and an increase in income tax expense related to the our acquisition of PMRU and CVRI (the “Canadian Acquisition”).
	For the three months ended March 31, 2015, the Company’s effective tax rate differs from the statutory rate primarily due to the U.S. valuation allowance and foreign operations. For the three months ended March 31, 2014, the Company’s effective tax rate differs from the statutory rate primarily due to the U.S. valuation allowance.
Noncontrolling Interest	Noncontrolling Interest
	The Company owns 100% of the GP equity units and thereby has controlling interest of WMLP. The Company includes the accounts of the GP and provides for a noncontrolling interest in WMLP, which was approximately 21% at March 31, 2015.
Recently Adopted Accounting Pronouncements	Recently Adopted 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. This ASU is effective beginning in fiscal 2017 and can be adopted by the Company either 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 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 new guidance should be applied on a retrospective basis, wherein the balance sheet of each individual period presented should be adjusted to reflect the period-specific effects of applying the new guidance. Upon transition, an entity is required to comply with the applicable disclosures for a change in an accounting principle. These disclosures include the nature of and reason for the change in accounting principle, the transition method, a description of the prior-period information that has been retrospectively adjusted, and the effect of the change on the financial statement line items (i.e., debt issuance cost asset and the debt liability). The new guidance is effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years, with early adoption permitted for financial statement that have not been previous issued. Management projects the impact to the financial statements resulting in balance sheet reclassification for which the Deferred financing costs, net account is recharacterized as a a contra-liability reducing the Long-term debt, less current installments balance for each of the respective periods upon adoption.

ACQUISITIONS_Tables

ACQUISITIONS (Tables)	3 Months Ended
	Mar. 31, 2015
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 acquisitions occurred on January 1, 2013, in the case of the Canadian Acquisition and the WMLP Transactions, and on January 1, 2014, in the case of the Buckingham Acquisition. 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,
		2014
	Total Revenues
	As reported	$	180,202
	Pro forma (unaudited)	$	465,791
	Operating Income
	As reported	$	8,053
	Pro forma (unaudited)	$	36,176
	Net income (loss) applicable to common shareholders
	As reported	$	(19,291	)
	Pro forma (unaudited)	$	1,382
	Net income (loss) per share applicable to common shareholders
	As reported	$	(1.30	)
	Pro forma (unaudited)	$	0.09
Buckingham Coal Company, LLC
Business Acquisition [Line Items]
Summary of purchase consideration and allocation of purchase consideration	A summary of the purchase consideration and a preliminary allocation of the purchase consideration follows (in millions):
		Provisional
		as of
		March 31,
		2015
	Purchase Price:
	Cash paid - Initial payment	$	34
	Cash received - Working capital adjustment	(1.6		)
	Net cash consideration	$	32.4
	Preliminary allocation of purchase price:
	Assets:
	Cash and cash equivalents	$	2.8
	Inventories - materials and supplies	2
	Inventories - coal	—
	Other current assets	0.1
	Total current assets	4.9
	Land and mineral rights	11
	Plant and equipment	24.7
	Total Assets	40.6
	Liabilities:
	Trade payables and other accrued liabilities	(4.4		)
	Asset retirement obligations	(1.0		)
	Total current liabilities	(5.4		)
	Asset retirement obligations, less current portion	(2.8		)
	Total Liabilities	(8.2		)
	Net fair value	$	32.4
Westmoreland Resources GP, LLC
Business Acquisition [Line Items]
Summary of purchase consideration and allocation of purchase consideration	A summary of the purchase consideration and a preliminary allocation of the purchase consideration follows (in millions):
	Purchase Price:
	Cash paid at closing	$	30
	Contingent consideration	3.5
	Fair value of outstanding WMLP units (1)	10.8
	Total purchase consideration	$	44.3
	Preliminary allocation of purchase price:
	Assets:
	Trade receivables and other	$	22.5
	Inventories - materials and supplies	7.4
	Inventories - coal	6.6
	Other current assets	1.3
	Total current assets	37.8
	Land and mineral rights	38.6
	Plant and equipment	134
	Advanced coal royalties	9.2
	Restricted investments and bond collateral	10.6
	Intangible assets	31
	Other assets	0.2
	Total Assets	261.4
	Liabilities:
	Trade payables and other accrued liabilities	(19.1		)
	Asset retirement obligations	(7.8		)
	Other current liabilities	(4.0		)
	Total current liabilities	(30.9		)
	Long-term debt, less current installments	(160.1		)
	Asset retirement obligations, less current portion	(23.9		)
	Warrants	(2.0		)
	Other liabilities	(0.2		)
	Total Liabilities	(217.1		)
	Net Assets	44.3
	Non-controlling Interest	(10.8		)
	Invested Equity	$	33.5
	(1) Represents the market price of WMLP units outstanding using the December 31, 2014 closing price of $1.00.

INVENTORIES_Tables

INVENTORIES (Tables)	3 Months Ended
	Mar. 31, 2015
Inventory Disclosure [Abstract]
Inventories	Inventories consisted of the following:
		March 31, 2015			December 31, 2014
		(In thousands)
	Coal stockpiles	$	42,266		$	41,795
	Coal fuel inventories	9,524			6,531
	Materials and supplies	84,713			88,584
	Reserve for obsolete inventory	(2,684		)	(3,055		)
	Total	$	133,819		$	133,855

RESTRICTED_INVESTMENTS_AND_BON1

RESTRICTED INVESTMENTS AND BOND COLLATERAL (Tables)	3 Months Ended
	Mar. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Components of restricted investments and bond collateral	The Company’s restricted investments and bond collateral consist of the following:
		March 31, 2015			31-Dec-14
		(In thousands)
	Coal - U.S. Segment:
	Reclamation bond collateral:
	Kemmerer Mine	$	25,692		$	25,282
	Absaloka Mine	11,799			11,781
	Rosebud Mine	3,145			3,145
	Beulah Mine	1,270			1,270
	Buckingham acquisition escrow	—			34,000
	Coal - Canada Segment:
	PMRU	18,209			18,199
	CVRI	31,869			31,866
	Coal - WMLP Segment:
	WMLP	9,547			10,634
	Power Segment:
	Power contract collateral	12,600			12,600
	Corporate Segment:
	Postretirement medical benefit bonds	8,834			8,780
	Workers’ compensation bonds	6,848			6,832
	Total restricted investments and bond collateral	$	129,813		$	164,389
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, 2015 were as follows:
		Carrying Value			Fair Value		Fair Value Hierarchy
		(In thousands)
	Cash and cash equivalents	$	92,771		$	92,771	Level 1
	Time deposits	2,451			2,451		Level 1
	Available-for-sale	34,591			34,591		Level 1
		$	129,813		$	129,813
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, 2015 were as follows (in thousands):
	Cost basis	$	34,212
	Gross unrealized holding gains	901
	Gross unrealized holding losses	(522		)
	Fair value	$	34,591
Restricted Investments and Bond Collateral
Schedule of Available-for-sale Securities [Line Items]
Investments Classified by Contractual Maturity Date	Maturities of available-for-sale securities were as follows at March 31, 2015:
		Cost Basis			Fair Value
		(In thousands)
	Due within one year	$	391		$	378
	Due in five years or less	12,262			12,424
	Due after five years to ten years	12,953			12,993
	Due in more than ten years	8,606			8,796
		$	34,212		$	34,591

RESTRUCTURING_CHARGES_Tables

RESTRUCTURING CHARGES (Tables)	3 Months Ended
	Mar. 31, 2015
ROVA Contract
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Costs	The table below represents the restructuring provision activity related to the ROVA restructuring affecting our Power segment during the three months ended March 31, 2015 (in millions):
	Beginning Balance		Restructuring Charges		Restructuring Payments		Ending Balance
	$	0.4	$	—	$	0.4	$	—
Sherritt International Corporation and Westmoreland Resources LP
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Costs	The table below represents the restructuring provision activity related to the Canadian Acquisition and the GP Acquisition affecting our Coal - Canada, Coal - U.S. and Coal - WMLP segments during the three months ended March 31, 2015 (in millions):
	Beginning Balance		Restructuring Charges		Restructuring Payments		Ending Balance
	$	8.8	$	0.6	$	5.8	$	3.6

LINES_OF_CREDIT_AND_LONGTERM_D1

LINES OF CREDIT AND LONG-TERM DEBT (Tables)	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Outstanding lines of credit and long-term debt	The amounts outstanding under the Company’s debt consisted of the following as of the dates indicated:
		Total Debt Outstanding
		March 31, 2015			December 31, 2014
		(In thousands)
	8.75% Notes due 2022	$	350,000		$	350,000
	WCC Term Loan Facility due 2020	423,938			350,000
	WMLP Term Loan Facility due 2018	176,327			175,000
	Capital lease obligations	101,893			109,351
	Revolving line of credit	—			9,576
	Other	9,627			4,062
	Debt discount	(14,608		)	(13,202		)
	Total debt outstanding	1,047,177			984,787
	Less current installments	(42,554		)	(52,712		)
	Total debt outstanding, less current installments	$	1,004,623		$	932,075
Contractual maturities of all long-term debt	The following table presents aggregate contractual debt maturities of all debt:
		As of March 31, 2015
		(In thousands)
	2015	$	32,756
	2016	41,944
	2017	33,031
	2018	12,505
	2019	186,514
	Thereafter	755,035
	Total	1,061,785
	Less: debt discount	(14,608		)
	Total debt	$	1,047,177

POSTRETIREMENT_MEDICAL_BENEFIT1

POSTRETIREMENT MEDICAL BENEFITS AND PENSION (Tables)	3 Months Ended
	Mar. 31, 2015
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,
		2015			2014
		(In thousands)
	Components of net periodic benefit cost:
	Service cost	$	1,054		$	822
	Interest cost	2,907			3,203
	Amortization of deferred items	327			5
	Total net periodic benefit cost	$	4,288		$	4,030
	The following table shows the net periodic postretirement medical benefit costs that relate to current and former mining operations:
		Three Months Ended March 31,
		2015			2014
		(In thousands)
	Former mining operations	$	2,034		$	2,403
	Current operations	2,254			1,627
	Total net periodic benefit cost	$	4,288		$	4,030
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,
		2015			2014
		(In thousands)
	Components of net periodic benefit cost:
	Service cost	$	506		$	500
	Interest cost	1,985			1,747
	Expected return on plan assets	(2,639		)	(2,154		)
	Amortization of deferred items	1,110			359
	Total net periodic pension cost	$	962		$	452

HERITAGE_HEALTH_BENEFIT_EXPENS1

HERITAGE HEALTH BENEFIT EXPENSES (Tables)	3 Months Ended
	Mar. 31, 2015
Heritage Health Benefit Expenses [Abstract]
Components of costs of benefits to former mining operation employees	The components of these expenses are as follows:
		Three Months Ended March 31,
		2015		2014
		(In thousands)
	Health care benefits	$	2,049	$	2,276
	Combined benefit fund payments	462		512
	Workers’ compensation benefits	110		136
	Black lung benefits	438		620
	Total	$	3,059	$	3,544

ASSET_RETIREMENT_OBLIGATIONS_C1

ASSET RETIREMENT OBLIGATIONS, CONTRACTUAL THIRD-PARTY RECLAMATION RECEIVABLES, AND RECLAMATION DEPOSITS (Tables)	3 Months Ended
	Mar. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Summary of asset retirement obligations, contractual third-party reclamation receivables and reclamation deposits	The asset retirement obligation, contractual third-party reclamation receivable, and reclamation deposits for each of the Company’s operating segments at March 31, 2015 are summarized below:
		Asset			Contractual			Reclamation
		Retirement			Third-Party			Deposits
		Obligation			Reclamation
					Receivable
		(In thousands)
	Coal - U.S.	$	295,569		$	109,126		$	76,715
	Coal - Canada	118,285			6,149			—
	Coal - WMLP	32,569			—			—
	Power	979			—			—
	Total	$	447,402		$	115,275		$	76,715
Changes in Company's asset retirement obligations	Changes in the Company’s asset retirement obligations were as follows:
		Three Months Ended March 31,
		2015			2014
		(In thousands)
	Asset retirement obligations, beginning of year (including current portion)	$	452,745		$	279,864
	Accretion	9,701			5,836
	Liabilities settled	(8,195		)	(4,437		)
	Changes due to amount and timing of reclamation	336			—
	Asset retirement obligations acquired	3,769			—
	Changes due to foreign currency translation	(10,954		)	—
	Asset retirement obligations, end of period	447,402			281,263
	Less current portion	(48,024		)	(22,227		)
	Asset retirement obligations, less current portion	$	399,378		$	259,036
Carrying value and estimated fair value of reclamation deposits	The Company’s carrying value and estimated fair value of its reclamation deposits at March 31, 2015 were as follows:
		Carrying Value			Fair Value			Fair Value Hierarchy
		(In thousands)
	Cash and cash equivalents	$	43,228		$	43,228		Level 1
	Available-for-sale securities	33,487			33,487			Level 1
		$	76,715		$	76,715
Available for sale reclamation deposits	The cost basis, gross unrealized holding gains and losses, and fair value of available-for-sale securities at March 31, 2015 were as follows (in thousands):
	Cost basis	$	33,118
	Gross unrealized holding gains	964
	Gross unrealized holding losses	(595		)
	Fair value	$	33,487
Reclamation Deposits
Schedule of Available-for-sale Securities [Line Items]
Investments Classified by Contractual Maturity Date	Maturities of available-for-sale securities were as follows at March 31, 2015:
		Cost Basis			Fair Value
		(In thousands)
	Within one year	$	226		$	240
	Due in five years or less	17,820			18,030
	Due after five years to ten years	6,622			6,514
	Due in more than ten years	8,450			8,703
		$	33,118		$	33,487

DERIVATIVE_INSTRUMENTS_Tables

DERIVATIVE INSTRUMENTS (Tables)	3 Months Ended
	Mar. 31, 2015
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 Consolidated Balance Sheets was as follows (in thousands):
	Derivative Instruments	Balance Sheet Location	March 31, 2015		31-Dec-14
	Contracts to purchase power	Other current liabilities	$	6,546	$	8,265
	Contracts to purchase power	Other liabilities	21,666		21,103
	The effect of derivative instruments not designated as hedging instruments on the accompanying Consolidated Statements of Operations was as follows (in thousands):
	Derivative Instruments	Statement of	Three Months Ended March 31, 2015		Three Months Ended March 31, 2014
		Operations Location
	Canadian dollar foreign exchange forward contracts	Gain (loss) on foreign exchange	$	—	$	(6,790	)
	Contracts to purchase power	Derivative gain	5,276		—

FAIR_VALUE_MEASUREMENTS_Tables

FAIR VALUE MEASUREMENTS (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Summary of financial assets at fair value	The table below sets forth, by level, the Company’s financial assets that are accounted for at fair value at March 31, 2015:
		Level 1
		(In thousands)
	Assets:
	Available-for-sale investments included in Restricted investments and bond collateral	$	34,591
	Available-for-sale investments included in Reclamation deposits	33,487
	Total assets	$	68,078
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)
	31-Dec-14	$	345,498	$	348,250	$	341,300	$	344,750
	March 31, 2015	$	345,617	$	350,875	$	413,712	$	421,818

SHAREHOLDERS_DEFICIT_AND_ACCUM1

SHAREHOLDERS' DEFICIT AND ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Tables)	3 Months Ended
	Mar. 31, 2015
Stockholders' Equity Note [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			Accumulated
						medical benefits			securities, net					other			other
														comprehensive			comprehensive
														income gains			income (loss)
		(In thousands)
	Balance at December 31, 2014	$	(36,065	)		$	(39,716	)	$	413	$	(17,880	)	$	(31,048	)	$	(124,296	)
	Other comprehensive income (loss) before reclassifications	203				—			311		(27,140		)	(575		)	(27,201		)
	Amounts reclassified from accumulated other comprehensive income (loss)	1,110				327			14		—			—			1,451
	Balance at March 31, 2015	$	(34,752	)		$	(39,389	)	$	738	$	(45,020	)	$	(31,623	)	$	(150,046	)
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, 2015 are as follows (in thousands):
	Details about accumulated other comprehensive loss components		Amount reclassified from accumulated				Affected line item
			other comprehensive loss1				in the statement
							where net income
			Three Months Ended March 31, 2015				(loss) is presented
	Available-for sale securities
	Realized gains and losses on available-for sale securities		$	14			Other income (loss)
	Amortization of defined benefit pension items
	Prior service costs		$	2
	Actuarial losses		1,108				2
	Total		$	1,110
	Amortization of postretirement medical items
	Prior service costs		$	(159	)		3
	Actuarial losses		486				3
	Total		$	327
	____________________
	-1	Amounts in parentheses indicate debits to income/loss.
	-2	These accumulated other comprehensive loss components are included in the computation of net periodic pension cost. (See Note 7 - Pension for additional details)
	-3	These accumulated other comprehensive loss components are included in the computation of net periodic postretirement medical cost. (See Note 7 - Postretirement Medical Benefits for additional details)

SHAREBASED_COMPENSATION_Tables

SHARE-BASED COMPENSATION (Tables)	3 Months Ended
	Mar. 31, 2015
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,
		2015			2014
		(In thousands)
	Recognition of fair value of restricted stock units, stock options and SARs over vesting period; and issuance of stock	$	663		$	728
	Contributions of stock to the Company’s 401(k) plan	859			—
	Total share-based compensation expense	$	1,522		$	728
Summary of Restricted Stock Unit activity	A summary of restricted stock award activity for the three months ended March 31, 2015 is as follows:
		Units		Weighted			Unamortized
				Average			Compensation
				Grant-Date			Expense
				Fair Value			(In thousands)
	Non-vested at December 31, 2014	409,362		$	13.87
	Vested	(9,639	)	9.49
	Forfeited	(3,610	)	30.76
	Non-vested at March 31, 2015	396,113		$	15.41		$	2,516		(1)
	____________________
	-1	Expected to be recognized over the next three years.
Summary of Stock Option Activity	A summary of stock option activity for the three months ended March 31, 2015 is as follows:
		Stock Options		Weighted			Weighted		Aggregate Intrinsic		Unamortized
				Average			Average		Value		Compensation
				Exercise Price			Remaining		(In thousands)		Expense
							Contractual				(In thousands)
							Life
							(In years)
	Outstanding at December 31, 2014	110,806		$	22.15
	Expired	—		—
	Outstanding and exercisable at March 31, 2015	110,806		$	22.15		2.9		$	510	$	—
Summary of Stock Appreciation Rights	A summary of SARs activity for the three months ended March 31, 2015 is as follows:
		SARs		Weighted			Weighted		Aggregate Intrinsic		Unamortized
				Average Exercise Price			Average		Value		Compensation
							Remaining		(In thousands)		Expense
							Contractual				(In thousands)
							Life
							(In years)
	Outstanding at December 31, 2014	16,943		$	25.44
	Expired	—		—
	Outstanding and exercisable at March 31, 2015	16,943		$	25.44		1.1		$	22	$	—

EARNINGS_PER_SHARE_Tables

EARNINGS PER SHARE (Tables)	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
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 loss per share because their inclusion would be anti-dilutive to the calculation:
		Three Months Ended March 31,
		2015		2014
		(In thousands)
	Convertible securities	$	—	$	828
	Restricted stock units, stock options and SARs	524		779
	Total shares excluded from diluted shares calculation	$	524	$	1,607

BUSINESS_SEGMENT_INFORMATION_T

BUSINESS SEGMENT INFORMATION (Tables)	3 Months Ended
	Mar. 31, 2015
Segment Reporting [Abstract]
Summarized financial information by segment	Summarized financial information by segment is as follows:
		Coal -			Coal - Canada(2)			Coal - WMLP(3)			Power		Heritage			Corporate and Eliminations(4)			Consolidated
		U.S.(1)
		(In thousands)
	Three Months Ended March 31, 2015
	Revenues	$	196,392		$	103,242		$	67,567		$	20,647	$	—		$	(16,365	)	$	371,483
	Restructuring charges	—			—			553			—		—			—			553
	Depreciation, depletion, and amortization	14,088			11,265			10,180			2,484		—			42			38,059
	Operating income (loss)	11,266			9,865			(4,517		)	413		(3,349		)	(5,223		)	8,455
	Total assets	733,833			593,684			296,131			172,310		16,005			17,785			1,829,748
	Capital expenditures	10,399			4,049			1,570			579		—			(3,570		)	13,027
	Three Months Ended March 31, 2014
	Revenues	$	158,190		$	—		$	—		$	22,012	$	—		$	—		$	180,202
	Restructuring charges	—			—			—			397		—			—			397
	Depreciation, depletion, and amortization	13,459			—			—			2,524		—			76			16,059
	Operating income (loss)	13,447			—			—			1,744		(3,830		)	(3,308		)	8,053
	Total assets	697,916			—			—			167,998		15,622			525,611			1,407,147
	Capital expenditures	3,053			—			—			35		—			(38		)	3,050
	____________________
	-1	The Buckingham Acquisition was completed on January 1, 2015. For the three months ended March 31, 2015, revenues and operating income for Buckingham were $30.1 million and $1.0 million, respectively.
	-2	The Canadian operations were acquired on April 28, 2014, therefore, there is no activity for the three months ended March 31, 2014.
	-3	The operations reported under the segment Coal - WMLP were acquired on December 31, 2014, therefore, there is no activity for the three months ended March 31, 2014.
	-4	The Coal - WMLP segment recorded revenues of $16.4 million for intersegment revenues to the Coal - U.S. segment.
Reconciliation of segment operating income to income (loss)	A reconciliation of segment income from operations to loss before income taxes follows:
		Three Months Ended March 31,
		2015			2014
		(In thousands)
	Income from operations	$	8,455		$	8,053
	Interest expense	(24,735		)	(20,798		)
	Interest income	2,140			302
	Gain (loss) on foreign exchange	2,109			(6,790		)
	Other income	193			93
	Loss before income taxes	$	(11,838	)	$	(19,140	)

BASIS_OF_PRESENTATION_Business

BASIS OF PRESENTATION - Business Operations (Details)	0 Months Ended	3 Months Ended	0 Months Ended
	Apr. 28, 2014	Mar. 31, 2015	Dec. 31, 2014
	mines	mines
Canadian Acquisition
Business Acquisition [Line Items]
Number of mines	6	6
Westmoreland Resource Partners LP
Business Acquisition [Line Items]
Ownership percentage in partnership (percent)			79.00%
PMRU
Business Acquisition [Line Items]
Number of mines		5
Corporate Joint Venture | Canadian Acquisition
Business Acquisition [Line Items]
Ownership percentage in joint venture (percent)		50.00%
Corporate Joint Venture | PMRU
Business Acquisition [Line Items]
Ownership percentage in joint venture (percent)		50.00%

BASIS_OF_PRESENTATION_Addition

BASIS OF PRESENTATION - Additional Information (Details) (USD $)	0 Months Ended	3 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Mar. 31, 2015
Debt Instrument [Line Items]
Debt arrangements	984,787	1,047,177
PMRU | Minimum
Debt Instrument [Line Items]
Finance income, recognition period		3 years
PMRU | Maximum
Debt Instrument [Line Items]
Finance income, recognition period		27 years
Senior secured notes
Debt Instrument [Line Items]
Stated interest rate (percent)		8.75%
Westmoreland Resources GP, LLC
Debt Instrument [Line Items]
Ownership percentage in partnership (percent)	100.00%	100.00%
Westmoreland Resource Partners LP
Debt Instrument [Line Items]
Ownership percentage in partnership (percent)	79.00%
Noncontrolling interest, ownership percentage by noncontrolling owners (percent)		21.00%
Corporate Joint Venture | PMRU
Debt Instrument [Line Items]
Ownership percentage in joint venture (percent)		50.00%
Senior secured notes at the parent level | Senior secured notes
Debt Instrument [Line Items]
Debt arrangements	350,000	350,000
Stated interest rate (percent)		8.75%
Secured term loan facility at the Parent Level | Term Notes
Debt Instrument [Line Items]
Debt arrangements	350,000	423,938
WMLP term loan facility | Term Notes
Debt Instrument [Line Items]
Debt arrangements	175,000	176,327

ACQUISITIONS_Narrative_Details

ACQUISITIONS - Narrative (Details) (USD $)	3 Months Ended		0 Months Ended			1 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Jan. 01, 2015	Apr. 28, 2014	Dec. 31, 2014	Jan. 31, 2015
				mines
Business Acquisition [Line Items]
Cash paid	$35,887,000	$0
Buckingham Coal Company, LLC
Business Acquisition [Line Items]
Cash paid - Initial payment			34,000,000
Cash received - working capital adjustment			1,600,000
Cash paid			32,400,000
Canadian Acquisition
Business Acquisition [Line Items]
Number of mines	6			6
Voting interests acquired (percent)				50.00%
Westmoreland Resource Partners LP
Business Acquisition [Line Items]
Units of partnership interest acquired (shares)					4,512,500
Partnership interest, reverse split, conversion ratio					12
Westmoreland Resources GP, LLC
Business Acquisition [Line Items]
Cash paid					30,000,000	3,500,000
Intangible assets					31,000,000
Finite-Lived Intangible Asset, Useful Life					15 years

ACQUISITIONS_Summary_of_purcha

ACQUISITIONS - Summary of purchase consideration and allocation of purchase consideration (Details) (USD $)	3 Months Ended		0 Months Ended			1 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Jan. 01, 2015	Dec. 31, 2014		Jan. 31, 2015
Purchase Price:
Cash paid	$35,887,000	$0
Buckingham Coal Company, LLC
Purchase Price:
Cash paid - Initial payment			34,000,000
Cash received - Working capital adjustment			-1,600,000
Cash paid			32,400,000
Assets:
Cash and cash equivalents			2,800,000
Inventories - materials and supplies			2,000,000
Inventories - coal			0
Other current assets			100,000
Total current assets			4,900,000
Land and mineral rights			11,000,000
Plant and equipment			24,700,000
Total Assets			40,600,000
Liabilities:
Trade payables and other accrued liabilities			-4,400,000
Asset retirement obligations			-1,000,000
Total current liabilities			-5,400,000
Asset retirement obligations, less current portion			-2,800,000
Total Liabilities			-8,200,000
Net fair value			32,400,000
Westmoreland Resources GP, LLC
Purchase Price:
Cash paid				30,000,000		3,500,000
Contingent consideration				3,500,000
Fair value of outstanding WMLP units				10,800,000	[1]
Total purchase consideration				44,300,000
Assets:
Trade receivables and other				22,500,000
Inventories - materials and supplies				7,400,000
Inventories - coal				6,600,000
Other current assets				1,300,000
Total current assets				37,800,000
Land and mineral rights				38,600,000
Plant and equipment				134,000,000
Advanced coal royalties				9,200,000
Restricted investments and bond collateral				10,600,000
Intangible assets				31,000,000
Other assets				200,000
Total Assets				261,400,000
Liabilities:
Trade payables and other accrued liabilities				-19,100,000
Asset retirement obligations				-7,800,000
Other current liabilities				-4,000,000
Total current liabilities				-30,900,000
Long-term debt, less current installments				-160,100,000
Asset retirement obligations, less current portion				-23,900,000
Warrants				-2,000,000
Other liabilities				-200,000
Total Liabilities				-217,100,000
Net fair value				44,300,000
Non-controlling Interest				-10,800,000
Invested Equity				$33,500,000
WMLP units outstanding, closing price (in USD per share)				$1
[1]	Represents the market price of WMLP units outstanding using the December 31, 2014 closing price of $1.00.

ACQUISITIONS_Summary_of_Pro_Fo

ACQUISITIONS - Summary of Pro Forma Information (Details) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Total Revenues
As reported	$371,483	$180,202
Pro forma (unaudited)		465,791
Operating Income
As reported	8,455	8,053
Pro forma (unaudited)		36,176
Net income (loss) applicable to common shareholders
As reported	-11,732	-19,291
Pro forma (unaudited)		$1,382
Net income (loss) per share applicable to common shareholders
As reported, (in dollars per share)	($0.67)	($1.30)
Pro forma (unaudited) (in dollars per share)		$0.09

INVENTORIES_Detail

INVENTORIES (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Inventory Disclosure [Abstract]
Coal stockpiles	$42,266	$41,795
Coal fuel inventories	9,524	6,531
Materials and supplies	84,713	88,584
Reserve for obsolete inventory	-2,684	-3,055
Total	$133,819	$133,855

RESTRICTED_INVESTMENTS_AND_BON2

RESTRICTED INVESTMENTS AND BOND COLLATERAL - Components of Restricted Investments and Bond Collateral (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Restricted Investments and Bond Collateral [Line Items]
Total restricted investments and bond collateral	$129,813	$164,389
Coal - Canada Segment | CVRI
Restricted Investments and Bond Collateral [Line Items]
Total restricted investments and bond collateral	31,869	31,866
Coal - Canada Segment | PMRU
Restricted Investments and Bond Collateral [Line Items]
Total restricted investments and bond collateral	18,209	18,199
Reclamation Bond Collateral | Coal - U.S. Segment | Kemmerer Mine
Restricted Investments and Bond Collateral [Line Items]
Total restricted investments and bond collateral	25,692	25,282
Reclamation Bond Collateral | Coal - U.S. Segment | Absaloka Mine
Restricted Investments and Bond Collateral [Line Items]
Total restricted investments and bond collateral	11,799	11,781
Reclamation Bond Collateral | Coal - U.S. Segment | Rosebud Mine
Restricted Investments and Bond Collateral [Line Items]
Total restricted investments and bond collateral	3,145	3,145
Reclamation Bond Collateral | Coal - U.S. Segment | Beulah Mine
Restricted Investments and Bond Collateral [Line Items]
Total restricted investments and bond collateral	1,270	1,270
Power Contract Collateral | Power Segment
Restricted Investments and Bond Collateral [Line Items]
Total restricted investments and bond collateral	12,600	12,600
Postretirement Medical Benefit Bonds | Corporate Segment
Restricted Investments and Bond Collateral [Line Items]
Total restricted investments and bond collateral	8,834	8,780
Workers' Compensation Bonds | Corporate Segment
Restricted Investments and Bond Collateral [Line Items]
Total restricted investments and bond collateral	6,848	6,832
Buckingham acquisition escrow | Reclamation Bond Collateral | Coal - U.S. Segment
Restricted Investments and Bond Collateral [Line Items]
Total restricted investments and bond collateral	0	34,000
Westmoreland Resource Partners LP | Coal - WMLP Segment
Restricted Investments and Bond Collateral [Line Items]
Total restricted investments and bond collateral	$9,547	$10,634

RESTRICTED_INVESTMENTS_AND_BON3

RESTRICTED INVESTMENTS AND BOND COLLATERAL - Carrying Value and Estimated Fair Value of Restricted Investments and Bond Collateral (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Investment [Line Items]
Restricted investments and bond collateral	$129,813	$164,389
Carrying Value
Investment [Line Items]
Cash and cash equivalents	92,771
Time deposits	2,451
Available-for-sale	34,591
Restricted investments and bond collateral	129,813
Fair Value
Investment [Line Items]
Restricted investments and bond collateral	129,813
Level 1 | Fair Value
Investment [Line Items]
Cash and cash equivalents	92,771
Time deposits	2,451
Available-for-sale	$34,591

RESTRICTED_INVESTMENTS_AND_BON4

RESTRICTED INVESTMENTS AND BOND COLLATERAL - Amortized Cost, Gross Unrealized Holding Gains and Losses and Fair Value of Held-to-Maturity Securities (Detail) (Restricted Investments and Bond Collateral, USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Restricted Investments and Bond Collateral
Schedule of Available-for-sale Securities [Line Items]
Cost basis	$34,212
Gross unrealized holding gains	901
Gross unrealized holding losses	-522
Fair value	$34,591

RESTRICTED_INVESTMENTS_AND_BON5

RESTRICTED INVESTMENTS AND BOND COLLATERAL - Maturities of Available-for-Sale Securities (Details) (Restricted Investments and Bond Collateral, USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified
Restricted Investments and Bond Collateral
Schedule of Available-for-sale Securities [Line Items]
Due within one year, Amortized Cost Basis	$391
Due in five years or less, Amortized Cost Basis	12,262
Due after five years to ten years, Amortized Cost Basis	12,953
Due in more than ten years, Amortized Cost Basis	8,606
Available-for-sale Securities, Amortized Cost Basis	34,212
Due within one year, Fair Value	378
Due in five years or less, Fair Value	12,424
Due after five years to ten years, Fair Value	12,993
Due in more than ten years, Fair Value	8,796
Available-for-sale Securities, Fair Value	$34,591

RESTRUCTURING_CHARGES_Details

RESTRUCTURING CHARGES (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2013
Restructuring Reserve [Roll Forward]
Restructuring charges	$553,000	$397,000
ROVA Contract
Restructuring Cost and Reserve [Line Items]
Remaining Period of Contract			5 years
Restructuring Reserve [Roll Forward]
Beginning balance	400,000
Restructuring charges	0	400,000
Restructuring payments	400,000
Ending balance	0
Sherritt International Corporation and Westmoreland Resources LP
Restructuring Reserve [Roll Forward]
Beginning balance	8,800,000
Restructuring charges	600,000
Restructuring payments	5,800,000
Ending balance	3,600,000
One-time Employee Termination Benefits | Sherritt International Corporation and Westmoreland Resources LP
Restructuring Reserve [Roll Forward]
Restructuring charges	$600,000	$0

LINES_OF_CREDIT_AND_LONGTERM_D2

LINES OF CREDIT AND LONG-TERM DEBT - Outstanding Lines of Credit and Long-Term Debt (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Debt Instrument [Line Items]
Total debt outstanding	$1,047,177	$984,787
Less current portion	-42,554	-52,712
Total debt outstanding, less current installments	1,004,623	932,075
Senior Notes
Debt Instrument [Line Items]
Stated interest rate (percent)	8.75%
Capital lease obligations
Debt Instrument [Line Items]
Total debt outstanding	101,893	109,351
Other
Debt Instrument [Line Items]
Total debt outstanding	9,627	4,062
Debt discount
Debt Instrument [Line Items]
Total debt outstanding	-14,608	-13,202
Senior secured notes due 2022 | Senior Notes
Debt Instrument [Line Items]
Total debt outstanding	350,000	350,000
Stated interest rate (percent)	8.75%
Term loan facility due 2020 | Term Notes
Debt Instrument [Line Items]
Total debt outstanding	423,938	350,000
WMLP term loan facility due 2018 | Term Notes
Debt Instrument [Line Items]
Total debt outstanding	176,327	175,000
Revolving line of credit | Revolving line of credit
Debt Instrument [Line Items]
Total debt outstanding	$0	$9,576

LINES_OF_CREDIT_AND_LONGTERM_D3

LINES OF CREDIT AND LONG-TERM DEBT - Contractual Maturities of Long Term Debt (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Debt Disclosure [Abstract]
2015	$32,756
2016	41,944
2017	33,031
2018	12,505
2019	186,514
Thereafter	755,035
Total	1,061,785
Less: debt premium (discount), net	-14,608
Total debt outstanding	$1,047,177	$984,787

LINES_OF_CREDIT_AND_LONGTERM_D4

LINES OF CREDIT AND LONG-TERM DEBT - Additional Information (Detail) (USD $)	3 Months Ended	0 Months Ended
	Mar. 31, 2015	Jan. 22, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Aggregate principal amount	$1,061,785,000
Revolving lines of credit	0		9,576,000
Capital lease obligations incurred	12,700,000
Revolving line of credit
Debt Instrument [Line Items]
Maximum borrowing capacity	50,000,000
Revolving lines of credit	0
Outstanding letters of credit	22,800,000
Term loan facility due 2020 | Term Notes
Debt Instrument [Line Items]
Additional financing obtained per the Amended Financing Agreement		75,000,000
Aggregate principal amount		425,000,000
Proceeds from term loan		71,000,000
Discount rate used for issuance of add-on term loan (percent)		2.50%
Broker fee (percent)		1.50%
Consent fee (percent)		1.17%
Additional debt issuance cost		$100,000

POSTRETIREMENT_MEDICAL_BENEFIT2

POSTRETIREMENT MEDICAL BENEFITS AND PENSION - Postretirement Medicial Benefit Obligations Balance Sheet Disclosures (Details) (Postretirement Medical Benefits, USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Postretirement Medical Benefits
Components of net periodic benefit cost:
Service cost	$1,054	$822
Interest cost	2,907	3,203
Amortization of deferred items	327	5
Total net periodic benefit cost	$4,288	$4,030

POSTRETIREMENT_MEDICAL_BENEFIT3

POSTRETIREMENT MEDICAL BENEFITS AND PENSION - Postretirement Medical Benefit Obligations Income Statement Disclosures (Details) (Postretirement Medical Benefits, USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Net periodic postretirement medical benefit costs relating to current and former mining operations:
Total net periodic benefit cost	$4,288	$4,030
Former Mining Operations
Net periodic postretirement medical benefit costs relating to current and former mining operations:
Total net periodic benefit cost	2,034	2,403
Current Operations
Net periodic postretirement medical benefit costs relating to current and former mining operations:
Total net periodic benefit cost	$2,254	$1,627

POSTRETIREMENT_MEDICAL_BENEFIT4

POSTRETIREMENT MEDICAL BENEFITS AND PENSION - Pension Benefit Disclosures (Details) (Pension, USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$506,000	$500,000
Interest cost	1,985,000	1,747,000
Expected return on plan assets	-2,639,000	-2,154,000
Amortization of deferred items	1,110,000	359,000
Total net periodic benefit cost	962,000	452,000
Employer contributions during the period	0
Expected employer contributions to pension plans during the remainder of the year	$1,200,000

HERITAGE_HEALTH_BENEFIT_EXPENS2

HERITAGE HEALTH BENEFIT EXPENSES - Components of Costs of Benefits to Former Mining Operation Employees (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Heritage Health Benefit Expenses [Abstract]
Health care benefits	$2,049	$2,276
Combined benefit fund payments	462	512
Workers' compensation benefits	110	136
Black lung benefits	438	620
Total	$3,059	$3,544

ASSET_RETIREMENT_OBLIGATIONS_C2

ASSET RETIREMENT OBLIGATIONS, CONTRACTUAL THIRD-PARTY RECLAMATION RECEIVABLES, AND RECLAMATION DEPOSITS - Summary of Asset Retirement Obligations, Contractual Third-Party Reclamation Receivables, and Reclamation Deposits (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	$447,402	$452,745	$281,263	$279,864
Contractual Third- Party Reclamation Receivable	115,275
Reclamation deposits	76,715
Coal - U.S. Segment
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	295,569
Contractual Third- Party Reclamation Receivable	109,126
Reclamation deposits	76,715
Coal - Canada Segment
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	118,285
Contractual Third- Party Reclamation Receivable	6,149
Reclamation deposits	0
Coal - WMLP Segment
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	32,569
Contractual Third- Party Reclamation Receivable	0
Reclamation deposits	0
Power Segment
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation	979
Contractual Third- Party Reclamation Receivable	0
Reclamation deposits	$0

ASSET_RETIREMENT_OBLIGATIONS_C3

ASSET RETIREMENT OBLIGATIONS, CONTRACTUAL THIRD-PARTY RECLAMATION RECEIVABLES, AND RECLAMATION DEPOSITS - Changes in Company's Asset Retirement Obligations (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Asset Retirement Obligation Disclosure [Abstract]
Asset retirement obligations, beginning of period (including current portion)	$452,745	$279,864
Accretion	9,701	5,836
Liabilities settled	-8,195	-4,437
Changes due to amount and timing of reclamation	336	0
Asset retirement obligations acquired	3,769	0
Changes due to foreign currency translation	-10,954	0
Asset retirement obligations, end of period	447,402	281,263
Less current portion	-48,024	-22,227	-43,289
Asset retirement obligations, less current portion	$399,378	$259,036	$409,456

ASSET_RETIREMENT_OBLIGATIONS_C4

ASSET RETIREMENT OBLIGATIONS, CONTRACTUAL THIRD-PARTY RECLAMATION RECEIVABLES, AND RECLAMATION DEPOSITS - Carrying Value and Estimated Fair Value of Reclamation Deposits (Detail) (USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified
Asset Retirement Obligation [Line Items]
Reclamation deposits	$76,715
Carrying Value
Asset Retirement Obligation [Line Items]
Reclamation deposits	76,715
Carrying Value | Cash and cash equivalents
Asset Retirement Obligation [Line Items]
Reclamation deposits	43,228
Carrying Value | Available-for-sale Securities
Asset Retirement Obligation [Line Items]
Reclamation deposits	33,487
Fair Value
Asset Retirement Obligation [Line Items]
Reclamation deposits	76,715
Fair Value | Cash and cash equivalents | Level 1
Asset Retirement Obligation [Line Items]
Reclamation deposits	43,228
Fair Value | Available-for-sale Securities | Level 1
Asset Retirement Obligation [Line Items]
Reclamation deposits	$33,487

ASSET_RETIREMENT_OBLIGATIONS_C5

ASSET RETIREMENT OBLIGATIONS, CONTRACTUAL THIRD-PARTY RECLAMATION RECEIVABLES, AND RECLAMATION DEPOSITS - Amortized Cost, Gross Unrealized Holding Gains and Losses and Fair Value of Available for Sale Securities (Details) (Reclamation Deposits, USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Reclamation Deposits
Schedule of Available-for-sale Securities [Line Items]
Cost basis	$33,118
Gross unrealized holding gains	964
Gross unrealized holding losses	-595
Fair value	$33,487

ASSET_RETIREMENT_OBLIGATIONS_C6

ASSET RETIREMENT OBLIGATIONS, CONTRACTUAL THIRD-PARTY RECLAMATION RECEIVABLES, AND RECLAMATION DEPOSITS Maturities of Available for Sale Maturities (Details) (Reclamation Deposits, USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified
Reclamation Deposits
Schedule of Available-for-sale Securities [Line Items]
Due within one year, Amortized Cost Basis	$226
Due in five years or less, Amortized Cost Basis	17,820
Due after five years to ten years, Amortized Cost Basis	6,622
Due in more than ten years, Amortized Cost Basis	8,450
Available-for-sale Securities, Amortized Cost Basis	33,118
Due within one year, Fair Value	240
Due in five years or less, Fair Value	18,030
Due after five years to ten years, Fair Value	6,514
Due in more than ten years, Fair Value	8,703
Available-for-sale Securities, Fair Value	$33,487

DERIVATIVE_INSTRUMENTS_Details

DERIVATIVE INSTRUMENTS (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Not Designated as Hedging Instrument | Foreign Exchange Forward
Derivative [Line Items]
Number of foreign currency exchange forward contracts	2
Notional amount	$348,300,000
Not Designated as Hedging Instrument | Foreign Exchange Forward | Gain (loss) on foreign exchange
Derivative [Line Items]
Gain (loss) on derivative, net	0	-6,790,000
Not Designated as Hedging Instrument | Power Contract | Derivative gain
Derivative [Line Items]
Gain (loss) on derivative, net	5,276,000	0
Not Designated as Hedging Instrument | Power Contract | Other current liabilities
Derivative [Line Items]
Derivative Liability	6,546,000		8,265,000
Not Designated as Hedging Instrument | Power Contract | Other liabilities
Derivative [Line Items]
Derivative Liability	$21,666,000		$21,103,000
Minimum | Power Contract
Derivative [Line Items]
Contracted power price notional amount	41.05
Maximum | Power Contract
Derivative [Line Items]
Contracted power price notional amount	56.33
Weighted Average | Power Contract
Derivative [Line Items]
Contracted power price notional amount	43.39

FAIR_VALUE_MEASUREMENTS_Summar

FAIR VALUE MEASUREMENTS Summary of Financial Assets at Fair Value (Details) (USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments included in Reclamation deposits	$76,715
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments included in Reclamation deposits	76,715
Fair Value | 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	34,591
Available-for-sale investments	68,078
Available-for-sale Securities | Fair Value | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments included in Reclamation deposits	$33,487

FAIR_VALUE_MEASUREMENTS_Detail

FAIR VALUE MEASUREMENTS (Details) (Significant unobservable inputs, Level 3, USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt at fixed interest rate	$345,617	$345,498
Debt at variable interest rate	413,712	341,300
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt at fixed interest rate	350,875	348,250
Debt at variable interest rate	$421,818	$344,750

SHAREHOLDERS_DEFICIT_AND_ACCUM2

SHAREHOLDERS' DEFICIT AND ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Additional Information (Detail) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Class of Stock [Line Items]
Preferred dividends paid	($3)	($261)
Redemption of preferred stock	319	0
Preferred Stock
Class of Stock [Line Items]
Shares converted (shares)	88,494
Shares redeemed (shares)	3,175
Redemption of preferred stock	300
Common Stock
Class of Stock [Line Items]
Conversion of convertible notes and securities (shares)	604,557
Maximum
Class of Stock [Line Items]
Preferred dividends paid	($100)

SHAREHOLDERS_DEFICIT_AND_ACCUM3

SHAREHOLDERS' DEFICIT AND ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Changes in Accumulated Other Comprehensive Income by component (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	($124,296)
Other comprehensive income before reclassifications	-27,201
Amounts reclassified from accumulated other comprehensive income (loss)	1,451
Balance at end of period	-150,046
Defined benefit plans adjustment | Pension
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	-36,065
Other comprehensive income before reclassifications	203
Amounts reclassified from accumulated other comprehensive income (loss)	1,110
Balance at end of period	-34,752
Defined benefit plans adjustment | Postretirement Medical Benefits
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	-39,716
Amounts reclassified from accumulated other comprehensive income (loss)	327
Balance at end of period	-39,389
Available for sale securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	413
Other comprehensive income before reclassifications	311
Amounts reclassified from accumulated other comprehensive income (loss)	14
Balance at end of period	738
Foreign currency translation adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	-17,880
Other comprehensive income before reclassifications	-27,140
Balance at end of period	-45,020
Tax effect of other comprehensive income gains
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	-31,048
Other comprehensive income before reclassifications	-575
Balance at end of period	($31,623)

SHAREHOLDERS_DEFICIT_AND_ACCUM4

SHAREHOLDERS' DEFICIT AND ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Reclassifications out of Accumulated Other Comprehensive Income (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Defined benefit plans adjustment | Pension
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Prior service costs	$2	[1]
Actuarial losses	1,108	[1],[2]
Amortization of defined benefit pension and postretirement medical benefits	1,110	[1]
Defined benefit plans adjustment | Postretirement Medical Benefits
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Prior service costs	-159	[1],[3]
Actuarial losses	486	[1],[3]
Amortization of defined benefit pension and postretirement medical benefits	327	[1]
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	$14
[1]	Amounts in parentheses indicate debits to income/loss.
[2]	These accumulated other comprehensive loss components are included in the computation of net periodic pension cost. (See Note 7 - Pension for additional details)
[3]	These accumulated other comprehensive loss components are included in the computation of net periodic postretirement medical cost. (See Note 7 - Postretirement Medical Benefits for additional details)

SHAREBASED_COMPENSATION_Compen

SHARE-BASED COMPENSATION - Compensation Expense from Share-Based Arrangements (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
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	$663	$728
Contributions of stock to the Company's 401(k) plan	859	0
Total share-based compensation expense	$1,522	$728

SHAREBASED_COMPENSATION_Summar

SHARE-BASED COMPENSATION - Summary of Restricted Stock Unit Activity (Detail) (Restricted Stock Units (RSUs), USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Balance beginning of period (units)	409,362
Vested (units)	-9,639
Forfeited (units)	-3,610
Balance end of period (units)	396,113
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, beginning of period (in USD per share)	$13.87
Weighted Average Grant Date Fair Value, Awards vested (in USD per share)	$9.49
Weighted Average Grant Date Fair Value, Awards Forfeited (in USD per share)	$30.76
Weighted Average Grant Date Fair Value, end of period (in USD per share)	$15.41
Unamortized Compensation Expense	$2,516	[1]
[1]	Expected to be recognized over the next three years.

SHAREBASED_COMPENSATION_Summar1

SHARE-BASED COMPENSATION - Summary of Stock Options and SARs (Details) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance, beginning of period, shares	110,806
Exercised, shares	0
Expired, shares	0
Balance, end of period, shares	110,806
Balance, beginning of period, weighted average exercise price	$22.15
Exercised, weighted average exercise price	$0
Expired, weighted average exercise price	$0
Balance, end of period, weighted average exercise price	$22.15
Outstanding - Weighted Average Remaining Contractual Life (In years)	2 years 11 months 6 days
Exercisable - Weighted Average Remaining Contractual Life (In years)	2 years 11 months 6 days
Aggregate Intrinsic Value	$510
Unamortized Compensation Expense	0
Granted, shares	0
Stock Appreciation Rights (SARs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance, beginning of period, shares	16,943
Exercised, shares	0
Expired, shares	0
Balance, end of period, shares	16,943
Balance, beginning of period, weighted average exercise price	$25.44
Exercised, weighted average exercise price	$0
Expired, weighted average exercise price	$0
Balance, end of period, weighted average exercise price	$25.44
Outstanding - Weighted Average Remaining Contractual Life (In years)	1 year 1 month 6 days
Exercisable - Weighted Average Remaining Contractual Life (In years)	1 year 1 month 6 days
Aggregate Intrinsic Value	22
Unamortized Compensation Expense	$0
Granted, shares	0

SHAREBASED_COMPENSATION_Narrat

SHARE-BASED COMPENSATION - Narrative (Details) (USD $)	3 Months Ended	1 Months Ended
	Mar. 31, 2015	Apr. 28, 2015
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period for recognition of unamortized compensation expense	3 years
Amended And Restated Equity Incentive Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non Employee Directors Annual Equity Awards Amount	90,000
Subsequent Event | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (units)		233,974
Subsequent Event | Vesting Ratably Over Vesting Period | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (units)		117,003
Vesting period of new awards		3 years
Subsequent Event | Performance Based | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (units)		116,971
Vesting period of new awards		3 years

EARNINGS_PER_SHARE_Antidilutiv

EARNINGS PER SHARE - Antidilutive securities excluded from the computation of earnings per share (Details)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Class of Stock [Line Items]
Shares excluded from diluted shares calculation	524	1,607
Convertible securities
Class of Stock [Line Items]
Shares excluded from diluted shares calculation	0	828
Restricted stock units, stock options and SARs
Class of Stock [Line Items]
Shares excluded from diluted shares calculation	524	779

BUSINESS_SEGMENT_INFORMATION_S

BUSINESS SEGMENT INFORMATION - Summarized Financial Information by Segment (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014		Dec. 31, 2014
	segments
Segment Reporting Information [Line Items]
Number of Reportable Segments	6
Revenues	$371,483		$180,202
Restructuring charges	553		397
Depreciation, depletion and amortization	38,059		16,059
Operating income (loss)	8,455		8,053
Total assets	1,829,748		1,407,147		1,829,578
Capital expenditures	13,027		3,050
Coal - U.S. Segment
Segment Reporting Information [Line Items]
Revenues	196,392	[1]	158,190	[1]
Restructuring charges	0	[1]	0	[1]
Depreciation, depletion and amortization	14,088	[1]	13,459	[1]
Operating income (loss)	11,266	[1]	13,447	[1]
Total assets	733,833	[1]	697,916	[1]
Capital expenditures	10,399	[1]	3,053	[1]
Coal - Canada Segment
Segment Reporting Information [Line Items]
Revenues	103,242	[2]	0	[2]
Restructuring charges	0	[2]	0	[2]
Depreciation, depletion and amortization	11,265	[2]	0	[2]
Operating income (loss)	9,865	[2]	0	[2]
Total assets	593,684	[2]	0	[2]
Capital expenditures	4,049	[2]	0	[2]
Coal - WMLP Segment
Segment Reporting Information [Line Items]
Revenues	67,567	[3]	0	[3]
Restructuring charges	553	[3]	0	[3]
Depreciation, depletion and amortization	10,180	[3]	0	[3]
Operating income (loss)	-4,517	[3]	0	[3]
Total assets	296,131	[3]	0	[3]
Capital expenditures	1,570	[3]	0	[3]
Power Segment
Segment Reporting Information [Line Items]
Revenues	20,647		22,012
Restructuring charges	0		397
Depreciation, depletion and amortization	2,484		2,524
Operating income (loss)	413		1,744
Total assets	172,310		167,998
Capital expenditures	579		35
Heritage Segment
Segment Reporting Information [Line Items]
Revenues	0		0
Restructuring charges	0		0
Depreciation, depletion and amortization	0		0
Operating income (loss)	-3,349		-3,830
Total assets	16,005		15,622
Capital expenditures	0		0
Corporate and Eliminations
Segment Reporting Information [Line Items]
Revenues	-16,365	[4]	0
Restructuring charges	0		0
Depreciation, depletion and amortization	42		76
Operating income (loss)	-5,223		-3,308
Total assets	17,785		525,611
Capital expenditures	-3,570		-38
Buckingham Coal Company, LLC | Coal - U.S. Segment
Segment Reporting Information [Line Items]
Revenues	30,100	[1]
Operating income (loss)	1,000	[1]
Revenues to the Coal - U.S. segment | Coal - WMLP Segment
Segment Reporting Information [Line Items]
Revenues	$16,400	[3]
[1]	The Buckingham Acquisition was completed on January 1, 2015. For the three months ended March 31, 2015, revenues and operating income for Buckingham were $30.1 million and $1.0 million, respectively.
[2]	The Canadian operations were acquired on April 28, 2014, therefore, there is no activity for the three months ended March 31, 2014.
[3]	The operations reported under the segment Coal - WMLP were acquired on December 31, 2014, therefore, there is no activity for the three months ended March 31, 2014.
[4]	The Coal - WMLP segment recorded revenues of $16.4 million for intersegment revenues to the Coal - U.S. segment.

BUSINESS_SEGMENT_INFORMATION_R

BUSINESS SEGMENT INFORMATION - Reconciliation of Segment Operating Income to Income (Loss) (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting [Abstract]
Income from operations	$8,455	$8,053
Interest expense	-24,735	-20,798
Interest income	2,140	302
Gain (loss) on foreign exchange	2,109	-6,790
Other income	193	93
Loss before income taxes	($11,838)	($19,140)