BASIS OF PRESENTATION (Details) (USD $)	1 Months Ended	3 Months Ended	9 Months Ended						3 Months Ended		9 Months Ended
	May 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 Senior secured notes	Dec. 31, 2012 Senior secured notes	Sep. 30, 2013 Westmoreland Mining LLC (WML) Senior secured notes	Sep. 30, 2013 Westmoreland Coal Company Senior secured notes	Sep. 30, 2013 Other operating income	Sep. 30, 2012 Other operating income	Sep. 30, 2013 Other operating income	Sep. 30, 2012 Other operating income
Debt Instrument [Line Items]
Debt arrangements		$ 343,469,000	$ 343,469,000	$ 360,989,000	$ 251,500,000	$ 252,000,000	$ 90,000,000	$ 251,500,000
Percentage membership interest sold to third party	99.00%
Yearly average income since 2009 from ICTC			3,000,000
Yearly average cash receipts since 2009 from ICTC			6,200,000
Business interruption insurance proceeds recorded in income									5,000,000	3,300,000	16,300,000	11,900,000
Cash proceeds from business interruption insurance		$ 6,000,000	$ 13,400,000