BASIS OF PRESENTATION - (Liquidity and Capital Resources) (Details) (USD $)						3 Months Ended
Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Senior secured notes	Dec. 31, 2012 Senior secured notes	Mar. 31, 2013 Westmoreland Mining LLC (WML) Senior secured notes	Mar. 31, 2013 Westmoreland Coal Company Senior secured notes	Mar. 31, 2013 Other operating income
Debt Instrument [Line Items]
Debt and Capital Lease Obligations	$ 356,286,000	$ 360,989,000	$ 252,000,000	$ 252,000,000	$ 99,000,000	$ 252,000,000
Business interruption insurance proceeds recorded in income							$ 4,800,000

The net amount (to the extent disclosed within this portion of the income statement) by which an insurance settlement exceeds incremental costs incurred from the event causing an interruption of business, plus the insurance award for earnings lost from the event, such as a natural catastrophe, explosion or fire.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6365675&loc=d3e16285-107787

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 01-13

-Paragraph 7

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration